<?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 Inbox Handler
*
* @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_inbox_handler
{
private $activity;
private $actor;
private $object;
/**
* Create a Inbox Handler to receive something from someone.
*
* @param array $activity Activity we are receiving
* @param Profile $actor_profile Actor originating the activity
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
public function __construct($activity, $actor_profile = null)
{
$this->activity = $activity;
$this->object = $activity['object'];
// Validate Activity
if (!$this->validate_activity()) {
return; // Just ignore
}
// 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
$this->process();
}
/**
* Validates if a given Activity is valid. Throws exception if not.
*
* @throws Exception if invalid
* @return bool true if valid and acceptable, false if unsupported
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function validate_activity(): bool
{
// Activity validation
// Validate data
if (!(isset($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
$valid = true;
switch ($this->activity['type']) {
case 'Accept':
$valid = Activitypub_accept::validate_object($this->object);
break;
case 'Create':
$valid = Activitypub_create::validate_object($this->object);
break;
case 'Delete':
$valid = Activitypub_delete::validate_object($this->object);
break;
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':
$valid = Activitypub_undo::validate_object($this->object);
break;
default:
throw new Exception('Unknown Activity Type.');
}
return $valid;
}
/**
* Sends the Activity to proper handler in order to be processed.
*
* @throws AlreadyFulfilledException
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function process()
{
switch ($this->activity['type']) {
case 'Accept':
$this->handle_accept();
break;
case 'Create':
$this->handle_create();
break;
case 'Delete':
$this->handle_delete();
break;
case 'Follow':
$this->handle_follow();
break;
case 'Like':
$this->handle_like();
break;
case 'Undo':
$this->handle_undo();
break;
case 'Announce':
$this->handle_announce();
break;
}
}
/**
* Handles an Accept Activity received by our inbox.
*
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_accept()
{
switch ($this->object['type']) {
case 'Follow':
$this->handle_accept_follow();
break;
}
}
/**
* Handles an Accept Follow Activity received by our inbox.
*
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_accept_follow()
{
// Get valid Object profile
// Note that, since this an accept_follow, the $object
// profile is actually the actor that followed someone
$object_profile = new Activitypub_explorer;
$object_profile = $object_profile->lookup($this->object['object'])[0];
Activitypub_profile::subscribeCacheUpdate($object_profile, $this->actor);
$pending_list = new Activitypub_pending_follow_requests($object_profile->getID(), $this->actor->getID());
$pending_list->remove();
}
/**
* Handles a Create Activity received by our inbox.
*
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_create()
{
switch ($this->object['type']) {
case 'Note':
$this->handle_create_note();
break;
}
}
/**
* Handle a Create Note Activity received by our inbox.
*
* @throws Exception
* @author Bruno Casteleiro <brunoccast@fc.up.pt>
*/
private function handle_create_note()
{
if (Activitypub_create::isPrivateNote($this->activity)) {
Activitypub_message::create_message($this->object, $this->actor);
} else {
Activitypub_notice::create_notice($this->object, $this->actor);
}
}
/**
* Handles a Delete Activity received by our inbox.
*
* @throws NoProfileException
* @throws Exception
* @author Bruno Casteleiro <brunoccast@fc.up.pt>
*/
private function handle_delete()
{
$object = $this->object;
if (is_array($object)) {
$object = $object['id'];
}
// profile deletion ?
if ($this->activity['actor'] == $object) {
$aprofile = Activitypub_profile::from_profile($this->actor);
$this->handle_delete_profile($aprofile);
return;
}
// note deletion ?
try {
$notice = ActivityPubPlugin::grab_notice_from_url($object, false);
if ($notice instanceof Notice) {
$this->handle_delete_note($notice);
}
return;
} catch (Exception $e) {
// either already deleted or not an object at all
// nothing to do..
}
common_log(LOG_INFO, "Ignoring Delete activity, nothing that we can/need to handle.");
}
/**
* Handles a Delete-Profile Activity.
*
* Note that the actual ap_profile is deleted during the ProfileDeleteRelated event,
* subscribed by ActivityPubPlugin.
*
* @param Activitypub_profile $aprofile remote user being deleted
* @return void
* @throws NoProfileException
* @author Bruno Casteleiro <brunoccast@fc.up.pt>
*/
private function handle_delete_profile(Activitypub_profile $aprofile): void
{
$profile = $aprofile->local_profile();
$profile->delete();
}
/**
* Handles a Delete-Note Activity.
*
* @param Notice $note remote note being deleted
* @return void
* @throws AuthorizationException
* @author Bruno Casteleiro <brunoccast@fc.up.pt>
*/
private function handle_delete_note(Notice $note): void
{
$note->deleteAs($this->actor);
}
/**
* Handles a Follow Activity received by our inbox.
*
* @throws AlreadyFulfilledException
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_follow()
{
Activitypub_follow::follow($this->actor, $this->object, $this->activity['id']);
}
/**
* Handles a Like Activity received by our inbox.
*
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_like()
{
$notice = ActivityPubPlugin::grab_notice_from_url($this->object);
Fave::addNew($this->actor, $notice);
}
/**
* Handles a Undo Activity received by our inbox.
*
* @throws AlreadyFulfilledException
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_undo()
{
switch ($this->object['type']) {
case 'Follow':
$this->handle_undo_follow();
break;
case 'Like':
$this->handle_undo_like();
break;
}
}
/**
* Handles a Undo Follow Activity received by our inbox.
*
* @throws AlreadyFulfilledException
* @throws HTTP_Request2_Exception
* @throws NoProfileException
* @throws ServerException
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_undo_follow()
{
// Get Object profile
$object_profile = new Activitypub_explorer;
$object_profile = $object_profile->lookup($this->object['object'])[0];
if (Subscription::exists($this->actor, $object_profile)) {
Subscription::cancel($this->actor, $object_profile);
// You are no longer following this person.
Activitypub_profile::unsubscribeCacheUpdate($this->actor, $object_profile);
} /*else {
// 409: You already aren't following this person.
}*/
}
/**
* Handles a Undo Like Activity received by our inbox.
*
* @throws AlreadyFulfilledException
* @throws ServerException
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_undo_like()
{
$notice = ActivityPubPlugin::grab_notice_from_url($this->object['object']);
Fave::removeEntry($this->actor, $notice);
}
/**
* Handles a Announce Activity received by our inbox.
*
* @throws Exception
* @author Diogo Cordeiro <diogo@fc.up.pt>
*/
private function handle_announce()
{
$object_notice = ActivityPubPlugin::grab_notice_from_url($this->object);
$object_notice->repeat($this->actor, 'ActivityPub');
}
}