]> git.mxchange.org Git - friendica.git/blob - src/Protocol/ActivityPub/Receiver.php
Merge pull request #8230 from AlfredSK/AlfredSK-statistics-query
[friendica.git] / src / Protocol / ActivityPub / Receiver.php
1 <?php
2 /**
3  * @copyright Copyright (C) 2020, Friendica
4  *
5  * @license GNU AGPL version 3 or any later version
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU Affero General Public License as
9  * published by the Free Software Foundation, either version 3 of the
10  * License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU Affero General Public License for more details.
16  *
17  * You should have received a copy of the GNU Affero General Public License
18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
19  *
20  */
21
22 namespace Friendica\Protocol\ActivityPub;
23
24 use Friendica\Database\DBA;
25 use Friendica\Content\Text\HTML;
26 use Friendica\Content\Text\Markdown;
27 use Friendica\Core\Logger;
28 use Friendica\Core\Protocol;
29 use Friendica\Model\Contact;
30 use Friendica\Model\APContact;
31 use Friendica\Model\Conversation;
32 use Friendica\Model\Item;
33 use Friendica\Model\User;
34 use Friendica\Protocol\Activity;
35 use Friendica\Protocol\ActivityPub;
36 use Friendica\Util\DateTimeFormat;
37 use Friendica\Util\HTTPSignature;
38 use Friendica\Util\JsonLD;
39 use Friendica\Util\LDSignature;
40 use Friendica\Util\Strings;
41
42 /**
43  * ActivityPub Receiver Protocol class
44  *
45  * To-Do:
46  * @todo Undo Announce
47  *
48  * Check what this is meant to do:
49  * - Add
50  * - Block
51  * - Flag
52  * - Remove
53  * - Undo Block
54  */
55 class Receiver
56 {
57         const PUBLIC_COLLECTION = 'as:Public';
58         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
59         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event'];
60         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
61
62         /**
63          * Checks if the web request is done for the AP protocol
64          *
65          * @return bool is it AP?
66          */
67         public static function isRequest()
68         {
69                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
70                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
71         }
72
73         /**
74          * Checks incoming message from the inbox
75          *
76          * @param         $body
77          * @param         $header
78          * @param integer $uid User ID
79          * @throws \Exception
80          */
81         public static function processInbox($body, $header, $uid)
82         {
83                 $http_signer = HTTPSignature::getSigner($body, $header);
84                 if (empty($http_signer)) {
85                         Logger::warning('Invalid HTTP signature, message will be discarded.');
86                         return;
87                 } else {
88                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
89                 }
90
91                 $activity = json_decode($body, true);
92
93                 if (empty($activity)) {
94                         Logger::warning('Invalid body.');
95                         return;
96                 }
97
98                 $ldactivity = JsonLD::compact($activity);
99
100                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
101
102                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
103
104                 if (LDSignature::isSigned($activity)) {
105                         $ld_signer = LDSignature::getSigner($activity);
106                         if (empty($ld_signer)) {
107                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
108                         }
109                         if (!empty($ld_signer && ($actor == $http_signer))) {
110                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
111                                 $trust_source = true;
112                         } elseif (!empty($ld_signer)) {
113                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
114                                 $trust_source = true;
115                         } elseif ($actor == $http_signer) {
116                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
117                                 $trust_source = true;
118                         } else {
119                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
120                                 $trust_source = false;
121                         }
122                 } elseif ($actor == $http_signer) {
123                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
124                         $trust_source = true;
125                 } else {
126                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
127                         $trust_source = false;
128                 }
129
130                 self::processActivity($ldactivity, $body, $uid, $trust_source);
131         }
132
133         /**
134          * Fetches the object type for a given object id
135          *
136          * @param array   $activity
137          * @param string  $object_id Object ID of the the provided object
138          * @param integer $uid       User ID
139          *
140          * @return string with object type
141          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
142          * @throws \ImagickException
143          */
144         private static function fetchObjectType($activity, $object_id, $uid = 0)
145         {
146                 if (!empty($activity['as:object'])) {
147                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
148                         if (!empty($object_type)) {
149                                 return $object_type;
150                         }
151                 }
152
153                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
154                         // We just assume "note" since it doesn't make a difference for the further processing
155                         return 'as:Note';
156                 }
157
158                 $profile = APContact::getByURL($object_id);
159                 if (!empty($profile['type'])) {
160                         return 'as:' . $profile['type'];
161                 }
162
163                 $data = ActivityPub::fetchContent($object_id, $uid);
164                 if (!empty($data)) {
165                         $object = JsonLD::compact($data);
166                         $type = JsonLD::fetchElement($object, '@type');
167                         if (!empty($type)) {
168                                 return $type;
169                         }
170                 }
