src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub/Processor.php
   4  */
   5 namespace Friendica\Protocol\ActivityPub;
   6
   7 use Friendica\Database\DBA;
   8 use Friendica\Content\Text\HTML;
   9 use Friendica\Core\Config;
  10 use Friendica\Core\Logger;
  11 use Friendica\Core\Protocol;
  12 use Friendica\Model\Contact;
  13 use Friendica\Model\APContact;
  14 use Friendica\Model\Item;
  15 use Friendica\Model\Event;
  16 use Friendica\Model\Term;
  17 use Friendica\Model\User;
  18 use Friendica\Protocol\ActivityPub;
  19 use Friendica\Util\DateTimeFormat;
  20 use Friendica\Util\JsonLD;
  21 use Friendica\Util\Strings;
  22
  23 /**
  24  * ActivityPub Processor Protocol class
  25  */
  26 class Processor
  27 {
  28         /**
  29          * Converts mentions from Pleroma into the Friendica format
  30          *
  31          * @param string $body
  32          *
  33          * @return string converted body
  34          */
  35         private static function convertMentions($body)
  36         {
  37                 $URLSearchString = "^\[\]";
  38                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  39
  40                 return $body;
  41         }
  42
  43         /**
  44          * Replaces emojis in the body
  45          *
  46          * @param array $emojis
  47          * @param string $body
  48          *
  49          * @return string with replaced emojis
  50          */
  51         public static function replaceEmojis($body, array $emojis)
  52         {
  53                 foreach ($emojis as $emoji) {
  54                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  55                         $body = str_replace($emoji['name'], $replace, $body);
  56                 }
  57                 return $body;
  58         }
  59
  60         /**
  61          * Constructs a string with tags for a given tag array
  62          *
  63          * @param array   $tags
  64          * @param boolean $sensitive
  65          * @param array   $implicit_mentions List of profile URLs to skip
  66          * @return string with tags
  67          */
  68         private static function constructTagString(array $tags, $sensitive)
  69         {
  70                 if (empty($tags)) {
  71                         return '';
  72                 }
  73
  74                 $tag_text = '';
  75                 foreach ($tags as $tag) {
  76                         if (in_array(defaults($tag, 'type', ''), ['Mention', 'Hashtag'])) {
  77                                 if (!empty($tag_text)) {
  78                                         $tag_text .= ',';
  79                                 }
  80
  81                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
  82                         }
  83                 }
  84
  85                 /// @todo add nsfw for $sensitive
  86
  87                 return $tag_text;
  88         }
  89
  90         /**
  91          * Add attachment data to the item array
  92          *
  93          * @param array $attachments
  94          * @param array $item
  95          *
  96          * @return array array
  97          */
  98         private static function constructAttachList($attachments, $item)
  99         {
 100                 if (empty($attachments)) {
 101                         return $item;
 102                 }
 103
 104                 foreach ($attachments as $attach) {
 105                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 106                         if ($filetype == 'image') {
 107                                 $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 108                         } else {
 109                                 if (!empty($item["attach"])) {
 110                                         $item["attach"] .= ',';
 111                                 } else {
 112                                         $item["attach"] = '';
 113                                 }
 114                                 if (!isset($attach['length'])) {
 115                                         $attach['length'] = "0";
 116                                 }
 117                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
 118                         }
 119                 }
 120
 121                 return $item;
 122         }
 123
 124         /**
 125          * Updates a message
 126          *
 127          * @param array $activity Activity array
 128          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 129          */
 130         public static function updateItem($activity)
 131         {
 132                 $item = Item::selectFirst(['uri', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 133                 if (!DBA::isResult($item)) {
 134                         Logger::warning('Unknown item', ['uri' => $activity['id']]);
 135                         return;
 136                 }
 137
 138                 $item['changed'] = DateTimeFormat::utcNow();
 139                 $item['edited'] = $activity['updated'];
 140                 $item['title'] = HTML::toBBCode($activity['name']);
 141                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
 142
 143                 $content = HTML::toBBCode($activity['content']);
 144                 $content = self::replaceEmojis($content, $activity['emojis']);
 145                 $content = self::convertMentions($content);
 146
 147                 if (($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 148                         $parent = Item::selectFirst(['id', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 149                         if (!DBA::isResult($parent)) {
