First draft of HTTP Signatures Inbox Validation

Improve update_activitypub_profiles.php daemon
Add sanity case to ensure public key method of rsa class
2018-08-07 04:31:50 +01:00 · 2018-08-07 03:55:32 +01:00 · 2018-08-07 03:10:31 +01:00 · 2018-08-06 19:57:28 +01:00 · 2018-08-06 18:51:36 +01:00 · 2018-08-06 16:44:11 +01:00
50 changed files with 6243 additions and 1771 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/vendor/
+composer.lock
--- a/ActivityPubPlugin.php
+++ b/ActivityPubPlugin.php
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -0,0 +1,93 @@
+# Contributing
+
+When contributing to this repository, please first discuss the change you wish to make via issue,
+email, or any other method with the owners of this repository before making a change.
+
+Please note we have a code of conduct, please follow it in all your interactions with the project.
+
+# Coding Style
+- We follow every [PSR-2](https://www.php-fig.org/psr/psr-2/) ...
+- ... except camelCase, that's too bad, we use snake_case
+
+## Merge Request Process
+
+1. Ensure you strip any trailing spaces off
+2. Increase the version numbers in any examples files and the README.md to the new version that this
+   Pull Request would represent. The versioning scheme we use is [SemVer](http://semver.org/).
+3. You may merge the Pull Request in once you have the sign-off of two other developers, or if you
+   do not have permission to do that, you may request the second reviewer to merge it for you.
+
+## Code of Conduct
+
+### Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of experience,
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+orientation.
+
+### Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
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+
+Examples of unacceptable behavior by participants include:
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+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+### Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
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+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
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+
+### Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
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+### Enforcement
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+
+Project maintainers who do not follow or enforce the Code of Conduct in good
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+
+### Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at [http://contributor-covenant.org/version/1/4][version]
+
+[homepage]: http://contributor-covenant.org
+[version]: http://contributor-covenant.org/version/1/4/
--- a/661
+++ b/661
@@ -0,0 +1,661 @@
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+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
+supports such interaction) an opportunity to receive the Corresponding
+Source of your version by providing access to the Corresponding Source
+from a network server at no charge, through some standard or customary
+means of facilitating copying of software.  This Corresponding Source
+shall include the Corresponding Source for any work covered by version 3
+of the GNU General Public License that is incorporated pursuant to the
+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<http://www.gnu.org/licenses/>.
--- a/README.md
+++ b/README.md
@@ -1,2 +1,73 @@
-# ActivityPub GNU/Social Plugin
-Warning: This is still a work in progress, not every ActivityPub property is fully implemented yet.
+# ActivityPub plugin for GNU Social 1.0 Alpha
+2018
+
+(c) Free Software Foundation, Inc
+
+This is the README file for GNU Social's ActivityPub plugin.
+It includes general information about the plugin.
+
+## About
+
+This plugin adds [ActivityPub](https://www.w3.org/TR/activitypub/) support to
+GNU Social.
+
+## Setup
+
+1. Put all files in /plugins/ActivityPub
+
+2. Add `addPlugin('ActivityPub');` to your /config.php file.
+
+3. For better performance consider both:
+   - disabling checkschema (instructions in GNU social's config.php), but don't forget to run it when updating plugins (including ActivityPub plugin)
+   - installing Chimo's Redis plugin
+
+##  For testing, (shouldn't be used in production)
+
+        composer install && vendor/bin/phpunit
+
+## Built With
+
+* [PHPUnit](https://phpunit.de/) - Automated tests
+
+## Contributing
+
+Please read [CONTRIBUTING.md](CONTRIBUTING.md) for details on our code of conduct, and the process for submitting merge requests to us.
+
+## Versioning
+
+We use [SemVer](http://semver.org/) for versioning. For the versions available, see the [tags on this repository](https://git.gnu.io/gnu/GS-ActivityPub-Plugin/tags).
+
+## Credits
+
+* **[Diogo Cordeiro](https://www.diogo.site/)**
+
+See also the list of [contributors](https://git.gnu.io/gnu/GS-ActivityPub-Plugin/contributors) who participated in this project.
+
+## Extra special thanks
+
+* **[Daniel Supernault](https://github.com/dansup)**
+* **[Mikael Nordfeldth](https://mmn-o.se/)**
+
+## License
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program, in the file "COPYING".  If not, see
+<http://www.gnu.org/licenses/>.
+
+    IMPORTANT NOTE: The GNU Affero General Public License (AGPL) has
+    *different requirements* from the "regular" GPL. In particular, if
+    you make modifications to the plugin source code on your server,
+    you *MUST MAKE AVAILABLE* the modified version of the source code
+    to your users under the same license. This is a legal requirement
+    of using the software, and if you do not wish to share your
+    modifications, *YOU MAY NOT USE THIS PLUGIN*.
--- a/actions/apactorfollowers.php
+++ b/actions/apactorfollowers.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -46,69 +45,91 @@ class apActorFollowersAction extends ManagedAction
    /**
     * Handle the Followers Collection request
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return void
     */
    protected function handle()
    {
-                $nickname = $this->trimmed ('nickname');
        try {
-                        $user    = User::getByNickname ($nickname);
-                        $profile = $user->getProfile ();
-                        $url     = $profile->profileurl;
+            $profile = Profile::getByID($this->trimmed('id'));
+            $profile_id = $profile->getID();
        } catch (Exception $e) {
-                        ActivityPubReturn::error ('Invalid username.');
+            ActivityPubReturn::error('Invalid Actor URI.', 404);
+        }
+
+        if (!$profile->isLocal()) {
+            ActivityPubReturn::error("This is not a local user.", 403);
        }

        if (!isset($_GET["page"])) {
-                        $page = 1;
+            $page = 0;
        } else {
            $page = intval($this->trimmed('page'));
        }

-                if ($page <= 0) {
+        if ($page < 0) {
            ActivityPubReturn::error('Invalid page number.');
        }

-                /* Fetch Followers */
-                try {
        $since = ($page - 1) * PROFILES_PER_MINILIST;
        $limit = (($page - 1) == 0 ? 1 : $page) * PROFILES_PER_MINILIST;
-                        $sub   = $profile->getSubscribers ($since, $limit);
-                } catch (NoResultException $e) {
-                        ActivityPubReturn::error ('This user has no followers.');
-                }

        /* Calculate total items */
        $total_subs  = $profile->subscriberCount();
        $total_pages = ceil($total_subs / PROFILES_PER_MINILIST);

-                if ($total_pages == 0) {
-                        ActivityPubReturn::error ('This user has no followers.');
-                }
-
-                if ($page > $total_pages) {
-                        ActivityPubReturn::error ("There are only {$total_pages} pages.");
-                }
-
-                /* Get followers' URLs */
-                $subs = array ();
-                while ($sub->fetch ()) {
-                        $subs[] = $sub->profileurl;
-                }
-
        $res = [
            '@context'     => [
              "https://www.w3.org/ns/activitystreams",
              "https://w3id.org/security/v1",
            ],
-                  'id'           => "{$url}/followers.json",
+            'id'           => common_local_url('apActorFollowers', ['id' => $profile_id]).(($page != 0) ? '?page='.$page : ''),
            'type'         => ($page == 0 ? 'OrderedCollection' : 'OrderedCollectionPage'),
-                  'totalItems'   => $total_subs,
-                  'next'         => $page+1 > $total_pages ? null : "{$url}/followers.json?page=".($page+1 == 1 ? 2 : $page+1),
-                  'prev'         => $page == 1 ? null : "{$url}/followers.json?page=".($page-1 <= 0 ? 1 : $page-1),
-                  'orderedItems' => $subs
+            'totalItems'   => $total_subs
        ];

+        if ($page == 0) {
+            $res['first'] = common_local_url('apActorFollowers', ['id' => $profile_id]).'?page=1';
+        } else {
+            $res['orderedItems'] = $this->generate_followers($profile, $since, $limit);
+            $res['partOf'] = common_local_url('apActorFollowers', ['id' => $profile_id]);
+
+            if ($page+1 < $total_pages) {
+                $res['next'] = common_local_url('apActorFollowers', ['id' => $profile_id]).'page='.($page+1 == 1 ? 2 : $page+1);
+            }
+
+            if ($page > 1) {
+                $res['prev'] = common_local_url('apActorFollowers', ['id' => $profile_id]).'?page='.($page-1 <= 0 ? 1 : $page-1);
+            }
+        }
+
        ActivityPubReturn::answer($res);
    }
+
+    /**
+     * Generates a list of stalkers for a given profile.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $profile
+     * @param int32 $since
+     * @param int32 $limit
+     * @return Array of URIs
+     */
+    public static function generate_followers($profile, $since, $limit)
+    {
+        /* Fetch Followers */
+        try {
+            $sub = $profile->getSubscribers($since, $limit);
+        } catch (NoResultException $e) {
+            // Just let the exception go on its merry way
+        }
+
+        /* Get followers' URLs */
+        $subs = [];
+        while ($sub->fetch()) {
+            $subs[] = ActivityPubPlugin::actor_uri($sub);
+        }
+
+        return $subs;
+    }
 }
--- a/actions/apactorfollowing.php
+++ b/actions/apactorfollowing.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -46,69 +45,90 @@ class apActorFollowingAction extends ManagedAction
    /**
     * Handle the Following Collection request
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return void
     */
    protected function handle()
    {
-                $nickname = $this->trimmed ('nickname');
        try {
-                        $user    = User::getByNickname ($nickname);
-                        $profile = $user->getProfile ();
-                        $url     = $profile->profileurl;
+            $profile = Profile::getByID($this->trimmed('id'));
+            $profile_id = $profile->getID();
        } catch (Exception $e) {
-                        ActivityPubReturn::error ('Invalid username.');
+            ActivityPubReturn::error('Invalid Actor URI.', 404);
+        }
+
+        if (!$profile->isLocal()) {
+            ActivityPubReturn::error("This is not a local user.", 403);
        }

        if (!isset($_GET["page"])) {
-                        $page = 1;
+            $page = 0;
        } else {
            $page = intval($this->trimmed('page'));
        }

-                if ($page <= 0) {
+        if ($page < 0) {
            ActivityPubReturn::error('Invalid page number.');
        }

-                /* Fetch Following */
-                try {
        $since = ($page - 1) * PROFILES_PER_MINILIST;
        $limit = (($page - 1) == 0 ? 1 : $page) * PROFILES_PER_MINILIST;
-                        $sub   = $profile->getSubscribed ($since, $limit);
-                } catch (NoResultException $e) {
-                        ActivityPubReturn::error ('This user is not following anyone.');
-                }

        /* Calculate total items */
        $total_subs  = $profile->subscriptionCount();
        $total_pages = ceil($total_subs / PROFILES_PER_MINILIST);

-                if ($total_pages == 0) {
-                        ActivityPubReturn::error ('This user is not following anyone.');
-                }
-
-                if ($page > $total_pages) {
-                        ActivityPubReturn::error ("There are only {$total_pages} pages.");
-                }
-
-                /* Get followed' URLs */
-                $subs = array ();
-                while ($sub->fetch ()) {
-                        $subs[] = $sub->profileurl;
-                }
-
        $res = [
            '@context'     => [
              "https://www.w3.org/ns/activitystreams",
              "https://w3id.org/security/v1",
            ],
-                  'id'           => "{$url}/following.json",
+            'id'           => common_local_url('apActorFollowing', ['id' => $profile_id]).(($page != 0) ? '?page='.$page : ''),
            'type'         => ($page == 0 ? 'OrderedCollection' : 'OrderedCollectionPage'),
-                  'totalItems'   => $total_subs,
-                  'next'         => $page+1 > $total_pages ? null : "{$url}/followers.json?page=".($page+1 == 1 ? 2 : $page+1),
-                  'prev'         => $page == 1 ? null : "{$url}/followers.json?page=".($page-1 <= 0 ? 1 : $page-1),
-                  'orderedItems' => $subs
+            'totalItems'   => $total_subs
        ];

+        if ($page == 0) {
+            $res['first'] = common_local_url('apActorFollowing', ['id' => $profile_id]).'?page=1';
+        } else {
+            $res['orderedItems'] = $this->generate_following($profile, $since, $limit);
+            $res['partOf'] = common_local_url('apActorFollowing', ['id' => $profile_id]);
+
+            if ($page+1 < $total_pages) {
+                $res['next'] = common_local_url('apActorFollowing', ['id' => $profile_id]).'page='.($page+1 == 1 ? 2 : $page+1);
+            }
+
+            if ($page > 1) {
+                $res['prev'] = common_local_url('apActorFollowing', ['id' => $profile_id]).'?page='.($page-1 <= 0 ? 1 : $page-1);
+            }
+        }
+
        ActivityPubReturn::answer($res);
    }
+
+    /**
+     * Generates the list of those a given profile is stalking.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $profile
+     * @param int32 $since
+     * @param int32 $limit
+     * @return Array of URIs
+     */
+    public function generate_following($profile, $since, $limit)
+    {
+        /* Fetch Following */
+        try {
+            $sub = $profile->getSubscribed($since, $limit);
+        } catch (NoResultException $e) {
+            // Just let the exception go on its merry way
+        }
+
+        /* Get followed' URLs */
+        $subs = [];
+        while ($sub->fetch()) {
+            $subs[] = ActivityPubPlugin::actor_uri($sub);
+        }
+        return $subs;
+    }
 }
--- a/actions/apactorinbox.php
+++ b/actions/apactorinbox.php
@@ -1,115 +0,0 @@
-<?php
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined ('GNUSOCIAL')) {
-        exit (1);
-}
-
-/**
- * Actor's Inbox
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      http://www.gnu.org/software/social/
- */
-class apActorInboxAction extends ManagedAction
-{
-        protected $needLogin = false;
-        protected $canPost   = true;
-
-        /**
-         * Handle the Actor Inbox request
-         *
-         * @return void
-         */
-        protected function handle ()
-        {
-                $nickname  = $this->trimmed ('nickname');
-                try {
-                        $user    = User::getByNickname ($nickname);
-                        $profile = $user->getProfile ();
-                        $url     = $profile->profileurl;
-                } catch (Exception $e) {
-                        ActivityPubReturn::error ("Invalid username.");
-                }
-
-                if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
-                        ActivityPubReturn::error ("C2S not implemented just yet.");
-                }
-
-                $data = json_decode (file_get_contents ('php://input'));
-
-                // Validate data
-                if (!(isset($data->type))) {
-                        ActivityPubReturn::error ("Type was not specified.");
-                }
-                if (!isset($data->actor)) {
-                        ActivityPubReturn::error ("Actor was not specified.");
-                }
-                if (!isset($data->object)) {
-                        ActivityPubReturn::error ("Object was not specified.");
-                }
-
-                // Get valid Actor object
-                try {
-                        require_once dirname (__DIR__) . DIRECTORY_SEPARATOR . "utils" . DIRECTORY_SEPARATOR . "explorer.php";
-                        $actor_profile = new Activitypub_explorer;
-                        $actor_profile = $actor_profile->lookup ($data->actor);
-                        $actor_profile = $actor_profile[0];
-                } catch (Exception $e) {
-                        ActivityPubReturn::error ("Invalid Actor.", 404);
-                }
-
-                $to_profiles = array ($user);
-
-                // Process request
-                switch ($data->type) {
-                        case "Create":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Create.php";
-                                break;
-                        case "Delete":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Delete.php";
-                                break;
-                        case "Follow":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Follow.php";
-                                break;
-                        case "Like":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Like.php";
-                                break;
-                        case "Undo":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Undo.php";
-                                break;
-                        case "Announce":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Announce.php";
-                                break;
-                        default:
-                                ActivityPubReturn::error ("Invalid type value.");
-                }
-        }
-}
--- a/actions/apactorliked.php
+++ b/actions/apactorliked.php
@@ -0,0 +1,152 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * Actor's Liked Collection
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class apActorLikedAction extends ManagedAction
+{
+    protected $needLogin = false;
+    protected $canPost   = true;
+
+    /**
+     * Handle the Liked Collection request
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return void
+     */
+    protected function handle()
+    {
+        try {
+            $profile = Profile::getByID($this->trimmed('id'));
+            $profile_id = $profile->getID();
+        } catch (Exception $e) {
+            ActivityPubReturn::error('Invalid Actor URI.', 404);
+        }
+
+        if (!$profile->isLocal()) {
+            ActivityPubReturn::error("This is not a local user.", 403);
+        }
+
+        $limit    = intval($this->trimmed('limit'));
+        $since_id = intval($this->trimmed('since_id'));
+        $max_id   = intval($this->trimmed('max_id'));
+
+        $limit    = empty($limit) ? 40 : $limit;       // Default is 40
+        $since_id = empty($since_id) ? null : $since_id;
+        $max_id   = empty($max_id) ? null : $max_id;
+
+        // Max is 80
+        if ($limit > 80) {
+            $limit = 80;
+        }
+
+        $fave = $this->fetch_faves($profile_id, $limit, $since_id, $max_id);
+
+        $faves = array();
+        while ($fave->fetch()) {
+            $faves[] = $this->pretty_fave(clone ($fave));
+        }
+
+        $res = [
+            '@context'     => [
+              "https://www.w3.org/ns/activitystreams",
+              "https://w3id.org/security/v1",
+            ],
+            'id'           => common_local_url('apActorLiked', ['id' => $profile_id]),
+            'type'         => 'OrderedCollection',
+            'totalItems'   => Fave::countByProfile($profile),
+            'orderedItems' => $faves
+        ];
+
+        ActivityPubReturn::answer($res);
+    }
+
+    /**
+     * Take a fave object and turns it in a pretty array to be used
+     * as a plugin answer
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Fave $fave_object
+     * @return array pretty array representating a Fave
+     */
+    protected function pretty_fave($fave_object)
+    {
+        $res = [
+            'created' => $fave_object->created,
+            'object' => Activitypub_notice::notice_to_array(Notice::getByID($fave_object->notice_id))
+        ];
+
+        return $res;
+    }
+
+    /**
+     * Fetch faves
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param int32 $user_id
+     * @param int32 $limit
+     * @param int32 $since_id
+     * @param int32 $max_id
+     * @return Fave fetchable fave collection
+     */
+    private static function fetch_faves(
+            $user_id,
+            $limit = 40,
+            $since_id = null,
+            $max_id = null
+        ) {
+        $fav = new Fave();
+
+        $fav->user_id = $user_id;
+
+        $fav->orderBy('modified DESC');
+
+        if ($since_id != null) {
+            $fav->whereAdd("notice_id  > {$since_id}");
+        }
+
+        if ($max_id != null) {
+            $fav->whereAdd("notice_id  < {$max_id}");
+        }
+
+        $fav->limit($limit);
+
+        $fav->find();
+
+        return $fav;
+    }
+}
--- a/actions/apactorlikedcollection.php
+++ b/actions/apactorlikedcollection.php
@@ -1,146 +0,0 @@
-<?php
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined ('GNUSOCIAL')) {
-        exit (1);
-}
-
-/**
- * Actor's Liked Collection
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      http://www.gnu.org/software/social/
- */
-class apActorLikedCollectionAction extends ManagedAction
-{
-        protected $needLogin = false;
-        protected $canPost   = true;
-
-        /**
-         * Handle the Liked Collection request
-         *
-         * @return void
-         */
-        protected function handle ()
-        {
-                $nickname = $this->trimmed ('nickname');
-                try {
-                        $user    = User::getByNickname ($nickname);
-                        $profile = $user->getProfile ();
-                        $url     = $profile->profileurl;
-                } catch (Exception $e) {
-                        ActivityPubReturn::error ('Invalid username.');
-                }
-
-                $limit    = intval ($this->trimmed ('limit'));
-                $since_id = intval ($this->trimmed ('since_id'));
-                $max_id   = intval ($this->trimmed ('max_id'));
-
-                $limit    = empty ($limit) ? 40 : $limit;       // Default is 40
-                $since_id = empty ($since_id) ? null : $since_id;
-                $max_id   = empty ($max_id) ? null : $max_id;
-
-                // Max is 80
-                if ($limit > 80) {
-                        $limit = 80;
-                }
-
-                $fave = $this->fetch_faves($user->getID(), $limit, $since_id, $max_id);
-
-                $faves = array();
-                while ($fave->fetch ()) {
-                        $faves[] = $this->pretty_fave (clone ($fave));
-                }
-
-                $res = [
-                  '@context'          => [
-                    "https://www.w3.org/ns/activitystreams",
-                    [
-                      "@language" => "en"
-                    ]
-                  ],
-                  'id'           => "{$url}/liked.json",
-                  'type'         => 'OrderedCollection',
-                  'totalItems'   => Fave::countByProfile ($profile),
-                  'orderedItems' => $faves
-                ];
-
-                ActivityPubReturn::answer ($res);
-        }
-
-        /**
-         * Take a fave object and turns it in a pretty array to be used
-         * as a plugin answer
-         *
-         * @param Fave $fave_object
-         * @return array pretty array representating a Fave
-         */
-        protected function pretty_fave ($fave_object)
-        {
-                $res = array("uri" => $fave_object->uri,
-                             "created" => $fave_object->created,
-                             "object" => Activitypub_notice::notice_to_array (Notice::getByID ($fave_object->notice_id)));
-
-                return $res;
-        }
-
-        /**
-         * Fetch faves
-         *
-         * @param int32 $user_id
-         * @param int32 $limit
-         * @param int32 $since_id
-         * @param int32 $max_id
-         * @return Fave fetchable fave collection
-         */
-        private static function fetch_faves ($user_id, $limit = 40, $since_id = null,
-                                             $max_id = null)
-        {
-                $fav = new Fave ();
-
-                $fav->user_id = $user_id;
-
-                $fav->orderBy ('modified DESC');
-
-                if ($since_id != null) {
-                        $fav->whereAdd ("notice_id  > {$since_id}");
-                }
-
-                if ($max_id != null) {
-                        $fav->whereAdd ("notice_id  < {$max_id}");
-                }
-
-                $fav->limit ($limit);
-
-                $fav->find ();
-
-                return $fav;
-        }
-}
--- a/actions/apactoroutbox.php
+++ b/actions/apactoroutbox.php
@@ -0,0 +1,134 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * Inbox Request Handler
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class apActorOutboxAction extends ManagedAction
+{
+    protected $needLogin = false;
+    protected $canPost   = true;
+
+    /**
+     * Handle the Outbox request
+     *
+     * @author Daniel Supernault <danielsupernault@gmail.com>
+     */
+    protected function handle()
+    {
+        try {
+            $profile = Profile::getByID($this->trimmed('id'));
+            $profile_id = $profile->getID();
+        } catch (Exception $e) {
+            ActivityPubReturn::error('Invalid Actor URI.', 404);
+        }
+
+        if (!$profile->isLocal()) {
+            ActivityPubReturn::error("This is not a local user.", 403);
+        }
+
+        if (!isset($_GET["page"])) {
+            $page = 0;
+        } else {
+            $page = intval($this->trimmed('page'));
+        }
+
+        if ($page < 0) {
+            ActivityPubReturn::error('Invalid page number.');
+        }
+
+        $since = ($page - 1) * PROFILES_PER_MINILIST;
+        $limit = (($page - 1) == 0 ? 1 : $page) * PROFILES_PER_MINILIST;
+
+        /* Calculate total items */
+        $total_notes = $profile->noticeCount();
+        $total_pages = ceil($total_notes / PROFILES_PER_MINILIST);
+
+        $res = [
+            '@context'     => [
+              "https://www.w3.org/ns/activitystreams",
+              "https://w3id.org/security/v1",
+            ],
+            'id'           => common_local_url('apActorOutbox', ['id' => $profile_id]).(($page != 0) ? '?page='.$page : ''),
+            'type'         => ($page == 0 ? 'OrderedCollection' : 'OrderedCollectionPage'),
+            'totalItems'   => $total_notes
+        ];
+
+        if ($page == 0) {
+            $res['first'] = common_local_url('apActorOutbox', ['id' => $profile_id]).'?page=1';
+        } else {
+            $res['orderedItems'] = $this->generate_outbox($profile);
+            $res['partOf'] = common_local_url('apActorOutbox', ['id' => $profile_id]);
+
+            if ($page+1 < $total_pages) {
+                $res['next'] = common_local_url('apActorOutbox', ['id' => $profile_id]).'page='.($page+1 == 1 ? 2 : $page+1);
+            }
+
+            if ($page > 1) {
+                $res['prev'] = common_local_url('apActorOutbox', ['id' => $profile_id]).'?page='.($page-1 <= 0 ? 1 : $page-1);
+            }
+        }
+
+        ActivityPubReturn::answer($res);
+    }
+
+    /**
+     * Generates a list of people following given profile.
+     *
+     * @author Daniel Supernault <danielsupernault@gmail.com>
+     * @param Profile $profile
+     * @return Array of Notices
+     */
+    public function generate_outbox($profile)
+    {
+        /* Fetch Notices */
+        $notices = [];
+        $notice = $profile->getNotices();
+        while ($notice->fetch()) {
+            $note = $notice;
+
+            // TODO: Handle other types
+            if ($note->object_type == 'http://activitystrea.ms/schema/1.0/note') {
+                $notices[] = Activitypub_create::create_to_array(
+                    ActivityPubPlugin::actor_uri($note->getProfile()),
+                    Activitypub_notice::notice_to_array($note)
+                );
+            }
+        }
+
+        return $notices;
+    }
+}
--- a/actions/apactorprofile.php
+++ b/actions/apactorprofile.php
@@ -19,7 +19,6 @@
 *
 * @category  Plugin
 * @package   GNUsocial
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
@@ -34,7 +33,6 @@ if (!defined ('GNUSOCIAL')) {
 *
 * @category  Plugin
 * @package   GNUsocial
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://www.gnu.org/software/social/
@@ -47,18 +45,29 @@ class apActorProfileAction extends ManagedAction
    /**
     * Handle the Actor Profile request
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return void
     */
    protected function handle()
    {
-                $nickname = $this->trimmed ('nickname');
+        if (!empty($id = $this->trimmed('id'))) {
            try {
-                        $user    = User::getByNickname ($nickname);
-                        $profile = $user->getProfile ();
+                $profile = Profile::getByID($id);
+            } catch (Exception $e) {
+                ActivityPubReturn::error('Invalid Actor URI.', 404);
            }
-                catch (Exception $e) {
+            unset($id);
+        } else {
+            try {
+                $profile = User::getByNickname($this->trimmed('nickname'))->getProfile();
+            } catch (Exception $e) {
                ActivityPubReturn::error('Invalid username.', 404);
            }
+        }
+
+        if (!$profile->isLocal()) {
+            ActivityPubReturn::error("This is not a local user.", 403);
+        }