171
172                 return null;
173         }
174
175         /**
176          * Prepare the object array
177          *
178          * @param array   $activity
179          * @param integer $uid User ID
180          * @param         $trust_source
181          *
182          * @return array with object data
183          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
184          * @throws \ImagickException
185          */
186         private static function prepareObjectData($activity, $uid, &$trust_source)
187         {
188                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
189                 if (empty($actor)) {
190                         Logger::log('Empty actor', Logger::DEBUG);
191                         return [];
192                 }
193
194                 $type = JsonLD::fetchElement($activity, '@type');
195
196                 // Fetch all receivers from to, cc, bto and bcc
197                 $receivers = self::getReceivers($activity, $actor);
198
199                 // When it is a delivery to a personal inbox we add that user to the receivers
200                 if (!empty($uid)) {
201                         $additional = ['uid:' . $uid => $uid];
202                         $receivers = array_merge($receivers, $additional);
203                 } else {
204                         // We possibly need some user to fetch private content,
205                         // so we fetch the first out ot the list.
206                         $uid = self::getFirstUserFromReceivers($receivers);
207                 }
208
209                 Logger::log('Receivers: ' . $uid . ' - ' . json_encode($receivers), Logger::DEBUG);
210
211                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
212                 if (empty($object_id)) {
213                         Logger::log('No object found', Logger::DEBUG);
214                         return [];
215                 }
216
217                 if (!is_string($object_id)) {
218                         Logger::info('Invalid object id', ['object' => $object_id]);
219                         return [];
220                 }
221
222                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
223
224                 // Fetch the content only on activities where this matters
225                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
226                         if ($type == 'as:Announce') {
227                                 $trust_source = false;
228                         }
229                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $uid);
230                         if (empty($object_data)) {
231                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
232                                 return [];
233                         }
234                         $object_data['object_id'] = $object_id;
235
236                         // Test if it is an answer to a mail
237                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
238                                 $object_data['directmessage'] = true;
239                         } else {
240                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
241                         }
242
243                         // We had been able to retrieve the object data - so we can trust the source
244                         $trust_source = true;
245                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
246                         // Create a mostly empty array out of the activity data (instead of the object).
247                         // This way we later don't have to check for the existence of ech individual array element.
248                         $object_data = self::processObject($activity);
249                         $object_data['name'] = $type;
250                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
251                         $object_data['object_id'] = $object_id;
252                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
253                 } elseif (in_array($type, ['as:Add'])) {
254                         $object_data = [];
255                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
256                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
257                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
258                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
259                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
260                 } else {
261                         $object_data = [];
262                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
263                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
264                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
265                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
266                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
267
268                         // An Undo is done on the object of an object, so we need that type as well
269                         if ($type == 'as:Undo') {
270                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
271                         }
272                 }
273
274                 $object_data = self::addActivityFields($object_data, $activity);
275
276                 if (empty($object_data['object_type'])) {
277                         $object_data['object_type'] = $object_type;
278                 }
279
280                 $object_data['type'] = $type;
281                 $object_data['actor'] = $actor;
282                 $object_data['item_receiver'] = $receivers;
283                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
284
285                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
286
287                 return $object_data;
288         }
289
290         /**
291          * Fetches the first user id from the receiver array
292          *
293          * @param array $receivers Array with receivers
294          * @return integer user id;
295          */
296         public static function getFirstUserFromReceivers($receivers)
297         {
298                 foreach ($receivers as $receiver) {
299                         if (!empty($receiver)) {
300                                 return $receiver;
301                         }
302                 }
303                 return 0;
304         }
305
306         /**
307          * Store the unprocessed data into the conversation table
308          * This has to be done outside the regular function,
309          * since we store everything - not only item posts.