 150                                 Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 151                                 return;
 152                         }
 153
 154                         $potential_implicit_mentions = self::getImplicitMentionList($parent);
 155                         $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 156                         $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 157                 }
 158
 159                 $item['body'] = $content;
 160                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive']);
 161
 162                 Item::update($item, ['uri' => $activity['id']]);
 163         }
 164
 165         /**
 166          * Prepares data for a message
 167          *
 168          * @param array $activity Activity array
 169          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 170          * @throws \ImagickException
 171          */
 172         public static function createItem($activity)
 173         {
 174                 $item = [];
 175                 $item['verb'] = ACTIVITY_POST;
 176                 $item['thr-parent'] = $activity['reply-to-id'];
 177
 178                 if ($activity['reply-to-id'] == $activity['id']) {
 179                         $item['gravity'] = GRAVITY_PARENT;
 180                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
 181                 } else {
 182                         $item['gravity'] = GRAVITY_COMMENT;
 183                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
 184                 }
 185
 186                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 187                         Logger::log('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
 188                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 189                 }
 190
 191                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:comment', '');
 192
 193                 self::postItem($activity, $item);
 194         }
 195
 196         /**
 197          * Delete items
 198          *
 199          * @param array $activity
 200          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 201          * @throws \ImagickException
 202          */
 203         public static function deleteItem($activity)
 204         {
 205                 $owner = Contact::getIdForURL($activity['actor']);
 206
 207                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 208                 Item::delete(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 209         }
 210
 211         /**
 212          * Prepare the item array for an activity
 213          *
 214          * @param array  $activity Activity array
 215          * @param string $verb     Activity verb
 216          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 217          * @throws \ImagickException
 218          */
 219         public static function createActivity($activity, $verb)
 220         {
 221                 $item = [];
 222                 $item['verb'] = $verb;
 223                 $item['thr-parent'] = $activity['object_id'];
 224                 $item['gravity'] = GRAVITY_ACTIVITY;
 225                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
 226
 227                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:like', '');
 228
 229                 self::postItem($activity, $item);
 230         }
 231
 232         /**
 233          * Create an event
 234          *
 235          * @param array $activity Activity array
 236          * @param array $item
 237          * @throws \Exception
 238          */
 239         public static function createEvent($activity, $item)
 240         {
 241                 $event['summary']  = HTML::toBBCode($activity['name']);
 242                 $event['desc']     = HTML::toBBCode($activity['content']);
 243                 $event['start']    = $activity['start-time'];
 244                 $event['finish']   = $activity['end-time'];
 245                 $event['nofinish'] = empty($event['finish']);
 246                 $event['location'] = $activity['location'];
 247                 $event['adjust']   = true;
 248                 $event['cid']      = $item['contact-id'];
 249                 $event['uid']      = $item['uid'];
 250                 $event['uri']      = $item['uri'];
 251                 $event['edited']   = $item['edited'];
 252                 $event['private']  = $item['private'];
 253                 $event['guid']     = $item['guid'];
 254                 $event['plink']    = $item['plink'];
 255
 256                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 257                 $ev = DBA::selectFirst('event', ['id'], $condition);
 258                 if (DBA::isResult($ev)) {
 259                         $event['id'] = $ev['id'];
 260                 }
 261
 262                 $event_id = Event::store($event);
 263                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 264         }
 265
 266         /**
 267          * Creates an item post
 268          *
 269          * @param array $activity Activity data
 270          * @param array $item     item array
 271          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 272          * @throws \ImagickException
 273          */
 274         private static function postItem($activity, $item)
 275         {
 276                 /// @todo What to do with $activity['context']?