        $res = Activitypub_profile::profile_to_array($profile);

--- a/actions/apfeed.php
+++ b/actions/apfeed.php
@@ -1,342 +0,0 @@
-<?php
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined('GNUSOCIAL')) {
-        exit(1);
-}
-
-/**
- * ActivityPub Feed
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      http://www.gnu.org/software/social/
- */
-class apFeedAction extends ManagedAction
-{
-        protected $needLogin = false;
-        protected $canPost = true;
-
-        var $page = 1;
-        var $count = 20;
-        var $max_id = 0;
-        var $since_id = 0;
-
-        /**
-         * Handle the Actor Inbox request
-         *
-         * @return void
-         */
-        protected function handle ()
-        {
-                $this->showJsonTimeline($this->getNotices());
-        }
-
-        /**
-         * Get notices
-         *
-         * @return array notices
-         */
-         function getNotices()
-         {
-                $notices = array ();
-
-                $stream = new PublicNoticeStream (null);
-
-                $notice = $stream->getNotices (($this->page - 1) * $this->count,
-                                              $this->count,
-                                              $this->since_id, $this->max_id);
-
-                $notices = $notice->fetchAll ();
-
-                NoticeList::prefill ($notices);
-
-                return $notices;
-        }
-
-        function showJsonTimeline ($notice)
-        {
-                header ('Content-Type: application/json; charset=utf-8');
-
-                $statuses = array ();
-
-                if (is_array ($notice)) {
-                        //FIXME: make everything calling showJsonTimeline use only Notice objects
-                        $ids = array ();
-                        foreach($notice as $n) {
-                                $ids[] = $n->getID ();
-                        }
-                        $notice = Notice::multiGet ('id', $ids);
-                }
-
-                while ($notice->fetch ()) {
-                        try {
-                                $twitter_status = $this->twitterStatusArray ($notice);
-                                array_push ($statuses, $twitter_status);
-                        } catch (Exception $e) {
-                                common_log (LOG_ERR, $e->getMessage ());
-                                continue;
-                        }
-                }
-
-                $this->showJsonObjects ($statuses);
-        }
-
-        function showJsonObjects ($objects)
-        {
-                $json_objects = json_encode ($objects);
-                if ($json_objects === false) {
-                        $this-> clientError(_('JSON encoding failed. Error: ').json_last_error_msg ());
-                } else {
-                        print $json_objects;
-                }
-        }
-
-        function twitterStatusArray ($notice, $include_user = true)
-        {
-                $base = $this->twitterSimpleStatusArray ($notice, $include_user);
-
-                // FIXME: MOVE TO SHARE PLUGIN
-                if (!empty ($notice->repeat_of)) {
-                        $original = Notice::getKV ('id', $notice->repeat_of);
-                        if ($original instanceof Notice) {
-                                $orig_array = $this->twitterSimpleStatusArray($original, $include_user);
-                                $base['retweeted_status'] = $orig_array;
-                        }
-                }
-
-                return $base;
-        }
-
-        function twitterSimpleStatusArray ($notice, $include_user = true)
-        {
-                $profile = $notice->getProfile ();
-
-                $twitter_status = array ();
-                $twitter_status['text'] = $notice->content;
-                $twitter_status['truncated'] = false;
-                $twitter_status['created_at'] = self::dateTwitter ($notice->created);
-                try {
-                        // We could just do $notice->reply_to but maybe the future holds a
-                        // different story for parenting.
-                        $parent = $notice->getParent ();
-                        $in_reply_to = $parent->id;
-                } catch (NoParentNoticeException $e) {
-                        $in_reply_to = null;
-                } catch (NoResultException $e) {
-                        // the in_reply_to message has probably been deleted
-                        $in_reply_to = null;
-                }
-                $twitter_status['in_reply_to_status_id'] = $in_reply_to;
-
-                $source = null;
-                $source_link = null;
-
-                $ns = $notice->getSource ();
-                if ($ns instanceof Notice_source) {
-                        $source = $ns->code;
-                        if (!empty ($ns->url)) {
-                                $source_link = $ns->url;
-                                if (!empty ($ns->name)) {
-                                        $source = $ns->name;
-                                }
-                        }
-                }
-
-                $twitter_status['uri'] = $notice->getUri ();
-                $twitter_status['source'] = $source;
-                $twitter_status['source_link'] = $source_link;
-                $twitter_status['id'] = intval ($notice->id);
-
-                $replier_profile = null;
-
-                if ($notice->reply_to) {
-                        $reply = Notice::getKV (intval ($notice->reply_to));
-                        if ($reply) {
-                                $replier_profile = $reply->getProfile ();
-                        }
-                }
-
-                $twitter_status['in_reply_to_user_id'] =
-                    ($replier_profile) ? intval ($replier_profile->id) : null;
-                $twitter_status['in_reply_to_screen_name'] =
-                    ($replier_profile) ? $replier_profile->nickname : null;
-
-                try {
-                        $notloc = Notice_location::locFromStored ($notice);
-                        // This is the format that GeoJSON expects stuff to be in
-                        $twitter_status['geo'] = array ('type' => 'Point',
-                                                        'coordinates' => array (
-                                                            (float) $notloc->lat,
-                                                            (float) $notloc->lon));
-                } catch (ServerException $e) {
-                        $twitter_status['geo'] = null;
-                }
-
-                // Enclosures
-                $attachments = $notice->attachments ();
-
-                if (!empty ($attachments)) {
-
-                        $twitter_status['attachments'] = array ();
-
-                        foreach ($attachments as $attachment) {
-                                try {
-                                        $enclosure_o = $attachment->getEnclosure ();
-                                        $enclosure = array();
-                                        $enclosure['url'] = $enclosure_o->url;
-                                        $enclosure['mimetype'] = $enclosure_o->mimetype;
-                                        $enclosure['size'] = $enclosure_o->size;
-                                        $twitter_status['attachments'][] = $enclosure;
-                                } catch (ServerException $e) {
-                                        // There was not enough metadata available
-                                }
-                        }
-                }
-
-                if ($include_user && $profile) {
-                        // Don't get notice (recursive!)
-                        $twitter_user = $this->twitterUserArray($profile, false);
-                        $twitter_status['user'] = $twitter_user;
-                }
-                // StatusNet-specific
-
-                $twitter_status['statusnet_html'] = $notice->getRendered();
-                $twitter_status['statusnet_conversation_id'] = intval($notice->conversation);
-
-                // The event call to handle NoticeSimpleStatusArray lets plugins add data to the output array
-                Event::handle('NoticeSimpleStatusArray',
-                              array ($notice, &$twitter_status, $this->scoped,
-                                    array ('include_user' => $include_user)));
-
-                return $twitter_status;
-        }
-
-        static function dateTwitter($dt)
-        {
-                $dateStr = date ('d F Y H:i:s', strtotime ($dt));
-                $d = new DateTime ($dateStr, new DateTimeZone ('UTC'));
-                $d->setTimezone (new DateTimeZone(common_timezone()));
-                return $d->format ('D M d H:i:s O Y');
-        }
-
-        function twitterUserArray ($profile, $get_notice = false)
-        {
-                $twitter_user = array ();
-
-                try {
-                        $user = $profile->getUser ();
-                } catch (NoSuchUserException $e) {
-                        $user = null;
-                }
-
-                $twitter_user['id'] = $profile->getID ();
-                $twitter_user['name'] = $profile->getBestName ();
-                $twitter_user['screen_name'] = $profile->getNickname ();
-                $twitter_user['location'] = $profile->location;
-                $twitter_user['description'] = $profile->getDescription ();
-
-                // TODO: avatar url template (example.com/user/avatar?size={x}x{y})
-                $twitter_user['profile_image_url'] = Avatar::urlByProfile($profile, AVATAR_STREAM_SIZE);
-                $twitter_user['profile_image_url_https'] = $twitter_user['profile_image_url'];
-
-                // START introduced by qvitter API, not necessary for StatusNet API
-                $twitter_user['profile_image_url_profile_size'] = Avatar::urlByProfile($profile, AVATAR_PROFILE_SIZE);
-                try {
-                        $avatar = Avatar::getUploaded ($profile);
-                        $origurl = $avatar->displayUrl ();
-                } catch(Exception $e) {
-                        $origurl = $twitter_user['profile_image_url_profile_size'];
-                }
-                $twitter_user['profile_image_url_original'] = $origurl;
-
-                $twitter_user['groups_count'] = $profile->getGroupCount();
-                foreach (array('linkcolor', 'backgroundcolor') as $key) {
-                        $twitter_user[$key] =  Profile_prefs::getConfigData($profile, 'theme', $key);
-                }
-                // END introduced by qvitter API, not necessary for StatusNet API
-
-                $twitter_user['url'] = ($profile->homepage) ? $profile->homepage : null;
-                $twitter_user['protected'] = (!empty($user) && $user->private_stream) ? true : false;
-                $twitter_user['followers_count'] = $profile->subscriberCount();
-
-                // Note: some profiles don't have an associated user
-
-                $twitter_user['friends_count'] = $profile->subscriptionCount ();
-
-                $twitter_user['created_at'] = self::dateTwitter($profile->created);
-
-                $timezone = 'UTC';
-
-                if (!empty($user) && $user->timezone) {
-                        $timezone = $user->timezone;
-                }
-
-                $t = new DateTime;
-                $t->setTimezone (new DateTimeZone ($timezone));
-
-                $twitter_user['utc_offset']     = $t->format('Z');
-                $twitter_user['time_zone']      = $timezone;
-                $twitter_user['statuses_count'] = $profile->noticeCount();
-
-                // Is the requesting user following this user?
-                // These values might actually also mean "unknown". Ambiguity issues?
-                $twitter_user['following']          = false;
-                $twitter_user['statusnet_blocking'] = false;
-                $twitter_user['notifications']      = false;
-
-                if ($this->scoped instanceof Profile) {
-                        try {
-                                $sub = Subscription::getSubscription($this->scoped, $profile);
-                                // Notifications on?
-                                $twitter_user['following'] = true;
-                                $twitter_user['notifications'] = ($sub->jabber || $sub->sms);
-                        } catch (NoResultException $e) {
-                                // well, the values are already false...
-                        }
-                        $twitter_user['statusnet_blocking'] = $this->scoped->hasBlocked($profile);
-                }
-
-                if ($get_notice) {
-                        $notice = $profile->getCurrentNotice ();
-                        if ($notice instanceof Notice) {
-                                // don't get user!
-                                $twitter_user['status'] = $this->twitterStatusArray($notice, false);
-                        }
-                }
-                // StatusNet-specific
-
-                $twitter_user['statusnet_profile_url'] = $profile->profileurl;
-
-                // The event call to handle NoticeSimpleStatusArray lets plugins add data to the output array
-                Event::handle('TwitterUserArray', array ($profile, &$twitter_user, $this->scoped, array()));
-
-                return $twitter_user;
-        }
-}
--- a/actions/apinbox.php
+++ b/actions/apinbox.php
@@ -0,0 +1,136 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * Inbox Request Handler
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+
+use GuzzleHttp\Psr7;
+use HttpSignatures\Context;
+
+class apInboxAction extends ManagedAction
+{
+    protected $needLogin = false;
+    protected $canPost   = true;
+
+    /**
+     * Handle the Inbox request
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return void
+     */
+    protected function handle()
+    {
+        if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+            ActivityPubReturn::error('Only POST requests allowed.');
+        }
+
+        common_debug('ActivityPub Inbox: Received a POST request.');
+        $data = file_get_contents('php://input');
+        common_debug('ActivityPub Inbox: Request contents: '.$data);
+        $data = json_decode(file_get_contents('php://input'), true);
+
+        if (!isset($data['actor'])) {
+            ActivityPubReturn::error('Actor not found in the request.');
+        }
+
+        $actor = ActivityPub_explorer::get_profile_from_url($data['actor']);
+        $actor_public_key = new Activitypub_rsa();
+        $actor_public_key = $actor_public_key->ensure_public_key($actor);
+
+        common_debug('ActivityPub Inbox: HTTP Signature: Validation will now start!');
+
+        $headers = $this->get_all_headers();
+        common_debug('ActivityPub Inbox: Request Headers: '.print_r($headers, true));
+        try {
+            $res = HTTPSignature::parse($headers);
+            common_debug('ActivityPub Inbox: Request Res: '.print_r($res, true));
+        } catch (HttpSignatureError $e) {
+            common_debug('ActivityPub Inbox: HTTP Signature Error: '. $e->getMessage());
+            ActivityPubReturn::error('HTTP Signature Error: '. $e->getMessage());
+        } catch (Exception $e) {
+            ActivityPubReturn::error($e->getMessage());
+        }
+
+        /*if (HTTPSignature::verify($res,
+                $actor_public_key, 'rsa') == FALSE) {
+           common_debug('ActivityPub Inbox: Could not authorize request.');
+           ActivityPubReturn::error('Unauthorized.', 403);
+        }*/
+
+        $context = new Context([
+            'keys' => [$res['params']['keyId'] => $actor_public_key],
+            'algorithm' => $res['params']['algorithm'],
+            'headers' => $res['headers'],
+        ]);
+
+        $request = new Psr7\Request($_SERVER['REQUEST_METHOD'],
+                (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? "https" : "http") . "://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]",
+                $headers);
+
+        if ($context->verifier()->isValid($request) == false)
+        {
+            common_debug('ActivityPub Inbox: HTTP Signature: Unauthorized request.');
+            ActivityPubReturn::error('Unauthorized.', 403);
+        }
+
+        common_debug('ActivityPub Inbox: HTTP Signature: Authorized request. Will now start the inbox handler.');
+
+        try {
+            new Activitypub_inbox_handler($data, $actor);
+            ActivityPubReturn::answer();
+        } catch (Exception $e) {
+            ActivityPubReturn::error($e->getMessage());
+        }
+    }
+
+    /**
+     * Get all HTTP header key/values as an associative array for the current request.
+     *
+     * @author PHP Manual Contributed Notes <joyview@gmail.com>
+     * @return string[string] The HTTP header key/value pairs.
+     */
+    private function get_all_headers()
+    {
+        $headers = [];
+        foreach ($_SERVER as $name => $value) {
+            if (substr($name, 0, 5) == 'HTTP_') {
+                $headers[strtolower(str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5))))))] = $value;
+            }
+        }
+        return $headers;
+    }
+}
--- a/actions/inbox/Follow.php
+++ b/actions/inbox/Follow.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -29,30 +28,40 @@ if (!defined ('GNUSOCIAL')) {
    exit(1);
 }

-// Validate Object
-if (!is_string ($data->object)) {
-        ActivityPubReturn::error ("Invalid Object object, URL expected.");
-}
+/**
+ * Notice (Local notices only)
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class apNoticeAction extends ManagedAction
+{
+    protected $needLogin = false;
+    protected $canPost   = true;

-// Get valid Object profile
+    /**
+     * Handle the Notice request
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return void
+     */
+    protected function handle()
+    {
        try {
-        $object_profile = new Activitypub_explorer;
-        $object_profile = $object_profile->lookup ($data->object)[0];
+            $notice = Notice::getByID($this->trimmed('id'));
        } catch (Exception $e) {
-        ActivityPubReturn::error ("Invalid Object Actor URL.", 404);
+            ActivityPubReturn::error('Invalid Notice URI.', 404);
        }

