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\BBCode;
   9 use Friendica\Content\Text\HTML;
  10 use Friendica\Core\Config;
  11 use Friendica\Core\Logger;
  12 use Friendica\Core\Protocol;
  13 use Friendica\Model\Contact;
  14 use Friendica\Model\APContact;
  15 use Friendica\Model\Item;
  16 use Friendica\Model\Event;
  17 use Friendica\Model\Term;
  18 use Friendica\Model\User;
  19 use Friendica\Model\Mail;
  20 use Friendica\Protocol\ActivityPub;
  21 use Friendica\Util\DateTimeFormat;
  22 use Friendica\Util\JsonLD;
  23 use Friendica\Util\Strings;
  24
  25 /**
  26  * ActivityPub Processor Protocol class
  27  */
  28 class Processor
  29 {
  30         /**
  31          * Converts mentions from Pleroma into the Friendica format
  32          *
  33          * @param string $body
  34          *
  35          * @return string converted body
  36          */
  37         private static function convertMentions($body)
  38         {
  39                 $URLSearchString = "^\[\]";
  40                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  41
  42                 return $body;
  43         }
  44
  45         /**
  46          * Replaces emojis in the body
  47          *
  48          * @param array $emojis
  49          * @param string $body
  50          *
  51          * @return string with replaced emojis
  52          */
  53         private static function replaceEmojis($body, array $emojis)
  54         {
  55                 foreach ($emojis as $emoji) {
  56                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  57                         $body = str_replace($emoji['name'], $replace, $body);
  58                 }
  59                 return $body;
  60         }
  61
  62         /**
  63          * Constructs a string with tags for a given tag array
  64          *
  65          * @param array   $tags
  66          * @param boolean $sensitive
  67          * @param array   $implicit_mentions List of profile URLs to skip
  68          * @return string with tags
  69          */
  70         private static function constructTagString(array $tags, $sensitive)
  71         {
  72                 if (empty($tags)) {
  73                         return '';
  74                 }
  75
  76                 $tag_text = '';
  77                 foreach ($tags as $tag) {
  78                         if (in_array(defaults($tag, 'type', ''), ['Mention', 'Hashtag'])) {
  79                                 if (!empty($tag_text)) {
  80                                         $tag_text .= ',';
  81                                 }
  82
  83                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
  84                         }
  85                 }
  86
  87                 /// @todo add nsfw for $sensitive
  88
  89                 return $tag_text;
  90         }
  91
  92         /**
  93          * Add attachment data to the item array
  94          *
  95          * @param array   $attachments
  96          * @param array   $item
  97          * @param boolean $no_images
  98          *
  99          * @return array array
 100          */
 101         private static function constructAttachList($attachments, $item, $no_images)
 102         {
 103                 if (empty($attachments)) {
 104                         return $item;
 105                 }
 106
 107                 foreach ($attachments as $attach) {
 108                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 109                         if ($filetype == 'image') {
 110                                 if ($no_images) {
 111                                         continue;
 112                                 }
 113
 114                                 $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 115                         } else {
 116                                 if (!empty($item["attach"])) {
 117                                         $item["attach"] .= ',';
 118                                 } else {
 119                                         $item["attach"] = '';
 120                                 }
 121                                 if (!isset($attach['length'])) {
 122                                         $attach['length'] = "0";
 123                                 }
 124                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
 125                         }
 126                 }
 127
 128                 return $item;
 129         }
 130
 131         /**
 132          * Updates a message
 133          *
 134          * @param array $activity Activity array
 135          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 136          */
 137         public static function updateItem($activity)
 138         {
 139                 $item = Item::selectFirst(['uri', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 140                 if (!DBA::isResult($item)) {
 141                         Logger::warning('Unknown item', ['uri' => $activity['id']]);
 142                         return;
 143                 }
 144
 145                 $item['changed'] = DateTimeFormat::utcNow();
 146                 $item['edited'] = $activity['updated'];
 147
 148                 $item = self::processContent($activity, $item);
 149                 if (empty($item)) {
 150                         return;
 151                 }
 152
 153                 Item::update($item, ['uri' => $activity['id']]);
 154         }
 155
 156         /**
 157          * Prepares data for a message
 158          *
 159          * @param array $activity Activity array
 160          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 161          * @throws \ImagickException
 162          */
 163         public static function createItem($activity)
 164         {
 165                 $item = [];
 166                 $item['verb'] = ACTIVITY_POST;
 167                 $item['thr-parent'] = $activity['reply-to-id'];
 168
 169                 if ($activity['reply-to-id'] == $activity['id']) {
 170                         $item['gravity'] = GRAVITY_PARENT;
 171                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
 172                 } else {
 173                         $item['gravity'] = GRAVITY_COMMENT;
 174                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
 175                 }
 176
 177                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 178                         Logger::log('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
