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\Content\Text\BBCode;
   8 use Friendica\Content\Text\HTML;
   9 use Friendica\Core\Logger;
  10 use Friendica\Core\Protocol;
  11 use Friendica\Database\DBA;
  12 use Friendica\DI;
  13 use Friendica\Model\APContact;
  14 use Friendica\Model\Contact;
  15 use Friendica\Model\Event;
  16 use Friendica\Model\Item;
  17 use Friendica\Model\Mail;
  18 use Friendica\Model\Term;
  19 use Friendica\Model\User;
  20 use Friendica\Protocol\Activity;
  21 use Friendica\Protocol\ActivityPub;
  22 use Friendica\Util\DateTimeFormat;
  23 use Friendica\Util\JsonLD;
  24 use Friendica\Util\Strings;
  25
  26 /**
  27  * ActivityPub Processor Protocol class
  28  */
  29 class Processor
  30 {
  31         /**
  32          * Converts mentions from Pleroma into the Friendica format
  33          *
  34          * @param string $body
  35          *
  36          * @return string converted body
  37          */
  38         private static function convertMentions($body)
  39         {
  40                 $URLSearchString = "^\[\]";
  41                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  42
  43                 return $body;
  44         }
  45
  46         /**
  47          * Replaces emojis in the body
  48          *
  49          * @param array $emojis
  50          * @param string $body
  51          *
  52          * @return string with replaced emojis
  53          */
  54         private static function replaceEmojis($body, array $emojis)
  55         {
  56                 foreach ($emojis as $emoji) {
  57                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  58                         $body = str_replace($emoji['name'], $replace, $body);
  59                 }
  60                 return $body;
  61         }
  62
  63         /**
  64          * Constructs a string with tags for a given tag array
  65          *
  66          * @param array   $tags
  67          * @param boolean $sensitive
  68          * @return string with tags
  69          */
  70         private static function constructTagString(array $tags = null, $sensitive = false)
  71         {
  72                 if (empty($tags)) {
  73                         return '';
  74                 }
  75
  76                 $tag_text = '';
  77                 foreach ($tags as $tag) {
  78                         if (in_array($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   $activity
  96          * @param array   $item
  97          *
  98          * @return array array
  99          */
 100         private static function constructAttachList($activity, $item)
 101         {
 102                 if (empty($activity['attachments'])) {
 103                         return $item;
 104                 }
 105
 106                 foreach ($activity['attachments'] as $attach) {
 107                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 108                         if ($filetype == 'image') {
 109                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 110                                         continue;
 111                                 }
 112
 113                                 if (empty($attach['name'])) {
 114                                         $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 115                                 } else {
 116                                         $item['body'] .= "\n[img=" . $attach['url'] . ']' . $attach['name'] . '[/img]';
 117                                 }
 118                         } else {
 119                                 if (!empty($item["attach"])) {
 120                                         $item["attach"] .= ',';
 121                                 } else {
 122                                         $item["attach"] = '';
 123                                 }
 124                                 if (!isset($attach['length'])) {
 125                                         $attach['length'] = "0";
 126                                 }
 127                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.($attach['name'] ?? '') .'"[/attach]';
 128                         }
 129                 }
 130
 131                 return $item;
 132         }
 133
 134         /**
 135          * Updates a message
 136          *
 137          * @param array $activity Activity array
 138          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 139          */
 140         public static function updateItem($activity)
 141         {
 142                 $item = Item::selectFirst(['uri', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 143                 if (!DBA::isResult($item)) {
 144                         Logger::warning('Unknown item', ['uri' => $activity['id']]);
 145                         return;
 146                 }
 147
 148                 $item['changed'] = DateTimeFormat::utcNow();
 149                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 150
 151                 $item = self::processContent($activity, $item);
 152                 if (empty($item)) {
 153                         return;
 154                 }
 155
 156                 Item::update($item, ['uri' => $activity['id']]);
 157         }
 158
 159         /**
 160          * Prepares data for a message
 161          *
 162          * @param array $activity Activity array
 163          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 164          * @throws \ImagickException
 165          */
 166         public static function createItem($activity)
 167         {
 168                 $item = [];
 169                 $item['verb'] = Activity::POST;