-try {
-        if (!Subscription::exists ($actor_profile, $object_profile)) {
-                Subscription::start ($actor_profile, $object_profile);
-                $res = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                          "type"   => "Follow",
-                          "actor"  => $data->actor,
-                          "object" => $data->object);
+        if (!$notice->isLocal()) {
+            ActivityPubReturn::error("This is not a local notice.", 403);
+        }
+
+        $res = Activitypub_notice::notice_to_array($notice);
+
        ActivityPubReturn::answer($res);
-        } else {
-                ActivityPubReturn::error ("Already following.", 409);
    }
-} catch (Exception $e) {
-        ActivityPubReturn::error ("Invalid Object Actor URL.", 404);
 }
--- a/actions/apsharedinbox.php
+++ b/actions/apsharedinbox.php
@@ -1,135 +0,0 @@
-<?php
-require_once dirname (__DIR__) . DIRECTORY_SEPARATOR . "utils" . DIRECTORY_SEPARATOR . "explorer.php";
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined ('GNUSOCIAL')) {
-        exit (1);
-}
-
-/**
- * Shared Inbox Handler
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      http://www.gnu.org/software/social/
- */
-class apSharedInboxAction extends ManagedAction
-{
-        protected $needLogin = false;
-        protected $canPost   = true;
-
-        /**
-         * Handle the Shared Inbox request
-         *
-         * @return void
-         */
-        protected function handle ()
-        {
-                if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
-                        ActivityPubReturn::error ("Only POST requests allowed.");
-                }
-
-                $data = json_decode (file_get_contents ('php://input'));
-
-                // Validate data
-                if (!isset($data->type)) {
-                        ActivityPubReturn::error ("Type was not specified.");
-                }
-                if (!isset($data->actor)) {
-                        ActivityPubReturn::error ("Actor was not specified.");
-                }
-                if (!isset($data->object)) {
-                        ActivityPubReturn::error ("Object was not specified.");
-                }
-
-                $discovery = new Activitypub_explorer;
-
-                // Get valid Actor object
-                try {
-                        $actor_profile = $discovery->lookup ($data->actor);
-                        $actor_profile = $actor_profile[0];
-                } catch (Exception $e) {
-                        ActivityPubReturn::error ("Invalid Actor.", 404);
-                }
-
-                unset ($discovery);
-
-                // Public To:
-                $public_to = array ("https://www.w3.org/ns/activitystreams#Public",
-                                    "Public",
-                                    "as:Public");
-
-                // Process request
-                switch ($data->type) {
-                        case "Create":
-                                if (!isset($data->to)) {
-                                        ActivityPubReturn::error ("To was not specified.");
-                                }
-                                $discovery = new Activitypub_Discovery;
-                                $to_profiles = array ();
-                                // Generate To objects
-                                if (is_array ($data->to)) {
-                                        // Remove duplicates from To actors set
-                                        array_unique ($data->to);
-                                        foreach ($data->to as $to_url) {
-                                                try {
-                                                        $to_profiles = array_merge ($to_profiles, $discovery->lookup ($to_url));
-                                                } catch (Exception $e) {
-                                                        // XXX: Invalid actor found, not sure how we handle those
-                                                }
-                                        }
-                                } else if (empty ($data->to) || in_array ($data->to, $public_to)) {
-                                        // No need to do anything else at this point, let's just break out the if
-                                } else {
-                                        try {
-                                                $to_profiles[]= $discovery->lookup ($data->to);
-                                        } catch (Exception $e) {
-                                                ActivityPubReturn::error ("Invalid Actor.", 404);
-                                        }
-                                }
-                                unset ($discovery);
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Create.php";
-                                break;
-                        case "Follow":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Follow.php";
-                                break;
-                        case "Like":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Like.php";
-                                break;
-                        case "Announce":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Announce.php";
-                                break;
-                        case "Undo":
-                                require_once __DIR__ . DIRECTORY_SEPARATOR . "inbox" . DIRECTORY_SEPARATOR . "Undo.php";
-                                break;
-                        default:
-                                ActivityPubReturn::error ("Invalid type value.");
-                }
-    }
-}
--- a/actions/inbox/Create.php
+++ b/actions/inbox/Create.php
@@ -1,93 +0,0 @@
-<?php
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined ('GNUSOCIAL')) {
-        exit (1);
-}
-
-$valid_object_types = array ("Note");
-
-// Validate data
-if (!(isset ($data->object->type) && in_array ($data->object->type, $valid_object_types))) {
-        ActivityPubReturn::error ("Invalid Object type.");
-}
-if (!isset ($data->object->content)) {
-        ActivityPubReturn::error ("Object content was not specified.");
-}
-
-$content = $data->object->content;
-
-$act = new Activity ();
-$act->verb = ActivityVerb::POST;
-$act->time = time ();
-$act->actor = $actor_profile->asActivityObject ();
-
-$act->context = new ActivityContext ();
-
-// Is this a reply?
-if (isset ($data->object->reply_to)) {
-        $reply_to = Notice::getByUri ($data->object->reply_to);
-        $act->context->replyToID = $reply_to->getUri ();
-        $act->context->replyToUrl = $data->object->reply_to;
-} else {
-        $reply_to = null;
-}
-
-$act->context->attention = common_get_attentions ($content, $actor_profile, $reply_to);
-
-foreach ($to_profiles as $to)
-{
-        $act->context->attention[$to->getUri ()] = "http://activitystrea.ms/schema/1.0/person";
-}
-
-// Reject notice if it is too long (without the HTML)
-// This is done after MediaFile::fromUpload etc. just to act the same as the ApiStatusesUpdateAction
-if (Notice::contentTooLong ($content)) {
-        ActivityPubReturn::error ("That's too long. Maximum notice size is %d character.");
-}
-
-$options = array ('source' => 'ActivityPub', 'uri' => $data->id);
-// $options gets filled with possible scoping settings
-ToSelector::fillActivity ($this, $act, $options);
-
-$actobj = new ActivityObject ();
-$actobj->type = ActivityObject::NOTE;
-$actobj->content = common_render_content ($content, $actor_profile, $reply_to);
-
-// Finally add the activity object to our activity
-$act->objects[] = $actobj;
-
-try {
-        $res = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                  "id"     => $data->id,
-                  "type"   => "Create",
-                  "actor"  => $data->actor,
-                  "object" => Activitypub_notice::notice_to_array (Notice::saveActivity ($act, $actor_profile, $options)));
-        ActivityPubReturn::answer ($res);
-} catch (Exception $e) {
-        ActivityPubReturn::error ($e->getMessage ());
-}
--- a/actions/inbox/Undo.php
+++ b/actions/inbox/Undo.php
@@ -1,78 +0,0 @@
-<?php
-/**
- * GNU social - a federating social network
- *
- * ActivityPubPlugin implementation for GNU Social
- *
- * LICENCE: This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * @category  Plugin
- * @package   GNUsocial
- * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
- * @copyright 2018 Free Software Foundation http://fsf.org
- * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      https://www.gnu.org/software/social/
- */
-if (!defined ('GNUSOCIAL')) {
-        exit (1);
-}
-
-// Validate data
-if (!isset ($data->type)) {
-        ActivityPubReturn::error ("Type was not specified.");
-}
-
-switch ($data->object->type) {
-case "Like":
-        try {
-                // Validate data
-                if (!isset ($data->object->object)) {
-                        ActivityPubReturn::error ("Object Notice URL was not specified.");
-                }
-
-                Fave::removeEntry ($actor_profile, Notice::getByUri ($data->object->object));
-                ActivityPubReturn::answer ("Notice disfavorited successfully.");
-        } catch (Exception $e) {
-                ActivityPubReturn::error ($e->getMessage (), 403);
-        }
-        break;
-case "Follow":
-        // Validate data
-        if (!isset ($data->object->object)) {
-                ActivityPubReturn::error ("Object Actor URL was not specified.");
-        }
-        // Get valid Object profile
-        try {
-                $object_profile = new Activitypub_explorer;
-                $object_profile = $object_profile->lookup ($data->object->object)[0];
-        } catch (Exception $e) {
-                ActivityPubReturn::error ("Invalid Object Actor URL.", 404);
-        }
-
-        try {
-                if (Subscription::exists ($actor_profile, $object_profile)) {
-                        Subscription::cancel ($actor_profile, $object_profile);
-                        ActivityPubReturn::answer ("You are no longer following this person.");
-                } else {
-                        ActivityPubReturn::error ("You are not following this person already.", 409);
-                }
-        } catch (Exception $e) {
-                ActivityPubReturn::error ("Invalid Object Actor URL.", 404);
-        }
-        break;
-default:
-        ActivityPubReturn::error ("Invalid object type.");
-        break;
-}
--- a/classes/Activitypub_accept.php
+++ b/classes/Activitypub_accept.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_accept extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Accept
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function accept_to_array($object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => common_root_url().'accept_follow_from_'.urlencode($object['actor']).'_to_'.urlencode($object['object']),
+            'type'   => 'Accept',
+            'actor'  => $object['object'],
+            'object' => $object
+        ];
+        return $res;
+    }
+
+    /**
+     * Verifies if a given object is acceptable for an Accept Activity.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Array $object
+     * @throws Exception
+     */
+    public static function validate_object($object)
+    {
+        if (!is_array($object)) {
+            throw new Exception('Invalid Object Format for Accept Activity.');
+        }
+        if (!isset($object['type'])) {
+            throw new Exception('Object type was not specified for Accept Activity.');
+        }
+        switch ($object['type']) {
+            case 'Follow':
+                // Validate data
+                if (!filter_var($object['object'], FILTER_VALIDATE_URL)) {
+                    throw new Exception("Object is not a valid Object URI for Activity.");
+                }
+                break;
+            default:
+                throw new Exception('This is not a supported Object Type for Accept Activity.');
+        }
+        return true;
+    }
+}
--- a/classes/Activitypub_announce.php
+++ b/classes/Activitypub_announce.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -29,13 +28,32 @@ if (!defined ('GNUSOCIAL')) {
    exit(1);
 }

-try {
-        Fave::addNew ($actor_profile, Notice::getByUri ($data->object));
-        $res = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                  "type"   => "Like",
-                  "actor"  => $data->actor,
-                  "object" => $data->object);
-        ActivityPubReturn::answer ($res);
-} catch (Exception $e) {
-        ActivityPubReturn::error ($e->getMessage (), 403);
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_announce extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Announce
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function announce_to_array($actor, $object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            "type"   => "Announce",
+            "actor"  => $actor,
+            "object" => $object
+        ];
+        return $res;
+    }
 }
--- a/classes/Activitypub_attachment.php
+++ b/classes/Activitypub_attachment.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -43,29 +42,23 @@ class Activitypub_attachment extends Managed_DataObject
    /**
     * Generates a pretty array from an Attachment object
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param Attachment $attachment
     * @return pretty array to be used in a response
     */
    public static function attachment_to_array($attachment)
    {
        $res = [
-                        '@context'  => [
-                                "https://www.w3.org/ns/activitystreams",
-                                [
-                                        "@language" => "en"
-                                ]
-                        ],
-                        'id'       => $attachment->getID (),
-                        'mimetype' => $attachment->mimetype,
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'type'      => 'Document',
+            'mediaType' => $attachment->mimetype,
            'url'       => $attachment->getUrl(),
            'size'      => intval($attachment->size), // $attachment->getSize ()
-                        'title'    => $attachment->getTitle (),
-                        'meta'     => null
+            'name'      => $attachment->getTitle(),
        ];

        // Image
-                if (substr ($res["mimetype"], 0, 5) == "image")
-                {
+        if (substr($res["mediaType"], 0, 5) == "image") {
            $res["meta"]= [
                'width'  => $attachment->width,
                'height' => $attachment->height
--- a/classes/Activitypub_create.php
+++ b/classes/Activitypub_create.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_create extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Create
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function create_to_array($actor, $object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => $object['id'].'/create',
+            'type'   => 'Create',
+            'to'     => $object['to'],
+            'cc'     => $object['cc'],
+            'actor'  => $actor,
+            'object' => $object
+        ];
+        return $res;
+    }
+
+    /**
+     * Verifies if a given object is acceptable for a Create Activity.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Array $object
+     * @throws Exception
+     */
+    public static function validate_object($object)
+    {
+        if (!is_array($object)) {
+            throw new Exception('Invalid Object Format for Create Activity.');
+        }
+        if (!isset($object['type'])) {
+            throw new Exception('Object type was not specified for Create Activity.');
+        }
+        switch ($object['type']) {
+            case 'Note':
+                // Validate data
+                Activitypub_notice::validate_note($object);
+                break;
+            default:
+                throw new Exception('This is not a supported Object Type for Create Activity.');
+        }
+    }
+}
--- a/classes/Activitypub_delete.php
+++ b/classes/Activitypub_delete.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -29,13 +28,33 @@ if (!defined ('GNUSOCIAL')) {
    exit(1);
 }

-try {
-        Activitypub_notice::getByUri ($data->object)->deleteAs ($actor_profile);
-        $res = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                  "type"   => "Delete",
-                  "actor"  => $data->actor,
-                  "object" => $data->object);
-        ActivityPubReturn::answer ($res);
-} catch (Exception $e) {
-        ActivityPubReturn::error ($e->getMessage (), 403);
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_delete extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Delete
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function delete_to_array($actor, $object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => $object.'/delete',
+            'type'   => 'Delete',
+            'actor'  => $actor,
+            'object' => $object
+        ];
+        return $res;
+    }
 }
--- a/classes/Activitypub_error.php
+++ b/classes/Activitypub_error.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -43,6 +42,7 @@ class Activitypub_error extends Managed_DataObject
    /**
     * Generates a pretty error from a string
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param string $m
     * @return pretty array to be used in a response
     */
--- a/classes/Activitypub_follow.php
+++ b/classes/Activitypub_follow.php
@@ -0,0 +1,91 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_follow extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a subscription
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor
+     * @param string $object
+     * @return pretty array to be used in a response
+     */
+    public static function follow_to_array($actor, $object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => common_root_url().'follow_from_'.urlencode($actor).'_to_'.urlencode($object),
+            'type'   => 'Follow',
+            'actor'  => $actor,
+            'object' => $object
+       ];
+        return $res;
+    }
+
+    /**
+     * Handles a Follow Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $actor_profile Remote Actor
+     * @param string $object Local Actor
+     * @throws Exception
+     */
+    public static function follow($actor_profile, $object)
+    {
+        // Get Actor's Aprofile
+        $actor_aprofile = Activitypub_profile::from_profile($actor_profile);
+
+        // Get Object profile
+        $object_profile = new Activitypub_explorer;
+        $object_profile = $object_profile->lookup($object)[0];
+
+        if (!Subscription::exists($actor_profile, $object_profile)) {
+            Subscription::start($actor_profile, $object_profile);
+            common_debug('ActivityPubPlugin: Accepted Follow request from '.ActivityPubPlugin::actor_uri($actor_profile).' to '.$object);
+        } else {
+            common_debug('ActivityPubPlugin: Received a repeated Follow request from '.ActivityPubPlugin::actor_uri($actor_profile).' to '.$object);
+        }
+
+        // Notify remote instance that we have accepted their request
+        common_debug('ActivityPubPlugin: Notifying remote instance that we have accepted their Follow request request from '.ActivityPubPlugin::actor_uri($actor_profile).' to '.$object);
+        $postman = new Activitypub_postman($actor_profile, [$actor_aprofile]);
+        $postman->accept_follow();
+    }
+}
--- a/classes/Activitypub_like.php
+++ b/classes/Activitypub_like.php
@@ -0,0 +1,61 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_like extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Like
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor  Actor URI
+     * @param string $object Notice URI
+     * @return pretty array to be used in a response
+     */
+    public static function like_to_array($actor, $object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => common_root_url().'like_from_'.urlencode($actor).'_to_'.urlencode($object),
+            "type"   => "Like",
+            "actor"  => $actor,
+            "object" => $object
+        ];
+        return $res;
+    }
+}
--- a/classes/Activitypub_mention_tag.php
+++ b/classes/Activitypub_mention_tag.php
@@ -0,0 +1,60 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub Mention Tag representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_mention_tag extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Mention Tag
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $href Actor Uri
+     * @param array $name Mention name
+     * @return pretty array to be used in a response
+     */
+    public static function mention_tag_to_array_from_values($href, $name)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            "type" => "Mention",
+            "href" => $href,
+            "name" => $name
+         ];
+        return $res;
+    }
+}
--- a/classes/Activitypub_notice.php
+++ b/classes/Activitypub_notice.php
@@ -19,7 +19,6 @@
 *
 * @category  Plugin
 * @package   GNUsocial
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
@@ -34,7 +33,6 @@ if (!defined ('GNUSOCIAL')) {
 *
 * @category  Plugin
 * @package   GNUsocial
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://www.gnu.org/software/social/
@@ -44,46 +42,250 @@ class Activitypub_notice extends Managed_DataObject
    /**
     * Generates a pretty notice from a Notice object
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param Notice $notice
     * @return pretty array to be used in a response
     */
    public static function notice_to_array($notice)
    {
-                $attachments = array ();
+        $profile = $notice->getProfile();
+        $attachments = [];
        foreach ($notice->attachments() as $attachment) {
            $attachments[] = Activitypub_attachment::attachment_to_array($attachment);
        }

-                $tags = array ();
+        $tags = [];
        foreach ($notice->getTags() as $tag) {
            if ($tag != "") {       // Hacky workaround to avoid stupid outputs
                $tags[] = Activitypub_tag::tag_to_array($tag);
            }
        }

-                $to = array ();
-                foreach ($notice->getAttentionProfileIDs () as $to_id) {
-                        $to[] = Profile::getById ($to_id)->getUri ();
-                }
-                if (!is_null($to)) {
-                        $to = array ("https://www.w3.org/ns/activitystreams#Public");
+        $cc = [common_local_url('apActorFollowers', ['id' => $profile->getID()])];
+        foreach ($notice->getAttentionProfiles() as $to_profile) {
+            $cc[]  = $href = $to_profile->getUri();
+            $tags[] = Activitypub_mention_tag::mention_tag_to_array_from_values($href, $to_profile->getNickname().'@'.parse_url($href, PHP_URL_HOST));
        }

+        // In a world without walls and fences, we should make everything Public!
+        $to[]= 'https://www.w3.org/ns/activitystreams#Public';
+
        $item = [
-                        'id'           => $notice->getUrl (),
-                        'type'         => 'Notice',
-                        'actor'        => $notice->getProfile ()->getUrl (),
-                        'published'    => $notice->getCreated (),
-                        'to'           => $to,
-                        'content'      => $notice->getContent (),
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'           => common_local_url('apNotice', ['id' => $notice->getID()]),
+            'type'         => 'Note',
+            'published'    => str_replace(' ', 'T', $notice->getCreated()).'Z',
            'url'          => $notice->getUrl(),
-                        'reply_to'     => empty($notice->reply_to) ? null : Notice::getById($notice->reply_to)->getUrl (),
-                        'is_local'     => $notice->isLocal (),
-                        'conversation' => intval ($notice->conversation),
+            'attributedTo' => ActivityPubPlugin::actor_uri($profile),
+            'to'           => ['https://www.w3.org/ns/activitystreams#Public'],
+            'cc'           => $cc,
+            'atomUri'      => $notice->getUrl(),
+            'conversation' => $notice->getConversationUrl(),
+            'content'      => $notice->getRendered(),
+            'isLocal'      => $notice->isLocal(),
            'attachment'   => $attachments,
            'tag'          => $tags
        ];

+        // Is this a reply?
+        if (!empty($notice->reply_to)) {
+            $item['inReplyTo'] = common_local_url('apNotice', ['id' => $notice->getID()]);
+            $item['inReplyToAtomUri'] = Notice::getById($notice->reply_to)->getUrl();
+        }
+
+        // Do we have a location for this notice?
+        try {
+            $location = Notice_location::locFromStored($notice);
+            $item['latitude']  = $location->lat;
+            $item['longitude'] = $location->lon;
+        } catch (Exception $e) {
+            // Apparently no.
+        }
+
        return $item;
    }
+
+    /**
+     * Create a Notice via ActivityPub Note Object.
+     * Returns created Notice.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Array $object
+     * @param Profile|null $actor_profile
+     * @return Notice
+     * @throws Exception
+     */
+    public static function create_notice($object, $actor_profile = null)
+    {
+        $id      = $object['id'];         // int32
+        $url     = $object['url'];        // string
+        $content = $object['content'];    // string
+
+        // possible keys: ['inReplyTo', 'latitude', 'longitude', 'attachment']
+        $settings = [];
+        if (isset($object['inReplyTo'])) {
+            $settings['inReplyTo'] = $object['inReplyTo'];
+        }
+        if (isset($object['latitude'])) {
+            $settings['latitude']  = $object['latitude'];
+        }
+        if (isset($object['longitude'])) {
+            $settings['longitude'] = $object['longitude'];
+        }
+        if (isset($object['attachment'])) {
+            $settings['attachment'] = $object['attachment'];
+        }
+
+        // Ensure Actor Profile
+        if (is_null($actor_profile)) {
+            $actor_profile = ActivityPub_explorer::get_profile_from_url($object['actor']);
+        }
+
+        $act = new Activity();
+        $act->verb = ActivityVerb::POST;
+        $act->time = time();
+        $act->actor = $actor_profile->asActivityObject();
+        $act->context = new ActivityContext();
+        $options = ['source' => 'ActivityPub', 'uri' => $id, 'url' => $url];
+
+        // Do we have an attachment?
+        if (isset($settings['attachment'][0])) {
+            $attach = $settings['attachment'][0];
+            $attach_url = $settings['attachment'][0]['url'];
+            // Is it an image?
+            if (ActivityPubPlugin::$store_images_from_remote_notes_attachments && substr($attach["mediaType"], 0, 5) == "image") {
+                $temp_filename = tempnam(sys_get_temp_dir(), 'apCreateNoteAttach_');
+                try {
+                    $imgData = HTTPClient::quickGet($attach_url);
+                    // Make sure it's at least an image file. ImageFile can do the rest.
+                    if (false === getimagesizefromstring($imgData)) {
+                        common_debug('ActivityPub Create Notice: Failed because the downloaded image: '.$attach_url. 'is not valid.');
+                        throw new UnsupportedMediaException('Downloaded image was not an image.');
+                    }
+                    file_put_contents($temp_filename, $imgData);
+                    common_debug('ActivityPub Create Notice: Stored dowloaded image in: '.$temp_filename);
+
+                    $id = $actor_profile->getID();
+
+                    $imagefile = new ImageFile(null, $temp_filename);
+                    $filename = hash(File::FILEHASH_ALG, $imgData).image_type_to_extension($imagefile->type);
+
+                    unset($imgData);    // No need to carry this in memory.
+                    rename($temp_filename, File::path($filename));
+                    common_debug('ActivityPub Create Notice: Moved image from: '.$temp_filename.' to '.$filename);
+                    $mediaFile = new MediaFile($filename, $attach['mediaType']);
+                    $act->enclosures[] = $mediaFile->getEnclosure();
+                } catch (Exception $e) {
+                    common_debug('ActivityPub Create Notice: Something went wrong while processing the image from: '.$attach_url.' details: '.$e->getMessage());
+                    unlink($temp_filename);
+                }
+            }
+            $content .= ($content==='' ? '' : ' ') . '<br><a href="'.$attach_url.'">Remote Attachment Source</a>';
+        }
+
+        // Is this a reply?
+        if (isset($settings['inReplyTo'])) {
+            try {
+                $inReplyTo = ActivityPubPlugin::grab_notice_from_url($settings['inReplyTo']);
+                $act->context->replyToID  = $inReplyTo->getUri();
+                $act->context->replyToUrl = $inReplyTo->getUrl();
+            } catch (Exception $e) {
+                // It failed to grab, maybe we got this note from another source
+                // (e.g.: OStatus) that handles this differently or we really
+                // failed to get it...
+                // Welp, nothing that we can do about, let's
+                // just fake we don't have such notice.
+            }
+        } else {
+            $inReplyTo = null;
+        }
+
+        // Mentions
+        $mentions = [];
+        if (isset($object['tag']) && is_array($object['tag'])) {
+            foreach ($object['tag'] as $tag) {
+                if ($tag['type'] == 'Mention') {
+                    $mentions[] = $tag['href'];
+                }
+            }
+        }
+        $mentions_profiles = [];
+        $discovery = new Activitypub_explorer;
+        foreach ($mentions as $mention) {
+            try {
+                $mentions_profiles[] = $discovery->lookup($mention)[0];
+            } catch (Exception $e) {
+                // Invalid actor found, just let it go. // TODO: Fallback to OStatus
+            }
+        }
+        unset($discovery);
+
+        foreach ($mentions_profiles as $mp) {
+            $act->context->attention[ActivityPubPlugin::actor_uri($mp)] = 'http://activitystrea.ms/schema/1.0/person';
+        }
+
+        // Add location if that is set
+        if (isset($settings['latitude'], $settings['longitude'])) {
+            $act->context->location = Location::fromLatLon($settings['latitude'], $settings['longitude']);
+        }
+
+        // Reject notice if it is too long (without the HTML)
+        if (Notice::contentTooLong($content)) {
+            //throw new Exception('That\'s too long. Maximum notice size is %d character.');
+        }
+
+        $actobj = new ActivityObject();
+        $actobj->type = ActivityObject::NOTE;
+        $actobj->content = strip_tags($content, '<p><b><i><u><a><ul><ol><li>');
+
+        // Finally add the activity object to our activity
+        $act->objects[] = $actobj;
+
+        $note = Notice::saveActivity($act, $actor_profile, $options);
+        if (ActivityPubPlugin::$store_images_from_remote_notes_attachments && isset($mediaFile)) {
+            $mediaFile->attachToNotice($note);
+        }
+        return $note;
+    }
+
+    /**
+     * Validates a note.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param  Array $object
+     * @throws Exception
+     */
+    public static function validate_note($object)
+    {
+        if (!isset($object['attributedTo'])) {
+            common_debug('ActivityPub Notice Validator: Rejected because attributedTo was not specified.');
+            throw new Exception('No attributedTo specified.');
+        }
+        if (!isset($object['id'])) {
+            common_debug('ActivityPub Notice Validator: Rejected because Object ID was not specified.');
+            throw new Exception('Object ID not specified.');
+        } elseif (!filter_var($object['id'], FILTER_VALIDATE_URL)) {
+            common_debug('ActivityPub Notice Validator: Rejected because Object ID is invalid.');
+            throw new Exception('Invalid Object ID.');
+        }
+        if (!isset($object['type']) || $object['type'] !== 'Note') {
+            common_debug('ActivityPub Notice Validator: Rejected because of Type.');
+            throw new Exception('Invalid Object type.');
+        }
+        if (!isset($object['content'])) {
+            common_debug('ActivityPub Notice Validator: Rejected because Content was not specified.');
+            throw new Exception('Object content was not specified.');
+        }
+        if (!isset($object['url'])) {
+            throw new Exception('Object URL was not specified.');
+        } elseif (!filter_var($object['url'], FILTER_VALIDATE_URL)) {
+            common_debug('ActivityPub Notice Validator: Rejected because Object URL is invalid.');
+            throw new Exception('Invalid Object URL.');
+        }
+        if (!isset($object['cc'])) {
+            common_debug('ActivityPub Notice Validator: Rejected because Object CC was not specified.');
+            throw new Exception('Object CC was not specified.');
+        }
+        return true;
+    }
 }
--- a/classes/Activitypub_pending_follow_requests.php
+++ b/classes/Activitypub_pending_follow_requests.php
@@ -0,0 +1,117 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub's Pending follow requests
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_pending_follow_requests extends Managed_DataObject
+{
+    public $__table = 'Activitypub_pending_follow_requests';
+    public $local_profile_id;
+    public $remote_profile_id;
+    private $_reldb = null;
+
+    /**
+     * Return table definition for Schema setup and DB_DataObject usage.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return array array of column definitions
+     */
+    public static function schemaDef()
+    {
+        return [
+            'fields' => [
+                'local_profile_id'  => ['type' => 'integer', 'not null' => true],
+                'remote_profile_id' => ['type' => 'integer', 'not null' => true],
+                'relation_id'       => ['type' => 'serial',  'not null' => true],
+            ],
+            'primary key' => ['relation_id'],
+            'unique keys' => [
+                'Activitypub_pending_follow_requests_relation_id_key' => ['relation_id'],
+            ],
+            'foreign keys' => [
+                'Activitypub_pending_follow_requests_local_profile_id_fkey'  => ['profile', ['local_profile_id' => 'id']],
+                'Activitypub_pending_follow_requests_remote_profile_id_fkey' => ['profile', ['remote_profile_id' => 'id']],
+            ],
+        ];
+    }
+
+    public function __construct($actor, $remote_actor)
+    {
+        $this->local_profile_id  = $actor;
+        $this->remote_profile_id = $remote_actor;
+    }
+
+    /**
+     * Add Follow request to table.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param int32 $actor actor id
+     * @param int32 $remote_actor remote actor id
+     * @return boolean true if added, false otherwise
+     */
+    public function add()
+    {
+        return !$this->exists() && $this->insert();
+    }
+
+    /**
+     * Check if a Follow request is pending.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return boolean true if is pending, false otherwise
+     */
+    public function exists()
+    {
+        $this->_reldb = clone ($this);
+        if ($this->_reldb->find() > 0) {
+            $this->_reldb->fetch();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Remove a request from the pending table.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return boolean true if removed, false otherwise
+     */
+    public function remove()
+    {
+        return $this->exists() && $this->_reldb->delete();
+    }
+}
--- a/classes/Activitypub_profile.php
+++ b/classes/Activitypub_profile.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -35,103 +34,126 @@ if (!defined ('GNUSOCIAL')) {
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://www.gnu.org/software/social/
 */
-class Activitypub_profile extends Profile
+class Activitypub_profile extends Managed_DataObject
 {
    public $__table = 'Activitypub_profile';
-
-        protected $_profile = null;
+    public $uri;                             // text()   not_null
+    public $profile_id;                      // int(4)  primary_key not_null
+    public $inboxuri;                        // text()   not_null
+    public $sharedInboxuri;                  // text()
+    public $nickname;                        // varchar(64)  multiple_key not_null
+    public $fullname;                        // text()
+    public $profileurl;                      // text()
+    public $homepage;                        // text()
+    public $bio;                             // text()  multiple_key
+    public $location;                        // text()
+    public $created;                         // datetime()   not_null
+    public $modified;                        // timestamp()   not_null default_CURRENT_TIMESTAMP

