[ActivityPub] Move models from 'classes' to 'lib/models'

plugins/ActivityPub/lib/models/Activitypub_accept.php

@@ -0,0 +1,86 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_accept
+{
+    /**
+     * Generates an ActivityPub representation of a Accept
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return array pretty array to be used in a response
+     */
+    public static function accept_to_array($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.
+     *
+     * @param array $object
+     * @return bool
+     * @throws Exception
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function validate_object($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;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_announce.php

@@ -0,0 +1,70 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_announce
+{
+    /**
+     * Generates an ActivityPub representation of a Announce
+     *
+     * @param Profile $actor
+     * @param Notice $notice
+     * @return array pretty array to be used in a response
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function announce_to_array(Profile $actor, Notice $notice): array
+    {
+        $actor_uri = ActivityPubPlugin::actor_uri($actor);
+        $notice_url = Activitypub_notice::getUrl($notice);
+
+        $to = [common_local_url('apActorFollowers', ['id' => $actor->getID()])];
+        foreach ($notice->getAttentionProfiles() as $to_profile) {
+            $to[] = $to_profile->getUri();
+        }
+
+        $cc[]= 'https://www.w3.org/ns/activitystreams#Public';
+
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => common_root_url().'share_from_'.urlencode($actor_uri).'_to_'.urlencode($notice_url),
+            "type"   => "Announce",
+            "actor"  => $actor_uri,
+            "object" => $notice_url,
+            "to"     => $to,
+            "cc"     => $cc
+        ];
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_attachment.php

@@ -0,0 +1,67 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub Attachment representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_attachment
+{
+    /**
+     * Generates a pretty array from an Attachment object
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param Attachment $attachment
+     * @return array pretty array to be used in a response
+     */
+    public static function attachment_to_array($attachment)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'type'      => 'Document',
+            'mediaType' => $attachment->mimetype,
+            'url'       => $attachment->getUrl(),
+            'size'      => $attachment->getSize(),
+            'name'      => $attachment->getTitle(),
+        ];
+
+        // Image
+        if (substr($res["mediaType"], 0, 5) == "image") {
+            $res["meta"]= [
+                'width'  => $attachment->width,
+                'height' => $attachment->height
+            ];
+        }
+
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_create.php

@@ -0,0 +1,85 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_create
+{
+    /**
+     * Generates an ActivityPub representation of a Create
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor
+     * @param array $object
+     * @return array pretty array to be used in a response
+     */
+    public static function create_to_array($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.');
+        }
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_delete.php

@@ -0,0 +1,87 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_delete
+{
+    /**
+     * Generates an ActivityPub representation of a Delete
+     *
+     * @param string $actor actor URI
+     * @param string $object object URI
+     * @return array pretty array to be used in a response
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function delete_to_array(string $actor, string $object): array
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => $object.'/delete',
+            'type'   => 'Delete',
+            'actor'  => $actor,
+            'object' => $object
+        ];
+        return $res;
+    }
+
+    /**
+     * Verifies if a given object is acceptable for a Delete Activity.
+     *
+     * @param array|string $object
+     * @return bool
+     * @throws Exception
+     * @author Bruno Casteleiro <brunoccast@fc.up.pt>
+     */
+    public static function validate_object($object): bool
+    {
+        if (!is_array($object)) {
+            if (!filter_var($object, FILTER_VALIDATE_URL)) {
+                throw new Exception('Object is not a valid Object URI for Activity.');
+            }
+        } else {
+            if (!isset($object['type'])) {
+                throw new Exception('Object type was not specified for Delete Activity.');
+            } else if ($object['type'] !== "Tombstone") {
+                throw new Exception('Invalid Object type for Delete Activity.');
+            }
+
+            if (!isset($object['id'])) {
+                throw new Exception('Object id was not specified for Delete Activity.');
+            }
+        }
+
+        return true;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_error.php

@@ -0,0 +1,53 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_error
+{
+    /**
+     * Generates a pretty error from a string
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $m
+     * @return array pretty array to be used in a response
+     */
+    public static function error_message_to_array($m)
+    {
+        $res = [
+            'error'=> $m
+        ];
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_follow.php

@@ -0,0 +1,98 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_follow
+{
+    /**
+     * Generates an ActivityPub representation of a subscription
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor
+     * @param string $object
+     * @param string|null $id Activity id, to be used when generating for an Accept Activity
+     * @return array pretty array to be used in a response
+     */
+    public static function follow_to_array(string $actor, string $object, ?string $id = null): array
+    {
+        if ($id === null) {
+            $id = common_root_url().'follow_from_'.urlencode($actor).'_to_'.urlencode($object);
+        }
+
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'     => $id,
+            'type'   => 'Follow',
+            'actor'  => $actor,
+            'object' => $object
+       ];
+        return $res;
+    }
+
+    /**
+     * Handles a Follow Activity received by our inbox.
+     *
+     * @param Profile $actor_profile Remote Actor
+     * @param string $object Local Actor
+     * @param string $id Activity id
+     * @throws AlreadyFulfilledException
+     * @throws HTTP_Request2_Exception
+     * @throws NoProfileException
+     * @throws ServerException
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function follow(Profile $actor_profile, string $object, string $id)
+    {
+        // 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, $object_profile);
+            Activitypub_profile::subscribeCacheUpdate($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);
+        $postman = new Activitypub_postman($object_profile, [$actor_aprofile]);
+        $postman->accept_follow($id);
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_like.php

