src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Exception;
  25 use Friendica\Content\Text\BBCode;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Core\System;
  31 use Friendica\Database\DBA;
  32 use Friendica\DI;
  33 use Friendica\Model\APContact;
  34 use Friendica\Model\Contact;
  35 use Friendica\Model\Conversation;
  36 use Friendica\Model\Event;
  37 use Friendica\Model\GServer;
  38 use Friendica\Model\Item;
  39 use Friendica\Model\ItemURI;
  40 use Friendica\Model\Mail;
  41 use Friendica\Model\Tag;
  42 use Friendica\Model\User;
  43 use Friendica\Model\Post;
  44 use Friendica\Network\HTTPException\InternalServerErrorException;
  45 use Friendica\Protocol\Activity;
  46 use Friendica\Protocol\ActivityPub;
  47 use Friendica\Protocol\Relay;
  48 use Friendica\Util\DateTimeFormat;
  49 use Friendica\Util\JsonLD;
  50 use Friendica\Util\Strings;
  51
  52 /**
  53  * ActivityPub Processor Protocol class
  54  */
  55 class Processor
  56 {
  57         /**
  58          * Extracts the tag character (#, @, !) from mention links
  59          *
  60          * @param string $body
  61          * @return string
  62          */
  63         protected static function normalizeMentionLinks(string $body): string
  64         {
  65                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  66         }
  67
  68         /**
  69          * Convert the language array into a language JSON
  70          *
  71          * @param array $languages
  72          * @return string language JSON
  73          */
  74         private static function processLanguages(array $languages)
  75         {
  76                 $codes = array_keys($languages);
  77                 $lang = [];
  78                 foreach ($codes as $code) {
  79                         $lang[$code] = 1;
  80                 }
  81
  82                 if (empty($lang)) {
  83                         return '';
  84                 }
  85
  86                 return json_encode($lang);
  87         }
  88         /**
  89          * Replaces emojis in the body
  90          *
  91          * @param array $emojis
  92          * @param string $body
  93          *
  94          * @return string with replaced emojis
  95          */
  96         private static function replaceEmojis(int $uri_id, $body, array $emojis)
  97         {
  98                 $body = strtr($body,
  99                         array_combine(
 100                                 array_column($emojis, 'name'),
 101                                 array_map(function ($emoji) {
 102                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 103                                 }, $emojis)
 104                         )
 105                 );
 106
 107                 // We store the emoji here to be able to avoid storing it in the media
 108                 foreach ($emojis as $emoji) {
 109                         Post\Link::getByLink($uri_id, $emoji['href']);
 110                 }
 111                 return $body;
 112         }
 113
 114         /**
 115          * Store attached media files in the post-media table
 116          *
 117          * @param int $uriid
 118          * @param array $attachment
 119          * @return void
 120          */
 121         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 122         {
 123                 if (empty($attachment['url'])) {
 124                         return;
 125                 }
 126
 127                 $data = ['uri-id' => $uriid];
 128                 $data['type'] = Post\Media::UNKNOWN;
 129                 $data['url'] = $attachment['url'];
 130                 $data['mimetype'] = $attachment['mediaType'] ?? null;
 131                 $data['height'] = $attachment['height'] ?? null;
 132                 $data['width'] = $attachment['width'] ?? null;
 133                 $data['size'] = $attachment['size'] ?? null;
 134                 $data['preview'] = $attachment['image'] ?? null;
 135                 $data['description'] = $attachment['name'] ?? null;
 136
 137                 Post\Media::insert($data);
 138         }
 139
 140         /**
 141          * Stire attachment data
 142          *
 143          * @param array   $activity
 144          * @param array   $item
 145          */
 146         private static function storeAttachments($activity, $item)
 147         {
 148                 if (empty($activity['attachments'])) {
 149                         return;
 150                 }
 151
 152                 foreach ($activity['attachments'] as $attach) {
 153                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 154                 }
 155         }
 156
 157         /**
 158          * Updates a message
 159          *
 160          * @param array $activity Activity array
 161          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 162          */
 163         public static function updateItem($activity)
 164         {
 165                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
 166                 if (!DBA::isResult($item)) {
 167                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 168                         $item = self::createItem($activity);
 169                         if (empty($item)) {
 170                                 return;
 171                         }
 172
 173                         self::postItem($activity, $item);
 174                         return;
 175                 }
 176
 177                 $item['changed'] = DateTimeFormat::utcNow();
 178                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 179
 180                 $item = self::processContent($activity, $item);
 181
 182                 self::storeAttachments($activity, $item);
 183
 184                 if (empty($item)) {
 185                         return;
 186                 }
 187
 188                 Item::update($item, ['uri' => $activity['id']]);
 189
 190                 if ($activity['object_type'] == 'as:Event') {
 191                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
 192                         while ($post = DBA::fetch($posts)) {
 193                                 self::updateEvent($post['event-id'], $activity);
 194                         }
 195                 }
 196         }
 197
 198         /**
 199          * Update an existing event
 200          *
 201          * @param int $event_id
 202          * @param array $activity
 203          */
 204         private static function updateEvent(int $event_id, array $activity)
 205         {
 206                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
 207
 208                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
 209                 $event['summary']  = HTML::toBBCode($activity['name']);
 210                 $event['desc']     = HTML::toBBCode($activity['content']);
 211                 $event['start']    = $activity['start-time'];
 212                 $event['finish']   = $activity['end-time'];
 213                 $event['nofinish'] = empty($event['finish']);
 214                 $event['location'] = $activity['location'];