 179                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 180                 }
 181
 182                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:comment', '');
 183
 184                 self::postItem($activity, $item);
 185         }
 186
 187         /**
 188          * Delete items
 189          *
 190          * @param array $activity
 191          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 192          * @throws \ImagickException
 193          */
 194         public static function deleteItem($activity)
 195         {
 196                 $owner = Contact::getIdForURL($activity['actor']);
 197
 198                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 199                 Item::delete(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 200         }
 201
 202         /**
 203          * Prepare the item array for an activity
 204          *
 205          * @param array  $activity Activity array
 206          * @param string $verb     Activity verb
 207          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 208          * @throws \ImagickException
 209          */
 210         public static function createActivity($activity, $verb)
 211         {
 212                 $item = [];
 213                 $item['verb'] = $verb;
 214                 $item['thr-parent'] = $activity['object_id'];
 215                 $item['gravity'] = GRAVITY_ACTIVITY;
 216                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
 217
 218                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:like', '');
 219
 220                 self::postItem($activity, $item);
 221         }
 222
 223         /**
 224          * Create an event
 225          *
 226          * @param array $activity Activity array
 227          * @param array $item
 228          * @throws \Exception
 229          */
 230         public static function createEvent($activity, $item)
 231         {
 232                 $event['summary']  = HTML::toBBCode($activity['name']);
 233                 $event['desc']     = HTML::toBBCode($activity['content']);
 234                 $event['start']    = $activity['start-time'];
 235                 $event['finish']   = $activity['end-time'];
 236                 $event['nofinish'] = empty($event['finish']);
 237                 $event['location'] = $activity['location'];
 238                 $event['adjust']   = true;
 239                 $event['cid']      = $item['contact-id'];
 240                 $event['uid']      = $item['uid'];
 241                 $event['uri']      = $item['uri'];
 242                 $event['edited']   = $item['edited'];
 243                 $event['private']  = $item['private'];
 244                 $event['guid']     = $item['guid'];
 245                 $event['plink']    = $item['plink'];
 246
 247                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 248                 $ev = DBA::selectFirst('event', ['id'], $condition);
 249                 if (DBA::isResult($ev)) {
 250                         $event['id'] = $ev['id'];
 251                 }
 252
 253                 $event_id = Event::store($event);
 254                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 255         }
 256
 257         /**
 258          * Process the content
 259          *
 260          * @param array $activity Activity array
 261          * @param array $item
 262          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 263          * @throws \Exception
 264          */
 265         private static function processContent($activity, $item)
 266         {
 267                 $item['title'] = HTML::toBBCode($activity['name']);
 268
 269                 if (!empty($activity['source'])) {
 270                         $item['body'] = $activity['source'];
 271                 } else {
 272                         $content = HTML::toBBCode($activity['content']);
 273
 274                         if (!empty($activity['emojis'])) {
 275                                 $content = self::replaceEmojis($content, $activity['emojis']);
 276                         }
 277
 278                         $content = self::convertMentions($content);
 279
 280                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 281                                 $item_private = !in_array(0, $activity['item_receiver']);
 282                                 $parent = Item::selectFirst(['id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 283                                 if (!DBA::isResult($parent)) {
 284                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 285                                         return false;
 286                                 }
 287                                 if ($item_private && !$parent['private']) {
 288                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 289                                         return false;
 290                                 }
 291
 292                                 $potential_implicit_mentions = self::getImplicitMentionList($parent);
 293                                 $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 294                                 $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 295                         }
 296                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 297                         $item['body'] = $content;
 298
 299                         if (($activity['object_type'] == 'as:Video') && !empty($activity['alternate-url'])) {
 300                                 $item['body'] .= "\n[video]" . $activity['alternate-url'] . '[/video]';
 301                         }
 302                 }
 303
 304                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive']);
 305
 306                 $item['location'] = $activity['location'];
 307
 308                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 309                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 310                 }
 311
 312                 $item['app'] = $activity['generator'];
 313
 314                 return $item;
 315         }
 316
 317         /**
 318          * Creates an item post
 319          *
 320          * @param array $activity Activity data
 321          * @param array $item     item array
 322          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 323          * @throws \ImagickException
 324          */
 325         private static function postItem($activity, $item)
 326         {
 327                 /// @todo What to do with $activity['context']?