 170                 $item['thr-parent'] = $activity['reply-to-id'];
 171
 172                 if ($activity['reply-to-id'] == $activity['id']) {
 173                         $item['gravity'] = GRAVITY_PARENT;
 174                         $item['object-type'] = Activity\ObjectType::NOTE;
 175                 } else {
 176                         $item['gravity'] = GRAVITY_COMMENT;
 177                         $item['object-type'] = Activity\ObjectType::COMMENT;
 178
 179                         // Ensure that the comment reaches all receivers of the referring post
 180                         $activity['receiver'] = self::addReceivers($activity);
 181                 }
 182
 183                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 184                         Logger::log('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
 185                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 186                 }
 187
 188                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 189
 190                 self::postItem($activity, $item);
 191         }
 192
 193         /**
 194          * Delete items
 195          *
 196          * @param array $activity
 197          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 198          * @throws \ImagickException
 199          */
 200         public static function deleteItem($activity)
 201         {
 202                 $owner = Contact::getIdForURL($activity['actor']);
 203
 204                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 205                 Item::delete(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 206         }
 207
 208         /**
 209          * Prepare the item array for an activity
 210          *
 211          * @param array $activity Activity array
 212          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 213          * @throws \ImagickException
 214          */
 215         public static function addTag($activity)
 216         {
 217                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 218                         return;
 219                 }
 220
 221                 foreach ($activity['receiver'] as $receiver) {
 222                         $item = Item::selectFirst(['id', 'tag', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 223                         if (!DBA::isResult($item)) {
 224                                 // We don't fetch missing content for this purpose
 225                                 continue;
 226                         }
 227
 228                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 229                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 230                                 continue;
 231                         }
 232
 233                         // To-Do:
 234                         // - Check if "blocktag" is set
 235                         // - Check if actor is a contact
 236
 237                         if (!stristr($item['tag'], trim($activity['object_content']))) {
 238                                 $tag = $item['tag'] . (strlen($item['tag']) ? ',' : '') . '#[url=' . $activity['object_id'] . ']'. $activity['object_content'] . '[/url]';
 239                                 Item::update(['tag' => $tag], ['id' => $item['id']]);
 240                                 Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 241                         }
 242                 }
 243         }
 244
 245         /**
 246          * Add users to the receiver list of the given public activity.
 247          * This is used to ensure that the activity will be stored in every thread.
 248          *
 249          * @param array $activity Activity array
 250          * @return array Modified receiver list
 251          */
 252         private static function addReceivers(array $activity)
 253         {
 254                 if (!in_array(0, $activity['receiver'])) {
 255                         // Private activities will not be modified
 256                         return $activity['receiver'];
 257                 }
 258
 259                 // Add all owners of the referring item to the receivers
 260                 $original = $receivers = $activity['receiver'];
 261                 $items = Item::select(['uid'], ['uri' => $activity['object_id']]);
 262                 while ($item = DBA::fetch($items)) {
 263                         $receivers['uid:' . $item['uid']] = $item['uid'];
 264                 }
 265                 DBA::close($items);
 266
 267                 if (count($original) != count($receivers)) {
 268                         Logger::info('Improved data', ['id' => $activity['id'], 'object' => $activity['object_id'], 'original' => $original, 'improved' => $receivers]);
 269                 }
 270
 271                 return $receivers;
 272         }
 273
 274         /**
 275          * Prepare the item array for an activity
 276          *
 277          * @param array  $activity Activity array
 278          * @param string $verb     Activity verb
 279          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 280          * @throws \ImagickException
 281          */
 282         public static function createActivity($activity, $verb)
 283         {
 284                 $item = [];
 285                 $item['verb'] = $verb;
 286                 $item['thr-parent'] = $activity['object_id'];
 287                 $item['gravity'] = GRAVITY_ACTIVITY;
 288                 $item['object-type'] = Activity\ObjectType::NOTE;
 289
 290                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 291
 292                 $activity['receiver'] = self::addReceivers($activity);