    /**
     * Return table definition for Schema setup and DB_DataObject usage.
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return array array of column definitions
     */
-        static function schemaDef ()
+    public static function schemaDef()
    {
-            return array (
-                'fields' => array (
-                    'uri' => array ('type' => 'varchar', 'length' => 191, 'not null' => true),
-                    'profile_id' => array ('type' => 'integer'),
-                    'inboxuri' => array ('type' => 'varchar', 'length' => 191),
-                    'sharedInboxuri' => array ('type' => 'varchar', 'length' => 191),
-                    'created' => array ('type' => 'datetime', 'not null' => true),
-                    'modified' => array ('type' => 'datetime', 'not null' => true),
-                ),
-                'primary key' => array ('uri'),
-                'unique keys' => array (
-                    'Activitypub_profile_profile_id_key' => array ('profile_id'),
-                    'Activitypub_profile_inboxuri_key' => array ('inboxuri'),
-                ),
-                'foreign keys' => array (
-                    'Activitypub_profile_profile_id_fkey' => array ('profile', array ('profile_id' => 'id')),
-                ),
-            );
+        return [
+            'fields' => [
+                'uri' => ['type' => 'text', 'not null' => true],
+                'profile_id' => ['type' => 'integer'],
+                'inboxuri' => ['type' => 'text', 'not null' => true],
+                'sharedInboxuri' => ['type' => 'text'],
+                'created' => ['type' => 'datetime', 'not null' => true],
+                'modified' => ['type' => 'datetime', 'not null' => true],
+            ],
+            'primary key' => ['profile_id'],
+            'unique keys' => [
+                'Activitypub_profile_profile_id_key' => ['profile_id'],
+            ],
+            'foreign keys' => [
+                'Activitypub_profile_profile_id_fkey' => ['profile', ['profile_id' => 'id']],
+            ],
+        ];
    }

    /**
     * Generates a pretty profile from a Profile object
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param Profile $profile
     * @return pretty array to be used in a response
     */
    public static function profile_to_array($profile)
    {
-                $url = $profile->getURL ();
+        $uri = ActivityPubPlugin::actor_uri($profile);
+        $id = $profile->getID();
+        $rsa = new Activitypub_rsa();
+        $public_key = $rsa->ensure_public_key($profile);
+        unset($rsa);
        $res = [
-                        '@context'        => [
-                                "https://www.w3.org/ns/activitystreams",
-                                [
-                                        "@language"   => "en"
-                                ]
-                        ],
-                        'id'              => $profile->getID (),
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'                => $uri,
            'type'              => 'Person',
-                        'nickname'        => $profile->getNickname (),
-                        'is_local'        => $profile->isLocal (),
-                        'inbox'           => "{$url}/inbox.json",
-                        'sharedInbox'     => common_root_url ()."inbox.json",
-                        'outbox'          => "{$url}/outbox.json",
-                        'display_name'    => $profile->getFullname (),
-                        'followers'       => "{$url}/followers.json",
-                        'followers_count' => $profile->subscriberCount (),
-                        'following'       => "{$url}/following.json",
-                        'following_count' => $profile->subscriptionCount (),
-                        'liked'           => "{$url}/liked.json",
-                        'liked_count'     => Fave::countByProfile ($profile),
+            'following'         => common_local_url('apActorFollowing', ['id' => $id]),
+            'followers'         => common_local_url('apActorFollowers', ['id' => $id]),
+            'liked'             => common_local_url('apActorLiked', ['id' => $id]),
+            'inbox'             => common_local_url('apInbox', ['id' => $id]),
+            'outbox'            => common_local_url('apActorOutbox', ['id' => $id]),
+            'preferredUsername' => $profile->getNickname(),
+            'name'              => $profile->getBestName(),
            'summary'           => ($desc = $profile->getDescription()) == null ? "" : $desc,
-                        'url'             => $profile->getURL (),
-                        'avatar'          => [
+            'url'               => $profile->getUrl(),
+            'manuallyApprovesFollowers' => false,
+            'publicKey' => [
+                'id'    => $uri."#public-key",
+                'owner' => $uri,
+                'publicKeyPem' => $public_key
+            ],
+            'tag' => [],
+            'attachment' => [],
+            'icon' => [
                'type'      => 'Image',
-                                'width'  => 96,
-                                'height' => 96,
+                'mediaType' => 'image/png',
+                'height'    => AVATAR_PROFILE_SIZE,
+                'width'     => AVATAR_PROFILE_SIZE,
                'url'       => $profile->avatarUrl(AVATAR_PROFILE_SIZE)
            ]
        ];
+
+        if ($profile->isLocal()) {
+            $res['endpoints']['sharedInbox'] = common_local_url('apInbox');
+        } else {
+            $aprofile = new Activitypub_profile();
+            $aprofile = $aprofile->from_profile($profile);
+            $res['endpoints']['sharedInbox'] = $aprofile->sharedInboxuri;
+        }
+
        return $res;
    }

    /**
-         * Insert the current objects variables into the database
+     * Insert the current object variables into the database
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @access public
     * @throws ServerException
     */
-        public function doInsert ()
+    public function do_insert()
    {
        $profile = new Profile();

        $profile->created = $this->created = $this->modified = common_sql_now();

-                $fields = array (
+        $fields = [
                    'uri'      => 'profileurl',
                    'nickname' => 'nickname',
                    'fullname' => 'fullname',
                    'bio'      => 'bio'
-                            );
+                    ];

        foreach ($fields as $af => $pf) {
            $profile->$pf = $this->$af;
@@ -147,16 +169,19 @@ class Activitypub_profile extends Profile

        if ($ok === false) {
            $profile->query('ROLLBACK');
+            $this->query('ROLLBACK');
            throw new ServerException('Cannot save ActivityPub profile.');
        }
    }

    /**
     * Fetch the locally stored profile for this Activitypub_profile
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return Profile
     * @throws NoProfileException if it was not found
     */
-        public function localProfile ()
+    public function local_profile()
    {
        $profile = Profile::getKV('id', $this->profile_id);
        if (!$profile instanceof Profile) {
@@ -168,32 +193,81 @@ class Activitypub_profile extends Profile
    /**
     * Generates an Activitypub_profile from a Profile
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param Profile $profile
     * @return Activitypub_profile
     * @throws Exception if no Activitypub_profile exists for given Profile
     */
-        static function fromProfile (Profile $profile)
+    public static function from_profile(Profile $profile)
    {
        $profile_id = $profile->getID();

-                $aprofile = Activitypub_profile::getKV ('profile_id', $profile_id);
+        $aprofile = self::getKV('profile_id', $profile_id);
        if (!$aprofile instanceof Activitypub_profile) {
-                        throw new Exception('No Activitypub_profile for Profile ID: '.$profile_id);
+            // No Activitypub_profile for this profile_id,
+            if (!$profile->isLocal()) {
+                // create one!
+                $aprofile = self::create_from_local_profile($profile);
+            } else {
+                throw new Exception('No Activitypub_profile for Profile ID: '.$profile_id. ', this is a local user.');
+            }
        }

-                foreach ($profile as $key => $value) {
-                        $aprofile->$key = $value;
+        $fields = [
+                    'uri'      => 'profileurl',
+                    'nickname' => 'nickname',
+                    'fullname' => 'fullname',
+                    'bio'      => 'bio'
+                    ];
+
+        foreach ($fields as $af => $pf) {
+            $aprofile->$af = $profile->$pf;
        }

        return $aprofile;
    }

+    /**
+     * Given an existent local profile creates an ActivityPub profile.
+     * One must be careful not to give a user profile to this function
+     * as only remote users have ActivityPub_profiles on local instance
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $profile
+     * @return Activitypub_profile
+     */
+    private static function create_from_local_profile(Profile $profile)
+    {
+        $url = $profile->getUri();
+        $inboxes = Activitypub_explorer::get_actor_inboxes_uri($url);
+
+        if ($inboxes == null) {
+            throw new Exception('This is not an ActivityPub user thus AProfile is politely refusing to proceed.');
+        }
+
+        $aprofile->created = $aprofile->modified = common_sql_now();
+
+        $aprofile                 = new Activitypub_profile;
+        $aprofile->profile_id     = $profile->getID();
+        $aprofile->uri            = $url;
+        $aprofile->nickname       = $profile->getNickname();
+        $aprofile->fullname       = $profile->getFullname();
+        $aprofile->bio            = substr($profile->getDescription(), 0, 1000);
+        $aprofile->inboxuri       = $inboxes["inbox"];
+        $aprofile->sharedInboxuri = $inboxes["sharedInbox"];
+
+        $aprofile->insert();
+
+        return $aprofile;
+    }
+
    /**
     * Returns sharedInbox if possible, inbox otherwise
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @return string Inbox URL
     */
-        public function getInbox ()
+    public function get_inbox()
    {
        if (is_null($this->sharedInboxuri)) {
            return $this->inboxuri;
@@ -201,4 +275,195 @@ class Activitypub_profile extends Profile

        return $this->sharedInboxuri;
    }
+
+    /**
+     * Getter for uri property
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return string URI
+     */
+    public function getUri()
+    {
+        return $this->uri;
+    }
+
+    /**
+     * Getter for url property
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return string URL
+     */
+    public function getUrl()
+    {
+        return $this->getUri();
+    }
+
+    /**
+     * Getter for id property
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return int32
+     */
+    public function getID()
+    {
+        return $this->profile_id;
+    }
+
+    /**
+     * Ensures a valid Activitypub_profile when provided with a valid URI.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $url
+     * @return Activitypub_profile
+     * @throws Exception if it isn't possible to return an Activitypub_profile
+     */
+    public static function fromUri($url)
+    {
+        try {
+            return self::from_profile(Activitypub_explorer::get_profile_from_url($url));
+        } catch (Exception $e) {
+            throw new Exception('No valid ActivityPub profile found for given URI.');
+        }
+    }
+
+    /**
+     * Look up, and if necessary create, an Activitypub_profile for the remote
+     * entity with the given webfinger address.
+     * This should never return null -- you will either get an object or
+     * an exception will be thrown.
+     *
+     * @author GNU Social
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $addr webfinger address
+     * @return Activitypub_profile
+     * @throws Exception on error conditions
+     */
+    public static function ensure_web_finger($addr)
+    {
+        // Normalize $addr, i.e. add 'acct:' if missing
+        $addr = Discovery::normalize($addr);
+
+        // Try the cache
+        $uri = self::cacheGet(sprintf('activitypub_profile:webfinger:%s', $addr));
+
+        if ($uri !== false) {
+            if (is_null($uri)) {
+                // Negative cache entry
+                // TRANS: Exception.
+                throw new Exception(_m('Not a valid webfinger address (via cache).'));
+            }
+            try {
+                return self::fromUri($uri);
+            } catch (Exception $e) {
+                common_log(LOG_ERR, sprintf(__METHOD__ . ': Webfinger address cache inconsistent with database, did not find Activitypub_profile uri==%s', $uri));
+                self::cacheSet(sprintf('activitypub_profile:webfinger:%s', $addr), false);
+            }
+        }
+
+        // Now, try some discovery
+
+        $disco = new Discovery();
+
+        try {
+            $xrd = $disco->lookup($addr);
+        } catch (Exception $e) {
+            // Save negative cache entry so we don't waste time looking it up again.
+            // @todo FIXME: Distinguish temporary failures?
+            self::cacheSet(sprintf('activitypub_profile:webfinger:%s', $addr), null);
+            // TRANS: Exception.
+            throw new Exception(_m('Not a valid webfinger address.'));
+        }
+
+        $hints = array_merge(
+                    array('webfinger' => $addr),
+                DiscoveryHints::fromXRD($xrd)
+                );
+
+        // If there's an Hcard, let's grab its info
+        if (array_key_exists('hcard', $hints)) {
+            if (!array_key_exists('profileurl', $hints) ||
+                        $hints['hcard'] != $hints['profileurl']) {
+                $hcardHints = DiscoveryHints::fromHcardUrl($hints['hcard']);
+                $hints = array_merge($hcardHints, $hints);
+            }
+        }
+
+        // If we got a profile page, try that!
+        $profileUrl = null;
+        if (array_key_exists('profileurl', $hints)) {
+            $profileUrl = $hints['profileurl'];
+            try {
+                common_log(LOG_INFO, "Discovery on acct:$addr with profile URL $profileUrl");
+                $aprofile = self::fromUri($hints['profileurl']);
+                self::cacheSet(sprintf('activitypub_profile:webfinger:%s', $addr), $aprofile->getUri());
+                return $aprofile;
+            } catch (Exception $e) {
+                common_log(LOG_WARNING, "Failed creating profile from profile URL '$profileUrl': " . $e->getMessage());
+                // keep looking
+                                //
+                                // @todo FIXME: This means an error discovering from profile page
+                                // may give us a corrupt entry using the webfinger URI, which
+                                // will obscure the correct page-keyed profile later on.
+            }
+        }
+
+        // XXX: try hcard
+        // XXX: try FOAF
+
+        // TRANS: Exception. %s is a webfinger address.
+        throw new Exception(sprintf(_m('Could not find a valid profile for "%s".'), $addr));
+    }
+
+    /**
+     * Update remote user profile in local instance
+     * Depends on do_update
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $res remote response
+     * @return Profile remote Profile object
+     */
+    public static function update_profile($aprofile, $res)
+    {
+        // ActivityPub Profile
+        $aprofile->uri            = $res['id'];
+        $aprofile->nickname       = $res['preferredUsername'];
+        $aprofile->fullname       = isset($res['name']) ? $res['name'] : null;
+        $aprofile->bio            = isset($res['summary']) ? substr(strip_tags($res['summary']), 0, 1000) : null;
+        $aprofile->inboxuri       = $res['inbox'];
+        $aprofile->sharedInboxuri = isset($res['endpoints']['sharedInbox']) ? $res['endpoints']['sharedInbox'] : $res['inbox'];
+
+        $profile = $aprofile->local_profile();
+
+        $profile->modified = $aprofile->modified = common_sql_now();
+
+        $fields = [
+                    'uri'      => 'profileurl',
+                    'nickname' => 'nickname',
+                    'fullname' => 'fullname',
+                    'bio'      => 'bio'
+                    ];
+
+        foreach ($fields as $af => $pf) {
+            $profile->$pf = $aprofile->$af;
+        }
+
+        // Profile
+        $profile->update();
+        $aprofile->update();
+
+        // Public Key
+        Activitypub_rsa::update_public_key($profile, $res['publicKey']['publicKeyPem']);
+
+        // Avatar
+        if (isset($res['icon']['url'])) {
+            try {
+                Activitypub_explorer::update_avatar($profile, $res['icon']['url']);
+            } catch (Exception $e) {
+                // Let the exception go, it isn't a serious issue
+                common_debug('An error ocurred while grabbing remote avatar'.$e->getMessage());
+            }
+        }
+
+        return $profile;
+    }
 }
--- a/classes/Activitypub_reject.php
+++ b/classes/Activitypub_reject.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -29,9 +28,31 @@ if (!defined ('GNUSOCIAL')) {
    exit(1);
 }