310          *
311          * @param array  $activity Array with activity data
312          * @param string $body     The raw message
313          * @throws \Exception
314          */
315         private static function storeConversation($activity, $body)
316         {
317                 if (empty($body) || empty($activity['id'])) {
318                         return;
319                 }
320
321                 $conversation = [
322                         'protocol' => Conversation::PARCEL_ACTIVITYPUB,
323                         'item-uri' => $activity['id'],
324                         'reply-to-uri' => $activity['reply-to-id'] ?? '',
325                         'conversation-href' => $activity['context'] ?? '',
326                         'conversation-uri' => $activity['conversation'] ?? '',
327                         'source' => $body,
328                         'received' => DateTimeFormat::utcNow()];
329
330                 DBA::insert('conversation', $conversation, true);
331         }
332
333         /**
334          * Processes the activity object
335          *
336          * @param array   $activity     Array with activity data
337          * @param string  $body
338          * @param integer $uid          User ID
339          * @param boolean $trust_source Do we trust the source?
340          * @throws \Exception
341          */
342         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
343         {
344                 $type = JsonLD::fetchElement($activity, '@type');
345                 if (!$type) {
346                         Logger::log('Empty type', Logger::DEBUG);
347                         return;
348                 }
349
350                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
351                         Logger::log('Empty object', Logger::DEBUG);
352                         return;
353                 }
354
355                 if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
356                         Logger::log('Empty actor', Logger::DEBUG);
357                         return;
358
359                 }
360
361                 // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
362                 if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
363                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
364                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
365                         $trust_source = ($actor == $attributed_to);
366                         if (!$trust_source) {
367                                 Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
368                         }
369                 }
370
371                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
372                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
373                 if (empty($object_data)) {
374                         Logger::log('No object data found', Logger::DEBUG);
375                         return;
376                 }
377
378                 if (!$trust_source) {
379                         Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
380                         return;
381                 }
382
383                 // Only store content related stuff - and no announces, since they possibly overwrite the original content
384                 if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
385                         self::storeConversation($object_data, $body);
386                 }
387
388                 // Internal flag for thread completion. See Processor.php
389                 if (!empty($activity['thread-completion'])) {
390                         $object_data['thread-completion'] = $activity['thread-completion'];
391                 }
392
393                 switch ($type) {
394                         case 'as:Create':
395                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
396                                         ActivityPub\Processor::createItem($object_data);
397                                 }
398                                 break;
399
400                         case 'as:Add':
401                                 if ($object_data['object_type'] == 'as:tag') {
402                                         ActivityPub\Processor::addTag($object_data);
403                                 }
404                                 break;
405
406                         case 'as:Announce':
407                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
408                                         $profile = APContact::getByURL($object_data['actor']);
409                                         // Reshared posts from persons appear as summary at the bottom
410                                         // If this isn't set, then a single reshare appears on top. This is used for groups.
411                                         $object_data['thread-completion'] = ($profile['type'] != 'Group');
412
413                                         ActivityPub\Processor::createItem($object_data);
414
415                                         // Add the bottom reshare information only for persons
416                                         if ($profile['type'] != 'Group') {
417                                                 $announce_object_data = self::processObject($activity);
418                                                 $announce_object_data['name'] = $type;
419                                                 $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
420                                                 $announce_object_data['object_id'] = $object_data['object_id'];
421                                                 $announce_object_data['object_type'] = $object_data['object_type'];
422
423                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
424                                         }
425                                 }
426                                 break;
427
428                         case 'as:Like':
429                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
430                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
431                                 }
432                                 break;
433
434                         case 'as:Dislike':
435                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
436                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
437                                 }
438                                 break;
439
440                         case 'as:TentativeAccept':
441                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
442                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
443                                 }
444                                 break;
445
446                         case 'as:Update':
447                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
448                                         ActivityPub\Processor::updateItem($object_data);
449                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
450                                         ActivityPub\Processor::updatePerson($object_data);
451                                 }
452                                 break;
453
454                         case 'as:Delete':
455                                 if ($object_data['object_type'] == 'as:Tombstone') {
456                                         ActivityPub\Processor::deleteItem($object_data);
457                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
458                                         ActivityPub\Processor::deletePerson($object_data);
459                                 }
460                                 break;
461
462                         case 'as:Follow':
463                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
464                                         ActivityPub\Processor::followUser($object_data);
465                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
466                                         $object_data['reply-to-id'] = $object_data['object_id'];
467                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
468                                 }
469                                 break;
470
471                         case 'as:Accept':
472                                 if ($object_data['object_type'] == 'as:Follow') {
473                                         ActivityPub\Processor::acceptFollowUser($object_data);
474                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
475                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
476                                 }
477                                 break;
478