 293
 294                 self::postItem($activity, $item);
 295         }
 296
 297         /**
 298          * Create an event
 299          *
 300          * @param array $activity Activity array
 301          * @param array $item
 302          * @throws \Exception
 303          */
 304         public static function createEvent($activity, $item)
 305         {
 306                 $event['summary']  = HTML::toBBCode($activity['name']);
 307                 $event['desc']     = HTML::toBBCode($activity['content']);
 308                 $event['start']    = $activity['start-time'];
 309                 $event['finish']   = $activity['end-time'];
 310                 $event['nofinish'] = empty($event['finish']);
 311                 $event['location'] = $activity['location'];
 312                 $event['adjust']   = true;
 313                 $event['cid']      = $item['contact-id'];
 314                 $event['uid']      = $item['uid'];
 315                 $event['uri']      = $item['uri'];
 316                 $event['edited']   = $item['edited'];
 317                 $event['private']  = $item['private'];
 318                 $event['guid']     = $item['guid'];
 319                 $event['plink']    = $item['plink'];
 320
 321                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 322                 $ev = DBA::selectFirst('event', ['id'], $condition);
 323                 if (DBA::isResult($ev)) {
 324                         $event['id'] = $ev['id'];
 325                 }
 326
 327                 $event_id = Event::store($event);
 328                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 329         }
 330
 331         /**
 332          * Process the content
 333          *
 334          * @param array $activity Activity array
 335          * @param array $item
 336          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 337          * @throws \Exception
 338          */
 339         private static function processContent($activity, $item)
 340         {
 341                 $item['title'] = HTML::toBBCode($activity['name']);
 342
 343                 if (!empty($activity['source'])) {
 344                         $item['body'] = $activity['source'];
 345                 } else {
 346                         $content = HTML::toBBCode($activity['content']);
 347
 348                         if (!empty($activity['emojis'])) {
 349                                 $content = self::replaceEmojis($content, $activity['emojis']);
 350                         }
 351
 352                         $content = self::convertMentions($content);
 353
 354                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 355                                 $item_private = !in_array(0, $activity['item_receiver']);
 356                                 $parent = Item::selectFirst(['id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 357                                 if (!DBA::isResult($parent)) {
 358                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 359                                         return false;
 360                                 }
 361                                 if ($item_private && !$parent['private']) {
 362                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 363                                         return false;
 364                                 }
 365
 366                                 $potential_implicit_mentions = self::getImplicitMentionList($parent);
 367                                 $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 368                                 $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 369                         }
 370                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 371                         $item['body'] = $content;
 372
 373                         if (($activity['object_type'] == 'as:Video') && !empty($activity['alternate-url'])) {
 374                                 $item['body'] .= "\n[video]" . $activity['alternate-url'] . '[/video]';
 375                         }
 376                 }
 377
 378                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive']);
 379
 380                 $item['location'] = $activity['location'];
 381
 382                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 383                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 384                 }
 385
 386                 $item['app'] = $activity['generator'];
 387
 388                 return $item;
 389         }
 390
 391         /**
 392          * Generate a GUID out of an URL
 393          *
 394          * @param string $url message URL
 395          * @return string with GUID
 396          */
 397         private static function getGUIDByURL(string $url)
 398         {
 399                 $parsed = parse_url($url);
 400
 401                 $host_hash = hash('crc32', $parsed['host']);
 402
 403                 unset($parsed["scheme"]);
 404                 unset($parsed["host"]);
 405
 406                 $path = implode("/", $parsed);
 407
 408                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 409         }
 410
 411         /**
 412          * Creates an item post
 413          *
 414          * @param array $activity Activity data
 415          * @param array $item     item array
 416          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 417          * @throws \ImagickException
 418          */
 419         private static function postItem($activity, $item)
 420         {
 421                 /// @todo What to do with $activity['context']?