 328                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 329                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 330                         return;
 331                 }
 332
 333                 $item['network'] = Protocol::ACTIVITYPUB;
 334                 $item['private'] = !in_array(0, $activity['receiver']);
 335                 $item['author-link'] = $activity['author'];
 336                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 337
 338                 if (empty($activity['thread-completion'])) {
 339                         $item['owner-link'] = $activity['actor'];
 340                         $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 341                 } else {
 342                         Logger::info('Ignoring actor because of thread completion.');
 343                         $item['owner-link'] = $item['author-link'];
 344                         $item['owner-id'] = $item['author-id'];
 345                 }
 346
 347                 $item['uri'] = $activity['id'];
 348
 349                 $item['created'] = $activity['published'];
 350                 $item['edited'] = $activity['updated'];
 351                 $item['guid'] = $activity['diaspora:guid'];
 352
 353                 $item = self::processContent($activity, $item);
 354                 if (empty($item)) {
 355                         return;
 356                 }
 357
 358                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
 359
 360                 $item = self::constructAttachList($activity['attachments'], $item, !empty($activity['source']));
 361
 362                 $stored = false;
 363
 364                 foreach ($activity['receiver'] as $receiver) {
 365                         $item['uid'] = $receiver;
 366                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 367
 368                         if (($receiver != 0) && empty($item['contact-id'])) {
 369                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 370                         }
 371
 372                         if (!empty($activity['directmessage'])) {
 373                                 self::postMail($activity, $item);
 374                                 continue;
 375                         }
 376
 377                         if ($activity['object_type'] == 'as:Event') {
 378                                 self::createEvent($activity, $item);
 379                         }
 380
 381                         $item_id = Item::insert($item);
 382                         if ($item_id) {
 383                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 384                         } else {
 385                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 386                         }
 387
 388                         if ($item['uid'] == 0) {
 389                                 $stored = $item_id;
 390                         }
 391                 }
 392
 393                 // Store send a follow request for every reshare - but only when the item had been stored
 394                 if ($stored && !$item['private'] && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 395                         $author = APContact::getByURL($item['owner-link'], false);
 396                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 397                         if ($author['type'] != 'Group') {
 398                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 399                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 400                         }
 401                 }
 402         }
 403
 404         /**
 405          * Creates an mail post
 406          *
 407          * @param array $activity Activity data
 408          * @param array $item     item array
 409          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 410          * @throws \ImagickException
 411          */
 412         private static function postMail($activity, $item)
 413         {
 414                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 415                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 416                         return false;
 417                 }
 418
 419                 Logger::info('Direct Message', $item);
 420
 421                 $msg = [];
 422                 $msg['uid'] = $item['uid'];
 423
 424                 $msg['contact-id'] = $item['contact-id'];
 425
 426                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 427                 $msg['from-name'] = $contact['name'];
 428                 $msg['from-url'] = $contact['url'];
 429                 $msg['from-photo'] = $contact['photo'];
 430
 431                 $msg['uri'] = $item['uri'];
 432                 $msg['created'] = $item['created'];
 433
 434                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 435                 if (DBA::isResult($parent)) {
 436                         $msg['parent-uri'] = $parent['parent-uri'];
 437                         $msg['title'] = $parent['title'];
 438                 } else {
 439                         $msg['parent-uri'] = $item['thr-parent'];
 440
 441                         if (!empty($item['title'])) {
 442                                 $msg['title'] = $item['title'];
 443                         } elseif (!empty($item['content-warning'])) {
 444                                 $msg['title'] = $item['content-warning'];
 445                         } else {
 446                                 // Trying to generate a title out of the body
 447                                 $title = $item['body'];
 448
 449                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 450                                         $title = $matches[3];
 451                                 }
 452
 453                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, 2, true), 0));
 454
 455                                 if (strlen($title) > 20) {
 456                                         $title = substr($title, 0, 20) . '...';
 457                                 }
 458
 459                                 $msg['title'] = $title;
 460                         }
 461                 }
 462                 $msg['body'] = $item['body'];
 463
 464                 Mail::insert($msg);
 465         }
 466
 467         /**
 468          * Fetches missing posts
 469          *
 470          * @param $url
 471          * @param $child
 472          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 473          */
 474         private static function fetchMissingActivity($url, $child)
 475         {
 476                 if (Config::get('system', 'ostatus_full_threads')) {
 477                         return;
 478                 }
 479
 480                 $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 481
 482                 $object = ActivityPub::fetchContent($url, $uid);
 483                 if (empty($object)) {