 277
 278                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 279                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 280                         return;
 281                 }
 282
 283                 $item['network'] = Protocol::ACTIVITYPUB;
 284                 $item['private'] = !in_array(0, $activity['receiver']);
 285                 $item['author-link'] = $activity['author'];
 286                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 287
 288                 if (empty($activity['thread-completion'])) {
 289                         $item['owner-link'] = $activity['actor'];
 290                         $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 291                 } else {
 292                         Logger::info('Ignoring actor because of thread completion.');
 293                         $item['owner-link'] = $item['author-link'];
 294                         $item['owner-id'] = $item['author-id'];
 295                 }
 296
 297                 $item['uri'] = $activity['id'];
 298                 $content = HTML::toBBCode($activity['content']);
 299                 $content = self::replaceEmojis($content, $activity['emojis']);
 300                 $content = self::convertMentions($content);
 301
 302                 if (($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 303                         $item_private = !in_array(0, $activity['item_receiver']);
 304                         $parent = Item::selectFirst(['id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 305                         if (!DBA::isResult($parent)) {
 306                                 return;
 307                         }
 308                         if ($item_private && !$parent['private']) {
 309                                 Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 310                                 return;
 311                         }
 312
 313                         $potential_implicit_mentions = self::getImplicitMentionList($parent);
 314                         $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 315                         $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 316                 }
 317
 318                 $item['created'] = $activity['published'];
 319                 $item['edited'] = $activity['updated'];
 320                 $item['guid'] = $activity['diaspora:guid'];
 321                 $item['title'] = HTML::toBBCode($activity['name']);
 322                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
 323                 $item['body'] = $content;
 324
 325                 if (($activity['object_type'] == 'as:Video') && !empty($activity['alternate-url'])) {
 326                         $item['body'] .= "\n[video]" . $activity['alternate-url'] . '[/video]';
 327                 }
 328
 329                 $item['location'] = $activity['location'];
 330
 331                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 332                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 333                 }
 334
 335                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive']);
 336                 $item['app'] = $activity['generator'];
 337                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
 338
 339                 $item = self::constructAttachList($activity['attachments'], $item);
 340
 341                 if (!empty($activity['source'])) {
 342                         $item['body'] = $activity['source'];
 343                 }
 344
 345                 $stored = false;
 346
 347                 foreach ($activity['receiver'] as $receiver) {
 348                         $item['uid'] = $receiver;
 349                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 350
 351                         if (($receiver != 0) && empty($item['contact-id'])) {
 352                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 353                         }
 354
 355                         if ($activity['object_type'] == 'as:Event') {
 356                                 self::createEvent($activity, $item);
 357                         }
 358
 359                         $item_id = Item::insert($item);
 360                         if ($item_id) {
 361                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 362                         } else {
 363                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 364                         }
 365
 366                         if ($item['uid'] == 0) {
 367                                 $stored = $item_id;
 368                         }
 369                 }
 370
 371                 // Store send a follow request for every reshare - but only when the item had been stored
 372                 if ($stored && !$item['private'] && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 373                         $author = APContact::getByURL($item['owner-link'], false);
 374                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 375                         if ($author['type'] != 'Group') {
 376                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 377                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 378                         }
 379                 }
 380         }
 381
 382         /**
 383          * Fetches missing posts
 384          *
 385          * @param $url
 386          * @param $child
 387          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 388          */
 389         private static function fetchMissingActivity($url, $child)
 390         {
 391                 if (Config::get('system', 'ostatus_full_threads')) {
 392                         return;
 393                 }
 394
 395                 $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 396
 397                 $object = ActivityPub::fetchContent($url, $uid);
 398                 if (empty($object)) {
 399                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 400                         return;
 401                 }
 402
 403                 if (empty($object['id'])) {
 404                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 405                         return;
 406                 }
 407
 408                 $activity = [];
 409                 $activity['@context'] = $object['@context'];
 410                 unset($object['@context']);
 411                 $activity['id'] = $object['id'];
 412                 $activity['to'] = defaults($object, 'to', []);
 413                 $activity['cc'] = defaults($object, 'cc', []);