 215
 216                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
 217                 Event::store($event);
 218         }
 219
 220         /**
 221          * Prepares data for a message
 222          *
 223          * @param array $activity Activity array
 224          * @return array Internal item
 225          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 226          * @throws \ImagickException
 227          */
 228         public static function createItem($activity)
 229         {
 230                 $item = [];
 231                 $item['verb'] = Activity::POST;
 232                 $item['thr-parent'] = $activity['reply-to-id'];
 233
 234                 if ($activity['reply-to-id'] == $activity['id']) {
 235                         $item['gravity'] = GRAVITY_PARENT;
 236                         $item['object-type'] = Activity\ObjectType::NOTE;
 237                 } else {
 238                         $item['gravity'] = GRAVITY_COMMENT;
 239                         $item['object-type'] = Activity\ObjectType::COMMENT;
 240                 }
 241
 242                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 243                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 244                         self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 245                 }
 246
 247                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 248
 249                 /// @todo What to do with $activity['context']?
 250                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 251                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 252                         return [];
 253                 }
 254
 255                 $item['network'] = Protocol::ACTIVITYPUB;
 256                 $item['author-link'] = $activity['author'];
 257                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 258                 $item['owner-link'] = $activity['actor'];
 259                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 260
 261                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 262                         $item['private'] = Item::UNLISTED;
 263                 } elseif (in_array(0, $activity['receiver'])) {
 264                         $item['private'] = Item::PUBLIC;
 265                 } else {
 266                         $item['private'] = Item::PRIVATE;
 267                 }
 268
 269                 if (!empty($activity['raw'])) {
 270                         $item['source'] = $activity['raw'];
 271                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 272                         $item['conversation-href'] = $activity['context'] ?? '';
 273                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 274
 275                         if (isset($activity['push'])) {
 276                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 277                         }
 278                 }
 279
 280                 if (!empty($activity['from-relay'])) {
 281                         $item['direction'] = Conversation::RELAY;
 282                 }
 283
 284                 if ($activity['object_type'] == 'as:Article') {
 285                         $item['post-type'] = Item::PT_ARTICLE;
 286                 } elseif ($activity['object_type'] == 'as:Audio') {
 287                         $item['post-type'] = Item::PT_AUDIO;
 288                 } elseif ($activity['object_type'] == 'as:Document') {
 289                         $item['post-type'] = Item::PT_DOCUMENT;
 290                 } elseif ($activity['object_type'] == 'as:Event') {
 291                         $item['post-type'] = Item::PT_EVENT;
 292                 } elseif ($activity['object_type'] == 'as:Image') {
 293                         $item['post-type'] = Item::PT_IMAGE;
 294                 } elseif ($activity['object_type'] == 'as:Page') {
 295                         $item['post-type'] = Item::PT_PAGE;
 296                 } elseif ($activity['object_type'] == 'as:Question') {
 297                         $item['post-type'] = Item::PT_POLL;
 298                 } elseif ($activity['object_type'] == 'as:Video') {
 299                         $item['post-type'] = Item::PT_VIDEO;
 300                 } else {
 301                         $item['post-type'] = Item::PT_NOTE;
 302                 }
 303
 304                 $item['isForum'] = false;
 305
 306                 if (!empty($activity['thread-completion'])) {
 307                         if ($activity['thread-completion'] != $item['owner-id']) {
 308                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 309                                 $item['causer-link'] = $actor['url'];
 310                                 $item['causer-id'] = $activity['thread-completion'];
 311                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 312                         } else {
 313                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 314                                 $item['causer-link'] = $item['owner-link'];
 315                                 $item['causer-id']   = $item['owner-id'];
 316                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 317                         }
 318
 319                         $item['owner-link'] = $item['author-link'];
 320                         $item['owner-id'] = $item['author-id'];
 321                 } else {
 322                         $actor = APContact::getByURL($item['owner-link'], false);
 323                         $item['isForum'] = ($actor['type'] == 'Group');
 324                 }
 325
 326                 $item['uri'] = $activity['id'];
 327
 328                 if (empty($activity['published']) || empty($activity['updated'])) {
 329                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 330                 }
 331
 332                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 333                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 334                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 335                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 336
 337                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 338                 if (empty($item['uri-id'])) {
 339                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 340                         return [];
 341                 }
 342
 343                 $item = self::processContent($activity, $item);
 344                 if (empty($item)) {
 345                         Logger::info('Message was not processed');
 346                         return [];
 347                 }
 348
 349                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 350
 351                 self::storeAttachments($activity, $item);
 352
 353                 // We received the post via AP, so we set the protocol of the server to AP
 354                 $contact = Contact::getById($item['author-id'], ['gsid']);
 355                 if (!empty($contact['gsid'])) {
 356                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 357                 }
