src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   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\Content\Text\BBCode;
  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\Core\System;
  30 use Friendica\Database\DBA;
  31 use Friendica\DI;
  32 use Friendica\Model\APContact;
  33 use Friendica\Model\Contact;
  34 use Friendica\Model\Conversation;
  35 use Friendica\Model\Event;
  36 use Friendica\Model\GServer;
  37 use Friendica\Model\Item;
  38 use Friendica\Model\ItemURI;
  39 use Friendica\Model\Mail;
  40 use Friendica\Model\Tag;
  41 use Friendica\Model\User;
  42 use Friendica\Model\Post;
  43 use Friendica\Protocol\Activity;
  44 use Friendica\Protocol\ActivityPub;
  45 use Friendica\Protocol\Relay;
  46 use Friendica\Util\DateTimeFormat;
  47 use Friendica\Util\JsonLD;
  48 use Friendica\Util\Strings;
  49
  50 /**
  51  * ActivityPub Processor Protocol class
  52  */
  53 class Processor
  54 {
  55         /**
  56          * Extracts the tag character (#, @, !) from mention links
  57          *
  58          * @param string $body
  59          * @return string
  60          */
  61         protected static function normalizeMentionLinks(string $body): string
  62         {
  63                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  64         }
  65
  66         /**
  67          * Convert the language array into a language JSON
  68          *
  69          * @param array $languages
  70          * @return string language JSON
  71          */
  72         private static function processLanguages(array $languages)
  73         {
  74                 $codes = array_keys($languages);
  75                 $lang = [];
  76                 foreach ($codes as $code) {
  77                         $lang[$code] = 1;
  78                 }
  79
  80                 if (empty($lang)) {
  81                         return '';
  82                 }
  83
  84                 return json_encode($lang);
  85         }
  86         /**
  87          * Replaces emojis in the body
  88          *
  89          * @param array $emojis
  90          * @param string $body
  91          *
  92          * @return string with replaced emojis
  93          */
  94         private static function replaceEmojis(int $uri_id, $body, array $emojis)
  95         {
  96                 $body = strtr($body,
  97                         array_combine(
  98                                 array_column($emojis, 'name'),
  99                                 array_map(function ($emoji) {
 100                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 101                                 }, $emojis)
 102                         )
 103                 );
 104
 105                 // We store the emoji here to be able to avoid storing it in the media
 106                 foreach ($emojis as $emoji) {
 107                         Post\Link::getByLink($uri_id, $emoji['href']);
 108                 }
 109                 return $body;
 110         }
 111
 112         /**
 113          * Store attached media files in the post-media table
 114          *
 115          * @param int $uriid
 116          * @param array $attachment
 117          * @return void
 118          */
 119         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 120         {
 121                 if (empty($attachment['url'])) {
 122                         return;
 123                 }
 124
 125                 $data = ['uri-id' => $uriid];
 126                 $data['type'] = Post\Media::UNKNOWN;
 127                 $data['url'] = $attachment['url'];
 128                 $data['mimetype'] = $attachment['mediaType'] ?? null;
 129                 $data['height'] = $attachment['height'] ?? null;
 130                 $data['width'] = $attachment['width'] ?? null;
 131                 $data['size'] = $attachment['size'] ?? null;
 132                 $data['preview'] = $attachment['image'] ?? null;
 133                 $data['description'] = $attachment['name'] ?? null;
 134
 135                 Post\Media::insert($data);
 136         }
 137
 138         /**
 139          * Stire attachment data
 140          *
 141          * @param array   $activity
 142          * @param array   $item
 143          */
 144         private static function storeAttachments($activity, $item)
 145         {
 146                 if (empty($activity['attachments'])) {
 147                         return;
 148                 }
 149
 150                 foreach ($activity['attachments'] as $attach) {
 151                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 152                 }
 153         }
 154
 155         /**
 156          * Updates a message
 157          *
 158          * @param array $activity Activity array
 159          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 160          */
 161         public static function updateItem($activity)
 162         {
 163                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
 164                 if (!DBA::isResult($item)) {
 165                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 166                         $item = self::createItem($activity);
 167                         self::postItem($activity, $item);
 168                         return;
 169                 }
 170
 171                 $item['changed'] = DateTimeFormat::utcNow();
 172                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 173
 174                 $item = self::processContent($activity, $item);
 175
 176                 self::storeAttachments($activity, $item);
 177
 178                 if (empty($item)) {
 179                         return;
 180                 }
 181
 182                 Item::update($item, ['uri' => $activity['id']]);
 183
 184                 if ($activity['object_type'] == 'as:Event') {
 185                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
 186                         while ($post = DBA::fetch($posts)) {
 187                                 self::updateEvent($post['event-id'], $activity);
 188                         }
 189                 }
 190         }
 191
 192         /**
 193          * Update an existing event
 194          *
 195          * @param int $event_id
 196          * @param array $activity
 197          */
 198         private static function updateEvent(int $event_id, array $activity)