-try {
-        Notice::getByUri ($data->object)->repeat ($actor_profile, "ActivityPub");
-        ActivityPubReturn::answer ("Notice repeated successfully.");
-} catch (Exception $e) {
-        ActivityPubReturn::error ($e->getMessage (), 403);
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_reject extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Reject
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function reject_to_array($object)
+    {
+        $res = [
+                '@context' => 'https://www.w3.org/ns/activitystreams',
+                "type"   => "Reject",
+                "object" => $object
+        ];
+        return $res;
+    }
 }
--- a/classes/Activitypub_rsa.php
+++ b/classes/Activitypub_rsa.php
@@ -0,0 +1,178 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub Keys System
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_rsa extends Managed_DataObject
+{
+    public $__table = 'Activitypub_rsa';
+
+    /**
+     * Return table definition for Schema setup and DB_DataObject usage.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return array array of column definitions
+     */
+    public static function schemaDef()
+    {
+        return [
+                'fields' => [
+                    'profile_id'  => ['type' => 'integer'],
+                    'private_key' => ['type' => 'text'],
+                    'public_key'  => ['type' => 'text', 'not null' => true],
+                    'created'     => ['type' => 'datetime', 'not null' => true],
+                    'modified'    => ['type' => 'datetime', 'not null' => true],
+                ],
+                'primary key' => ['profile_id'],
+                'unique keys' => [
+                    'Activitypub_rsa_profile_id_key'  => ['profile_id'],
+                ],
+                'foreign keys' => [
+                    'Activitypub_profile_profile_id_fkey' => ['profile', ['profile_id' => 'id']],
+                ],
+        ];
+    }
+
+    public function get_private_key($profile)
+    {
+        $this->profile_id = $profile->getID();
+        $apRSA = self::getKV('profile_id', $this->profile_id);
+        if (!$apRSA instanceof Activitypub_rsa) {
+            // No existing key pair for this profile
+            if ($profile->isLocal()) {
+                self::generate_keys($this->private_key, $this->public_key);
+                $this->store_keys();
+            } else {
+                throw new Exception('This is a remote Profile, there is no Private Key for this Profile.');
+            }
+        }
+        return $apRSA->private_key;
+    }
+
+    /**
+     * Guarantees a Public Key for a given profile.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $profile
+     * @return string The public key
+     * @throws ServerException It should never occur, but if so, we break everything!
+     */
+    public function ensure_public_key($profile, $fetch = true)
+    {
+        $this->profile_id = $profile->getID();
+        $apRSA = self::getKV('profile_id', $this->profile_id);
+        if (!$apRSA instanceof Activitypub_rsa) {
+            // No existing key pair for this profile
+            if ($profile->isLocal()) {
+                self::generate_keys($this->private_key, $this->public_key);
+                $this->store_keys();
+            } else {
+                // This should never happen, but try to recover!
+                if ($fetch) {
+                    $res = Activitypub_explorer::get_remote_user_activity(ActivityPubPlugin::actor_uri($profile));
+                    Activitypub_rsa::update_public_key($profile, $res['publicKey']['publicKeyPem']);
+                    return ensure_public_key($profile, false);
+                } else {
+                    throw new ServerException('Activitypub_rsa: Failed to find keys for given profile. That should have not happened!');
+                }
+            }
+        }
+        return $apRSA->public_key;
+    }
+
+    /**
+     * Insert the current object variables into the database.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @access public
+     * @throws ServerException
+     */
+    public function store_keys()
+    {
+        $this->created = $this->modified = common_sql_now();
+        $ok = $this->insert();
+        if ($ok === false) {
+            throw new ServerException('Cannot save ActivityPub RSA.');
+        }
+    }
+
+    /**
+     * Generates a pair of RSA keys.
+     *
+     * @author PHP Manual Contributed Notes <dirt@awoms.com>
+     * @param string $private_key in/out
+     * @param string $public_key in/out
+     */
+    public static function generate_keys(&$private_key, &$public_key)
+    {
+        $config = [
+            'digest_alg'       => 'sha512',
+            'private_key_bits' => 2048,
+            'private_key_type' => OPENSSL_KEYTYPE_RSA,
+        ];
+
+        // Create the private and public key
+        $res = openssl_pkey_new($config);
+
+        // Extract the private key from $res to $private_key
+        openssl_pkey_export($res, $private_key);
+
+        // Extract the public key from $res to $pubKey
+        $pubKey = openssl_pkey_get_details($res);
+        $public_key = $pubKey["key"];
+        unset($pubKey);
+    }
+
+    /**
+     * Update public key.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $profile
+     * @param string $public_key
+     */
+    public static function update_public_key($profile, $public_key)
+    {
+        // Public Key
+        $apRSA = new Activitypub_rsa();
+        $apRSA->profile_id = $profile->getID();
+        $apRSA->public_key = $public_key;
+        $apRSA->modified = common_sql_now();
+        if(!$apRSA->update()) {
+            $apRSA->insert();
+        }
+    }
+}
--- a/classes/Activitypub_tag.php
+++ b/classes/Activitypub_tag.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -43,22 +42,17 @@ class Activitypub_tag extends Managed_DataObject
    /**
     * Generates a pretty tag from a Tag object
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param Tag $tag
     * @return pretty array to be used in a response
     */
    public static function tag_to_array($tag)
    {
        $res = [
-                '@context'          => [
-                "https://www.w3.org/ns/activitystreams",
-                [
-                  "@language" => "en"
-                ]
-                ],
+            '@context' => 'https://www.w3.org/ns/activitystreams',
            'name' => $tag,
-                'url'  => common_local_url ('tag', array('tag' => $tag))
+            'url'  => common_local_url('tag', ['tag' => $tag])
        ];
-
        return $res;
    }
 }
--- a/classes/Activitypub_undo.php
+++ b/classes/Activitypub_undo.php
@@ -0,0 +1,89 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_undo extends Managed_DataObject
+{
+    /**
+     * Generates an ActivityPub representation of a Undo
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return pretty array to be used in a response
+     */
+    public static function undo_to_array($object)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => $object['id'].'/undo',
+            'type'   => 'Undo',
+            'actor'  => $object['actor'],
+            'object' => $object
+        ];
+        return $res;
+    }
+
+    /**
+     * Verifies if a given object is acceptable for a Undo Activity.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Array $object
+     * @throws Exception
+     */
+    public static function validate_object($object)
+    {
+        if (!is_array($object)) {
+            throw new Exception('Invalid Object Format for Undo Activity.');
+        }
+        if (!isset($object['type'])) {
+            throw new Exception('Object type was not specified for Undo Activity.');
+        }
+        switch ($object['type']) {
+            case 'Follow':
+            case 'Like':
+                // Validate data
+                if (!filter_var($object['object'], FILTER_VALIDATE_URL)) {
+                    throw new Exception('Object is not a valid Object URI for Activity.');
+                }
+                break;
+            default:
+                throw new Exception('This is not a supported Object Type for Undo Activity.');
+        }
+        return true;
+    }
+}
--- a/composer.json
+++ b/composer.json
@@ -0,0 +1,24 @@
+{
+    "name": "dansup/activity-pub",
+    "description": "ActivityPub plugin for GNU/Social",
+    "type": "gnusocial-plugin",
+    "require": {
+        "pixelfed/http-signatures-guzzlehttp": "^4.0"
+    },
+    "license": "AGPL",
+    "autoload": {
+        "psr-4": {
+            "Tests\\": "tests/"
+        }
+    },
+    "authors": [
+        {
+            "name": "Daniel Supernault",
+            "email": "danielsupernault@gmail.com"
+        },
+        {
+            "name": "Diogo Cordeiro",
+            "email": "diogo@fc.up.pt"
+        }
+    ]
+}
--- a/daemons/update_activitypub_profiles.php
+++ b/daemons/update_activitypub_profiles.php
@@ -0,0 +1,104 @@
+#!/usr/bin/env php
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+
+define('INSTALLDIR', realpath(__DIR__ . '/../../..'));
+
+$shortoptions = 'u:af';
+$longoptions = ['uri=', 'all', 'force'];
+
+$helptext = <<<END_OF_HELP
+update_activitypub_profiles.php [options]
+Refetch / update ActivityPub RSA keys, profile info and avatars. Useful if you
+do something like accidentally delete your avatars directory when
+you have no backup.
+
+    -u --uri ActivityPub profile URI to update
+    -a --all update all
+
+END_OF_HELP;
+
+require_once INSTALLDIR.'/scripts/commandline.inc';
+
+$quiet = have_option('q', 'quiet');
+
+if (!$quiet) {
+    echo "ActivityPub Profiles updater will now start!\n";
+    echo "Summoning Diogo Cordeiro, Richard Stallman and Chuck Norris to help us with this task!\n";
+}
+
+if (have_option('u', 'uri')) {
+    $uri = get_option_value('u', 'uri');
+    $discovery = new Activitypub_explorer();
+    $discovery = $discovery->lookup($uri);
+    if (empty($discovery)) {
+        echo "Bad URI\n";
+        exit(1);
+    }
+    $user = $discovery->lookup($uri)[0];
+    try {
+        $res = Activitypub_explorer::get_remote_user_activity($uri);
+    } catch (Exception $e) {
+        echo $e->getMessage()."\n";
+        exit(1);
+    }
+    if (!$quiet) {
+        echo "Updated ".Activitypub_profile::update_profile($user, $res)->getBestName()."\n";
+    }
+} else if (!have_option('a', 'all')) {
+    show_help();
+    exit(1);
+}
+
+$user = new Activitypub_profile();
+$cnt = $user->find();
+if (!empty($cnt)) {
+    if (!$quiet) {
+        echo "Found {$cnt} ActivityPub profiles:\n";
+    }
+} else {
+    if (have_option('u', 'uri')) {
+        if (!$quiet) {
+            echo "Couldn't find an existing ActivityPub profile with that URI.\n";
+        }
+    } else {
+        if (!$quiet) {
+            echo "Couldn't find any existing ActivityPub profiles.\n";
+        }
+    }
+    exit(0);
+}
+while ($user->fetch()) {
+    try {
+        $res = Activitypub_explorer::get_remote_user_activity($user->uri);
+        if (!$quiet) {
+            echo "Updated ".Activitypub_profile::update_profile($user, $res)->getBestName()."\n";
+        }
+    } catch (Exception $e) {
+        // let it go
+    }
+}
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false">
+    <testsuites>
+        <testsuite name="Feature">
+            <directory suffix="Test.php">./tests/Feature</directory>
+        </testsuite>
+
+        <testsuite name="Unit">
+            <directory suffix="Test.php">./tests/Unit</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">./app</directory>
+        </whitelist>
+    </filter>
+</phpunit>
--- a/tests/CreatesApplication.php
+++ b/tests/CreatesApplication.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Tests;
+
+trait CreatesApplication
+{
+    /**
+     * Creates the application.
+     *
+     * @return todo
+     */
+    public static function createApplication()
+    {
+        if (!defined('INSTALLDIR')) {
+            define('INSTALLDIR', __DIR__ . '/../../../');
+        }
+        if (!defined('GNUSOCIAL')) {
+            define('GNUSOCIAL', true);
+        }
+        if (!defined('STATUSNET')) {
+            define('STATUSNET', true);  // compatibility
+        }
+
+        require INSTALLDIR . '/lib/common.php';
+
+        return true;
+    }
+}
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Tests;
+
+use PHPUnit\Framework\TestCase as BaseTestCase;
+
+abstract class TestCase extends BaseTestCase
+{
+    use CreatesApplication;
+
+    protected function setUp()
+    {
+        $this->createApplication();
+    }
+}
--- a/tests/Unit/AcceptHeaderTest.php
+++ b/tests/Unit/AcceptHeaderTest.php
@@ -0,0 +1,43 @@
+<?php
+
+require 'AcceptHeader.php';
+
+class ContainerTest extends \PHPUnit_Framework_TestCase
+{
+    public function testHeader1()
+    {
+        $acceptHeader = new AcceptHeader('audio/*; q=0.2, audio/basic');
+        $this->assertEquals('audio/basic', $this->_getMedia($acceptHeader[0]));
+        $this->assertEquals('audio/*; q=0.2', $this->_getMedia($acceptHeader[1]));
+    }
+
+    public function testHeader2()
+    {
+        $acceptHeader = new AcceptHeader('text/*;q=0.3, text/html;q=0.7, text/html;level=1, text/html;level=2;q=0.4, */*;q=0.5');
+        $this->assertEquals('text/html; level=1', $this->_getMedia($acceptHeader[0]));
+        $this->assertEquals('text/html; q=0.7', $this->_getMedia($acceptHeader[1]));
+        $this->assertEquals('*/*; q=0.5', $this->_getMedia($acceptHeader[2]));
+        $this->assertEquals('text/html; level=2; q=0.4', $this->_getMedia($acceptHeader[3]));
+        $this->assertEquals('text/*; q=0.3', $this->_getMedia($acceptHeader[4]));
+    }
+
+    public function testHeader3()
+    {
+        $acceptHeader = new AcceptHeader('text/*, text/html, text/html;level=1, */*');
+        $this->assertEquals('text/html; level=1', $this->_getMedia($acceptHeader[0]));
+        $this->assertEquals('text/html', $this->_getMedia($acceptHeader[1]));
+        $this->assertEquals('text/*', $this->_getMedia($acceptHeader[2]));
+        $this->assertEquals('*/*', $this->_getMedia($acceptHeader[3]));
+    }
+
+    private function _getMedia(array $mediaType)
+    {
+        $str = $mediaType['type'] . '/' . $mediaType['subtype'];
+        if (!empty($mediaType['params'])) {
+            foreach ($mediaType['params'] as $k => $v) {
+                $str .= '; ' . $k . '=' . $v;
+            }
+        }
+        return $str;
+    }
+}
--- a/tests/Unit/ActivitypubProfileTest.php
+++ b/tests/Unit/ActivitypubProfileTest.php
@@ -0,0 +1,159 @@
+<?php
+
+namespace Tests\Unit;
+
+use Tests\TestCase;
+
+class ProfileObjectTest extends TestCase
+{
+    public function testLibraryInstalled()
+    {
+        $this->assertTrue(class_exists('\Activitypub_profile'));
+    }
+
+    public function testActivitypubProfile()
+    {
+        // Mimic proper ACCEPT header
+        $_SERVER['HTTP_ACCEPT'] = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams';
+
+        /* Test do_insert() */
+        $aprofile = new \Activitypub_profile();
+        $aprofile->uri = 'https://testinstance.net/index.php/user/1';
+        $aprofile->nickname = 'test1';
+        $aprofile->fullname = 'Test User 1';
+        $aprofile->bio      = 'I am a nice test 1 guy';
+        $aprofile->inboxuri = "https://testinstance.net/index.php/user/1/inbox.json";
+        $aprofile->sharedInboxuri = "https://testinstance.net/inbox.json";
+        $aprofile->do_insert();
+
+        /* Test local_profile() */
+        $profile = $aprofile->local_profile();
+
+        /* Test from_profile() and create_from_local_profile() */
+        $this->assertTrue($this->compare_aprofiles($aprofile, \Activitypub_profile::from_profile($profile)));
+
+        /* Create Keys for Test User 1 */
+        $apRSA = new \Activitypub_rsa();
+        $apRSA->profile_id = $profile->getID();
+        \Activitypub_rsa::generate_keys($apRSA->private_key, $apRSA->public_key);
+        $apRSA->store_keys();
+
+        /* Test profile_to_array() */
+        // Fetch ActivityPub Actor Object representation
+        $profile_array = \Activitypub_profile::profile_to_array($profile);
+        // Check type
+        $this->assertTrue(is_array($profile_array));
+        // Test with Explorer's Profile Tester
+        $this->assertTrue(\Activitypub_explorer::validate_remote_response($profile_array));
+
+        /* Test get_inbox() */
+        $this->assertTrue($aprofile->sharedInboxuri == $aprofile->get_inbox());
+
+        /* Test getUri() */
+        $this->assertTrue($aprofile->uri == $aprofile->getUri());
+
+        /* Test getUrl() */
+        $this->assertTrue($profile->getUrl() == $aprofile->getUrl());
+
+        /* Test getID() */
+        $this->assertTrue($profile->getID() == $aprofile->getID());
+
+        /* Test fromUri() */
+        $this->assertTrue($this->compare_aprofiles($aprofile, \Activitypub_profile::fromUri($aprofile->uri)));
+
+        /* Remove Remote User Test 1 */
+        $old_id = $profile->getID();
+        $apRSA->delete();
+        $aprofile->delete();
+        $profile->delete();
+        // Check if successfuly removed
+        try {
+            \Profile::getById($old_id);
+            $this->assertTrue(false);
+        } catch (\NoResultException $e) {
+            $this->assertTrue(true);
+        }
+
+        /* Test ensure_web_finger() */
+        // TODO: Maybe elaborate on this function's tests
+        try {
+            \Activitypub_profile::ensure_web_finger('test1@testinstance.net');
+            $this->assertTrue(false);
+        } catch (\Exception $e) {
+            $this->assertTrue($e->getMessage() == 'Not a valid webfinger address.' ||
+                              $e->getMessage() == 'Not a valid webfinger address (via cache).');
+        }
+    }
+
+    // Helpers
+
+    private function compare_profiles(\Profile $a, \Profile $b)
+    {
+        if (($av = $a->getID()) != ($bv = $b->getID())) {
+            throw new Exception('Compare Profiles 1 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getNickname()) != ($bv = $b->getNickname())) {
+            throw new Exception('Compare Profiles 2 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getFullname()) != ($bv = $b->getFullname())) {
+            throw new Exception('Compare Profiles 3 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getUrl()) != ($bv = $b->getUrl())) {
+            throw new Exception('Compare Profiles 4 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getDescription()) != ($bv = $b->getDescription())) {
+            throw new Exception('Compare Profiles 5 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getLocation()) != ($bv = $b->getLocation())) {
+            throw new Exception('Compare Profiles 6 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getNickname()) != ($bv = $b->getNickname())) {
+            throw new Exception('Compare Profiles 7 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->lat) != ($bv = $b->lat)) {
+            throw new Exception('Compare Profiles 8 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->lon) != ($bv = $b->lon)) {
+            throw new Exception('Compare Profiles 9 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        return true;
+    }
+
+    private function compare_aprofiles(\Activitypub_profile $a, \Activitypub_profile $b)
+    {
+        if (($av = $a->getUri()) != ($bv = $b->getUri())) {
+            throw new Exception('Compare AProfiles 1 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getUrl()) != ($bv = $b->getUrl())) {
+            throw new Exception('Compare AProfiles 2 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->getID()) != ($bv = $b->getID())) {
+            throw new Exception('Compare AProfiles 3 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->profile_id) != ($bv = $b->profile_id)) {
+            throw new Exception('Compare AProfiles 4 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->inboxuri) != ($bv = $b->inboxuri)) {
+            throw new Exception('Compare AProfiles 5 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        if (($av = $a->sharedInboxuri) != ($bv = $b->sharedInboxuri)) {
+            throw new Exception('Compare AProfiles 6 Fail: $a: '.$av.' is different from $b: '.$bv);
+        }
+
+        return true;
+    }
+}
--- a/tests/Unit/ExampleTest.php
+++ b/tests/Unit/ExampleTest.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Tests\Unit;
+
+use Tests\TestCase;
+
+class ExampleTest extends TestCase
+{
+    /**
+     * A basic test example.
+     *
+     * @return void
+     */
+    public function testBasicTest()
+    {
+        $this->assertTrue(true);
+    }
+}
--- a/tests/Unit/HTTPSignatureTest.php
+++ b/tests/Unit/HTTPSignatureTest.php
@@ -0,0 +1,141 @@
+<?php
+
+namespace Tests\Unit;
+
+use Tests\TestCase;
+use GuzzleHttp\Client;
+use GuzzleHttp\Handler\CurlHandler;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Middleware;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use HttpSignatures\Context;
+use HttpSignatures\GuzzleHttpSignatures;
+
+class HTTPSignatureTest extends TestCase
+{
+    /**
+     * @var Context
+     */
+    private $context;
+    /**
+     * @var Client
+     */
+    private $client;
+    /**
+     * @var
+     */
+    private $history = [];
+
+    public function testLibraryInstalled()
+    {
+        $this->assertTrue(class_exists('\GuzzleHttp\Client'));
+        $this->assertTrue(class_exists('\HttpSignatures\Context'));
+        $this->assertTrue(class_exists('\HttpSignatures\GuzzleHttpSignatures'));
+    }
+
+    public function setUp()
+    {
+        $this->context = new Context([
+            'keys' => ['pda' => 'secret'],
+            'algorithm' => 'hmac-sha256',
+            'headers' => ['(request-target)', 'date'],
+        ]);
+        $stack = new HandlerStack();
+        $stack->setHandler(new MockHandler([
+            new Response(200, ['Content-Length' => 0]),
+        ]));
+        $stack->push(GuzzleHttpSignatures::middlewareFromContext($this->context));
+        $stack->push(Middleware::history($this->history));
+        $this->client = new Client(['handler' => $stack]);
+    }
+    /**
+     * test signing a message
+     */
+    public function testGuzzleRequestHasExpectedHeaders()
+    {
+        $this->client->get('/path?query=123', [
+            'headers' => ['date' => 'today', 'accept' => 'llamas']
+        ]);
+        // get last request
+        $message = end($this->history);
+        /** @var Request $request */
+        $request = $message['request'];
+        /** @var Response $response */
+        $response = $message['request'];
+        $expectedString = implode(
+            ',',
+            [
+                'keyId="pda"',
+                'algorithm="hmac-sha256"',
+                'headers="(request-target) date"',
+                'signature="SFlytCGpsqb/9qYaKCQklGDvwgmrwfIERFnwt+yqPJw="',
+            ]
+        );
+        $this->assertEquals(
+            [$expectedString],
+            $request->getHeader('Signature')
+        );
+        $this->assertEquals(
+            ['Signature ' . $expectedString],
+            $request->getHeader('Authorization')
+        );
+    }
+    /**
+     * test signing a message with a URL that doesn't contain a ?query
+     */
+    public function testGuzzleRequestHasExpectedHeaders2()
+    {
+        $this->client->get('/path', [
+            'headers' => ['date' => 'today', 'accept' => 'llamas']
+        ]);
+        // get last request
+        $message = end($this->history);
+        /** @var Request $request */
+        $request = $message['request'];
+        /** @var Response $response */
+        $response = $message['request'];
+        $expectedString = implode(
+            ',',
+            [
+                'keyId="pda"',
+                'algorithm="hmac-sha256"',
+                'headers="(request-target) date"',
+                'signature="DAtF133khP05pS5Gh8f+zF/UF7mVUojMj7iJZO3Xk4o="',
+            ]
+        );
+        $this->assertEquals(
+            [$expectedString],
+            $request->getHeader('Signature')
+        );
+        $this->assertEquals(
+            ['Signature ' . $expectedString],
+            $request->getHeader('Authorization')
+        );
+    }
+    public function getVerifyGuzzleRequestVectors()
+    {
+        return [
+            /* path, headers */
+            ['/path?query=123', ['date' => 'today', 'accept' => 'llamas']],
+            ['/path?z=zebra&a=antelope', ['date' => 'today']],
+        ];
+    }
+    /**
+     * @dataProvider getVerifyGuzzleRequestVectors
+     * @param string $path
+     * @param array $headers
+     */
+    public function testVerifyGuzzleRequest($path, $headers)
+    {
+        $this->client->get($path, ['headers' => $headers]);
+        // get last request
+        $message = end($this->history);
+        /** @var Request $request */
+        $request = $message['request'];
+        /** @var Response $response */
+        $response = $message['request'];
+        $this->assertTrue($this->context->verifier()->isValid($request));
+    }
+}
--- a/utils/AcceptHeader.php
+++ b/utils/AcceptHeader.php
@@ -0,0 +1,116 @@
+<?php
+/**
+ * Note : Code is released under the GNU LGPL
+ *
+ * Please do not change the header of this file
+ *
+ * This library is free software; you can redistribute it and/or modify it under the terms of the GNU
+ * Lesser General Public License as published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License for more details.
+ */
+
+/**
+ * The AcceptHeader page will parse and sort the different
+ * allowed types for the content negociations
+ *
+ * @author Pierrick Charron <pierrick@webstart.fr>
+ */
+class AcceptHeader extends \ArrayObject
+{
+    /**
+     * Constructor
+     *
+     * @param string $header Value of the Accept header
+     * @return void
+     */
+    public function __construct($header)
+    {
+        $acceptedTypes = $this->_parse($header);
+        usort($acceptedTypes, [$this, '_compare']);
+        parent::__construct($acceptedTypes);
+    }
+
+    /**
+     * Parse the accept header and return an array containing
+     * all the informations about the Accepted types
+     *
+     * @param string $header Value of the Accept header
+     * @return array
+     */
+    private function _parse($data)
+    {
+        $array = [];
+        $items = explode(',', $data);
+        foreach ($items as $item) {
+            $elems = explode(';', $item);
+
+            $acceptElement = [];
+            $mime = current($elems);
+            list($type, $subtype) = explode('/', $mime);
+            $acceptElement['type'] = trim($type);
+            $acceptElement['subtype'] = trim($subtype);
+            $acceptElement['raw'] = $mime;
+
+            $acceptElement['params'] = [];
+            while (next($elems)) {
+                list($name, $value) = explode('=', current($elems));
+                $acceptElement['params'][trim($name)] = trim($value);
+            }
+
+            $array[] = $acceptElement;
+        }
+        return $array;
+    }
+
+    /**
+     * Compare two Accepted types with their parameters to know
+     * if one media type should be used instead of an other
+     *
+     * @param array $a The first media type and its parameters
+     * @param array $b The second media type and its parameters
+     * @return int
+     */
+    private function _compare($a, $b)
+    {
+        $a_q = isset($a['params']['q']) ? floatval($a['params']['q']) : 1.0;
+        $b_q = isset($b['params']['q']) ? floatval($b['params']['q']) : 1.0;
+        if ($a_q === $b_q) {
+            $a_count = count($a['params']);
+            $b_count = count($b['params']);
+            if ($a_count === $b_count) {
+                if ($r = $this->_compareSubType($a['subtype'], $b['subtype'])) {
+                    return $r;
+                } else {
+                    return $this->_compareSubType($a['type'], $b['type']);
+                }
+            } else {
+                return $a_count < $b_count;
+            }
+        } else {
+            return $a_q < $b_q;
+        }
+    }
+
+    /**
+     * Compare two subtypes
+     *
+     * @param string $a First subtype to compare
+     * @param string $b Second subtype to compare
+     * @return int
+     */
+    private function _compareSubType($a, $b)
+    {
+        if ($a === '*' && $b !== '*') {
+            return 1;
+        } elseif ($b === '*' && $a !== '*') {
+            return -1;
+        } else {
+            return 0;
+        }
+    }
+}
--- a/utils/Activitypub_activityverb2.php
+++ b/utils/Activitypub_activityverb2.php
@@ -0,0 +1,101 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * Utility class to hold a bunch of constant defining default verb types
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_activityverb2 extends Managed_DataObject
+{
+    const FULL_LIST =
+    [
+        'Accept'          => 'https://www.w3.org/ns/activitystreams#Accept',
+        'TentativeAccept' => 'https://www.w3.org/ns/activitystreams#TentativeAccept',
+        'Add'             => 'https://www.w3.org/ns/activitystreams#Add',
+        'Arrive'          => 'https://www.w3.org/ns/activitystreams#Arrive',
+        'Create'          => 'https://www.w3.org/ns/activitystreams#Create',
+        'Delete'          => 'https://www.w3.org/ns/activitystreams#Delete',
+        'Follow'          => 'https://www.w3.org/ns/activitystreams#Follow',
+        'Ignore'          => 'https://www.w3.org/ns/activitystreams#Ignore',
+        'Join'            => 'https://www.w3.org/ns/activitystreams#Join',
+        'Leave'           => 'https://www.w3.org/ns/activitystreams#Leave',
+        'Like'            => 'https://www.w3.org/ns/activitystreams#Like',
+        'Offer'           => 'https://www.w3.org/ns/activitystreams#Offer',
+        'Invite'          => 'https://www.w3.org/ns/activitystreams#Invite',
+        'Reject'          => 'https://www.w3.org/ns/activitystreams#Reject',
+        'TentativeReject' => 'https://www.w3.org/ns/activitystreams#TentativeReject',
+        'Remove'          => 'https://www.w3.org/ns/activitystreams#Remove',
+        'Undo'            => 'https://www.w3.org/ns/activitystreams#Undo',
+        'Update'          => 'https://www.w3.org/ns/activitystreams#Update',
+        'View'            => 'https://www.w3.org/ns/activitystreams#View',
+        'Listen'          => 'https://www.w3.org/ns/activitystreams#Listen',
+        'Read'            => 'https://www.w3.org/ns/activitystreams#Read',
+        'Move'            => 'https://www.w3.org/ns/activitystreams#Move',
+        'Travel'          => 'https://www.w3.org/ns/activitystreams#Travel',
+        'Announce'        => 'https://www.w3.org/ns/activitystreams#Announce',
+        'Block'           => 'https://www.w3.org/ns/activitystreams#Block',
+        'Flag'            => 'https://www.w3.org/ns/activitystreams#Flag',
+        'Dislike'         => 'https://www.w3.org/ns/activitystreams#Dislike',
+        'Question'        => 'https://www.w3.org/ns/activitystreams#Question'
+    ];
+
+    const KNOWN =
+    [
+        'Accept',
+        'Create',
+        'Delete',
+        'Follow',
+        'Like',
+        'Undo',
+        'Announce'
+    ];
+
+    /**
+     * Converts canonical into verb.
+     *
+     * @author GNU Social
+     * @param string $verb
+     * @return string
+     */
+    public static function canonical($verb)
+    {
+        $ns = 'https://www.w3.org/ns/activitystreams#';
+        if (substr($verb, 0, mb_strlen($ns)) == $ns) {
+            return substr($verb, mb_strlen($ns));
+        } else {
+            return $verb;
+        }
+    }
+}
--- a/utils/discoveryhints.php
+++ b/utils/discoveryhints.php
@@ -0,0 +1,157 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * Some utilities for generating hint data
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    GNUsocial
+ * @copyright 2010 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+class DiscoveryHints
+{
+    public static function fromXRD(XML_XRD $xrd)
+    {
+        $hints = [];
+
+        if (Event::handle('StartDiscoveryHintsFromXRD', [$xrd, &$hints])) {
+            foreach ($xrd->links as $link) {
+                switch ($link->rel) {
+                case WebFingerResource_Profile::PROFILEPAGE:
+                    $hints['profileurl'] = $link->href;
+                    break;
+                    $hints['salmon'] = $link->href;
+                    break;
+                case Discovery::UPDATESFROM:
+                    if (empty($link->type) || $link->type == 'application/atom+xml') {
+                        $hints['feedurl'] = $link->href;
+                    }
+                    break;
+                case Discovery::HCARD:
+                case Discovery::MF2_HCARD:
+                    $hints['hcard'] = $link->href;
+                    break;
+                default:
+                    break;
+                }
+            }
+            Event::handle('EndDiscoveryHintsFromXRD', [$xrd, &$hints]);
+        }
+
+        return $hints;
+    }
+
+    public static function fromHcardUrl($url)
+    {
+        $client = new HTTPClient();
+        $client->setHeader('Accept', 'text/html,application/xhtml+xml');
+        try {
+            $response = $client->get($url);
+
+            if (!$response->isOk()) {
+                return null;
+            }
+        } catch (HTTP_Request2_Exception $e) {
+            // Any HTTPClient error that might've been thrown
+            common_log(LOG_ERR, __METHOD__ . ':'.$e->getMessage());
+            return null;
+        }
+
+        return self::hcardHints(
+            $response->getBody(),
+                                $response->getEffectiveUrl()
+        );
+    }
+
+    public static function hcardHints($body, $url)
+    {
+        $hcard = self::_hcard($body, $url);
+
+        if (empty($hcard)) {
+            return [];
+        }
+
+        $hints = [];
+
+        // XXX: don't copy stuff into an array and then copy it again
+
+        if (array_key_exists('nickname', $hcard) && !empty($hcard['nickname'][0])) {
+            $hints['nickname'] = $hcard['nickname'][0];
+        }
+
+        if (array_key_exists('name', $hcard) && !empty($hcard['name'][0])) {
+            $hints['fullname'] = $hcard['name'][0];
+        }
+
+        if (array_key_exists('photo', $hcard) && count($hcard['photo'])) {
+            $hints['avatar'] = $hcard['photo'][0];
+        }
+
+        if (array_key_exists('note', $hcard) && !empty($hcard['note'][0])) {
+            $hints['bio'] = $hcard['note'][0];
+        }
+
+        if (array_key_exists('adr', $hcard) && !empty($hcard['adr'][0])) {
+            $hints['location'] = $hcard['adr'][0]['value'];
+        }
+
+        if (array_key_exists('url', $hcard) && !empty($hcard['url'][0])) {
+            $hints['homepage'] = $hcard['url'][0];
+        }
+
+        return $hints;
+    }
+
+    public static function _hcard($body, $url)
+    {
+        $mf2 = new Mf2\Parser($body, $url);
+        $mf2 = $mf2->parse();
+
+        if (empty($mf2['items'])) {
+            return null;
+        }
+
+        $hcards = [];
+
+        foreach ($mf2['items'] as $item) {
+            if (!in_array('h-card', $item['type'])) {
+                continue;
+            }
+
+            // We found a match, return it immediately
+            if (isset($item['properties']['url']) && in_array($url, $item['properties']['url'])) {
+                return $item['properties'];
+            }
+
+            // Let's keep all the hcards for later, to return one of them at least
+            $hcards[] = $item['properties'];
+        }
+
+        // No match immediately for the url we expected, but there were h-cards found
+        if (count($hcards) > 0) {
+            return $hcards[0];
+        }
+
+        return null;
+    }
+}
--- a/utils/explorer.php
+++ b/utils/explorer.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -32,7 +31,7 @@ if (!defined ('GNUSOCIAL')) {
 /**
 * ActivityPub's own Explorer
 *
- * Allows to discovery new (or the same) ActivityPub profiles
+ * Allows to discovery new (or the same) Profiles (both local or remote)
 *
 * @category  Plugin
 * @package   GNUsocial
@@ -42,19 +41,44 @@ if (!defined ('GNUSOCIAL')) {
 */
 class Activitypub_explorer
 {
-        private $discovered_actor_profiles = array ();
+    private $discovered_actor_profiles = [];
+
+    /**
+     * Shortcut function to get a single profile from its URL.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $url
+     * @return Profile
+     * @throws Exception
+     */
+    public static function get_profile_from_url($url)
+    {
+        $discovery = new Activitypub_explorer;
+        // Get valid Actor object
+        $actor_profile = $discovery->lookup($url);
+        if (!empty($actor_profile)) {
+            return $actor_profile[0];
+        }
+        throw new Exception('Invalid Actor.');
+    }