 358
 359                 if ($item['author-id'] != $item['owner-id']) {
 360                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 361                         if (!empty($contact['gsid'])) {
 362                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 363                         }
 364                 }
 365
 366                 return $item;
 367         }
 368
 369         /**
 370          * Delete items
 371          *
 372          * @param array $activity
 373          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 374          * @throws \ImagickException
 375          */
 376         public static function deleteItem($activity)
 377         {
 378                 $owner = Contact::getIdForURL($activity['actor']);
 379
 380                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 381                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 382         }
 383
 384         /**
 385          * Prepare the item array for an activity
 386          *
 387          * @param array $activity Activity array
 388          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 389          * @throws \ImagickException
 390          */
 391         public static function addTag($activity)
 392         {
 393                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 394                         return;
 395                 }
 396
 397                 foreach ($activity['receiver'] as $receiver) {
 398                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 399                         if (!DBA::isResult($item)) {
 400                                 // We don't fetch missing content for this purpose
 401                                 continue;
 402                         }
 403
 404                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 405                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 406                                 continue;
 407                         }
 408
 409                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 410                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 411                 }
 412         }
 413
 414         /**
 415          * Prepare the item array for an activity
 416          *
 417          * @param array  $activity Activity array
 418          * @param string $verb     Activity verb
 419          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 420          * @throws \ImagickException
 421          */
 422         public static function createActivity($activity, $verb)
 423         {
 424                 $item = self::createItem($activity);
 425                 if (empty($item)) {
 426                         return;
 427                 }
 428
 429                 $item['verb'] = $verb;
 430                 $item['thr-parent'] = $activity['object_id'];
 431                 $item['gravity'] = GRAVITY_ACTIVITY;
 432                 unset($item['post-type']);
 433                 $item['object-type'] = Activity\ObjectType::NOTE;
 434
 435                 if (!empty($activity['content'])) {
 436                         $item['body'] = HTML::toBBCode($activity['content']);
 437                 }
 438
 439                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 440
 441                 self::postItem($activity, $item);
 442         }
 443
 444         /**
 445          * Fetch the Uri-Id of a post for the "featured" collection
 446          *
 447          * @param array $activity
 448          * @return null|int
 449          */
 450         private static function getUriIdForFeaturedCollection(array $activity)
 451         {
 452                 $actor = APContact::getByURL($activity['actor']);
 453                 if (empty($actor)) {
 454                         return null;
 455                 }
 456
 457                 // Refetch the account when the "featured" collection is missing.
 458                 // This can be removed in a future version (end of 2022 should be good).
 459                 if (empty($actor['featured'])) {
 460                         $actor = APContact::getByURL($activity['actor'], true);
 461                         if (empty($actor)) {
 462                                 return null;
 463                         }
 464                 }
 465
 466                 if ($activity['target_id'] != $actor['featured']) {
 467                         return null;
 468                 }
 469
 470                 $id = Contact::getIdForURL($activity['actor']);
 471                 if (empty($id)) {
 472                         return null;
 473                 }
 474
 475                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id'], 'author-id' => $id]);
 476                 if (!empty($parent['uri-id'])) {
 477                         return $parent['uri-id'];
 478                 }
 479
 480                 return null;
 481         }
 482
 483         /**
 484          * Add a post to the "Featured" collection
 485          *
 486          * @param array $activity
 487          */
 488         public static function addToFeaturedCollection(array $activity)
 489         {
 490                 $uriid = self::getUriIdForFeaturedCollection($activity);
 491                 if (empty($uriid)) {
 492                         return;
 493                 }
 494
 495                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
 496
 497                 // @todo Add functionality
 498         }
 499
 500         /**
 501          * Remove a post to the "Featured" collection
 502          *
 503          * @param array $activity
 504          */
 505         public static function removeFromFeaturedCollection(array $activity)
 506         {
 507                 $uriid = self::getUriIdForFeaturedCollection($activity);
 508                 if (empty($uriid)) {
 509                         return;
 510                 }
 511
 512                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
 513
 514                 // @todo Add functionality
 515         }
 516
 517         /**
 518          * Create an event
 519          *
 520          * @param array $activity Activity array
 521          * @param array $item
 522          *
 523          * @return int event id
 524          * @throws \Exception
 525          */
 526         public static function createEvent($activity, $item)
 527         {
 528                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
 529                 $event['desc']      = HTML::toBBCode($activity['content']);
 530                 $event['start']     = $activity['start-time'];
 531                 $event['finish']    = $activity['end-time'];
 532                 $event['nofinish']  = empty($event['finish']);
 533                 $event['location']  = $activity['location'];
 534                 $event['cid']       = $item['contact-id'];
 535                 $event['uid']       = $item['uid'];
 536                 $event['uri']       = $item['uri'];
 537                 $event['edited']    = $item['edited'];
 538                 $event['private']   = $item['private'];