 199         {
 200                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
 201
 202                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
 203                 $event['summary']  = HTML::toBBCode($activity['name']);
 204                 $event['desc']     = HTML::toBBCode($activity['content']);
 205                 $event['start']    = $activity['start-time'];
 206                 $event['finish']   = $activity['end-time'];
 207                 $event['nofinish'] = empty($event['finish']);
 208                 $event['location'] = $activity['location'];
 209
 210                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
 211                 Event::store($event);
 212         }
 213
 214         /**
 215          * Prepares data for a message
 216          *
 217          * @param array $activity Activity array
 218          * @return array Internal item
 219          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 220          * @throws \ImagickException
 221          */
 222         public static function createItem($activity)
 223         {
 224                 $item = [];
 225                 $item['verb'] = Activity::POST;
 226                 $item['thr-parent'] = $activity['reply-to-id'];
 227
 228                 if ($activity['reply-to-id'] == $activity['id']) {
 229                         $item['gravity'] = GRAVITY_PARENT;
 230                         $item['object-type'] = Activity\ObjectType::NOTE;
 231                 } else {
 232                         $item['gravity'] = GRAVITY_COMMENT;
 233                         $item['object-type'] = Activity\ObjectType::COMMENT;
 234                 }
 235
 236                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 237                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 238                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 239                 }
 240
 241                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 242
 243                 /// @todo What to do with $activity['context']?
 244                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 245                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 246                         return [];
 247                 }
 248
 249                 $item['network'] = Protocol::ACTIVITYPUB;
 250                 $item['author-link'] = $activity['author'];
 251                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 252                 $item['owner-link'] = $activity['actor'];
 253                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 254
 255                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 256                         $item['private'] = Item::UNLISTED;
 257                 } elseif (in_array(0, $activity['receiver'])) {
 258                         $item['private'] = Item::PUBLIC;
 259                 } else {
 260                         $item['private'] = Item::PRIVATE;
 261                 }
 262
 263                 if (!empty($activity['raw'])) {
 264                         $item['source'] = $activity['raw'];
 265                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 266                         $item['conversation-href'] = $activity['context'] ?? '';
 267                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 268
 269                         if (isset($activity['push'])) {
 270                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 271                         }
 272                 }
 273
 274                 if (!empty($activity['from-relay'])) {
 275                         $item['direction'] = Conversation::RELAY;
 276                 }
 277
 278                 if ($activity['object_type'] == 'as:Article') {
 279                         $item['post-type'] = Item::PT_ARTICLE;
 280                 } elseif ($activity['object_type'] == 'as:Audio') {
 281                         $item['post-type'] = Item::PT_AUDIO;
 282                 } elseif ($activity['object_type'] == 'as:Document') {
 283                         $item['post-type'] = Item::PT_DOCUMENT;
 284                 } elseif ($activity['object_type'] == 'as:Event') {
 285                         $item['post-type'] = Item::PT_EVENT;
 286                 } elseif ($activity['object_type'] == 'as:Image') {
 287                         $item['post-type'] = Item::PT_IMAGE;
 288                 } elseif ($activity['object_type'] == 'as:Page') {
 289                         $item['post-type'] = Item::PT_PAGE;
 290                 } elseif ($activity['object_type'] == 'as:Question') {
 291                         $item['post-type'] = Item::PT_POLL;
 292                 } elseif ($activity['object_type'] == 'as:Video') {
 293                         $item['post-type'] = Item::PT_VIDEO;
 294                 } else {
 295                         $item['post-type'] = Item::PT_NOTE;
 296                 }
 297
 298                 $item['isForum'] = false;
 299
 300                 if (!empty($activity['thread-completion'])) {
 301                         if ($activity['thread-completion'] != $item['owner-id']) {
 302                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 303                                 $item['causer-link'] = $actor['url'];
 304                                 $item['causer-id'] = $activity['thread-completion'];
 305                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 306                         } else {
 307                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 308                                 $item['causer-link'] = $item['owner-link'];
 309                                 $item['causer-id']   = $item['owner-id'];
 310                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 311                         }
 312
 313                         $item['owner-link'] = $item['author-link'];
 314                         $item['owner-id'] = $item['author-id'];
 315                 } else {
 316                         $actor = APContact::getByURL($item['owner-link'], false);
 317                         $item['isForum'] = ($actor['type'] == 'Group');
 318                 }
 319
 320                 $item['uri'] = $activity['id'];
 321
 322                 if (empty($activity['published']) || empty($activity['updated'])) {
 323                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 324                 }