 484                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 485                         return;
 486                 }
 487
 488                 if (empty($object['id'])) {
 489                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 490                         return;
 491                 }
 492
 493                 $activity = [];
 494                 $activity['@context'] = $object['@context'];
 495                 unset($object['@context']);
 496                 $activity['id'] = $object['id'];
 497                 $activity['to'] = defaults($object, 'to', []);
 498                 $activity['cc'] = defaults($object, 'cc', []);
 499                 $activity['actor'] = $child['author'];
 500                 $activity['object'] = $object;
 501                 $activity['published'] = defaults($object, 'published', $child['published']);
 502                 $activity['type'] = 'Create';
 503
 504                 $ldactivity = JsonLD::compact($activity);
 505
 506                 $ldactivity['thread-completion'] = true;
 507
 508                 ActivityPub\Receiver::processActivity($ldactivity);
 509                 Logger::log('Activity ' . $url . ' had been fetched and processed.');
 510         }
 511
 512         /**
 513          * perform a "follow" request
 514          *
 515          * @param array $activity
 516          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 517          * @throws \ImagickException
 518          */
 519         public static function followUser($activity)
 520         {
 521                 $uid = User::getIdForURL($activity['object_id']);
 522                 if (empty($uid)) {
 523                         return;
 524                 }
 525
 526                 $owner = User::getOwnerDataById($uid);
 527
 528                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 529                 if (!empty($cid)) {
 530                         self::switchContact($cid);
 531                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 532                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 533                 } else {
 534                         $contact = false;
 535                 }
 536
 537                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 538                         'author-link' => $activity['actor']];
 539
 540                 $note = Strings::escapeTags(trim(defaults($activity, 'content', '')));
 541
 542                 // Ensure that the contact has got the right network type
 543                 self::switchContact($item['author-id']);
 544
 545                 Contact::addRelationship($owner, $contact, $item, '', false, $note);
 546                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 547                 if (empty($cid)) {
 548                         return;
 549                 }
 550
 551                 if (empty($contact)) {
 552                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 553                 }
 554
 555                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 556         }
 557
 558         /**
 559          * Update the given profile
 560          *
 561          * @param array $activity
 562          * @throws \Exception
 563          */
 564         public static function updatePerson($activity)
 565         {
 566                 if (empty($activity['object_id'])) {
 567                         return;
 568                 }
 569
 570                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 571                 APContact::getByURL($activity['object_id'], true);
 572         }
 573
 574         /**
 575          * Delete the given profile
 576          *
 577          * @param array $activity
 578          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 579          */
 580         public static function deletePerson($activity)
 581         {
 582                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 583                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 584                         return;
 585                 }
 586
 587                 if ($activity['object_id'] != $activity['actor']) {
 588                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 589                         return;
 590                 }
 591
 592                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 593                 while ($contact = DBA::fetch($contacts)) {
 594                         Contact::remove($contact['id']);
 595                 }
 596                 DBA::close($contacts);
 597
 598                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 599         }
 600
 601         /**
 602          * Accept a follow request
 603          *
 604          * @param array $activity
 605          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 606          * @throws \ImagickException
 607          */
 608         public static function acceptFollowUser($activity)
 609         {
 610                 $uid = User::getIdForURL($activity['object_actor']);
 611                 if (empty($uid)) {
 612                         return;
 613                 }
 614
 615                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 616                 if (empty($cid)) {
 617                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 618                         return;
 619                 }
 620
 621                 self::switchContact($cid);
 622
 623                 $fields = ['pending' => false];
 624
 625                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 626                 if ($contact['rel'] == Contact::FOLLOWER) {
 627                         $fields['rel'] = Contact::FRIEND;
 628                 }
 629
 630                 $condition = ['id' => $cid];
 631                 DBA::update('contact', $fields, $condition);
 632                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 633         }
 634
 635         /**
 636          * Reject a follow request
 637          *
 638          * @param array $activity
 639          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 640          * @throws \ImagickException
 641          */
 642         public static function rejectFollowUser($activity)
 643         {
 644                 $uid = User::getIdForURL($activity['object_actor']);
 645                 if (empty($uid)) {
 646                         return;
 647                 }
 648
 649                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 650                 if (empty($cid)) {
 651                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 652                         return;
 653                 }
 654
 655                 self::switchContact($cid);
 656
 657                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
 658                         Contact::remove($cid);
 659                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 660                 } else {