 539                 $event['guid']      = $item['guid'];
 540                 $event['plink']     = $item['plink'];
 541                 $event['network']   = $item['network'];
 542                 $event['protocol']  = $item['protocol'];
 543                 $event['direction'] = $item['direction'];
 544                 $event['source']    = $item['source'];
 545
 546                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 547                 if (DBA::isResult($ev)) {
 548                         $event['id'] = $ev['id'];
 549                 }
 550
 551                 $event_id = Event::store($event);
 552
 553                 Logger::info('Event was stored', ['id' => $event_id]);
 554
 555                 return $event_id;
 556         }
 557
 558         /**
 559          * Process the content
 560          *
 561          * @param array $activity Activity array
 562          * @param array $item
 563          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 564          * @throws \Exception
 565          */
 566         private static function processContent($activity, $item)
 567         {
 568                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 569                         $item['title'] = Markdown::toBBCode($activity['name']);
 570                         $content = Markdown::toBBCode($activity['content']);
 571                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 572                         $item['title'] = $activity['name'];
 573                         $content = $activity['content'];
 574                 } else {
 575                         // By default assume "text/html"
 576                         $item['title'] = HTML::toBBCode($activity['name']);
 577                         $content = HTML::toBBCode($activity['content']);
 578                 }
 579
 580                 if (!empty($activity['languages'])) {
 581                         $item['language'] = self::processLanguages($activity['languages']);
 582                 }
 583
 584                 if (!empty($activity['emojis'])) {
 585                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 586                 }
 587
 588                 $content = self::addMentionLinks($content, $activity['tags']);
 589
 590                 if (!empty($activity['source'])) {
 591                         $item['body'] = $activity['source'];
 592                         $item['raw-body'] = $content;
 593                         $item['body'] = Item::improveSharedDataInBody($item);
 594                 } else {
 595                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 596                                 $item_private = !in_array(0, $activity['item_receiver']);
 597                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 598                                 if (!DBA::isResult($parent)) {
 599                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 600                                         return false;
 601                                 }
 602                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 603                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 604                                         return false;
 605                                 }
 606
 607                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 608                         }
 609                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 610                         $item['raw-body'] = $item['body'] = $content;
 611                 }
 612
 613                 self::storeFromBody($item);
 614                 self::storeTags($item['uri-id'], $activity['tags']);
 615
 616                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 617
 618                 $item['location'] = $activity['location'];
 619
 620                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 621                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 622                 }
 623
 624                 $item['app'] = $activity['generator'];
 625
 626                 return $item;
 627         }
 628
 629         /**
 630          * Store hashtags and mentions
 631          *
 632          * @param array $item
 633          */
 634         private static function storeFromBody(array $item)
 635         {
 636                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 637                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 638
 639                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 640         }
 641
 642         /**
 643          * Generate a GUID out of an URL of an ActivityPub post.
 644          *
 645          * @param string $url message URL
 646          * @return string with GUID
 647          */
 648         private static function getGUIDByURL(string $url)
 649         {
 650                 $parsed = parse_url($url);
 651
 652                 $host_hash = hash('crc32', $parsed['host']);
 653
 654                 unset($parsed["scheme"]);
 655                 unset($parsed["host"]);
 656
 657                 $path = implode("/", $parsed);
 658
 659                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 660         }
 661
 662         /**
 663          * Checks if an incoming message is wanted
 664          *
 665          * @param array $activity
 666          * @param array $item
 667          * @return boolean Is the message wanted?
 668          */
 669         private static function isSolicitedMessage(array $activity, array $item)
 670         {
 671                 // The checks are split to improve the support when searching why a message was accepted.
 672                 if (count($activity['receiver']) != 1) {
 673                         // The message has more than one receiver, so it is wanted.
 674                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 675                         return true;
 676                 }
 677
 678                 if ($item['private'] == Item::PRIVATE) {
 679                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 680                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 681                         return true;
 682                 }
 683
 684                 if (!empty($activity['from-relay'])) {
 685                         // We check relay posts at another place. When it arrived here, the message is already checked.
 686                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 687                         return true;
 688                 }
 689
 690                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 691                         // Manual completions and completions caused by reshares are allowed without any further checks.
 692                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 693                         return true;
 694                 }
 695
 696                 if ($item['gravity'] != GRAVITY_PARENT) {
 697                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 698                         // This can possibly be improved in the future.