 325
 326                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 327                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 328                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 329                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 330
 331                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 332                 if (empty($item['uri-id'])) {
 333                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 334                         return [];
 335                 }
 336
 337                 $item = self::processContent($activity, $item);
 338                 if (empty($item)) {
 339                         Logger::info('Message was not processed');
 340                         return [];
 341                 }
 342
 343                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 344
 345                 self::storeAttachments($activity, $item);
 346
 347                 // We received the post via AP, so we set the protocol of the server to AP
 348                 $contact = Contact::getById($item['author-id'], ['gsid']);
 349                 if (!empty($contact['gsid'])) {
 350                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 351                 }
 352
 353                 if ($item['author-id'] != $item['owner-id']) {
 354                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 355                         if (!empty($contact['gsid'])) {
 356                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 357                         }
 358                 }
 359
 360                 return $item;
 361         }
 362
 363         /**
 364          * Delete items
 365          *
 366          * @param array $activity
 367          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 368          * @throws \ImagickException
 369          */
 370         public static function deleteItem($activity)
 371         {
 372                 $owner = Contact::getIdForURL($activity['actor']);
 373
 374                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 375                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 376         }
 377
 378         /**
 379          * Prepare the item array for an activity
 380          *
 381          * @param array $activity Activity array
 382          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 383          * @throws \ImagickException
 384          */
 385         public static function addTag($activity)
 386         {
 387                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 388                         return;
 389                 }
 390
 391                 foreach ($activity['receiver'] as $receiver) {
 392                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 393                         if (!DBA::isResult($item)) {
 394                                 // We don't fetch missing content for this purpose
 395                                 continue;
 396                         }
 397
 398                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 399                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 400                                 continue;
 401                         }
 402
 403                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 404                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 405                 }
 406         }
 407
 408         /**
 409          * Prepare the item array for an activity
 410          *
 411          * @param array  $activity Activity array
 412          * @param string $verb     Activity verb
 413          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 414          * @throws \ImagickException
 415          */
 416         public static function createActivity($activity, $verb)
 417         {
 418                 $item = self::createItem($activity);
 419                 $item['verb'] = $verb;
 420                 $item['thr-parent'] = $activity['object_id'];
 421                 $item['gravity'] = GRAVITY_ACTIVITY;
 422                 unset($item['post-type']);
 423                 $item['object-type'] = Activity\ObjectType::NOTE;
 424
 425                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 426
 427                 self::postItem($activity, $item);
 428         }
 429
 430         /**
 431          * Create an event
 432          *
 433          * @param array $activity Activity array
 434          * @param array $item
 435          *
 436          * @return int event id
 437          * @throws \Exception
 438          */
 439         public static function createEvent($activity, $item)
 440         {
 441                 $event['summary']   = HTML::toBBCode($activity['name']);
 442                 $event['desc']      = HTML::toBBCode($activity['content']);
 443                 $event['start']     = $activity['start-time'];
 444                 $event['finish']    = $activity['end-time'];
 445                 $event['nofinish']  = empty($event['finish']);
 446                 $event['location']  = $activity['location'];
 447                 $event['cid']       = $item['contact-id'];
 448                 $event['uid']       = $item['uid'];
 449                 $event['uri']       = $item['uri'];
 450                 $event['edited']    = $item['edited'];
 451                 $event['private']   = $item['private'];
 452                 $event['guid']      = $item['guid'];
 453                 $event['plink']     = $item['plink'];
 454                 $event['network']   = $item['network'];
 455                 $event['protocol']  = $item['protocol'];
 456                 $event['direction'] = $item['direction'];
 457                 $event['source']    = $item['source'];
 458
 459                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 460                 if (DBA::isResult($ev)) {
 461                         $event['id'] = $ev['id'];
 462                 }
 463
 464                 $event_id = Event::store($event);
 465
 466                 Logger::info('Event was stored', ['id' => $event_id]);
 467
 468                 return $event_id;
 469         }
 470
 471         /**
 472          * Process the content
 473          *
 474          * @param array $activity Activity array
 475          * @param array $item