 414                 $activity['actor'] = $child['author'];
 415                 $activity['object'] = $object;
 416                 $activity['published'] = defaults($object, 'published', $child['published']);
 417                 $activity['type'] = 'Create';
 418
 419                 $ldactivity = JsonLD::compact($activity);
 420
 421                 $ldactivity['thread-completion'] = true;
 422
 423                 ActivityPub\Receiver::processActivity($ldactivity);
 424                 Logger::log('Activity ' . $url . ' had been fetched and processed.');
 425         }
 426
 427         /**
 428          * perform a "follow" request
 429          *
 430          * @param array $activity
 431          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 432          * @throws \ImagickException
 433          */
 434         public static function followUser($activity)
 435         {
 436                 $uid = User::getIdForURL($activity['object_id']);
 437                 if (empty($uid)) {
 438                         return;
 439                 }
 440
 441                 $owner = User::getOwnerDataById($uid);
 442
 443                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 444                 if (!empty($cid)) {
 445                         self::switchContact($cid);
 446                         DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
 447                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 448                 } else {
 449                         $contact = false;
 450                 }
 451
 452                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 453                         'author-link' => $activity['actor']];
 454
 455                 // Ensure that the contact has got the right network type
 456                 self::switchContact($item['author-id']);
 457
 458                 Contact::addRelationship($owner, $contact, $item);
 459                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 460                 if (empty($cid)) {
 461                         return;
 462                 }
 463
 464                 if (empty($contact)) {
 465                         DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
 466                 }
 467
 468                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 469         }
 470
 471         /**
 472          * Update the given profile
 473          *
 474          * @param array $activity
 475          * @throws \Exception
 476          */
 477         public static function updatePerson($activity)
 478         {
 479                 if (empty($activity['object_id'])) {
 480                         return;
 481                 }
 482
 483                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 484                 APContact::getByURL($activity['object_id'], true);
 485         }
 486
 487         /**
 488          * Delete the given profile
 489          *
 490          * @param array $activity
 491          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 492          */
 493         public static function deletePerson($activity)
 494         {
 495                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 496                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 497                         return;
 498                 }
 499
 500                 if ($activity['object_id'] != $activity['actor']) {
 501                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 502                         return;
 503                 }
 504
 505                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 506                 while ($contact = DBA::fetch($contacts)) {
 507                         Contact::remove($contact['id']);
 508                 }
 509                 DBA::close($contacts);
 510
 511                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 512         }
 513
 514         /**
 515          * Accept a follow request
 516          *
 517          * @param array $activity
 518          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 519          * @throws \ImagickException
 520          */
 521         public static function acceptFollowUser($activity)
 522         {
 523                 $uid = User::getIdForURL($activity['object_actor']);
 524                 if (empty($uid)) {
 525                         return;
 526                 }
 527
 528                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 529                 if (empty($cid)) {
 530                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 531                         return;
 532                 }
 533
 534                 self::switchContact($cid);
 535
 536                 $fields = ['pending' => false];
 537
 538                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 539                 if ($contact['rel'] == Contact::FOLLOWER) {
 540                         $fields['rel'] = Contact::FRIEND;
 541                 }
 542
 543                 $condition = ['id' => $cid];
 544                 DBA::update('contact', $fields, $condition);
 545                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 546         }
 547
 548         /**
 549          * Reject a follow request
 550          *
 551          * @param array $activity
 552          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 553          * @throws \ImagickException
 554          */
 555         public static function rejectFollowUser($activity)
 556         {
 557                 $uid = User::getIdForURL($activity['object_actor']);
 558                 if (empty($uid)) {
 559                         return;
 560                 }
 561
 562                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 563                 if (empty($cid)) {
 564                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 565                         return;
 566                 }
 567
 568                 self::switchContact($cid);
 569
 570                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING, 'pending' => true])) {
 571                         Contact::remove($cid);
 572                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 573                 } else {
 574                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 575                 }
 576         }
 577
 578         /**
 579          * Undo activity like "like" or "dislike"
 580          *
 581          * @param array $activity
 582          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 583          * @throws \ImagickException
 584          */
 585         public static function undoActivity($activity)