    /**
     * Get every profile from the given URL
     * This function cleans the $this->discovered_actor_profiles array
     * so that there is no erroneous data
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param string $url User's url
     * @return array of Profile objects
     */
    public function lookup($url)
    {
-                $this->discovered_actor_profiles = array ();
+        if (in_array($url, ACTIVITYPUB_PUBLIC_TO)) {
+            return [];
+        }
+
+        common_debug('ActivityPub Explorer: Started now looking for '.$url);
+        $this->discovered_actor_profiles = [];

        return $this->_lookup($url);
    }
@@ -64,6 +88,7 @@ class Activitypub_explorer
     * This is a recursive function that will accumulate the results on
     * $discovered_actor_profiles array
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param string $url User's url
     * @return array of Profile objects
     */
@@ -72,43 +97,96 @@ class Activitypub_explorer
        // First check if we already have it locally and, if so, return it
        // If the local fetch fails: grab it remotely, store locally and return
        if (! ($this->grab_local_user($url) || $this->grab_remote_user($url))) {
-                    throw new Exception ("User not found");
+            throw new Exception('User not found.');
        }

-
        return $this->discovered_actor_profiles;
    }

    /**
-         * Get a local user profiles from its URL and joins it on
-         * $this->discovered_actor_profiles
+     * This ensures that we are using a valid ActivityPub URI
     *
-         * @param string $url User's url
-         * @return boolean success state
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $url
+     * @return boolean success state (related to the response)
+     * @throws Exception (If the HTTP request fails)
     */
-        private function grab_local_user ($url)
+    private function ensure_proper_remote_uri($url)
    {
-                if (($actor_profile = self::get_profile_by_url ($url)) != false) {
-                        $this->discovered_actor_profiles[]= $actor_profile;
+        $client    = new HTTPClient();
+        $headers   = [];
+        $headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
+        $headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
+        $response  = $client->get($url, $headers);
+        $res = json_decode($response->getBody(), true);
+        if (self::validate_remote_response($res)) {
+            $this->temp_res = $res;
            return true;
        } else {
-                        /******************************** XXX: ********************************
-                         * Sometimes it is not true that the user is not locally available,   *
-                         * mostly when it is a local user and URLs slightly changed           *
-                         * e.g.: GS instance owner changed from standard urls to pretty urls  *
-                         * (not sure if this is necessary, but anyway)                        *
-                         **********************************************************************/
+            common_debug('ActivityPub Explorer: Invalid potential remote actor while ensuring URI: '.$url. '. He returned the following: '.json_encode($res, JSON_UNESCAPED_SLASHES));
+        }

-                        // Iff we really are in the same instance
-                        $root_url_len = strlen (common_root_url ());
-                        if (substr ($url, 0, $root_url_len) == common_root_url ()) {
-                                // Grab the nickname and try to get the user
-                                if (($actor_profile = Profile::getKV ("nickname", substr ($url, $root_url_len))) != false) {
-                                        $this->discovered_actor_profiles[]= $actor_profile;
+        return false;
+    }
+
+    /**
+     * Get a local user profile from its URL and joins it on
+     * $this->discovered_actor_profiles
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $uri Actor's uri
+     * @return boolean success state
+     */
+    private function grab_local_user($uri, $online = false)
+    {
+        if ($online) {
+            common_debug('ActivityPub Explorer: Searching locally for '.$uri. ' with online resources.');
+        } else {
+            common_debug('ActivityPub Explorer: Searching locally for '.$uri. ' offline.');
+        }
+        // Ensure proper remote URI
+        // If an exception occurs here it's better to just leave everything
+        // break than to continue processing
+        if ($online && $this->ensure_proper_remote_uri($uri)) {
+            $uri = $this->temp_res["id"];
+        }
+
+        // Try standard ActivityPub route
+        // Is this a known filthy little mudblood?
+        $aprofile = self::get_aprofile_by_url($uri);
+        if ($aprofile instanceof Activitypub_profile) {
+            $profile = $aprofile->local_profile();
+            common_debug('ActivityPub Explorer: Found a local Aprofile for '.$uri);
+            // We found something!
+            $this->discovered_actor_profiles[]= $profile;
+            unset($this->temp_res); // IMPORTANT to avoid _dangerous_ noise in the Explorer system
            return true;
+        } else {
+            common_debug('ActivityPub Explorer: Unable to find a local Aprofile for '.$uri.' - looking for a Profile instead.');
+            // Well, maybe it is a pure blood?
+            // Iff, we are in the same instance:
+            $ACTIVITYPUB_BASE_ACTOR_URI_length = strlen(ACTIVITYPUB_BASE_ACTOR_URI);
+            if (substr($uri, 0, $ACTIVITYPUB_BASE_ACTOR_URI_length) == ACTIVITYPUB_BASE_ACTOR_URI) {
+                try {
+                    $profile = Profile::getByID(intval(substr($uri, $ACTIVITYPUB_BASE_ACTOR_URI_length)));
+                    common_debug('ActivityPub Explorer: Found a Profile for '.$uri);
+                    // We found something!
+                    $this->discovered_actor_profiles[]= $profile;
+                    unset($this->temp_res); // IMPORTANT to avoid _dangerous_ noise in the Explorer system
+                    return true;
+                } catch (Exception $e) {
+                    // Let the exception go on its merry way.
+                    common_debug('ActivityPub Explorer: Unable to find a Profile for '.$uri);
                }
            }
        }
+
+        // If offline grabbing failed, attempt again with online resources
+        if (!$online) {
+            common_debug('ActivityPub Explorer: Will try everything again with online resources against: '.$uri);
+            return $this->grab_local_user($uri, true);
+        }
+
        return false;
    }

@@ -116,70 +194,157 @@ class Activitypub_explorer
     * Get a remote user(s) profile(s) from its URL and joins it on
     * $this->discovered_actor_profiles
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param string $url User's url
     * @return boolean success state
     */
    private function grab_remote_user($url)
    {
+        common_debug('ActivityPub Explorer: Trying to grab a remote actor for '.$url);
+        if (!isset($this->temp_res)) {
            $client    = new HTTPClient();
-                $headers   = array();
+            $headers   = [];
            $headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
            $headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
            $response  = $client->get($url, $headers);
-                if (!$response->isOk ()) {
-                    throw new Exception ("Invalid Actor URL.");
-                }
-                $res = json_decode ($response->getBody (), JSON_UNESCAPED_SLASHES);
-                if (isset ($res["orderedItems"])) { // It's a potential collection of actors!!!
-                        foreach ($res["orderedItems"] as $profile) {
-                                if ($this->_lookup ($profile) == false) {
-                                        // XXX: Invalid actor found, not sure how we handle those
-                                }
-                        }
-                        // Go through entire collection
-                        if (!is_null ($res["next"])) {
-                                $this->_lookup ($res["next"]);
+            $res = json_decode($response->getBody(), true);
+        } else {
+            $res = $this->temp_res;
+            unset($this->temp_res);
        }
+        if (isset($res['type']) && $res['type'] === 'OrderedCollection' && isset($res['first'])) { // It's a potential collection of actors!!!
+            common_debug('ActivityPub Explorer: Found a collection of actors for '.$url);
+            $this->travel_collection($res['first']);
            return true;
-                } else if ($this->validate_remote_response ($res)) {
+        } elseif (self::validate_remote_response($res)) {
+            common_debug('ActivityPub Explorer: Found a valid remote actor for '.$url);
            $this->discovered_actor_profiles[]= $this->store_profile($res);
            return true;
+        } else {
+            common_debug('ActivityPub Explorer: Invalid potential remote actor while grabbing remotely: '.$url. '. He returned the following: '.json_encode($res, JSON_UNESCAPED_SLASHES));
        }

+        // TODO: Fallback to OStatus
        return false;
    }

    /**
     * Save remote user profile in local instance
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param array $res remote response
     * @return Profile remote Profile object
     */
    private function store_profile($res)
    {
+        // ActivityPub Profile
        $aprofile                 = new Activitypub_profile;
-                $aprofile->uri            = $res["url"];
-                $aprofile->nickname       = $res["nickname"];
-                $aprofile->fullname       = $res["display_name"];
-                $aprofile->bio            = substr ($res["summary"], 0, 1000);
-                $aprofile->inboxuri       = $res["inbox"];
-                $aprofile->sharedInboxuri = $res["sharedInbox"];
+        $aprofile->uri            = $res['id'];
+        $aprofile->nickname       = $res['preferredUsername'];
+        $aprofile->fullname       = isset($res['name']) ? $res['name'] : null;
+        $aprofile->bio            = isset($res['summary']) ? substr(strip_tags($res['summary']), 0, 1000) : null;
+        $aprofile->inboxuri       = $res['inbox'];
+        $aprofile->sharedInboxuri = isset($res['endpoints']['sharedInbox']) ? $res['endpoints']['sharedInbox'] : $res['inbox'];

-                $aprofile->doInsert ();
+        $aprofile->do_insert();
+        $profile = $aprofile->local_profile();

-                return $aprofile->localProfile ();
+        // Public Key
+        $apRSA = new Activitypub_rsa();
+        $apRSA->profile_id = $profile->getID();
+        $apRSA->public_key = $res['publicKey']['publicKeyPem'];
+        $apRSA->store_keys();
+
+        // Avatar
+        if (isset($res['icon']['url'])) {
+            try {
+                $this->update_avatar($profile, $res['icon']['url']);
+            } catch (Exception $e) {
+                // Let the exception go, it isn't a serious issue
+                common_debug('ActivityPub Explorer: An error ocurred while grabbing remote avatar: '.$e->getMessage());
+            }
+        }
+
+        return $profile;
+    }
+
+    /**
+     * Download and update given avatar image
+     *
+     * @author GNU Social
+     * @param  Profile $profile
+     * @param  string $url
+     * @return Avatar    The Avatar we have on disk.
+     * @throws Exception in various failure cases
+     */
+    public static function update_avatar(Profile $profile, $url)
+    {
+        common_debug('ActivityPub Explorer: Started grabbing remote avatar from: '.$url);
+        if (!filter_var($url, FILTER_VALIDATE_URL)) {
+            // TRANS: Server exception. %s is a URL.
+            common_debug('ActivityPub Explorer: Failed because it is an invalid url: '.$url);
+            throw new ServerException(sprintf('Invalid avatar URL %s.'), $url);
+        }
+
+        // @todo FIXME: This should be better encapsulated
+        // ripped from oauthstore.php (for old OMB client)
+        $temp_filename = tempnam(sys_get_temp_dir(), 'listener_avatar');
+        try {
+            $imgData = HTTPClient::quickGet($url);
+            // Make sure it's at least an image file. ImageFile can do the rest.
+            if (false === getimagesizefromstring($imgData)) {
+                common_debug('ActivityPub Explorer: Failed because the downloaded avatar: '.$url. 'is not a valid image.');
+                throw new UnsupportedMediaException('Downloaded avatar was not an image.');
+            }
+            file_put_contents($temp_filename, $imgData);
+            unset($imgData);    // No need to carry this in memory.
+            common_debug('ActivityPub Explorer: Stored dowloaded avatar in: '.$temp_filename);
+
+            $id = $profile->getID();
+
+            $imagefile = new ImageFile(null, $temp_filename);
+            $filename = Avatar::filename(
+                $id,
+                image_type_to_extension($imagefile->type),
+                null,
+                common_timestamp()
+            );
+            rename($temp_filename, Avatar::path($filename));
+            common_debug('ActivityPub Explorer: Moved avatar from: '.$temp_filename.' to '.$filename);
+        } catch (Exception $e) {
+            common_debug('ActivityPub Explorer: Something went wrong while processing the avatar from: '.$url.' details: '.$e->getMessage());
+            unlink($temp_filename);
+            throw $e;
+        }
+        // @todo FIXME: Hardcoded chmod is lame, but seems to be necessary to
+        // keep from accidentally saving images from command-line (queues)
+        // that can't be read from web server, which causes hard-to-notice
+        // problems later on:
+        //
+        // http://status.net/open-source/issues/2663
+        chmod(Avatar::path($filename), 0644);
+
+        $profile->setOriginal($filename);
+
+        $orig = clone($profile);
+        $profile->avatar = $url;
+        $profile->update($orig);
+
+        common_debug('ActivityPub Explorer: Seted Avatar from: '.$url.' to profile.');
+        return Avatar::getUploaded($profile);
    }

    /**
     * Validates a remote response in order to determine whether this
     * response is a valid profile or not
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param array $res remote response
     * @return boolean success state
     */
-        private function validate_remote_response ($res)
+    public static function validate_remote_response($res)
    {
-                if (!isset ($res["url"], $res["nickname"], $res["display_name"], $res["summary"], $res["inbox"], $res["sharedInbox"])) {
+        if (!isset($res['id'], $res['preferredUsername'], $res['inbox'], $res['publicKey']['publicKeyPem'])) {
            return false;
        }