 476          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 477          * @throws \Exception
 478          */
 479         private static function processContent($activity, $item)
 480         {
 481                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 482                         $item['title'] = Markdown::toBBCode($activity['name']);
 483                         $content = Markdown::toBBCode($activity['content']);
 484                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 485                         $item['title'] = $activity['name'];
 486                         $content = $activity['content'];
 487                 } else {
 488                         // By default assume "text/html"
 489                         $item['title'] = HTML::toBBCode($activity['name']);
 490                         $content = HTML::toBBCode($activity['content']);
 491                 }
 492
 493                 if (!empty($activity['languages'])) {
 494                         $item['language'] = self::processLanguages($activity['languages']);
 495                 }
 496
 497                 if (!empty($activity['emojis'])) {
 498                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 499                 }
 500
 501                 $content = self::addMentionLinks($content, $activity['tags']);
 502
 503                 if (!empty($activity['source'])) {
 504                         $item['body'] = $activity['source'];
 505                         $item['raw-body'] = $content;
 506                         $item['body'] = Item::improveSharedDataInBody($item);
 507                 } else {
 508                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 509                                 $item_private = !in_array(0, $activity['item_receiver']);
 510                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 511                                 if (!DBA::isResult($parent)) {
 512                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 513                                         return false;
 514                                 }
 515                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 516                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 517                                         return false;
 518                                 }
 519
 520                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 521                         }
 522                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 523                         $item['raw-body'] = $item['body'] = $content;
 524                 }
 525
 526                 self::storeFromBody($item);
 527                 self::storeTags($item['uri-id'], $activity['tags']);
 528
 529                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 530
 531                 $item['location'] = $activity['location'];
 532
 533                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 534                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 535                 }
 536
 537                 $item['app'] = $activity['generator'];
 538
 539                 return $item;
 540         }
 541
 542         /**
 543          * Store hashtags and mentions
 544          *
 545          * @param array $item
 546          */
 547         private static function storeFromBody(array $item)
 548         {
 549                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 550                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 551
 552                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 553         }
 554
 555         /**
 556          * Generate a GUID out of an URL
 557          *
 558          * @param string $url message URL
 559          * @return string with GUID
 560          */
 561         private static function getGUIDByURL(string $url)
 562         {
 563                 $parsed = parse_url($url);
 564
 565                 $host_hash = hash('crc32', $parsed['host']);
 566
 567                 unset($parsed["scheme"]);
 568                 unset($parsed["host"]);
 569
 570                 $path = implode("/", $parsed);
 571
 572                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 573         }
 574
 575         /**
 576          * Checks if an incoming message is wanted
 577          *
 578          * @param array $activity
 579          * @param array $item
 580          * @return boolean Is the message wanted?
 581          */
 582         private static function isSolicitedMessage(array $activity, array $item)
 583         {
 584                 // The checks are split to improve the support when searching why a message was accepted.
 585                 if (count($activity['receiver']) != 1) {
 586                         // The message has more than one receiver, so it is wanted.
 587                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 588                         return true;
 589                 }
 590
 591                 if ($item['private'] == Item::PRIVATE) {
 592                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 593                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 594                         return true;
 595                 }
 596
 597                 if (!empty($activity['from-relay'])) {
 598                         // We check relay posts at another place. When it arrived here, the message is already checked.
 599                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 600                         return true;
 601                 }
 602
 603                 if (!empty($activity['thread-completion'])) {
 604                         // The thread completion mode means that the post is fetched intentionally.
 605                         // This can have several causes, in doubt we keep the message.
 606                         // This can possibly be improved in the future.
 607                         Logger::debug('Message is in completion mode - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 608                         return true;
 609                 }
 610
 611                 if ($item['gravity'] != GRAVITY_PARENT) {
 612                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 613                         // This can possibly be improved in the future.