 422                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 423                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 424                         return;
 425                 }
 426
 427                 $item['network'] = Protocol::ACTIVITYPUB;
 428                 $item['private'] = !in_array(0, $activity['receiver']);
 429                 $item['author-link'] = $activity['author'];
 430                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 431                 $item['owner-link'] = $activity['actor'];
 432                 $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 433
 434                 $isForum = false;
 435
 436                 if (!empty($activity['thread-completion'])) {
 437                         // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 438                         $item['causer-link'] = $item['owner-link'];
 439                         $item['causer-id'] = $item['owner-id'];
 440
 441                         Logger::info('Ignoring actor because of thread completion.', ['actor' => $item['owner-link']]);
 442                         $item['owner-link'] = $item['author-link'];
 443                         $item['owner-id'] = $item['author-id'];
 444                 } else {
 445                         $actor = APContact::getByURL($item['owner-link'], false);
 446                         $isForum = ($actor['type'] == 'Group');
 447                 }
 448
 449                 $item['uri'] = $activity['id'];
 450
 451                 $item['created'] = DateTimeFormat::utc($activity['published']);
 452                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 453                 $item['guid'] = $activity['diaspora:guid'] ?: self::getGUIDByURL($item['uri']);
 454
 455                 $item = self::processContent($activity, $item);
 456                 if (empty($item)) {
 457                         return;
 458                 }
 459
 460                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 461
 462                 $item = self::constructAttachList($activity, $item);
 463
 464                 $stored = false;
 465
 466                 foreach ($activity['receiver'] as $receiver) {
 467                         $item['uid'] = $receiver;
 468
 469                         if ($isForum) {
 470                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver, true);
 471                         } else {
 472                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 473                         }
 474
 475                         if (($receiver != 0) && empty($item['contact-id'])) {
 476                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 477                         }
 478
 479                         if (!empty($activity['directmessage'])) {
 480                                 self::postMail($activity, $item);
 481                                 continue;
 482                         }
 483
 484                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 485                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 486
 487                                 if ($skip && (($activity['type'] == 'as:Announce') || $isForum)) {
 488                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 489                                 }
 490
 491                                 if ($skip) {
 492                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 493                                         continue;
 494                                 }
 495
 496                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 497                         }
 498
 499                         if ($activity['object_type'] == 'as:Event') {
 500                                 self::createEvent($activity, $item);
 501                         }
 502
 503                         $item_id = Item::insert($item);
 504                         if ($item_id) {
 505                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 506                         } else {
 507                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 508                         }
 509
 510                         if ($item['uid'] == 0) {
 511                                 $stored = $item_id;
 512                         }
 513                 }
 514
 515                 // Store send a follow request for every reshare - but only when the item had been stored
 516                 if ($stored && !$item['private'] && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 517                         $author = APContact::getByURL($item['owner-link'], false);
 518                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 519                         if ($author['type'] != 'Group') {
 520                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 521                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 522                         }
 523                 }
 524         }
 525
 526         /**
 527          * Creates an mail post
 528          *
 529          * @param array $activity Activity data
 530          * @param array $item     item array
 531          * @return int|bool New mail table row id or false on error
 532          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 533          */
 534         private static function postMail($activity, $item)
 535         {
 536                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 537                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 538                         return false;
 539                 }
 540
 541                 Logger::info('Direct Message', $item);
 542
 543                 $msg = [];
 544                 $msg['uid'] = $item['uid'];
 545
 546                 $msg['contact-id'] = $item['contact-id'];
 547