479                         case 'as:Reject':
480                                 if ($object_data['object_type'] == 'as:Follow') {
481                                         ActivityPub\Processor::rejectFollowUser($object_data);
482                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
483                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
484                                 }
485                                 break;
486
487                         case 'as:Undo':
488                                 if (($object_data['object_type'] == 'as:Follow') &&
489                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
490                                         ActivityPub\Processor::undoFollowUser($object_data);
491                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
492                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
493                                         ActivityPub\Processor::rejectFollowUser($object_data);
494                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
495                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
496                                         ActivityPub\Processor::undoActivity($object_data);
497                                 }
498                                 break;
499
500                         default:
501                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
502                                 break;
503                 }
504         }
505
506         /**
507          * Fetch the receiver list from an activity array
508          *
509          * @param array  $activity
510          * @param string $actor
511          * @param array  $tags
512          *
513          * @return array with receivers (user id)
514          * @throws \Exception
515          */
516         private static function getReceivers($activity, $actor, $tags = [])
517         {
518                 $receivers = [];
519
520                 // When it is an answer, we inherite the receivers from the parent
521                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
522                 if (!empty($replyto)) {
523                         // Fix possibly wrong item URI (could be an answer to a plink uri)
524                         $fixedReplyTo = Item::getURIByLink($replyto);
525                         $replyto = $fixedReplyTo ?: $replyto;
526
527                         $parents = Item::select(['uid'], ['uri' => $replyto]);
528                         while ($parent = Item::fetch($parents)) {
529                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
530                         }
531                 }
532
533                 if (!empty($actor)) {
534                         $profile = APContact::getByURL($actor);
535                         $followers = $profile['followers'] ?? '';
536
537                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
538                 } else {
539                         Logger::log('Empty actor', Logger::DEBUG);
540                         $followers = '';
541                 }
542
543                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
544                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
545                         if (empty($receiver_list)) {
546                                 continue;
547                         }
548
549                         foreach ($receiver_list as $receiver) {
550                                 if ($receiver == self::PUBLIC_COLLECTION) {
551                                         $receivers['uid:0'] = 0;
552                                 }
553
554                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
555                                         // This will most likely catch all OStatus connections to Mastodon
556                                         $condition = ['alias' => [$actor, Strings::normaliseLink($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
557                                                 , 'archive' => false, 'pending' => false];
558                                         $contacts = DBA::select('contact', ['uid'], $condition);
559                                         while ($contact = DBA::fetch($contacts)) {
560                                                 if ($contact['uid'] != 0) {
561                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
562                                                 }
563                                         }
564                                         DBA::close($contacts);
565                                 }
566
567                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
568                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
569                                         continue;
570                                 }
571
572                                 // Fetching all directly addressed receivers
573                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
574                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
575                                 if (!DBA::isResult($contact)) {
576                                         continue;
577                                 }
578
579                                 // Check if the potential receiver is following the actor
580                                 // Exception: The receiver is targetted via "to" or this is a comment
581                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
582                                         $networks = Protocol::FEDERATED;
583                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
584                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
585
586                                         // Forum posts are only accepted from forum contacts
587                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
588                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
589                                         }
590
591                                         if (!DBA::exists('contact', $condition)) {
592                                                 continue;
593                                         }
594                                 }
595
596                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
597                         }
598                 }
599
600                 self::switchContacts($receivers, $actor);
601
602                 return $receivers;
603         }
604
605         /**
606          * Fetch the receiver list of a given actor
607          *
608          * @param string $actor
609          * @param array  $tags
610          *
611          * @return array with receivers (user id)
612          * @throws \Exception
613          */
614         public static function getReceiverForActor($actor, $tags)
615         {
616                 $receivers = [];
617                 $networks = Protocol::FEDERATED;
618                 $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
619                         'network' => $networks, 'archive' => false, 'pending' => false];
620                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
621                 while ($contact = DBA::fetch($contacts)) {
622                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
623                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
624                         }
625                 }
626                 DBA::close($contacts);
627                 return $receivers;
628         }
629
630         /**
631          * Tests if the contact is a valid receiver for this actor
632          *
633          * @param array  $contact
634          * @param string $actor
635          * @param array  $tags
636          *
637          * @return bool with receivers (user id)
638          * @throws \Exception
639          */
640         private static function isValidReceiverForActor($contact, $actor, $tags)
641         {
642                 // Public contacts are no valid receiver
643                 if ($contact['uid'] == 0) {
644                         return false;
645                 }
646
647                 // Are we following the contact? Then this is a valid receiver
648                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
649                         return true;
650                 }
651
652                 // When the possible receiver isn't a community, then it is no valid receiver
653                 $owner = User::getOwnerDataById($contact['uid']);
654                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
655                         return false;
656                 }
657
658                 // Is the community account tagged?