@@ -187,20 +352,21 @@ class Activitypub_explorer
    }

    /**
-         * Get a profile from it's profileurl
+     * Get a ActivityPub Profile from it's uri
     * Unfortunately GNU Social cache is not truly reliable when handling
     * potential ActivityPub remote profiles, as so it is important to use
     * this hacky workaround (at least for now)
     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     * @param string $v URL
-         * @return boolean|Profile false if fails | Profile object if successful
+     * @return boolean|Activitypub_profile false if fails | Aprofile object if successful
     */
-        static function get_profile_by_url ($v)
+    public static function get_aprofile_by_url($v)
    {
-                $i = Managed_DataObject::getcached(Profile, "profileurl", $v);
+        $i = Managed_DataObject::getcached("Activitypub_profile", "uri", $v);
        if (empty($i)) { // false = cache miss
-                        $i = new Profile;
-                        $result = $i->get ("profileurl", $v);
+            $i = new Activitypub_profile;
+            $result = $i->get("uri", $v);
            if ($result) {
                // Hit!
                $i->encache();
@@ -210,4 +376,89 @@ class Activitypub_explorer
        }
        return $i;
    }
+
+    /**
+     * Given a valid actor profile url returns its inboxes
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $url of Actor profile
+     * @return boolean|array false if fails | array with inbox and shared inbox if successful
+     */
+    public static function get_actor_inboxes_uri($url)
+    {
+        $client    = new HTTPClient();
+        $headers   = [];
+        $headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
+        $headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
+        $response  = $client->get($url, $headers);
+        if (!$response->isOk()) {
+            throw new Exception('Invalid Actor URL.');
+        }
+        $res = json_decode($response->getBody(), true);
+        if (self::validate_remote_response($res)) {
+            return [
+                'inbox' => $res['inbox'],
+                'sharedInbox' => isset($res['endpoints']['sharedInbox']) ? $res['endpoints']['sharedInbox'] : $res['inbox']
+            ];
+        }
+
+        return false;
+    }
+
+    /**
+     * Allows the Explorer to transverse a collection of persons.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param type $url
+     * @return boolean
+     */
+    private function travel_collection($url)
+    {
+        $client    = new HTTPClient();
+        $headers   = [];
+        $headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
+        $headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
+        $response  = $client->get($url, $headers);
+        $res = json_decode($response->getBody(), true);
+
+        if (!isset($res['orderedItems'])) {
+            return false;
+        }
+
+        foreach ($res["orderedItems"] as $profile) {
+            if ($this->_lookup($profile) == false) {
+                common_debug('ActivityPub Explorer: Found an invalid actor for '.$profile);
+                // TODO: Invalid actor found, fallback to OStatus
+            }
+        }
+        // Go through entire collection
+        if (!is_null($res["next"])) {
+            $this->_lookup($res["next"]);
+        }
+
+        return true;
+    }
+
+    /**
+     * Get a remote user array from its URL (this function is only used for
+     * profile updating and shall not be used for anything else)
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $url User's url
+     * @throws Exception
+     */
+    public static function get_remote_user_activity($url)
+    {
+        $client    = new HTTPClient();
+        $headers   = [];
+        $headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
+        $headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
+        $response  = $client->get($url, $headers);
+        $res = json_decode($response->getBody(), true);
+        if (Activitypub_explorer::validate_remote_response($res)) {
+            common_debug('ActivityPub Explorer: Found a valid remote actor for '.$url);
+            return $res;
+        }
+        throw new Exception('ActivityPub Explorer: Failed to get activity.');
+    }
 }
--- a/utils/http-signature-auth.php
+++ b/utils/http-signature-auth.php
@@ -0,0 +1,348 @@
+<?php
+/*
+ * Copyright (c) 2014 David Gwynne <david@gwynne.id.au>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+class HttpSignatureError extends Exception { };
+class ExpiredRequestError extends HttpSignatureError { };
+class InvalidHeaderError extends HttpSignatureError { };
+class InvalidParamsError extends HttpSignatureError { };
+class MissingHeaderError extends HttpSignatureError { };
+class InvalidAlgorithmError extends HttpSignatureError { };
+
+class HTTPSignature {
+
+	static function parse(array $headers, array $options = array())
+	{
+		if (!array_key_exists('signature', $headers)) {
+			throw new MissingHeaderError('no signature header in the request');
+		}
+		$auth = 'Signature '.$headers['signature'];
+
+		if (!array_key_exists('headers', $options)) {
+			$options['headers'] = array(isset($headers['x-date']) ? 'x-date' : 'date');
+		} else {
+			if (!is_array($options['headers'])) {
+				throw new Exception('headers option is not an array');
+			}
+			if (sizeof(array_filter($options['headers'], function ($a) { return (!is_string($a)); }))) {
+				throw new Exception('headers option is not an array of strings');
+			}
+		}
+
+		if (!array_key_exists('clockSkew', $options)) {
+			$options['clockSkew'] = 300;
+		} elseif (!is_numeric($options['clockSkew'])) {
+			throw new Exception('clockSkew option is not numeric');
+		}
+
+		if (array_key_exists('algorithms', $options)) {
+			if (!is_array($options['algorithms'])) {
+				throw new Exception('algorithms option is not an array');
+			}
+			if (sizeof(array_filter($options['algorithms'], function ($a) { return (!is_string($a)); }))) {
+				throw new Exception('algorithms option is not an array of strings');
+			}
+		}
+
+		$headers['request-line'] = array_key_exists('requestLine', $options) ?
+		    $options['requestLine'] :
+		    sprintf("%s %s %s", $_SERVER['REQUEST_METHOD'], $_SERVER['REQUEST_URI'], $_SERVER['SERVER_PROTOCOL']);
+
+		foreach ($options['headers'] as $header) {
+			if (!array_key_exists($header, $headers)) {
+				throw new MissingHeaderError("$header was not in the request");
+			}
+		}
+
+		$states = array(
+			'start' => 0,
+			'scheme' => 1,
+			'space' => 2,
+			'param' => 3,
+			'quote' => 4,
+			'value' => 5,
+			'comma' => 6
+		);
+
+		$scheme = '';
+		$params = array();
+
+		$param = '';
+		$value = '';
+		$state = $states['start'];
+
+		for ($i = 0; $i < strlen($auth); $i++) {
+			$ch = $auth[$i];
+
+			switch ($state) {
+			case $states['start']:
+				if (ctype_space($ch)) {
+					break;
+				}
+
+				$state = $states['scheme'];
+				/* FALLTHROUGH */
+			case $states['scheme']:
+				if (ctype_space($ch)) {
+					$state = $states['space'];
+				} else {
+					$scheme .= $ch;
+				}
+
+				break;
+
+			case $states['space'];
+				if (ctype_space($ch)) {
+					continue;
+				}
+
+				$state = $states['param'];
+				/* FALLTHROUGH */
+			case $states['param']:
+				if ($ch === '=') {
+					if ($param === '') {
+						throw new InvalidHeaderError('bad param name');
+					}
+					if (array_key_exists($param, $params)) {
+						throw new InvalidHeaderError('param specified again');
+					}
+
+					$state = $states['quote'];
+					break;
+				}
+				if (!ctype_alpha($ch)) {
+					throw new InvalidHeaderError('bad param format');
+				}
+
+				$param .= $ch;
+				break;
+
+			case $states['quote'];
+				if ($ch !== '"') {
+					throw new InvalidHeaderError('bad param format');
+				}
+				$state = $states['value'];
+				break;
+
+			case $states['value']:
+				if ($ch === '"') {
+					$params[$param] = $value;
+					$param = '';
+					$value = '';
+
+					$state = $states['comma'];
+					break;
+				}
+
+				$value .= $ch;
+				break;
+
+			case $states['comma']:
+				if ($ch !== ',') {
+					throw new InvalidHeaderError('bad param format');
+				}
+
+				$state = $states['param'];
+				break;
+
+			default:
+				throw new Error('invalid state');
+			}
+		}
+
+		if ($state !== $states['comma']) {
+			throw new InvalidHeaderError("bad param format");
+		}
+
+		if ($scheme !== 'Signature') {
+			throw new InvalidHeaderError('scheme was not "Signature"');
+		}
+		$required = array('keyId', 'algorithm', 'signature');
+		foreach ($required as $param) {
+			if (!array_key_exists($param, $params)) {
+				throw new InvalidHeaderError("$param was not specified");
+			}
+		}
+
+		if (array_key_exists('headers', $params)) {
+			$params['headers'] = explode(' ', $params['headers']);
+		} else {
+			$params['headers'] = array(isset($headers['x-date']) ? 'x-date' : 'date');
+		}
+
+		foreach ($options['headers'] as $header) {
+			if (!in_array($header, $params['headers'])) {
+				throw new MissingHeaderError("$header was not a signed header");
+			}
+		}
+
+		if (isset($options['algorithms']) && !in_array($params['algorithm'], $options['algorithms'])) {
+			throw new InvalidParamsError($params['algorithm'] . " is not a supported algorithm");
+		}
+
+		$date = null;
+		if (isset($headers['date'])) {
+			$date = strtotime($headers['date']);
+		} elseif (isset($headers['x-date'])) {
+			$date = strtotime($headers['x-date']);
+		}
+		if (!is_null($date)) {
+			if ($date === FALSE) {
+				throw new InvalidHeaderError('unable to parse date header');
+			}
+			$skew = abs(time() - $date);
+			if ($skew > $options['clockSkew']) {
+				throw new ExpiredRequestError(sprintf("clock skew of %ds was greater than %ds", $skew, $options['clockSkew']));
+			}
+		}
+
+		$sign = array();
+		foreach ($params['headers'] as $header) {
+			$sign[] = $header === 'request-line' ? $headers['request-line'] : sprintf("%s: %s", $header, $headers[$header]);
+		}
+
+		return (array('scheme' => $scheme, 'params' => $params, 'signingString' => implode("\n", $sign)));
+	}
+
+	static function verify(array $res, $key, $keytype)
+	{
+		if (!is_string($key)) {
+			throw new Exception('key is not a string');
+		}
+
+		$alg = explode('-', $res['params']['algorithm'], 2);
+		if (sizeof($alg) != 2) {
+			throw new InvalidAlgorithmError("unsupported algorithm");
+		}
+		if ($alg[0] != $keytype) {
+			throw new InvalidAlgorithmError("algorithm type doesn't match key type");
+		}
+		switch ($alg[0]) {
+		case 'rsa':
+			$map = array('sha1' => OPENSSL_ALGO_SHA1, 'sha256' => OPENSSL_ALGO_SHA256, 'sha512' => OPENSSL_ALGO_SHA512);
+			if (!array_key_exists($alg[1], $map)) {
+				throw new InvalidAlgorithmError('unsupported algorithm');
+			}
+			$pkey = openssl_get_publickey($key);
+			if ($pkey === FALSE) {
+				throw new Exception('key could not be parsed');
+			}
+
+			$rv = openssl_verify($res['signingString'], base64_decode($res['params']['signature']), $pkey, $map[$alg[1]]);
+			openssl_free_key($pkey);
+
+			switch ($rv) {
+			case 0:
+				return (FALSE);
+			case 1:
+				return (TRUE);
+			default:
+				throw new Exception('key could not be verified');
+			}
+			break;
+
+		case 'hmac':
+			return (hash_hmac($alg[1], $res['signingString'], $key, true) === base64_decode($res['params']['signature']));
+			break;
+		default:
+			throw new InvalidAlgorithmError("unsupported algorithm");
+		}
+	}
+
+	static function sign(&$headers = array(), array $options = array())
+	{
+		if (is_null($headers)) {
+			$headers = array();
+		} elseif (!is_array($headers)) {
+			throw new Exception('headers are not an array');
+		}
+
+		if (!array_key_exists('keyId', $options)) {
+			throw new Exception('keyId option is missing');
+		} elseif (!is_string($options['keyId'])) {
+			throw new Exception('keyId option is not a string');
+		}
+		if (!array_key_exists('key', $options)) {
+			throw new Exception('key option is missing');
+		} elseif (!is_string($options['key'])) {
+			throw new Exception('key option is not a string');
+		}
+
+		if (!array_key_exists('headers', $options)) {
+			$options['headers'] = array('date');
+		} else {
+			if (!is_array($options['headers'])) {
+				throw new Exception('headers option is not an array');
+			}
+			if (sizeof(array_filter($options['headers'], function ($a) { return (!is_string($a)); }))) {
+				throw new Exception('headers option is not an array of strings');
+			}
+		}
+
+		if (!array_key_exists('algorithm', $options)) {
+			$options['algorithm'] = 'rsa-sha256';
+		}
+
+		if (!array_key_exists('date', $headers)) {
+			$headers['date'] = date(DATE_RFC1123);
+		}
+
+		$headers['request-line'] = array_key_exists('requestLine', $options) ?
+		    $options['requestLine'] :
+		    sprintf("%s %s %s", $_SERVER['REQUEST_METHOD'], $_SERVER['REQUEST_URI'], $_SERVER['SERVER_PROTOCOL']);
+
+		$sign = array();
+		foreach ($options['headers'] as $header) {
+			if (!array_key_exists($header, $headers)) {
+				throw new MissingHeaderError("$header was not in the request");
+			}
+			$sign[] = $header === 'request-line' ? $headers['request-line'] : sprintf("%s: %s", $header, $headers[$header]);
+		}
+		$data = join("\n", $sign);
+
+		$alg = explode('-', $options['algorithm'], 2);
+		if (sizeof($alg) != 2) {
+			throw new InvalidAlgorithmError("unsupported algorithm");
+		}
+		switch ($alg[0]) {
+		case 'rsa':
+			$map = array('sha1' => OPENSSL_ALGO_SHA1, 'sha256' => OPENSSL_ALGO_SHA256, 'sha512' => OPENSSL_ALGO_SHA512);
+			if (!array_key_exists($alg[1], $map)) {
+				throw new InvalidAlgorithmError('unsupported algorithm');
+			}
+			$key = openssl_get_privatekey($options['key']);
+			if ($key === FALSE) {
+				error_log(openssl_error_string());
+				throw new Exception('key option could not be parsed');
+			}
+
+			if (openssl_sign($data, $signature, $key, $map[$alg[1]]) === FALSE) {
+				throw new Exception('unable to sign');
+			}
+			break;
+
+		case 'hmac':
+			$signature = hash_hmac($alg[1], $data, $options['key'], true);
+			break;
+		default:
+			throw new InvalidAlgorithmError("unsupported algorithm");
+		}
+		unset($headers['request-line']);
+		$headers['authorization'] = sprintf('Signature keyId="%s",algorithm="%s",headers="%s",signature="%s"',
+		    $options['keyId'], $options['algorithm'], implode(' ', $options['headers']),
+		    base64_encode($signature));
+	}
+}
--- a/utils/inbox_handler.php
+++ b/utils/inbox_handler.php
@@ -0,0 +1,300 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * ActivityPubPlugin implementation for GNU Social
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+if (!defined('GNUSOCIAL')) {
+    exit(1);
+}
+
+/**
+ * ActivityPub Inbox Handler
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://www.gnu.org/software/social/
+ */
+class Activitypub_inbox_handler
+{
+    private $activity;
+    private $actor;
+    private $object;
+
+    /**
+     * Create a Inbox Handler to receive something from someone.
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Array $activity Activity we are receiving
+     * @param Profile $actor_profile Actor originating the activity
+     */
+    public function __construct($activity, $actor_profile = null)
+    {
+        $this->activity = $activity;
+        $this->object = $activity['object'];
+
+        // Validate Activity
+        $this->validate_activity();
+
+        // Get Actor's Profile
+        if (!is_null($actor_profile)) {
+            $this->actor = $actor_profile;
+        } else {
+            $this->actor = ActivityPub_explorer::get_profile_from_url($this->activity['actor']);
+        }
+
+        // Handle the Activity
+        $this->process();
+    }
+
+    /**
+     * Validates if a given Activity is valid. Throws exception if not.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @throws Exception
+     */
+    private function validate_activity()
+    {
+        // Activity validation
+        // Validate data
+        if (!(isset($this->activity['type']))) {
+            throw new Exception('Activity Validation Failed: Type was not specified.');
+        }
+        if (!isset($this->activity['actor'])) {
+            throw new Exception('Activity Validation Failed: Actor was not specified.');
+        }
+        if (!isset($this->activity['object'])) {
+            throw new Exception('Activity Validation Failed: Object was not specified.');
+        }
+
+        // Object validation
+        switch ($this->activity['type']) {
+            case 'Accept':
+                Activitypub_accept::validate_object($this->object);
+                break;
+            case 'Create':
+                Activitypub_create::validate_object($this->object);
+                break;
+            case 'Delete':
+            case 'Follow':
+            case 'Like':
+            case 'Announce':
+                if (!filter_var($this->object, FILTER_VALIDATE_URL)) {
+                    throw new Exception('Object is not a valid Object URI for Activity.');
+                }
+                break;
+            case 'Undo':
+                Activitypub_undo::validate_object($this->object);
+                break;
+            default:
+                throw new Exception('Unknown Activity Type.');
+        }
+    }
+
+    /**
+     * Sends the Activity to proper handler in order to be processed.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     */
+    private function process()
+    {
+        switch ($this->activity['type']) {
+            case 'Accept':
+                $this->handle_accept($this->actor, $this->object);
+                break;
+            case 'Create':
+                $this->handle_create($this->actor, $this->object);
+                break;
+            case 'Delete':
+                $this->handle_delete($this->actor, $this->object);
+                break;
+            case 'Follow':
+                $this->handle_follow($this->actor, $this->object);
+                break;
+            case 'Like':
+                $this->handle_like($this->actor, $this->object);
+                break;
+            case 'Undo':
+                $this->handle_undo($this->actor, $this->object);
+                break;
+            case 'Announce':
+                $this->handle_announce($this->actor, $this->object);
+                break;
+        }
+    }
+
+    /**
+     * Handles an Accept Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_accept($actor, $object)
+    {
+        switch ($object['type']) {
+            case 'Follow':
+                $this->handle_accept_follow($actor, $object);
+                break;
+        }
+    }
+
+    /**
+     * Handles an Accept Follow Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_accept_follow($actor, $object)
+    {
+        // Get valid Object profile
+        $object_profile = new Activitypub_explorer;
+        $object_profile = $object_profile->lookup($object['object'])[0];
+
+        $pending_list = new Activitypub_pending_follow_requests($actor->getID(), $object_profile->getID());
+        $pending_list->remove();
+    }
+
+    /**
+     * Handles a Create Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_create($actor, $object)
+    {
+        switch ($object['type']) {
+            case 'Note':
+                Activitypub_notice::create_notice($object, $actor);
+                break;
+        }
+    }
+
+    /**
+     * Handles a Delete Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_delete($actor, $object)
+    {
+        $notice = ActivityPubPlugin::grab_notice_from_url($object['object']);
+        $notice->deleteAs($actor);
+    }
+
+    /**
+     * Handles a Follow Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_follow($actor, $object)
+    {
+        Activitypub_follow::follow($actor, $object);
+    }
+
+    /**
+     * Handles a Like Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_like($actor, $object)
+    {
+        $notice = ActivityPubPlugin::grab_notice_from_url($object);
+        Fave::addNew($actor, $notice);
+    }
+
+    /**
+     * Handles a Undo Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_undo($actor, $object)
+    {
+        switch ($object['type']) {
+            case 'Follow':
+                $this->handle_undo_follow($actor, $object['object']);
+                break;
+            case 'Like':
+                $this->handle_undo_like($actor, $object['object']);
+                break;
+        }
+    }
+
+    /**
+     * Handles a Undo Like Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_undo_like($actor, $object)
+    {
+        $notice = ActivityPubPlugin::grab_notice_from_url($object);
+        Fave::removeEntry($actor, $notice);
+    }
+
+    /**
+     * Handles a Undo Follow Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_undo_follow($actor, $object)
+    {
+        // Get Object profile
+        $object_profile = new Activitypub_explorer;
+        $object_profile = $object_profile->lookup($object)[0];
+
+        if (Subscription::exists($actor, $object_profile)) {
+            Subscription::cancel($actor, $object_profile);
+        // You are no longer following this person.
+        } else {
+            // 409: You are not following this person already.
+        }
+    }
+
+    /**
+     * Handles a Announce Activity received by our inbox.
+     *
+     * @author Diogo Cordeiro <diogo@fc.upt.pt>
+     * @param Profile $actor Actor
+     * @param Array $object Activity
+     */
+    private function handle_announce($actor, $object)
+    {
+        $object_notice = ActivityPubPlugin::grab_notice_from_url($object);
+        $object_notice->repeat($actor, 'ActivityPub');
+    }
+}
--- a/utils/postman.php
+++ b/utils/postman.php
@@ -20,7 +20,6 @@
 * @category  Plugin
 * @package   GNUsocial
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
- * @author    Daniel Supernault <danielsupernault@gmail.com>
 * @copyright 2018 Free Software Foundation http://fsf.org
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      https://www.gnu.org/software/social/
@@ -29,6 +28,10 @@ if (!defined ('GNUSOCIAL')) {
    exit(1);
 }

+use GuzzleHttp\Client;
+use HttpSignatures\Context;
+use HttpSignatures\GuzzleHttpSignatures;
+
 /**
 * ActivityPub's own Postman
 *
@@ -44,53 +47,276 @@ if (!defined ('GNUSOCIAL')) {
 class Activitypub_postman
 {
    private $actor;
-        private $to = array ();
+    private $actor_uri;
+    private $to = [];
    private $client;
    private $headers;

    /**
     * Create a postman to deliver something to someone
     *
-         * @param Activitypub_profile $to array of destinataries
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Profile $from Profile of sender
+     * @param Array of Activitypub_profile $to destinataries
     */
    public function __construct($from, $to)
    {
        $this->actor = $from;
+        $discovery = new Activitypub_explorer();
        $this->to = $to;
-                $this->headers = array();
-                $this->headers[] = 'Accept: application/ld+json; profile="https://www.w3.org/ns/activitystreams"';
-                $this->headers[] = 'User-Agent: GNUSocialBot v0.1 - https://gnu.io/social';
+        $followers = apActorFollowersAction::generate_followers($this->actor, 0, null);
+        foreach ($followers as $sub) {
+            try {
+                $to[]= Activitypub_profile::from_profile($discovery->lookup($sub)[0]);
+            } catch (Exception $e) {
+                // Not an ActivityPub Remote Follower, let it go
+            }
+        }
+        unset($discovery);
+
+        $this->actor_uri = ActivityPubPlugin::actor_uri($this->actor);
+
+        $actor_private_key = new Activitypub_rsa();
+        $actor_private_key = $actor_private_key->get_private_key($this->actor);
+
+        $context = new Context([
+            'keys' => [$this->actor_uri.'#public-key' => $actor_private_key],
+            'algorithm' => 'rsa-sha256',
+            'headers' => ['(request-target)', 'date', 'content-type', 'accept', 'user-agent'],
+        ]);
+
+        $this->headers = [
+            'content-type' => 'application/activity+json',
+            'accept'       => 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
+            'user-agent'   => 'GNUSocialBot v0.1 - https://gnu.io/social',
+            'date'         => gmdate('D, d M Y H:i:s \G\M\T', time())
+        ];
+
+        $handlerStack = GuzzleHttpSignatures::defaultHandlerFromContext($context);
+        $this->client = new Client(['handler' => $handlerStack]);
+    }
+
+    /**
+     * Send something to remote instance
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $data request body
+     * @param string $inbox url of remote inbox
+     * @param string $method request method
+     * @return Psr\Http\Message\ResponseInterface
+     */
+    public function send($data, $inbox, $method = 'POST')
+    {
+        common_debug('ActivityPub Postman: Delivering '.$data.' to '.$inbox);
+        $response = $this->client->request($method, $inbox, ['headers' => array_merge($this->headers, ['(request-target)' => strtolower($method).' '.parse_url($inbox, PHP_URL_PATH)]),'body' => $data]);
+        common_debug('ActivityPub Postman: Delivery result with status code '.$response->getStatusCode().': '.$response->getBody()->getContents());
+        return $response;
    }