 548                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 549                 $msg['from-name'] = $contact['name'];
 550                 $msg['from-url'] = $contact['url'];
 551                 $msg['from-photo'] = $contact['photo'];
 552
 553                 $msg['uri'] = $item['uri'];
 554                 $msg['created'] = $item['created'];
 555
 556                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 557                 if (DBA::isResult($parent)) {
 558                         $msg['parent-uri'] = $parent['parent-uri'];
 559                         $msg['title'] = $parent['title'];
 560                 } else {
 561                         $msg['parent-uri'] = $item['thr-parent'];
 562
 563                         if (!empty($item['title'])) {
 564                                 $msg['title'] = $item['title'];
 565                         } elseif (!empty($item['content-warning'])) {
 566                                 $msg['title'] = $item['content-warning'];
 567                         } else {
 568                                 // Trying to generate a title out of the body
 569                                 $title = $item['body'];
 570
 571                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 572                                         $title = $matches[3];
 573                                 }
 574
 575                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, 2, true), 0));
 576
 577                                 if (strlen($title) > 20) {
 578                                         $title = substr($title, 0, 20) . '...';
 579                                 }
 580
 581                                 $msg['title'] = $title;
 582                         }
 583                 }
 584                 $msg['body'] = $item['body'];
 585
 586                 return Mail::insert($msg);
 587         }
 588
 589         /**
 590          * Fetches missing posts
 591          *
 592          * @param string $url message URL
 593          * @param array $child activity array with the child of this message
 594          * @return string fetched message URL
 595          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 596          */
 597         public static function fetchMissingActivity($url, $child = [])
 598         {
 599                 if (!empty($child['receiver'])) {
 600                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 601                 } else {
 602                         $uid = 0;
 603                 }
 604
 605                 $object = ActivityPub::fetchContent($url, $uid);
 606                 if (empty($object)) {
 607                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 608                         return '';
 609                 }
 610
 611                 if (empty($object['id'])) {
 612                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 613                         return '';
 614                 }
 615
 616                 if (!empty($child['author'])) {
 617                         $actor = $child['author'];
 618                 } elseif (!empty($object['actor'])) {
 619                         $actor = $object['actor'];
 620                 } elseif (!empty($object['attributedTo'])) {
 621                         $actor = $object['attributedTo'];
 622                 } else {
 623                         // Shouldn't happen
 624                         $actor = '';
 625                 }
 626
 627                 if (!empty($object['published'])) {
 628                         $published = $object['published'];
 629                 } elseif (!empty($child['published'])) {
 630                         $published = $child['published'];
 631                 } else {
 632                         $published = DateTimeFormat::utcNow();
 633                 }
 634
 635                 $activity = [];
 636                 $activity['@context'] = $object['@context'];
 637                 unset($object['@context']);
 638                 $activity['id'] = $object['id'];
 639                 $activity['to'] = $object['to'] ?? [];
 640                 $activity['cc'] = $object['cc'] ?? [];
 641                 $activity['actor'] = $actor;
 642                 $activity['object'] = $object;
 643                 $activity['published'] = $published;
 644                 $activity['type'] = 'Create';
 645
 646                 $ldactivity = JsonLD::compact($activity);
 647
 648                 $ldactivity['thread-completion'] = true;
 649
 650                 ActivityPub\Receiver::processActivity($ldactivity);
 651                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 652
 653                 return $activity['id'];
 654         }
 655
 656         /**
 657          * perform a "follow" request
 658          *
 659          * @param array $activity
 660          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 661          * @throws \ImagickException
 662          */
 663         public static function followUser($activity)
 664         {
 665                 $uid = User::getIdForURL($activity['object_id']);
 666                 if (empty($uid)) {
 667                         return;
 668                 }
 669
 670                 $owner = User::getOwnerDataById($uid);
 671
 672                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 673                 if (!empty($cid)) {
 674                         self::switchContact($cid);
 675                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 676                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 677                 } else {
 678                         $contact = [];
 679                 }
 680
 681                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 682                         'author-link' => $activity['actor']];
 683