 699                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 700                         return true;
 701                 }
 702
 703                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 704                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 705                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 706                         return true;
 707                 } else {
 708                         return false;
 709                 }
 710         }
 711
 712         /**
 713          * Creates an item post
 714          *
 715          * @param array $activity Activity data
 716          * @param array $item     item array
 717          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 718          * @throws \ImagickException
 719          */
 720         public static function postItem(array $activity, array $item)
 721         {
 722                 if (empty($item)) {
 723                         return;
 724                 }
 725
 726                 $stored = false;
 727                 ksort($activity['receiver']);
 728
 729                 if (!self::isSolicitedMessage($activity, $item)) {
 730                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 731                         return;
 732                 }
 733
 734                 foreach ($activity['receiver'] as $receiver) {
 735                         if ($receiver == -1) {
 736                                 continue;
 737                         }
 738
 739                         $item['uid'] = $receiver;
 740
 741                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 742                         switch($type) {
 743                                 case Receiver::TARGET_TO:
 744                                         $item['post-reason'] = Item::PR_TO;
 745                                         break;
 746                                 case Receiver::TARGET_CC:
 747                                         $item['post-reason'] = Item::PR_CC;
 748                                         break;
 749                                 case Receiver::TARGET_BTO:
 750                                         $item['post-reason'] = Item::PR_BTO;
 751                                         break;
 752                                 case Receiver::TARGET_BCC:
 753                                         $item['post-reason'] = Item::PR_BCC;
 754                                         break;
 755                                 case Receiver::TARGET_FOLLOWER:
 756                                         $item['post-reason'] = Item::PR_FOLLOWER;
 757                                         break;
 758                                 case Receiver::TARGET_ANSWER:
 759                                         $item['post-reason'] = Item::PR_COMMENT;
 760                                         break;
 761                                 case Receiver::TARGET_GLOBAL:
 762                                         $item['post-reason'] = Item::PR_GLOBAL;
 763                                         break;
 764                                 default:
 765                                         $item['post-reason'] = Item::PR_NONE;
 766                         }
 767
 768                         if (!empty($activity['from-relay'])) {
 769                                 $item['post-reason'] = Item::PR_RELAY;
 770                         } elseif (!empty($activity['thread-completion'])) {
 771                                 $item['post-reason'] = Item::PR_FETCHED;
 772                         }
 773
 774                         if ($item['isForum'] ?? false) {
 775                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 776                         } else {
 777                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 778                         }
 779
 780                         if (($receiver != 0) && empty($item['contact-id'])) {
 781                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 782                         }
 783
 784                         if (!empty($activity['directmessage'])) {
 785                                 self::postMail($activity, $item);
 786                                 continue;
 787                         }
 788
 789                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 790                                 if ($item['post-reason'] == Item::PR_BCC) {
 791                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 792                                         continue;
 793                                 }
 794
 795                                 if (
 796                                         !empty($activity['thread-children-type'])
 797                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
 798                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
 799                                 ) {
 800                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
 801                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
 802                                         continue;
 803                                 }
 804                         }
 805
 806                         $is_forum = false;
 807
 808                         if ($receiver != 0) {
 809                                 $user = User::getById($receiver, ['account-type']);
 810                                 if (!empty($user['account-type'])) {
 811                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
 812                                 }
 813                         }
 814
 815                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 816                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 817
 818                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 819                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 820                                 }
 821
 822                                 if ($skip) {
 823                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 824                                         continue;
 825                                 }
 826
 827                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 828                         }
 829
 830                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 831                                 $event_id = self::createEvent($activity, $item);
 832
 833                                 $item = Event::getItemArrayForImportedId($event_id, $item);
 834                         }
 835
 836                         $item_id = Item::insert($item);
 837                         if ($item_id) {
 838                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 839                         } else {
 840                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 841                         }
 842
 843                         if ($item['uid'] == 0) {
 844                                 $stored = $item_id;
 845                         }
 846                 }
 847
 848                 // Store send a follow request for every reshare - but only when the item had been stored
 849                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 850                         $author = APContact::getByURL($item['owner-link'], false);
 851                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 852                         if ($author['type'] != 'Group') {
 853                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 854                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 855                         }
 856                 }
 857         }
 858
 859         /**
 860          * Store tags and mentions into the tag table
 861          *
 862          * @param integer $uriid
 863          * @param array $tags
 864          */
 865         private static function storeTags(int $uriid, array $tags = null)
 866         {
 867                 foreach ($tags as $tag) {
 868                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 869                                 continue;