 614                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 615                         return true;
 616                 }
 617
 618                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 619                 return Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB);
 620         }
 621
 622         /**
 623          * Creates an item post
 624          *
 625          * @param array $activity Activity data
 626          * @param array $item     item array
 627          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 628          * @throws \ImagickException
 629          */
 630         public static function postItem(array $activity, array $item)
 631         {
 632                 if (empty($item)) {
 633                         return;
 634                 }
 635
 636                 $stored = false;
 637                 ksort($activity['receiver']);
 638
 639                 if (!self::isSolicitedMessage($activity, $item)) {
 640                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 641                         return;
 642                 }
 643
 644                 foreach ($activity['receiver'] as $receiver) {
 645                         if ($receiver == -1) {
 646                                 continue;
 647                         }
 648
 649                         $item['uid'] = $receiver;
 650
 651                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 652                         switch($type) {
 653                                 case Receiver::TARGET_TO:
 654                                         $item['post-reason'] = Item::PR_TO;
 655                                         break;
 656                                 case Receiver::TARGET_CC:
 657                                         $item['post-reason'] = Item::PR_CC;
 658                                         break;
 659                                 case Receiver::TARGET_BTO:
 660                                         $item['post-reason'] = Item::PR_BTO;
 661                                         break;
 662                                 case Receiver::TARGET_BCC:
 663                                         $item['post-reason'] = Item::PR_BCC;
 664                                         break;
 665                                 case Receiver::TARGET_FOLLOWER:
 666                                         $item['post-reason'] = Item::PR_FOLLOWER;
 667                                         break;
 668                                 case Receiver::TARGET_ANSWER:
 669                                         $item['post-reason'] = Item::PR_COMMENT;
 670                                         break;
 671                                 case Receiver::TARGET_GLOBAL:
 672                                         $item['post-reason'] = Item::PR_GLOBAL;
 673                                         break;
 674                                 default:
 675                                         $item['post-reason'] = Item::PR_NONE;
 676                         }
 677
 678                         if (!empty($activity['from-relay'])) {
 679                                 $item['post-reason'] = Item::PR_RELAY;
 680                         } elseif (!empty($activity['thread-completion'])) {
 681                                 $item['post-reason'] = Item::PR_FETCHED;
 682                         }
 683
 684                         if ($item['isForum'] ?? false) {
 685                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 686                         } else {
 687                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 688                         }
 689
 690                         if (($receiver != 0) && empty($item['contact-id'])) {
 691                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 692                         }
 693
 694                         if (!empty($activity['directmessage'])) {
 695                                 self::postMail($activity, $item);
 696                                 continue;
 697                         }
 698
 699                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 700                                 if ($item['post-reason'] == Item::PR_BCC) {
 701                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 702                                         continue;
 703                                 }
 704
 705                                 if (
 706                                         !empty($activity['thread-children-type'])
 707                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
 708                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
 709                                 ) {
 710                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
 711                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
 712                                         continue;
 713                                 }
 714                         }
 715
 716                         $is_forum = false;
 717
 718                         if ($receiver != 0) {
 719                                 $user = User::getById($receiver, ['account-type']);
 720                                 if (!empty($user['account-type'])) {
 721                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
 722                                 }
 723                         }
 724
 725                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 726                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 727
 728                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 729                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 730                                 }
 731
 732                                 if ($skip) {
 733                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 734                                         continue;
 735                                 }
 736
 737                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 738                         }
 739
 740                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 741                                 $event_id = self::createEvent($activity, $item);
 742
 743                                 $item = Event::getItemArrayForImportedId($event_id, $item);
 744                         }
 745
 746                         $item_id = Item::insert($item);
 747                         if ($item_id) {
 748                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 749                         } else {
 750                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 751                         }
 752
 753                         if ($item['uid'] == 0) {
 754                                 $stored = $item_id;
 755                         }
 756                 }
 757
 758                 // Store send a follow request for every reshare - but only when the item had been stored
 759                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 760                         $author = APContact::getByURL($item['owner-link'], false);
 761                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 762                         if ($author['type'] != 'Group') {
 763                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 764                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 765                         }
 766                 }
 767         }
 768
 769         /**
 770          * Store tags and mentions into the tag table
 771          *
 772          * @param integer $uriid
 773          * @param array $tags
 774          */
 775         private static function storeTags(int $uriid, array $tags = null)
 776         {
 777                 foreach ($tags as $tag) {
 778                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 779                                 continue;
 780                         }
 781
 782                         $hash = substr($tag['name'], 0, 1);