 661                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 662                 }
 663         }
 664
 665         /**
 666          * Undo activity like "like" or "dislike"
 667          *
 668          * @param array $activity
 669          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 670          * @throws \ImagickException
 671          */
 672         public static function undoActivity($activity)
 673         {
 674                 if (empty($activity['object_id'])) {
 675                         return;
 676                 }
 677
 678                 if (empty($activity['object_actor'])) {
 679                         return;
 680                 }
 681
 682                 $author_id = Contact::getIdForURL($activity['object_actor']);
 683                 if (empty($author_id)) {
 684                         return;
 685                 }
 686
 687                 Item::delete(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 688         }
 689
 690         /**
 691          * Activity to remove a follower
 692          *
 693          * @param array $activity
 694          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 695          * @throws \ImagickException
 696          */
 697         public static function undoFollowUser($activity)
 698         {
 699                 $uid = User::getIdForURL($activity['object_object']);
 700                 if (empty($uid)) {
 701                         return;
 702                 }
 703
 704                 $owner = User::getOwnerDataById($uid);
 705
 706                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 707                 if (empty($cid)) {
 708                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 709                         return;
 710                 }
 711
 712                 self::switchContact($cid);
 713
 714                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 715                 if (!DBA::isResult($contact)) {
 716                         return;
 717                 }
 718
 719                 Contact::removeFollower($owner, $contact);
 720                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 721         }
 722
 723         /**
 724          * Switches a contact to AP if needed
 725          *
 726          * @param integer $cid Contact ID
 727          * @throws \Exception
 728          */
 729         private static function switchContact($cid)
 730         {
 731                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 732                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN])) {
 733                         return;
 734                 }
 735
 736                 Logger::log('Change existing contact ' . $cid . ' from ' . $contact['network'] . ' to ActivityPub.');
 737                 Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
 738         }
 739
 740         /**
 741          * Collects implicit mentions like:
 742          * - the author of the parent item
 743          * - all the mentioned conversants in the parent item
 744          *
 745          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 746          * @return array
 747          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 748          */
 749         private static function getImplicitMentionList(array $parent)
 750         {
 751                 if (Config::get('system', 'disable_implicit_mentions')) {
 752                         return [];
 753                 }
 754
 755                 $parent_terms = Term::tagArrayFromItemId($parent['id'], [Term::MENTION, Term::IMPLICIT_MENTION]);
 756
 757                 $parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 758
 759                 $implicit_mentions = [];
 760                 if (empty($parent_author)) {
 761                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 762                 } else {
 763                         $implicit_mentions[] = $parent_author['url'];
 764                         $implicit_mentions[] = $parent_author['nurl'];
 765                         $implicit_mentions[] = $parent_author['alias'];
 766                 }
 767
 768                 if (!empty($parent['alias'])) {
 769                         $implicit_mentions[] = $parent['alias'];
 770                 }
 771
 772                 foreach ($parent_terms as $term) {
 773                         $contact = Contact::getDetailsByURL($term['url'], 0);
 774                         if (!empty($contact)) {
 775                                 $implicit_mentions[] = $contact['url'];
 776                                 $implicit_mentions[] = $contact['nurl'];
 777                                 $implicit_mentions[] = $contact['alias'];
 778                         }
 779                 }
 780
 781                 return $implicit_mentions;
 782         }
 783
 784         /**
 785          * Strips from the body prepended implicit mentions
 786          *
 787          * @param string $body
 788          * @param array $potential_mentions
 789          * @return string
 790          */
 791         private static function removeImplicitMentionsFromBody($body, array $potential_mentions)
 792         {
 793                 if (Config::get('system', 'disable_implicit_mentions')) {
 794                         return $body;
 795                 }
 796
 797                 $kept_mentions = [];
 798
 799                 // Extract one prepended mention at a time from the body
 800                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
 801                         if (!in_array($matches[2], $potential_mentions) ) {
 802                                 $kept_mentions[] = $matches[1];
 803                         }
 804
 805                         $body = $matches[3];
 806                 }
 807
 808                 // Re-appending the kept mentions to the body after extraction
 809                 $kept_mentions[] = $body;
 810
 811                 return implode('', $kept_mentions);
 812         }
 813
 814         private static function convertImplicitMentionsInTags($activity_tags, array $potential_mentions)
 815         {
 816                 if (Config::get('system', 'disable_implicit_mentions')) {
 817                         return $activity_tags;
 818                 }
 819
 820                 foreach ($activity_tags as $index => $tag) {
 821                         if (in_array($tag['href'], $potential_mentions)) {
 822                                 $activity_tags[$index]['name'] = preg_replace(
 823                                         '/' . preg_quote(Term::TAG_CHARACTER[Term::MENTION], '/') . '/',
 824                                         Term::TAG_CHARACTER[Term::IMPLICIT_MENTION],
 825                                         $activity_tags[$index]['name'],
 826                                         1
 827                                 );
 828                         }
 829                 }
 830
 831                 return $activity_tags;
 832         }
 833 }