 870                         }
 871
 872                         $hash = substr($tag['name'], 0, 1);
 873
 874                         if ($tag['type'] == 'Mention') {
 875                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 876                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 877                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 878                                         $tag['name'] = substr($tag['name'], 1);
 879                                 }
 880                                 $type = Tag::IMPLICIT_MENTION;
 881
 882                                 if (!empty($tag['href'])) {
 883                                         $apcontact = APContact::getByURL($tag['href']);
 884                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 885                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 886                                         }
 887                                 }
 888                         } elseif ($tag['type'] == 'Hashtag') {
 889                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 890                                         $tag['name'] = substr($tag['name'], 1);
 891                                 }
 892                                 $type = Tag::HASHTAG;
 893                         }
 894
 895                         if (empty($tag['name'])) {
 896                                 continue;
 897                         }
 898
 899                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 900                 }
 901         }
 902
 903         public static function storeReceivers(int $uriid, array $receivers)
 904         {
 905                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
 906                         if (!empty($receivers[$element])) {
 907                                 foreach ($receivers[$element] as $receiver) {
 908                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
 909                                                 $name = Receiver::PUBLIC_COLLECTION;
 910                                         } else {
 911                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
 912                                         }
 913                                         Tag::store($uriid, $type, $name, $receiver);
 914                                 }
 915                         }
 916                 }
 917         }
 918
 919         /**
 920          * Creates an mail post
 921          *
 922          * @param array $activity Activity data
 923          * @param array $item     item array
 924          * @return int|bool New mail table row id or false on error
 925          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 926          */
 927         private static function postMail($activity, $item)
 928         {
 929                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 930                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 931                         return false;
 932                 }
 933
 934                 Logger::info('Direct Message', $item);
 935
 936                 $msg = [];
 937                 $msg['uid'] = $item['uid'];
 938
 939                 $msg['contact-id'] = $item['contact-id'];
 940
 941                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 942                 $msg['from-name'] = $contact['name'];
 943                 $msg['from-url'] = $contact['url'];
 944                 $msg['from-photo'] = $contact['photo'];
 945
 946                 $msg['uri'] = $item['uri'];
 947                 $msg['created'] = $item['created'];
 948
 949                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 950                 if (DBA::isResult($parent)) {
 951                         $msg['parent-uri'] = $parent['parent-uri'];
 952                         $msg['title'] = $parent['title'];
 953                 } else {
 954                         $msg['parent-uri'] = $item['thr-parent'];
 955
 956                         if (!empty($item['title'])) {
 957                                 $msg['title'] = $item['title'];
 958                         } elseif (!empty($item['content-warning'])) {
 959                                 $msg['title'] = $item['content-warning'];
 960                         } else {
 961                                 // Trying to generate a title out of the body
 962                                 $title = $item['body'];
 963
 964                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 965                                         $title = $matches[3];
 966                                 }
 967
 968                                 $title = trim(BBCode::toPlaintext($title));
 969
 970                                 if (strlen($title) > 20) {
 971                                         $title = substr($title, 0, 20) . '...';
 972                                 }
 973
 974                                 $msg['title'] = $title;
 975                         }
 976                 }
 977                 $msg['body'] = $item['body'];
 978
 979                 return Mail::insert($msg);
 980         }
 981
 982         /**
 983          * Fetches missing posts
 984          *
 985          * @param string $url         message URL
 986          * @param array  $child       activity array with the child of this message
 987          * @param string $relay_actor Relay actor
 988          * @param int    $completion  Completion mode, see Receiver::COMPLETION_*
 989          * @return string fetched message URL
 990          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 991          */
 992         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL)
 993         {
 994                 if (!empty($child['receiver'])) {
 995                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 996                 } else {
 997                         $uid = 0;
 998                 }
 999
1000                 $object = ActivityPub::fetchContent($url, $uid);
1001                 if (empty($object)) {
1002                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
1003                         return '';
1004                 }
1005
1006                 if (empty($object['id'])) {
1007                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1008                         return '';
1009                 }
1010
1011                 if (!empty($object['actor'])) {
1012                         $object_actor = $object['actor'];
1013                 } elseif (!empty($object['attributedTo'])) {
1014                         $object_actor = $object['attributedTo'];
1015                         if (is_array($object_actor)) {
1016                                 $compacted = JsonLD::compact($object);
1017                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1018                         }
1019                 } else {
1020                         // Shouldn't happen
1021                         $object_actor = '';
1022                 }
1023
1024                 $signer = [$object_actor];
1025
1026                 if (!empty($child['author'])) {
1027                         $actor = $child['author'];
1028                         $signer[] = $actor;
1029                 } else {
1030                         $actor = $object_actor;
1031                 }
1032
1033                 if (!empty($object['published'])) {
1034                         $published = $object['published'];
1035                 } elseif (!empty($child['published'])) {
1036                         $published = $child['published'];
1037                 } else {
1038                         $published = DateTimeFormat::utcNow();
1039                 }
1040
1041                 $activity = [];
1042                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1043                 unset($object['@context']);
1044                 $activity['id'] = $object['id'];
1045                 $activity['to'] = $object['to'] ?? [];
1046                 $activity['cc'] = $object['cc'] ?? [];
1047                 $activity['actor'] = $actor;