 586         {
 587                 if (empty($activity['object_id'])) {
 588                         return;
 589                 }
 590
 591                 if (empty($activity['object_actor'])) {
 592                         return;
 593                 }
 594
 595                 $author_id = Contact::getIdForURL($activity['object_actor']);
 596                 if (empty($author_id)) {
 597                         return;
 598                 }
 599
 600                 Item::delete(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 601         }
 602
 603         /**
 604          * Activity to remove a follower
 605          *
 606          * @param array $activity
 607          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 608          * @throws \ImagickException
 609          */
 610         public static function undoFollowUser($activity)
 611         {
 612                 $uid = User::getIdForURL($activity['object_object']);
 613                 if (empty($uid)) {
 614                         return;
 615                 }
 616
 617                 $owner = User::getOwnerDataById($uid);
 618
 619                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 620                 if (empty($cid)) {
 621                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 622                         return;
 623                 }
 624
 625                 self::switchContact($cid);
 626
 627                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 628                 if (!DBA::isResult($contact)) {
 629                         return;
 630                 }
 631
 632                 Contact::removeFollower($owner, $contact);
 633                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 634         }
 635
 636         /**
 637          * Switches a contact to AP if needed
 638          *
 639          * @param integer $cid Contact ID
 640          * @throws \Exception
 641          */
 642         private static function switchContact($cid)
 643         {
 644                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 645                 if (!DBA::isResult($contact) || ($contact['network'] == Protocol::ACTIVITYPUB)) {
 646                         return;
 647                 }
 648
 649                 Logger::log('Change existing contact ' . $cid . ' from ' . $contact['network'] . ' to ActivityPub.');
 650                 Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
 651         }
 652
 653         /**
 654          * Collects implicit mentions like:
 655          * - the author of the parent item
 656          * - all the mentioned conversants in the parent item
 657          *
 658          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 659          * @return array
 660          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 661          */
 662         private static function getImplicitMentionList(array $parent)
 663         {
 664                 if (Config::get('system', 'disable_implicit_mentions')) {
 665                         return [];
 666                 }
 667
 668                 $parent_terms = Term::tagArrayFromItemId($parent['id'], [Term::MENTION, Term::IMPLICIT_MENTION]);
 669
 670                 $parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 671
 672                 $implicit_mentions = [];
 673                 if (empty($parent_author)) {
 674                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 675                 } else {
 676                         $implicit_mentions[] = $parent_author['url'];
 677                         $implicit_mentions[] = $parent_author['nurl'];
 678                         $implicit_mentions[] = $parent_author['alias'];
 679                 }
 680
 681                 if (!empty($parent['alias'])) {
 682                         $implicit_mentions[] = $parent['alias'];
 683                 }
 684
 685                 foreach ($parent_terms as $term) {
 686                         $contact = Contact::getDetailsByURL($term['url'], 0);
 687                         if (!empty($contact)) {
 688                                 $implicit_mentions[] = $contact['url'];
 689                                 $implicit_mentions[] = $contact['nurl'];
 690                                 $implicit_mentions[] = $contact['alias'];
 691                         }
 692                 }
 693
 694                 return $implicit_mentions;
 695         }
 696
 697         /**
 698          * Strips from the body prepended implicit mentions
 699          *
 700          * @param string $body
 701          * @param array $potential_mentions
 702          * @return string
 703          */
 704         private static function removeImplicitMentionsFromBody($body, array $potential_mentions)
 705         {
 706                 if (Config::get('system', 'disable_implicit_mentions')) {
 707                         return $body;
 708                 }
 709
 710                 $kept_mentions = [];
 711
 712                 // Extract one prepended mention at a time from the body
 713                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
 714                         if (!in_array($matches[2], $potential_mentions) ) {
 715                                 $kept_mentions[] = $matches[1];
 716                         }
 717
 718                         $body = $matches[3];
 719                 }
 720
 721                 // Re-appending the kept mentions to the body after extraction
 722                 $kept_mentions[] = $body;
 723
 724                 return implode('', $kept_mentions);
 725         }
 726
 727         private static function convertImplicitMentionsInTags($activity_tags, array $potential_mentions)
 728         {
 729                 if (Config::get('system', 'disable_implicit_mentions')) {
 730                         return $activity_tags;
 731                 }
 732
 733                 foreach ($activity_tags as $index => $tag) {
 734                         if (in_array($tag['href'], $potential_mentions)) {
 735                                 $activity_tags[$index]['name'] = preg_replace(
 736                                         '/' . preg_quote(Term::TAG_CHARACTER[Term::MENTION], '/') . '/',
 737                                         Term::TAG_CHARACTER[Term::IMPLICIT_MENTION],
 738                                         $activity_tags[$index]['name'],
 739                                         1
 740                                 );
 741                         }
 742                 }
 743
 744                 return $activity_tags;
 745         }
 746 }