 684                 $note = Strings::escapeTags(trim($activity['content'] ?? ''));
 685
 686                 // Ensure that the contact has got the right network type
 687                 self::switchContact($item['author-id']);
 688
 689                 $result = Contact::addRelationship($owner, $contact, $item, false, $note);
 690                 if ($result === true) {
 691                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $item['author-id'], $owner['uid']);
 692                 }
 693
 694                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 695                 if (empty($cid)) {
 696                         return;
 697                 }
 698
 699                 if (empty($contact)) {
 700                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 701                 }
 702
 703                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 704         }
 705
 706         /**
 707          * Update the given profile
 708          *
 709          * @param array $activity
 710          * @throws \Exception
 711          */
 712         public static function updatePerson($activity)
 713         {
 714                 if (empty($activity['object_id'])) {
 715                         return;
 716                 }
 717
 718                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 719                 Contact::updateFromProbeByURL($activity['object_id'], true);
 720         }
 721
 722         /**
 723          * Delete the given profile
 724          *
 725          * @param array $activity
 726          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 727          */
 728         public static function deletePerson($activity)
 729         {
 730                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 731                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 732                         return;
 733                 }
 734
 735                 if ($activity['object_id'] != $activity['actor']) {
 736                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 737                         return;
 738                 }
 739
 740                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 741                 while ($contact = DBA::fetch($contacts)) {
 742                         Contact::remove($contact['id']);
 743                 }
 744                 DBA::close($contacts);
 745
 746                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 747         }
 748
 749         /**
 750          * Accept a follow request
 751          *
 752          * @param array $activity
 753          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 754          * @throws \ImagickException
 755          */
 756         public static function acceptFollowUser($activity)
 757         {
 758                 $uid = User::getIdForURL($activity['object_actor']);
 759                 if (empty($uid)) {
 760                         return;
 761                 }
 762
 763                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 764                 if (empty($cid)) {
 765                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 766                         return;
 767                 }
 768
 769                 self::switchContact($cid);
 770
 771                 $fields = ['pending' => false];
 772
 773                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 774                 if ($contact['rel'] == Contact::FOLLOWER) {
 775                         $fields['rel'] = Contact::FRIEND;
 776                 }
 777
 778                 $condition = ['id' => $cid];
 779                 DBA::update('contact', $fields, $condition);
 780                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 781         }
 782
 783         /**
 784          * Reject a follow request
 785          *
 786          * @param array $activity
 787          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 788          * @throws \ImagickException
 789          */
 790         public static function rejectFollowUser($activity)
 791         {
 792                 $uid = User::getIdForURL($activity['object_actor']);
 793                 if (empty($uid)) {
 794                         return;
 795                 }
 796
 797                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 798                 if (empty($cid)) {
 799                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 800                         return;
 801                 }
 802
 803                 self::switchContact($cid);
 804
 805                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
 806                         Contact::remove($cid);
 807                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 808                 } else {
 809                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 810                 }
 811         }
 812
 813         /**
 814          * Undo activity like "like" or "dislike"
 815          *
 816          * @param array $activity
 817          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 818          * @throws \ImagickException
 819          */
 820         public static function undoActivity($activity)
 821         {
 822                 if (empty($activity['object_id'])) {
 823                         return;
 824                 }
 825
 826                 if (empty($activity['object_actor'])) {
 827                         return;
 828                 }
 829
 830                 $author_id = Contact::getIdForURL($activity['object_actor']);
 831                 if (empty($author_id)) {
 832                         return;
 833                 }
 834
 835                 Item::delete(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 836         }
 837
 838         /**
 839          * Activity to remove a follower
 840          *