1048                 $activity['object'] = $object;
1049                 $activity['published'] = $published;
1050                 $activity['type'] = 'Create';
1051
1052                 $ldactivity = JsonLD::compact($activity);
1053
1054                 if (!empty($relay_actor)) {
1055                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1056                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1057                 } elseif (!empty($child['thread-completion'])) {
1058                         $ldactivity['thread-completion'] = $child['thread-completion'];
1059                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1060                 } else {
1061                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1062                         $ldactivity['completion-mode']   = $completion;
1063                 }
1064
1065                 if (!empty($child['type'])) {
1066                         $ldactivity['thread-children-type'] = $child['type'];
1067                 }
1068
1069                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1070                         return '';
1071                 }
1072
1073                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
1074
1075                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
1076
1077                 return $activity['id'];
1078         }
1079
1080         /**
1081          * Test if incoming relay messages should be accepted
1082          *
1083          * @param array $activity activity array
1084          * @param string $id      object ID
1085          * @return boolean true if message is accepted
1086          */
1087         private static function acceptIncomingMessage(array $activity, string $id)
1088         {
1089                 if (empty($activity['as:object'])) {
1090                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1091                         return true;
1092                 }
1093
1094                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1095                 $uriid = ItemURI::getIdByURI($replyto);
1096                 if (Post::exists(['uri-id' => $uriid])) {
1097                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1098                         return true;
1099                 }
1100
1101                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1102                 $authorid = Contact::getIdForURL($attributed_to);
1103
1104                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
1105
1106                 $messageTags = [];
1107                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1108                 if (!empty($tags)) {
1109                         foreach ($tags as $tag) {
1110                                 if ($tag['type'] != 'Hashtag') {
1111                                         continue;
1112                                 }
1113                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1114                         }
1115                 }
1116
1117                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1118         }
1119
1120         /**
1121          * perform a "follow" request
1122          *
1123          * @param array $activity
1124          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1125          * @throws \ImagickException
1126          */
1127         public static function followUser($activity)
1128         {
1129                 $uid = User::getIdForURL($activity['object_id']);
1130                 if (empty($uid)) {
1131                         return;
1132                 }
1133
1134                 $owner = User::getOwnerDataById($uid);
1135                 if (empty($owner)) {
1136                         return;
1137                 }
1138
1139                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1140                 if (!empty($cid)) {
1141                         self::switchContact($cid);
1142                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1143                 }
1144
1145                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
1146                         'author-link' => $activity['actor']];
1147
1148                 // Ensure that the contact has got the right network type
1149                 self::switchContact($item['author-id']);
1150
1151                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1152                 if ($result === true) {
1153                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1154                 }
1155
1156                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1157                 if (empty($cid)) {
1158                         return;
1159                 }
1160
1161                 if (empty($contact)) {
1162                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1163                 }
1164
1165                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1166         }
1167
1168         /**
1169          * Update the given profile
1170          *
1171          * @param array $activity
1172          * @throws \Exception
1173          */
1174         public static function updatePerson($activity)
1175         {
1176                 if (empty($activity['object_id'])) {
1177                         return;
1178                 }
1179
1180                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1181                 Contact::updateFromProbeByURL($activity['object_id']);
1182         }
1183
1184         /**
1185          * Delete the given profile
1186          *
1187          * @param array $activity
1188          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1189          */
1190         public static function deletePerson($activity)
1191         {
1192                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1193                         Logger::info('Empty object id or actor.');
1194                         return;
1195                 }
1196
1197                 if ($activity['object_id'] != $activity['actor']) {
1198                         Logger::info('Object id does not match actor.');
1199                         return;
1200                 }
1201
1202                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1203                 while ($contact = DBA::fetch($contacts)) {
1204                         Contact::remove($contact['id']);
1205                 }
1206                 DBA::close($contacts);
1207
1208                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1209         }
1210
1211         /**
1212          * Accept a follow request
1213          *
1214          * @param array $activity
1215          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1216          * @throws \ImagickException
1217          */
1218         public static function acceptFollowUser($activity)
1219         {
1220                 $uid = User::getIdForURL($activity['object_actor']);
1221                 if (empty($uid)) {
1222                         return;
1223                 }
1224
1225                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1226                 if (empty($cid)) {
1227                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1228                         return;
1229                 }
1230
1231                 self::switchContact($cid);
1232
1233                 $fields = ['pending' => false];
1234
1235                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1236                 if ($contact['rel'] == Contact::FOLLOWER) {
1237                         $fields['rel'] = Contact::FRIEND;
1238                 }
1239
1240                 $condition = ['id' => $cid];
1241                 Contact::update($fields, $condition);
1242                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1243         }
1244
1245         /**
1246          * Reject a follow request
1247          *
1248          * @param array $activity
1249          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1250          * @throws \ImagickException
1251          */
1252         public static function rejectFollowUser($activity)
1253         {