659                 foreach ($tags as $tag) {
660                         if ($tag['type'] != 'Mention') {
661                                 continue;
662                         }
663
664                         if ($tag['href'] == $owner['url']) {
665                                 return true;
666                         }
667                 }
668
669                 return false;
670         }
671
672         /**
673          * Switches existing contacts to ActivityPub
674          *
675          * @param integer $cid Contact ID
676          * @param integer $uid User ID
677          * @param string  $url Profile URL
678          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
679          * @throws \ImagickException
680          */
681         public static function switchContact($cid, $uid, $url)
682         {
683                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
684                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
685                         return;
686                 }
687
688                 if (Contact::updateFromProbe($cid, '', true)) {
689                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
690                 }
691
692                 // Send a new follow request to be sure that the connection still exists
693                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
694                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
695                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
696                 }
697         }
698
699         /**
700          *
701          *
702          * @param $receivers
703          * @param $actor
704          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
705          * @throws \ImagickException
706          */
707         private static function switchContacts($receivers, $actor)
708         {
709                 if (empty($actor)) {
710                         return;
711                 }
712
713                 foreach ($receivers as $receiver) {
714                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
715                         if (DBA::isResult($contact)) {
716                                 self::switchContact($contact['id'], $receiver, $actor);
717                         }
718
719                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
720                         if (DBA::isResult($contact)) {
721                                 self::switchContact($contact['id'], $receiver, $actor);
722                         }
723                 }
724         }
725
726         /**
727          *
728          *
729          * @param       $object_data
730          * @param array $activity
731          *
732          * @return mixed
733          */
734         private static function addActivityFields($object_data, $activity)
735         {
736                 if (!empty($activity['published']) && empty($object_data['published'])) {
737                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
738                 }
739
740                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
741                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
742                 }
743
744                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
745                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
746
747                 if (!empty($object_data['object_id'])) {
748                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
749                         $objectId = Item::getURIByLink($object_data['object_id']);
750                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
751                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
752                                 $object_data['object_id'] = $objectId;
753                         }
754                 }
755
756                 return $object_data;
757         }
758
759         /**
760          * Fetches the object data from external ressources if needed
761          *
762          * @param string  $object_id    Object ID of the the provided object
763          * @param array   $object       The provided object array
764          * @param boolean $trust_source Do we trust the provided object?
765          * @param integer $uid          User ID for the signature that we use to fetch data
766          *
767          * @return array|false with trusted and valid object data
768          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
769          * @throws \ImagickException
770          */
771         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
772         {
773                 // By fetching the type we check if the object is complete.
774                 $type = JsonLD::fetchElement($object, '@type');
775
776                 if (!$trust_source || empty($type)) {
777                         $data = ActivityPub::fetchContent($object_id, $uid);
778                         if (!empty($data)) {
779                                 $object = JsonLD::compact($data);
780                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
781                         } else {
782                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
783
784                                 $item = Item::selectFirst([], ['uri' => $object_id]);
785                                 if (!DBA::isResult($item)) {
786                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
787                                         return false;
788                                 }
789                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
790                                 $data = ActivityPub\Transmitter::createNote($item);
791                                 $object = JsonLD::compact($data);
792                         }
793                 } else {
794                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
795                 }
796
797                 $type = JsonLD::fetchElement($object, '@type');
798
799                 if (empty($type)) {
800                         Logger::log('Empty type', Logger::DEBUG);
801                         return false;
802                 }
803
804                 if (in_array($type, self::CONTENT_TYPES)) {
805                         return self::processObject($object);
806                 }
807
808                 if ($type == 'as:Announce') {
809                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
810                         if (empty($object_id) || !is_string($object_id)) {
811                                 return false;
812                         }
813                         return self::fetchObject($object_id, [], false, $uid);
814                 }
815
816                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
817                 return false;
818         }
819
820         /**
821          * Convert tags from JSON-LD format into a simplified format
822          *
823          * @param array $tags Tags in JSON-LD format
824          *
825          * @return array with tags in a simplified format
826          */
827         private static function processTags($tags)
828         {
829                 $taglist = [];
830
831                 if (empty($tags)) {
832                         return [];
833                 }
834
835                 foreach ($tags as $tag) {
836                         if (empty($tag)) {
837                                 continue;
838                         }
839
840                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
841                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
842                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
843
844                         if (empty($element['type'])) {
845                                 continue;
846                         }
847
848                         $taglist[] = $element;
849                 }
850                 return $taglist;
851         }
852
853         /**
854          * Convert emojis from JSON-LD format into a simplified format
855          *
856          * @param $emojis
857          * @return array with emojis in a simplified format
858          */
859         private static function processEmojis($emojis)
860         {
861                 $emojilist = [];
862
863                 if (empty($emojis)) {
864                         return [];
865                 }