@@ -0,0 +1,58 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_like
+{
+    /**
+     * Generates an ActivityPub representation of a Like
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $actor  Actor URI
+     * @param string $object Notice URI
+     * @return array pretty array to be used in a response
+     */
+    public static function like_to_array($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;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_mention_tag.php

@@ -0,0 +1,57 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub Mention Tag representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_mention_tag
+{
+    /**
+     * Generates an ActivityPub representation of a Mention Tag
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param string $href Actor Uri
+     * @param array $name Mention name
+     * @return array pretty array to be used in a response
+     */
+    public static function mention_tag_to_array_from_values($href, $name)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            "type" => "Mention",
+            "href" => $href,
+            "name" => $name
+         ];
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_notice.php

@@ -0,0 +1,263 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub notice representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_notice
+{
+    /**
+     * Generates a pretty notice from a Notice object
+     *
+     * @param Notice $notice
+     * @return array array to be used in a response
+     * @throws EmptyPkeyValueException
+     * @throws InvalidUrlException
+     * @throws ServerException
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function notice_to_array($notice)
+    {
+        $profile = $notice->getProfile();
+        $attachments = [];
+        foreach ($notice->attachments() as $attachment) {
+            $attachments[] = Activitypub_attachment::attachment_to_array($attachment);
+        }
+
+        $tags = [];
+        foreach ($notice->getTags() as $tag) {
+            if ($tag != "") {       // Hacky workaround to avoid stupid outputs
+                $tags[] = Activitypub_tag::tag_to_array($tag);
+            }
+        }
+
+        $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';
+
+        $item = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id'           => self::getUrl($notice),
+            'type'         => 'Note',
+            'published'    => str_replace(' ', 'T', $notice->getCreated()).'Z',
+            'url'          => self::getUrl($notice),
+            'attributedTo' => ActivityPubPlugin::actor_uri($profile),
+            'to'           => $to,
+            'cc'           => $cc,
+            'conversation' => $notice->getConversationUrl(),
+            'content'      => $notice->getRendered(),
+            'isLocal'      => $notice->isLocal(),
+            'attachment'   => $attachments,
+            'tag'          => $tags
+        ];
+
+        // Is this a reply?
+        if (!empty($notice->reply_to)) {
+            $item['inReplyTo'] = self::getUrl(Notice::getById($notice->reply_to));
+        }
+
+        // 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'];                                // int
+        $url     = isset($object['url']) ? $object['url'] : $id; // string
+        $content = $object['content'];                           // string
+
+        // possible keys: ['inReplyTo', 'latitude', 'longitude']
+        $settings = [];
+        if (isset($object['inReplyTo'])) {
+            $settings['inReplyTo'] = $object['inReplyTo'];
+        }
+        if (isset($object['latitude'])) {
+            $settings['latitude']  = $object['latitude'];
+        }
+        if (isset($object['longitude'])) {
+            $settings['longitude'] = $object['longitude'];
+        }
+
+        // Ensure Actor Profile
+        if (is_null($actor_profile)) {
+            $actor_profile = ActivityPub_explorer::get_profile_from_url($object['attributedTo']);
+        }
+
+        $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' => $url];
+
+        // Is this a reply?
+        if (isset($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);
+
+        return $note;
+    }
+
+    /**
+     * Validates a note.
+     *
+     * @param array $object
+     * @return bool
+     * @throws Exception
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function validate_note($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($object['url']) && !filter_var($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;
+    }
+
+    /**
+     * Get the original representation URL of a given notice.
+     *
+     * @param Notice $notice notice from which to retrieve the URL
+     * @return string URL
+     * @author Bruno Casteleiro <brunoccast@fc.up.pt>
+     */
+    public static function getUrl(Notice $notice): string {
+	if ($notice->isLocal()) {
+	    return common_local_url('apNotice', ['id' => $notice->getID()]);
+	} else {
+	    return $notice->getUrl();
+	}
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_reject.php

@@ -0,0 +1,55 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_reject
+{
+    /**
+     * Generates an ActivityPub representation of a Reject
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return array pretty array to be used in a response
+     */
+    public static function reject_to_array($object)
+    {
+        $res = [
+                '@context' => 'https://www.w3.org/ns/activitystreams',
+                'type'     => 'Reject',
+                'object'   => $object
+        ];
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_tag.php

@@ -0,0 +1,55 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub representation of a Tag
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_tag
+{
+    /**
+     * Generates a pretty tag from a Tag object
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array Tag $tag
+     * @return array pretty array to be used in a response
+     */
+    public static function tag_to_array($tag)
+    {
+        $res = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'name' => $tag,
+            'url'  => common_local_url('tag', ['tag' => $tag])
+        ];
+        return $res;
+    }
+}

plugins/ActivityPub/lib/models/Activitypub_undo.php

@@ -0,0 +1,87 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * ActivityPub implementation for GNU social
+ *
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @copyright 2018-2019 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ * @link      http://www.gnu.org/software/social/
+ */
+
+defined('GNUSOCIAL') || die();
+
+/**
+ * ActivityPub error representation
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Diogo Cordeiro <diogo@fc.up.pt>
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Activitypub_undo
+{
+    /**
+     * Generates an ActivityPub representation of a Undo
+     *
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     * @param array $object
+     * @return array pretty array to be used in a response
+     */
+    public static function undo_to_array($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.
+     *
+     * @param array $object
+     * @return bool
+     * @throws Exception
+     * @author Diogo Cordeiro <diogo@fc.up.pt>
+     */
+    public static function validate_object($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;
+    }
+}