1254                 $uid = User::getIdForURL($activity['object_actor']);
1255                 if (empty($uid)) {
1256                         return;
1257                 }
1258
1259                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1260                 if (empty($cid)) {
1261                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1262                         return;
1263                 }
1264
1265                 self::switchContact($cid);
1266
1267                 $contact = Contact::getById($cid, ['rel']);
1268                 if ($contact['rel'] == Contact::SHARING) {
1269                         Contact::remove($cid);
1270                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1271                 } elseif ($contact['rel'] == Contact::FRIEND) {
1272                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1273                 } else {
1274                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1275                 }
1276         }
1277
1278         /**
1279          * Undo activity like "like" or "dislike"
1280          *
1281          * @param array $activity
1282          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1283          * @throws \ImagickException
1284          */
1285         public static function undoActivity($activity)
1286         {
1287                 if (empty($activity['object_id'])) {
1288                         return;
1289                 }
1290
1291                 if (empty($activity['object_actor'])) {
1292                         return;
1293                 }
1294
1295                 $author_id = Contact::getIdForURL($activity['object_actor']);
1296                 if (empty($author_id)) {
1297                         return;
1298                 }
1299
1300                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1301         }
1302
1303         /**
1304          * Activity to remove a follower
1305          *
1306          * @param array $activity
1307          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1308          * @throws \ImagickException
1309          */
1310         public static function undoFollowUser($activity)
1311         {
1312                 $uid = User::getIdForURL($activity['object_object']);
1313                 if (empty($uid)) {
1314                         return;
1315                 }
1316
1317                 $owner = User::getOwnerDataById($uid);
1318                 if (empty($owner)) {
1319                         return;
1320                 }
1321
1322                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1323                 if (empty($cid)) {
1324                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1325                         return;
1326                 }
1327
1328                 self::switchContact($cid);
1329
1330                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1331                 if (!DBA::isResult($contact)) {
1332                         return;
1333                 }
1334
1335                 Contact::removeFollower($contact);
1336                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1337         }
1338
1339         /**
1340          * Switches a contact to AP if needed
1341          *
1342          * @param integer $cid Contact ID
1343          * @throws \Exception
1344          */
1345         private static function switchContact($cid)
1346         {
1347                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1348                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1349                         return;
1350                 }
1351
1352                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1353                 Contact::updateFromProbe($cid);
1354         }
1355
1356         /**
1357          * Collects implicit mentions like:
1358          * - the author of the parent item
1359          * - all the mentioned conversants in the parent item
1360          *
1361          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1362          * @return array
1363          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1364          */
1365         private static function getImplicitMentionList(array $parent)
1366         {
1367                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1368
1369                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1370
1371                 $implicit_mentions = [];
1372                 if (empty($parent_author['url'])) {
1373                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1374                 } else {
1375                         $implicit_mentions[] = $parent_author['url'];
1376                         $implicit_mentions[] = $parent_author['nurl'];
1377                         $implicit_mentions[] = $parent_author['alias'];
1378                 }
1379
1380                 if (!empty($parent['alias'])) {
1381                         $implicit_mentions[] = $parent['alias'];
1382                 }
1383
1384                 foreach ($parent_terms as $term) {
1385                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1386                         if (!empty($contact['url'])) {
1387                                 $implicit_mentions[] = $contact['url'];
1388                                 $implicit_mentions[] = $contact['nurl'];
1389                                 $implicit_mentions[] = $contact['alias'];
1390                         }
1391                 }
1392
1393                 return $implicit_mentions;
1394         }
1395
1396         /**
1397          * Strips from the body prepended implicit mentions
1398          *
1399          * @param string $body
1400          * @param array $parent
1401          * @return string
1402          */
1403         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1404         {
1405                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1406                         return $body;
1407                 }
1408
1409                 $potential_mentions = self::getImplicitMentionList($parent);
1410
1411                 $kept_mentions = [];
1412
1413                 // Extract one prepended mention at a time from the body
1414                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1415                         if (!in_array($matches[2], $potential_mentions)) {
1416                                 $kept_mentions[] = $matches[1];
1417                         }
1418
1419                         $body = $matches[3];
1420                 }
1421
1422                 // Re-appending the kept mentions to the body after extraction
1423                 $kept_mentions[] = $body;
1424
1425                 return implode('', $kept_mentions);
1426         }
1427
1428         /**
1429          * Adds links to string mentions
1430          *
1431          * @param string $body
1432          * @param array  $tags
1433          * @return string
1434          */
1435         protected static function addMentionLinks(string $body, array $tags): string
1436         {
1437                 // This prevents links to be added again to Pleroma-style mention links
1438                 $body = self::normalizeMentionLinks($body);
1439
1440                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1441                         foreach ($tags as $tag) {
1442                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1443                                         continue;
1444                                 }
1445
1446                                 $hash = substr($tag['name'], 0, 1);
1447                                 $name = substr($tag['name'], 1);
1448                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1449                                         $hash = '';
1450                                         $name = $tag['name'];
1451                                 }
1452
1453                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1454                         }
1455
1456                         return $body;
1457                 });
1458
1459                 return $body;
1460         }
1461 }