866
867                 foreach ($emojis as $emoji) {
868                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
869                                 continue;
870                         }
871
872                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
873                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
874                                 'href' => $url];
875
876                         $emojilist[] = $element;
877                 }
878                 return $emojilist;
879         }
880
881         /**
882          * Convert attachments from JSON-LD format into a simplified format
883          *
884          * @param array $attachments Attachments in JSON-LD format
885          *
886          * @return array with attachmants in a simplified format
887          */
888         private static function processAttachments($attachments)
889         {
890                 $attachlist = [];
891
892                 if (empty($attachments)) {
893                         return [];
894                 }
895
896                 foreach ($attachments as $attachment) {
897                         if (empty($attachment)) {
898                                 continue;
899                         }
900
901                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
902                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
903                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
904                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
905                 }
906                 return $attachlist;
907         }
908
909         /**
910          * Fetch the original source or content with the "language" Markdown or HTML
911          *
912          * @param array $object
913          * @param array $object_data
914          *
915          * @return array
916          * @throws \Exception
917          */
918         private static function getSource($object, $object_data)
919         {
920                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
921                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
922                 if (!empty($object_data['source'])) {
923                         return $object_data;
924                 }
925
926                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
927                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
928                 if (!empty($object_data['source'])) {
929                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
930                         return $object_data;
931                 }
932
933                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
934                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
935                 if (!empty($object_data['source'])) {
936                         $object_data['source'] = HTML::toBBCode($object_data['source']);
937                         return $object_data;
938                 }
939
940                 return $object_data;
941         }
942
943         /**
944          * Fetches data from the object part of an activity
945          *
946          * @param array $object
947          *
948          * @return array
949          * @throws \Exception
950          */
951         private static function processObject($object)
952         {
953                 if (!JsonLD::fetchElement($object, '@id')) {
954                         return false;
955                 }
956
957                 $object_data = [];
958                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
959                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
960                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
961
962                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
963                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
964                         $object_data['reply-to-id'] = $object_data['id'];
965                 } else {
966                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
967                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
968                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
969                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
970                                 $object_data['reply-to-id'] = $replyToId;
971                         }
972                 }
973
974                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
975                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
976
977                 if (empty($object_data['updated'])) {
978                         $object_data['updated'] = $object_data['published'];
979                 }
980
981                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
982                         $object_data['published'] = $object_data['updated'];
983                 }
984
985                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
986                 if (empty($actor)) {
987                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
988                 }
989
990                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
991                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
992                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
993                 $object_data['actor'] = $object_data['author'] = $actor;
994                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
995                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
996                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
997                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
998                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
999                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1000                 $object_data = self::getSource($object, $object_data);
1001                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1002                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1003                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1004                 $object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
1005                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1006                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1007                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1008                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1009                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
1010                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
1011                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
1012                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1013                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1014                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1015
1016                 // Special treatment for Hubzilla links
1017                 if (is_array($object_data['alternate-url'])) {
1018                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1019
1020                         if (!is_string($object_data['alternate-url'])) {
1021                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1022                         }
1023                 }
1024
1025                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags']);
1026
1027                 // Common object data:
1028
1029                 // Unhandled
1030                 // @context, type, actor, signature, mediaType, duration, replies, icon
1031
1032                 // Also missing: (Defined in the standard, but currently unused)
1033                 // audience, preview, endTime, startTime, image
1034
1035                 // Data in Notes:
1036
1037                 // Unhandled
1038                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1039                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1040
1041                 // Data in video:
1042
1043                 // To-Do?
1044                 // category, licence, language, commentsEnabled
1045
1046                 // Unhandled
1047                 // views, waitTranscoding, state, support, subtitleLanguage
1048                 // likes, dislikes, shares, comments
1049
1050                 return $object_data;
1051         }
1052 }