 783
 784                         if ($tag['type'] == 'Mention') {
 785                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 786                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 787                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 788                                         $tag['name'] = substr($tag['name'], 1);
 789                                 }
 790                                 $type = Tag::IMPLICIT_MENTION;
 791
 792                                 if (!empty($tag['href'])) {
 793                                         $apcontact = APContact::getByURL($tag['href']);
 794                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 795                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 796                                         }
 797                                 }
 798                         } elseif ($tag['type'] == 'Hashtag') {
 799                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 800                                         $tag['name'] = substr($tag['name'], 1);
 801                                 }
 802                                 $type = Tag::HASHTAG;
 803                         }
 804
 805                         if (empty($tag['name'])) {
 806                                 continue;
 807                         }
 808
 809                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 810                 }
 811         }
 812
 813         public static function storeReceivers(int $uriid, array $receivers)
 814         {
 815                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
 816                         if (!empty($receivers[$element])) {
 817                                 foreach ($receivers[$element] as $receiver) {
 818                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
 819                                                 $name = Receiver::PUBLIC_COLLECTION;
 820                                         } else {
 821                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
 822                                         }
 823                                         Tag::store($uriid, $type, $name, $receiver);
 824                                 }
 825                         }
 826                 }
 827         }
 828
 829         /**
 830          * Creates an mail post
 831          *
 832          * @param array $activity Activity data
 833          * @param array $item     item array
 834          * @return int|bool New mail table row id or false on error
 835          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 836          */
 837         private static function postMail($activity, $item)
 838         {
 839                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 840                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 841                         return false;
 842                 }
 843
 844                 Logger::info('Direct Message', $item);
 845
 846                 $msg = [];
 847                 $msg['uid'] = $item['uid'];
 848
 849                 $msg['contact-id'] = $item['contact-id'];
 850
 851                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 852                 $msg['from-name'] = $contact['name'];
 853                 $msg['from-url'] = $contact['url'];
 854                 $msg['from-photo'] = $contact['photo'];
 855
 856                 $msg['uri'] = $item['uri'];
 857                 $msg['created'] = $item['created'];
 858
 859                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 860                 if (DBA::isResult($parent)) {
 861                         $msg['parent-uri'] = $parent['parent-uri'];
 862                         $msg['title'] = $parent['title'];
 863                 } else {
 864                         $msg['parent-uri'] = $item['thr-parent'];
 865
 866                         if (!empty($item['title'])) {
 867                                 $msg['title'] = $item['title'];
 868                         } elseif (!empty($item['content-warning'])) {
 869                                 $msg['title'] = $item['content-warning'];
 870                         } else {
 871                                 // Trying to generate a title out of the body
 872                                 $title = $item['body'];
 873
 874                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 875                                         $title = $matches[3];
 876                                 }
 877
 878                                 $title = trim(BBCode::toPlaintext($title));
 879
 880                                 if (strlen($title) > 20) {
 881                                         $title = substr($title, 0, 20) . '...';
 882                                 }
 883
 884                                 $msg['title'] = $title;
 885                         }
 886                 }
 887                 $msg['body'] = $item['body'];
 888
 889                 return Mail::insert($msg);
 890         }
 891
 892         /**
 893          * Fetches missing posts
 894          *
 895          * @param string $url         message URL
 896          * @param array  $child       activity array with the child of this message
 897          * @param string $relay_actor Relay actor
 898          * @return string fetched message URL
 899          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 900          */
 901         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '')
 902         {
 903                 if (!empty($child['receiver'])) {
 904                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 905                 } else {
 906                         $uid = 0;
 907                 }
 908
 909                 $object = ActivityPub::fetchContent($url, $uid);
 910                 if (empty($object)) {
 911                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
 912                         return '';
 913                 }
 914
 915                 if (empty($object['id'])) {
 916                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
 917                         return '';
 918                 }
 919
 920                 if (!empty($object['actor'])) {
 921                         $object_actor = $object['actor'];
 922                 } elseif (!empty($object['attributedTo'])) {
 923                         $object_actor = $object['attributedTo'];
 924                         if (is_array($object_actor)) {
 925                                 $compacted = JsonLD::compact($object);
 926                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
 927                         }
 928                 } else {
 929                         // Shouldn't happen
 930                         $object_actor = '';
 931                 }
 932
 933                 $signer = [$object_actor];
 934
 935                 if (!empty($child['author'])) {
 936                         $actor = $child['author'];
 937                         $signer[] = $actor;
 938                 } else {
 939                         $actor = $object_actor;
 940                 }
 941
 942                 if (!empty($object['published'])) {
 943                         $published = $object['published'];
 944                 } elseif (!empty($child['published'])) {
 945                         $published = $child['published'];
 946                 } else {
 947                         $published = DateTimeFormat::utcNow();
 948                 }
 949
 950                 $activity = [];
 951                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
 952                 unset($object['@context']);
 953                 $activity['id'] = $object['id'];
 954                 $activity['to'] = $object['to'] ?? [];
 955                 $activity['cc'] = $object['cc'] ?? [];
 956                 $activity['actor'] = $actor;
 957                 $activity['object'] = $object;