 841          * @param array $activity
 842          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 843          * @throws \ImagickException
 844          */
 845         public static function undoFollowUser($activity)
 846         {
 847                 $uid = User::getIdForURL($activity['object_object']);
 848                 if (empty($uid)) {
 849                         return;
 850                 }
 851
 852                 $owner = User::getOwnerDataById($uid);
 853
 854                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 855                 if (empty($cid)) {
 856                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 857                         return;
 858                 }
 859
 860                 self::switchContact($cid);
 861
 862                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 863                 if (!DBA::isResult($contact)) {
 864                         return;
 865                 }
 866
 867                 Contact::removeFollower($owner, $contact);
 868                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 869         }
 870
 871         /**
 872          * Switches a contact to AP if needed
 873          *
 874          * @param integer $cid Contact ID
 875          * @throws \Exception
 876          */
 877         private static function switchContact($cid)
 878         {
 879                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
 880                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
 881                         return;
 882                 }
 883
 884                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
 885                 Contact::updateFromProbe($cid);
 886         }
 887
 888         /**
 889          * Collects implicit mentions like:
 890          * - the author of the parent item
 891          * - all the mentioned conversants in the parent item
 892          *
 893          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 894          * @return array
 895          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 896          */
 897         private static function getImplicitMentionList(array $parent)
 898         {
 899                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
 900                         return [];
 901                 }
 902
 903                 $parent_terms = Term::tagArrayFromItemId($parent['id'], [Term::MENTION, Term::IMPLICIT_MENTION]);
 904
 905                 $parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 906
 907                 $implicit_mentions = [];
 908                 if (empty($parent_author)) {
 909                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 910                 } else {
 911                         $implicit_mentions[] = $parent_author['url'];
 912                         $implicit_mentions[] = $parent_author['nurl'];
 913                         $implicit_mentions[] = $parent_author['alias'];
 914                 }
 915
 916                 if (!empty($parent['alias'])) {
 917                         $implicit_mentions[] = $parent['alias'];
 918                 }
 919
 920                 foreach ($parent_terms as $term) {
 921                         $contact = Contact::getDetailsByURL($term['url'], 0);
 922                         if (!empty($contact)) {
 923                                 $implicit_mentions[] = $contact['url'];
 924                                 $implicit_mentions[] = $contact['nurl'];
 925                                 $implicit_mentions[] = $contact['alias'];
 926                         }
 927                 }
 928
 929                 return $implicit_mentions;
 930         }
 931
 932         /**
 933          * Strips from the body prepended implicit mentions
 934          *
 935          * @param string $body
 936          * @param array $potential_mentions
 937          * @return string
 938          */
 939         private static function removeImplicitMentionsFromBody($body, array $potential_mentions)
 940         {
 941                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
 942                         return $body;
 943                 }
 944
 945                 $kept_mentions = [];
 946
 947                 // Extract one prepended mention at a time from the body
 948                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
 949                         if (!in_array($matches[2], $potential_mentions)) {
 950                                 $kept_mentions[] = $matches[1];
 951                         }
 952
 953                         $body = $matches[3];
 954                 }
 955
 956                 // Re-appending the kept mentions to the body after extraction
 957                 $kept_mentions[] = $body;
 958
 959                 return implode('', $kept_mentions);
 960         }
 961
 962         private static function convertImplicitMentionsInTags($activity_tags, array $potential_mentions)
 963         {
 964                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
 965                         return $activity_tags;
 966                 }
 967
 968                 foreach ($activity_tags as $index => $tag) {
 969                         if (in_array($tag['href'], $potential_mentions)) {
 970                                 $activity_tags[$index]['name'] = preg_replace(
 971                                         '/' . preg_quote(Term::TAG_CHARACTER[Term::MENTION], '/') . '/',
 972                                         Term::TAG_CHARACTER[Term::IMPLICIT_MENTION],
 973                                         $activity_tags[$index]['name'],
 974                                         1
 975                                 );
 976                         }
 977                 }
 978
 979                 return $activity_tags;
 980         }
 981 }