    /**
     * Send a follow notification to remote instance
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @throws Exception
     */
    public function follow()
    {
-                $this->client = new HTTPClient ();
-                $data = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                          "type"   => "Follow",
-                          "actor"  => $this->actor->getUrl (),
-                          "object" => $this->to[0]->getUrl ());
-                $this->client->setBody (json_encode ($data));
-                $response = $this->client->post ($this->to[0]->getInbox (), $this->headers);
+        $data = Activitypub_follow::follow_to_array(ActivityPubPlugin::actor_uri($this->actor), $this->to[0]->getUrl());
+        $res = $this->send(json_encode($data, JSON_UNESCAPED_SLASHES), $this->to[0]->get_inbox());
+        $res_body = json_decode($res->getBody()->getContents());
+
+        if ($res->getStatusCode() == 200 || $res->getStatusCode() == 202 || $res->getStatusCode() == 409) {
+            $pending_list = new Activitypub_pending_follow_requests($this->actor->getID(), $this->to[0]->getID());
+            $pending_list->add();
+            return true;
+        } elseif (isset($res_body[0]->error)) {
+            throw new Exception($res_body[0]->error);
+        }
+
+        throw new Exception("An unknown error occurred.");
    }

    /**
     * Send a Undo Follow notification to remote instance
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
     */
    public function undo_follow()
    {
-                $this->client = new HTTPClient ();
-                $data = array ("@context" => "https://www.w3.org/ns/activitystreams",
-                            "type"   => "Undo",
-                            "actor"  => $this->actor->getUrl (),
-                            "object" => array (
-                                "type" => "Follow",
-                                "object" => $this->to[0]->getUrl ()
+        $data = Activitypub_undo::undo_to_array(
+                    Activitypub_follow::follow_to_array(
+                        ActivityPubPlugin::actor_uri($this->actor),
+                        $this->to[0]->getUrl()
                    )
                );
-                $this->client->setBody (json_encode ($data));
-                $response = $this->client->post ($this->to[0]->getInbox (), $this->headers);
+        $res = $this->send(json_encode($data, JSON_UNESCAPED_SLASHES), $this->to[0]->get_inbox());
+        $res_body = json_decode($res->getBody()->getContents());
+
+        if ($res->getStatusCode() == 200 || $res->getStatusCode() == 202 || $res->getStatusCode() == 409) {
+            $pending_list = new Activitypub_pending_follow_requests($this->actor->getID(), $this->to[0]->getID());
+            $pending_list->remove();
+            return true;
+        }
+        if (isset($res_body[0]->error)) {
+            throw new Exception($res_body[0]->error);
+        }
+        throw new Exception("An unknown error occurred.");
+    }
+
+    /**
+     * Send a Accept Follow notification to remote instance
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public function accept_follow()
+    {
+        $data = Activitypub_accept::accept_to_array(
+                    Activitypub_follow::follow_to_array(
+                       $this->to[0]->getUrl(),
+                       ActivityPubPlugin::actor_uri($this->actor)
+
+                    )
+               );
+        $res = $this->send(json_encode($data, JSON_UNESCAPED_SLASHES), $this->to[0]->get_inbox());
+        $res_body = json_decode($res->getBody()->getContents());
+
+        if ($res->getStatusCode() == 200 || $res->getStatusCode() == 202 || $res->getStatusCode() == 409) {
+            $pending_list = new Activitypub_pending_follow_requests($this->actor->getID(), $this->to[0]->getID());
+            $pending_list->remove();
+            return true;
+        }
+        if (isset($res_body[0]->error)) {
+            throw new Exception($res_body[0]->error);
+        }
+        throw new Exception("An unknown error occurred.");
+    }
+
+    /**
+     * Send a Like notification to remote instances holding the notice
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Notice $notice
+     */
+    public function like($notice)
+    {
+        $data = Activitypub_like::like_to_array(
+                    ActivityPubPlugin::actor_uri($this->actor),
+                    $notice->getUrl()
+                );
+        $data = json_encode($data, JSON_UNESCAPED_SLASHES);
+
+        foreach ($this->to_inbox() as $inbox) {
+            $this->send($data, $inbox);
+        }
+    }
+
+    /**
+     * Send a Undo Like notification to remote instances holding the notice
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Notice $notice
+     */
+    public function undo_like($notice)
+    {
+        $data = Activitypub_undo::undo_to_array(
+                         Activitypub_like::like_to_array(
+                             ActivityPubPlugin::actor_uri($this->actor),
+                            $notice->getUrl()
+                         )
+                );
+        $data = json_encode($data, JSON_UNESCAPED_SLASHES);
+
+        foreach ($this->to_inbox() as $inbox) {
+            $this->send($data, $inbox);
+        }
+    }
+
+    /**
+     * Send a Create notification to remote instances
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Notice $notice
+     */
+    public function create_note($notice)
+    {
+        $data = Activitypub_create::create_to_array(
+                    $this->actor_uri,
+                    Activitypub_notice::notice_to_array($notice)
+                );
+        $data = json_encode($data, JSON_UNESCAPED_SLASHES);
+
+        foreach ($this->to_inbox() as $inbox) {
+            $this->send($data, $inbox);
+        }
+    }
+
+    /**
+     * Send a Announce notification to remote instances
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Notice $notice
+     */
+    public function announce($notice)
+    {
+        $data = Activitypub_announce::announce_to_array(
+                         ActivityPubPlugin::actor_uri($this->actor),
+                         $notice->getUri()
+                        );
+        $data = json_encode($data, JSON_UNESCAPED_SLASHES);
+
+        foreach ($this->to_inbox() as $inbox) {
+            $this->send($data, $inbox);
+        }
+    }
+
+    /**
+     * Send a Delete notification to remote instances holding the notice
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Notice $notice
+     */
+    public function delete($notice)
+    {
+        $data = Activitypub_delete::delete_to_array(
+                    ActivityPubPlugin::actor_uri($notice->getProfile()),
+                    $notice->getUrl()
+                );
+        $errors = [];
+        $data = json_encode($data, JSON_UNESCAPED_SLASHES);
+        foreach ($this->to_inbox() as $inbox) {
+            $res = $this->send($data, $inbox);
+            if (!$res->getStatusCode() == 200) {
+                $res_body = json_decode($res->getBody()->getContents(), true);
+                if (isset($res_body[0]['error'])) {
+                    $errors[] = ($res_body[0]['error']);
+                    continue;
+                }
+                $errors[] = ("An unknown error occurred.");
+            }
+        }
+        if (!empty($errors)) {
+            throw new Exception(json_encode($errors));
+        }
+    }
+
+    /**
+     * Clean list of inboxes to deliver messages
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @return array To Inbox URLs
+     */
+    private function to_inbox()
+    {
+        $to_inboxes = [];
+        foreach ($this->to as $to_profile) {
+            $i = $to_profile->get_inbox();
+            // Prevent delivering to self
+            if ($i == [common_local_url('apInbox')]) {
+                continue;
+            }
+            $to_inboxes[] = $i;
+        }
+
+        return array_unique($to_inboxes);
    }
 }
Author	SHA1	Message	Date
Diogo Cordeiro	7f704f34fa	First draft of HTTP Signatures Inbox Validation	2018-08-07 04:31:50 +01:00
Diogo Cordeiro	6fbf37b7fe	Improve update_activitypub_profiles.php daemon Add sanity case to ensure public key method of rsa class	2018-08-07 03:55:32 +01:00
Diogo Cordeiro	b2f6f9f08e	Add first daemon, fix some minor issues and update licence headers	2018-08-07 03:10:31 +01:00
Diogo Cordeiro	935495415b	Don't break when notice grabber fails It's better to fragment the integrity of a note than to fail publishing a note	2018-08-06 19:57:28 +01:00
Diogo Cordeiro	334923e542	Make dummy function great again!	2018-08-06 18:51:36 +01:00
Diogo Cordeiro	76bea7b17e	Simplify some logic	2018-08-06 16:44:11 +01:00
Diogo Cordeiro	0475954741	A small step for AP, a jump to AP+OS	2018-08-06 16:29:47 +01:00
Diogo Cordeiro	ca8867c1c0	Make notes great again!	2018-08-06 08:35:48 +01:00
Diogo Cordeiro	fcbdf6aef2	OStatus plugin has the same error on line 1270	2018-08-06 08:19:08 +01:00
Diogo Cordeiro	f3ebbf472b	Merge branch 'ostatus' into 'dev' Beginning of OStatus support, various bug fixes See merge request dansup/ActivityPub!24	2018-08-06 07:10:37 +00:00
Diogo Cordeiro	287ebeb521	Beginning of OStatus support, various bug fixes	2018-08-06 08:09:25 +01:00
Diogo Cordeiro	edc62d4cb0	Go away LDS	2018-08-06 02:08:30 +01:00
Diogo Cordeiro	b9c76c2901	Fix some postman issues	2018-08-06 00:12:21 +01:00
Diogo Cordeiro	47b1f2219c	Let's respect mentions	2018-08-05 22:29:47 +01:00
Diogo Cordeiro	c10585da3f	Fix date in Postman header	2018-08-05 20:45:45 +01:00
Diogo Cordeiro	73d5fa79d7	just a bit more of consistency	2018-08-04 07:19:17 +01:00
Diogo Cordeiro	0c953142c4	Fix dumb mistake	2018-08-04 06:24:31 +01:00
Diogo Cordeiro	2bada457c2	Merge branch 'actor_outbox' into 'dev' Fix some issues from previous commit See merge request dansup/ActivityPub!19	2018-08-04 05:06:43 +00:00
Diogo Cordeiro	dca1d8f0c5	Fix some issues from previous commit	2018-08-04 06:05:41 +01:00
Diogo Cordeiro	7cf223fb24	Merge branch 'actor_outbox' into 'dev' Add a modern version of original Daniel's Outbox See merge request dansup/ActivityPub!18	2018-08-04 04:58:20 +00:00
Diogo Cordeiro	6a238e4176	Add a modern version of original Daniel's Outbox	2018-08-04 05:56:00 +01:00
Diogo Cordeiro	43ebdfa727	Inbox Reinvented	2018-08-04 04:11:17 +01:00
Diogo Cordeiro	de432cda88	Fix some issues	2018-08-03 18:47:20 +01:00
Diogo Cordeiro	442e66d112	Add Attachments to remote notices Fix Delete Notice	2018-08-03 05:24:21 +01:00
Diogo Cordeiro	f25d8278b1	Proper Accept Header Validation	2018-08-03 02:07:31 +01:00
Diogo Cordeiro	1f77983891	Do not return an error when attepting a repeated follow.	2018-08-03 00:50:48 +01:00
Diogo Cordeiro	2b98344bc4	Do not return an error message when attepting to create a repeated notice	2018-08-03 00:41:08 +01:00
Diogo Cordeiro	aa491271f7	Fixed various bugs, improved and refactored some stuff (remote avatars are working)	2018-08-02 18:10:32 +01:00
Diogo Cordeiro	cfc4eece38	fix issues	2018-08-02 07:36:28 +01:00
Diogo Cordeiro	7ce112471d	revert last nonsense changes and fix real issue	2018-08-02 07:33:22 +01:00
Diogo Cordeiro	6a608f08ed	improve debug and error controlling on explorer	2018-08-02 07:30:07 +01:00
Diogo Cordeiro	f38b6c482f	improve debug and error controlling on explorer	2018-08-02 07:28:04 +01:00
Diogo Cordeiro	aa49e97075	Fix typo	2018-08-02 07:17:04 +01:00
Diogo Cordeiro	554ba6dc91	Add debug info	2018-08-02 07:05:50 +01:00
Diogo Cordeiro	5226ca7d81	Proper ActivityPub collections	2018-08-02 07:01:39 +01:00
Diogo Cordeiro	0384890f7b	Some bug fixes for Avatar Grabber Replace Exceptions for I/O msg on remote notice validation	2018-08-02 05:54:27 +01:00
Diogo Cordeiro	5f979a32f9	Fix type	2018-08-02 05:05:47 +01:00
Diogo Cordeiro	0965ae459f	Fix json_decode	2018-08-02 05:00:35 +01:00
Diogo Cordeiro	e3086351e0	wrong argument	2018-08-02 04:24:10 +01:00
Diogo Cordeiro	956d5c9b7d	more debug info on inbox replies	2018-08-02 04:14:39 +01:00
Diogo Cordeiro	64dbb7b539	Go kill yourself isset	2018-08-02 04:02:58 +01:00
Diogo Cordeiro	c8f3f079cc	Bad parameter fixed	2018-08-02 03:55:15 +01:00
Diogo Cordeiro	8e80fb3528	Revert previous accidental commit	2018-08-02 02:43:15 +01:00
Diogo Cordeiro	5c9eac7d97	Wrong type	2018-08-02 02:41:01 +01:00
Diogo Cordeiro	0ae5b603ee	Add debug info to Notice Grabber	2018-08-02 02:34:08 +01:00
Diogo Cordeiro	1b1631b530	Redundant command removed	2018-08-02 02:16:45 +01:00
Diogo Cordeiro	a704053f6d	Fix notice author	2018-08-02 02:14:43 +01:00
Diogo Cordeiro	1d0d08544a	Fix typo	2018-08-02 02:08:15 +01:00
Diogo Cordeiro	51ebdcae30	Fix remote notice grabber Fixed bugs and simplified logic	2018-08-02 01:42:15 +01:00
Diogo Cordeiro	9f61de3c87	Add Remote Avatar	2018-08-01 21:24:36 +01:00
Diogo Cordeiro	12e5dc4b59	Fix some Inbox Create Bugs	2018-08-01 18:01:34 +01:00
Diogo Cordeiro	8b860d6da2	Proper ActivityPub Return Answers	2018-08-01 17:38:39 +01:00
Diogo Cordeiro	1f04b7ed40	Fix announce typo	2018-08-01 17:20:53 +01:00
Diogo Cordeiro	133066b9ac	Add Undo Announce entry point	2018-08-01 16:20:14 +01:00
Diogo Cordeiro	6e55a72179	Fix announce	2018-08-01 16:00:25 +01:00
Diogo Cordeiro	db3ce1e34a	Fix remote notices ids	2018-08-01 14:20:27 +01:00
Diogo Cordeiro	ec49aee44b	Wrong notice id on creation which is making AP Notice grabber fail	2018-08-01 03:58:47 +01:00
Diogo Cordeiro	30affa954f	Merge branch 'rendered_notices' into 'dev' some new federation related stuff See merge request dansup/ActivityPub!17	2018-08-01 01:09:48 +00:00
Diogo Cordeiro	d76ac3760b	Improve debug messages	2018-08-01 01:58:31 +01:00
Diogo Cordeiro	69b252b244	Proper Attentions	2018-08-01 01:50:27 +01:00
Diogo Cordeiro	42bfb78184	No XSS	2018-08-01 01:32:41 +01:00
Diogo Cordeiro	6943eee623	testing	2018-08-01 01:09:34 +01:00
Diogo Cordeiro	5c630c39a0	JSON_UNESCAPED_SLASHES on Postman	2018-08-01 00:59:31 +01:00
Diogo Cordeiro	aac82c7b2a	Add ID to Like and Undo	2018-08-01 00:50:31 +01:00
Diogo Cordeiro	83f5c513b4	Fix Inbox Undo Like	2018-08-01 00:46:33 +01:00
Diogo Cordeiro	5196edafa0	Proper Undo Like	2018-08-01 00:42:13 +01:00
Diogo Cordeiro	be1aadcd4c	Fix Likes on postman	2018-08-01 00:39:03 +01:00
Diogo Cordeiro	e4a65130f8	Fix Likes	2018-08-01 00:26:05 +01:00
Diogo Cordeiro	8f6c120620	Fix Accept ID	2018-08-01 00:10:35 +01:00
Diogo Cordeiro	a17e83582c	Fix typos on AP Accept class	2018-08-01 00:03:15 +01:00
Diogo Cordeiro	372a65b423	Fix typo	2018-07-31 23:56:43 +01:00
Diogo Cordeiro	f90b3773d1	Remove nonsense try..catch	2018-07-31 23:55:47 +01:00
Diogo Cordeiro	9c6aff46d9	Update inbox and fix Follow Accept bug	2018-07-31 23:51:39 +01:00
Diogo Cordeiro	b4880713d5	Fix Follow debug sequence	2018-07-31 23:35:15 +01:00
Diogo Cordeiro	edfd52e35f	Proper ActivityPub Accept	2018-07-31 23:28:27 +01:00
Diogo Cordeiro	80265024a7	Fix bugs	2018-07-31 23:11:44 +01:00
Diogo Cordeiro	3c021db5f0	patches for getBestSupportedMimeType	2018-07-31 23:02:32 +01:00
Diogo Cordeiro	9fddc0f606	Fix bugs	2018-07-31 22:47:20 +01:00
Diogo Cordeiro	dd5af79304	Very strange bug that I don't know how it got there	2018-07-31 22:41:40 +01:00
Diogo Cordeiro	c7a758b6c8	Fix issues from previous commit	2018-07-31 22:19:40 +01:00
Diogo Cordeiro	bb4bcd8ea1	Simplify Follow System Logic	2018-07-31 22:16:30 +01:00
Diogo Cordeiro	12b1fd7b1f	Add dummy id to follow	2018-07-31 21:42:17 +01:00
Diogo Cordeiro	5c26e34f5a	Add debug info to Inbox Follow	2018-07-31 21:03:55 +01:00
Diogo Cordeiro	aa196d383a	Add initial debug data for Actor Inbox	2018-07-31 20:58:06 +01:00
Diogo Cordeiro	b7ac51a967	Inbox proper response code for follow request	2018-07-31 20:55:24 +01:00
Diogo Cordeiro	933a228072	Analogous changes on Undo Follow	2018-07-31 20:34:03 +01:00
Diogo Cordeiro	b9a74d6ba4	Add missing case	2018-07-31 20:32:42 +01:00
Diogo Cordeiro	dd01971997	Revert some changes because mastodon folks know about 202	2018-07-31 20:31:28 +01:00
Diogo Cordeiro	3121d3435d	Improve postman debug message	2018-07-31 20:28:52 +01:00
Diogo Cordeiro	d90fabd15e	Fix Notice typo and follow request system	2018-07-31 20:25:47 +01:00
Diogo Cordeiro	f77bad0159	Add some initial debug information for shared inbox	2018-07-31 20:16:23 +01:00
Diogo Cordeiro	f8048c7565	First unstable federation release	2018-07-31 20:09:47 +01:00
Diogo Cordeiro	20738f48cd	Add location to notices (closes #44 )	2018-07-29 03:18:47 +01:00
Diogo Cordeiro	edb3633bcd	Proper AP Notices (fixed #46 ) Explorer now works both for local and remote URIs Fixed various serious errors (most of them in Explorer and some in AP Profiles)	2018-07-29 02:35:04 +01:00
Diogo Cordeiro	5c351efb06	Add ActivityPub Profile Test Fixed various serious issues while writing this test, namely database related.	2018-07-28 15:52:47 +01:00
Diogo Cordeiro	58262451e3	Forgot to remove this now useless function in a previous commit	2018-07-28 04:24:47 +01:00
dansup	995aec80c7	Merge branch 'http-signatures' into 'dev' Http signatures See merge request dansup/ActivityPub!16	2018-07-28 02:58:56 +00:00
dansup	5ee0fcbd9b	Http signatures	2018-07-28 02:58:56 +00:00
Diogo Cordeiro	4edd3ef398	Added Activitypub_RSA Fixed #35 and related serious issues We now have proper ActivityPub profiles	2018-07-28 02:18:30 +01:00
Diogo Cordeiro	01c16fcef0	Proper ActivityPub profiles	2018-07-27 21:45:43 +01:00
Diogo Cordeiro	e0d5b2ebd7	Remove ActivityPub Remote Subscribe since we should use OStatus for that after all	2018-07-27 19:23:33 +01:00
Ani	bff507bab8	Notice: Return Conversation URL instead of ID (#13 )	2018-07-27 16:43:58 +01:00
Diogo Cordeiro	78113620eb	Add activity+json mimetype to WebFinger Optimized Explorer so that it doesn't perform useless HTTP Requests	2018-07-27 16:43:53 +01:00
Diogo Cordeiro	eaad9423dd	Add Remote Flow (#43 ) and PHP Unit Tests from dansup (#37 ) Now the code is following most of PSR Various changes from various branches (some testing will be required) Fixed various issues	2018-07-26 23:08:32 +01:00
Diogo Cordeiro	e377b87ff7	Add Project's Coding Style	2018-07-22 23:41:08 +00:00
Diogo Cordeiro	b359c8206d	Start of a proper README.md Added CONTRIBUTING.md and COPYING	2018-07-22 23:02:50 +01:00
Diogo Cordeiro	30c073538c	Add webfinger integration, bug fixes and minor changes ( #21 ) Added author credits in every function so that we know who to bother when something goes wrong Refer to issues #34 and #35	2018-07-20 16:04:17 +01:00
Diogo Cordeiro	2d0f3de52a	Override the "from ActivityPub" and Profile URI for remote profiles.	2018-07-15 03:04:22 +01:00
Diogo Cordeiro	b693dab832	Add New notice and reblog delivery events, various bug fixes and improvements	2018-07-15 02:13:46 +01:00
Diogo Cordeiro	a5b56b3089	Add Delete delivery and some minor bug fixes	2018-07-14 01:18:31 +01:00
Diogo Cordeiro	2d4e634fad	Add Like delivery and some minor bug fixes	2018-07-14 00:13:28 +01:00