 958                 $activity['published'] = $published;
 959                 $activity['type'] = 'Create';
 960
 961                 $ldactivity = JsonLD::compact($activity);
 962
 963                 if (!empty($relay_actor)) {
 964                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
 965                 } elseif (!empty($child['thread-completion'])) {
 966                         $ldactivity['thread-completion'] = $child['thread-completion'];
 967                 } else {
 968                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
 969                 }
 970
 971                 if (!empty($child['type'])) {
 972                         $ldactivity['thread-children-type'] = $child['type'];
 973                 }
 974
 975                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
 976                         return '';
 977                 }
 978
 979                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
 980
 981                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 982
 983                 return $activity['id'];
 984         }
 985
 986         /**
 987          * Test if incoming relay messages should be accepted
 988          *
 989          * @param array $activity activity array
 990          * @param string $id      object ID
 991          * @return boolean true if message is accepted
 992          */
 993         private static function acceptIncomingMessage(array $activity, string $id)
 994         {
 995                 if (empty($activity['as:object'])) {
 996                         Logger::info('No object field in activity - accepted', ['id' => $id]);
 997                         return true;
 998                 }
 999
1000                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1001                 $uriid = ItemURI::getIdByURI($replyto);
1002                 if (Post::exists(['uri-id' => $uriid])) {
1003                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1004                         return true;
1005                 }
1006
1007                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1008                 $authorid = Contact::getIdForURL($attributed_to);
1009
1010                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
1011
1012                 $messageTags = [];
1013                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1014                 if (!empty($tags)) {
1015                         foreach ($tags as $tag) {
1016                                 if ($tag['type'] != 'Hashtag') {
1017                                         continue;
1018                                 }
1019                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1020                         }
1021                 }
1022
1023                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1024         }
1025
1026         /**
1027          * perform a "follow" request
1028          *
1029          * @param array $activity
1030          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1031          * @throws \ImagickException
1032          */
1033         public static function followUser($activity)
1034         {
1035                 $uid = User::getIdForURL($activity['object_id']);
1036                 if (empty($uid)) {
1037                         return;
1038                 }
1039
1040                 $owner = User::getOwnerDataById($uid);
1041                 if (empty($owner)) {
1042                         return;
1043                 }
1044
1045                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1046                 if (!empty($cid)) {
1047                         self::switchContact($cid);
1048                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1049                 }
1050
1051                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
1052                         'author-link' => $activity['actor']];
1053
1054                 // Ensure that the contact has got the right network type
1055                 self::switchContact($item['author-id']);
1056
1057                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1058                 if ($result === true) {
1059                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1060                 }
1061
1062                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1063                 if (empty($cid)) {
1064                         return;
1065                 }
1066
1067                 if (empty($contact)) {
1068                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1069                 }
1070
1071                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1072         }
1073
1074         /**
1075          * Update the given profile
1076          *
1077          * @param array $activity
1078          * @throws \Exception
1079          */
1080         public static function updatePerson($activity)
1081         {
1082                 if (empty($activity['object_id'])) {
1083                         return;
1084                 }
1085
1086                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1087                 Contact::updateFromProbeByURL($activity['object_id']);
1088         }
1089
1090         /**
1091          * Delete the given profile
1092          *
1093          * @param array $activity
1094          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1095          */
1096         public static function deletePerson($activity)
1097         {
1098                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1099                         Logger::info('Empty object id or actor.');
1100                         return;
1101                 }
1102
1103                 if ($activity['object_id'] != $activity['actor']) {
1104                         Logger::info('Object id does not match actor.');
1105                         return;
1106                 }
1107
1108                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1109                 while ($contact = DBA::fetch($contacts)) {
1110                         Contact::remove($contact['id']);
1111                 }
1112                 DBA::close($contacts);
1113
1114                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1115         }
1116
1117         /**
1118          * Accept a follow request
1119          *
1120          * @param array $activity
1121          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1122          * @throws \ImagickException
1123          */
1124         public static function acceptFollowUser($activity)
1125         {
1126                 $uid = User::getIdForURL($activity['object_actor']);
1127                 if (empty($uid)) {
1128                         return;
1129                 }
1130
1131                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1132                 if (empty($cid)) {
1133                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1134                         return;
1135                 }
1136
1137                 self::switchContact($cid);
1138
1139                 $fields = ['pending' => false];
1140
1141                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1142                 if ($contact['rel'] == Contact::FOLLOWER) {
1143                         $fields['rel'] = Contact::FRIEND;
1144                 }
1145
1146                 $condition = ['id' => $cid];
1147                 Contact::update($fields, $condition);
1148                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1149         }
1150
1151         /**
1152          * Reject a follow request
1153          *
1154          * @param array $activity
1155          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1156          * @throws \ImagickException
1157          */
1158         public static function rejectFollowUser($activity)
1159         {
1160                 $uid = User::getIdForURL($activity['object_actor']);
1161                 if (empty($uid)) {
1162                         return;
1163                 }
1164
1165                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1166                 if (empty($cid)) {
1167                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1168                         return;
1169                 }
1170
1171                 self::switchContact($cid);
1172
1173                 $contact = Contact::getById($cid, ['rel']);
1174                 if ($contact['rel'] == Contact::SHARING) {
1175                         Contact::remove($cid);
1176                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1177                 } elseif ($contact['rel'] == Contact::FRIEND) {
1178                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1179                 } else {
1180                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1181                 }
1182         }
1183
1184         /**
1185          * Undo activity like "like" or "dislike"
1186          *
1187          * @param array $activity
1188          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1189          * @throws \ImagickException
1190          */
1191         public static function undoActivity($activity)
1192         {
1193                 if (empty($activity['object_id'])) {
1194                         return;
1195                 }
1196
1197                 if (empty($activity['object_actor'])) {
1198                         return;
1199                 }
1200
1201                 $author_id = Contact::getIdForURL($activity['object_actor']);
1202                 if (empty($author_id)) {
1203                         return;
1204                 }
1205
1206                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1207         }
1208
1209         /**
1210          * Activity to remove a follower
1211          *
1212          * @param array $activity
1213          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1214          * @throws \ImagickException
1215          */
1216         public static function undoFollowUser($activity)
1217         {
1218                 $uid = User::getIdForURL($activity['object_object']);
1219                 if (empty($uid)) {
1220                         return;
1221                 }
1222
1223                 $owner = User::getOwnerDataById($uid);
1224                 if (empty($owner)) {
1225                         return;
1226                 }
1227
1228                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1229                 if (empty($cid)) {
1230                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1231                         return;
1232                 }
1233
1234                 self::switchContact($cid);
1235
1236                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1237                 if (!DBA::isResult($contact)) {
1238                         return;
1239                 }
1240
1241                 Contact::removeFollower($contact);
1242                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1243         }
1244
1245         /**
1246          * Switches a contact to AP if needed
1247          *
1248          * @param integer $cid Contact ID
1249          * @throws \Exception
1250          */
1251         private static function switchContact($cid)
1252         {
1253                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1254                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1255                         return;
1256                 }
1257
1258                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1259                 Contact::updateFromProbe($cid);
1260         }
1261
1262         /**
1263          * Collects implicit mentions like:
1264          * - the author of the parent item
1265          * - all the mentioned conversants in the parent item
1266          *
1267          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1268          * @return array
1269          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1270          */
1271         private static function getImplicitMentionList(array $parent)
1272         {
1273                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1274
1275                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1276
1277                 $implicit_mentions = [];
1278                 if (empty($parent_author['url'])) {
1279                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1280                 } else {
1281                         $implicit_mentions[] = $parent_author['url'];
1282                         $implicit_mentions[] = $parent_author['nurl'];
1283                         $implicit_mentions[] = $parent_author['alias'];
1284                 }
1285
1286                 if (!empty($parent['alias'])) {
1287                         $implicit_mentions[] = $parent['alias'];
1288                 }
1289
1290                 foreach ($parent_terms as $term) {
1291                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1292                         if (!empty($contact['url'])) {
1293                                 $implicit_mentions[] = $contact['url'];
1294                                 $implicit_mentions[] = $contact['nurl'];
1295                                 $implicit_mentions[] = $contact['alias'];
1296                         }
1297                 }
1298
1299                 return $implicit_mentions;
1300         }
1301
1302         /**
1303          * Strips from the body prepended implicit mentions
1304          *
1305          * @param string $body
1306          * @param array $parent
1307          * @return string
1308          */
1309         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1310         {
1311                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1312                         return $body;
1313                 }
1314
1315                 $potential_mentions = self::getImplicitMentionList($parent);
1316
1317                 $kept_mentions = [];
1318
1319                 // Extract one prepended mention at a time from the body
1320                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1321                         if (!in_array($matches[2], $potential_mentions)) {
1322                                 $kept_mentions[] = $matches[1];
1323                         }
1324
1325                         $body = $matches[3];
1326                 }
1327
1328                 // Re-appending the kept mentions to the body after extraction
1329                 $kept_mentions[] = $body;
1330
1331                 return implode('', $kept_mentions);
1332         }
1333
1334         /**
1335          * Adds links to string mentions
1336          *
1337          * @param string $body
1338          * @param array  $tags
1339          * @return string
1340          */
1341         protected static function addMentionLinks(string $body, array $tags): string
1342         {
1343                 // This prevents links to be added again to Pleroma-style mention links
1344                 $body = self::normalizeMentionLinks($body);
1345
1346                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1347                         foreach ($tags as $tag) {
1348                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1349                                         continue;
1350                                 }
1351
1352                                 $hash = substr($tag['name'], 0, 1);
1353                                 $name = substr($tag['name'], 1);
1354                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1355                                         $hash = '';
1356                                         $name = $tag['name'];
1357                                 }
1358
1359                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1360                         }
1361
1362                         return $body;
1363                 });
1364
1365                 return $body;
1366         }
1367 }