src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2021, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Content\Text\HTML;
  26 use Friendica\Content\Text\Markdown;
  27 use Friendica\Core\Logger;
  28 use Friendica\Core\Protocol;
  29 use Friendica\Core\System;
  30 use Friendica\Database\DBA;
  31 use Friendica\DI;
  32 use Friendica\Model\APContact;
  33 use Friendica\Model\Contact;
  34 use Friendica\Model\Conversation;
  35 use Friendica\Model\Event;
  36 use Friendica\Model\GServer;
  37 use Friendica\Model\Item;
  38 use Friendica\Model\ItemURI;
  39 use Friendica\Model\Mail;
  40 use Friendica\Model\Tag;
  41 use Friendica\Model\User;
  42 use Friendica\Model\Post;
  43 use Friendica\Protocol\Activity;
  44 use Friendica\Protocol\ActivityPub;
  45 use Friendica\Protocol\Relay;
  46 use Friendica\Util\DateTimeFormat;
  47 use Friendica\Util\JsonLD;
  48 use Friendica\Util\Strings;
  49
  50 /**
  51  * ActivityPub Processor Protocol class
  52  */
  53 class Processor
  54 {
  55         /**
  56          * Extracts the tag character (#, @, !) from mention links
  57          *
  58          * @param string $body
  59          * @return string
  60          */
  61         protected static function normalizeMentionLinks(string $body): string
  62         {
  63                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  64         }
  65
  66         /**
  67          * Convert the language array into a language JSON
  68          *
  69          * @param array $languages
  70          * @return string language JSON
  71          */
  72         private static function processLanguages(array $languages)
  73         {
  74                 $codes = array_keys($languages);
  75                 $lang = [];
  76                 foreach ($codes as $code) {
  77                         $lang[$code] = 1;
  78                 }
  79
  80                 if (empty($lang)) {
  81                         return '';
  82                 }
  83
  84                 return json_encode($lang);
  85         }
  86         /**
  87          * Replaces emojis in the body
  88          *
  89          * @param array $emojis
  90          * @param string $body
  91          *
  92          * @return string with replaced emojis
  93          */
  94         private static function replaceEmojis(int $uri_id, $body, array $emojis)
  95         {
  96                 $body = strtr($body,
  97                         array_combine(
  98                                 array_column($emojis, 'name'),
  99                                 array_map(function ($emoji) {
 100                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 101                                 }, $emojis)
 102                         )
 103                 );
 104
 105                 // We store the emoji here to be able to avoid storing it in the media
 106                 foreach ($emojis as $emoji) {
 107                         Post\Link::getByLink($uri_id, $emoji['href']);
 108                 }
 109                 return $body;
 110         }
 111
 112         /**
 113          * Store attached media files in the post-media table
 114          *
 115          * @param int $uriid
 116          * @param array $attachment
 117          * @return void
 118          */
 119         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 120         {
 121                 if (empty($attachment['url'])) {
 122                         return;
 123                 }
 124
 125                 $data = ['uri-id' => $uriid];
 126                 $data['type'] = Post\Media::UNKNOWN;
 127                 $data['url'] = $attachment['url'];
 128                 $data['mimetype'] = $attachment['mediaType'];
 129                 $data['height'] = $attachment['height'] ?? null;
 130                 $data['width'] = $attachment['width'] ?? null;
 131                 $data['size'] = $attachment['size'] ?? null;
 132                 $data['preview'] = $attachment['image'] ?? null;
 133                 $data['description'] = $attachment['name'] ?? null;
 134
 135                 Post\Media::insert($data);
 136         }
 137
 138         /**
 139          * Stire attachment data
 140          *
 141          * @param array   $activity
 142          * @param array   $item
 143          */
 144         private static function storeAttachments($activity, $item)
 145         {
 146                 if (empty($activity['attachments'])) {
 147                         return;
 148                 }
 149
 150                 foreach ($activity['attachments'] as $attach) {
 151                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 152                 }
 153         }
 154
 155         /**
 156          * Updates a message
 157          *
 158          * @param array $activity Activity array
 159          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 160          */
 161         public static function updateItem($activity)
 162         {
 163                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
 164                 if (!DBA::isResult($item)) {
 165                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 166                         $item = self::createItem($activity);
 167                         self::postItem($activity, $item);
 168                         return;
 169                 }
 170
 171                 $item['changed'] = DateTimeFormat::utcNow();
 172                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 173
 174                 $item = self::processContent($activity, $item);
 175
 176                 self::storeAttachments($activity, $item);
 177
 178                 if (empty($item)) {
 179                         return;
 180                 }
 181
 182                 Item::update($item, ['uri' => $activity['id']]);
 183         }
 184
 185         /**
 186          * Prepares data for a message
 187          *
 188          * @param array $activity Activity array
 189          * @return array Internal item
 190          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 191          * @throws \ImagickException
 192          */
 193         public static function createItem($activity)
 194         {
 195                 $item = [];
 196                 $item['verb'] = Activity::POST;
 197                 $item['thr-parent'] = $activity['reply-to-id'];
 198
 199                 if ($activity['reply-to-id'] == $activity['id']) {
 200                         $item['gravity'] = GRAVITY_PARENT;
 201                         $item['object-type'] = Activity\ObjectType::NOTE;
 202                 } else {
 203                         $item['gravity'] = GRAVITY_COMMENT;
 204                         $item['object-type'] = Activity\ObjectType::COMMENT;
 205                 }
 206
 207                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 208                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 209                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 210                 }
 211
 212                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 213
 214                 /// @todo What to do with $activity['context']?
 215                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 216                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 217                         return [];
 218                 }
 219
 220                 $item['network'] = Protocol::ACTIVITYPUB;
 221                 $item['author-link'] = $activity['author'];
 222                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 223                 $item['owner-link'] = $activity['actor'];
 224                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 225
 226                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 227                         $item['private'] = Item::UNLISTED;
 228                 } elseif (in_array(0, $activity['receiver'])) {
 229                         $item['private'] = Item::PUBLIC;
 230                 } else {
 231                         $item['private'] = Item::PRIVATE;
 232                 }
 233
 234                 if (!empty($activity['raw'])) {
 235                         $item['source'] = $activity['raw'];
 236                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 237                         $item['conversation-href'] = $activity['context'] ?? '';
 238                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 239
 240                         if (isset($activity['push'])) {
 241                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 242                         }
 243                 }
 244
 245                 if (!empty($activity['from-relay'])) {
 246                         $item['direction'] = Conversation::RELAY;
 247                 }
 248
 249                 if ($activity['object_type'] == 'as:Article') {
 250                         $item['post-type'] = Item::PT_ARTICLE;
 251                 } elseif ($activity['object_type'] == 'as:Audio') {
 252                         $item['post-type'] = Item::PT_AUDIO;
 253                 } elseif ($activity['object_type'] == 'as:Document') {
 254                         $item['post-type'] = Item::PT_DOCUMENT;
 255                 } elseif ($activity['object_type'] == 'as:Event') {
 256                         $item['post-type'] = Item::PT_EVENT;
 257                 } elseif ($activity['object_type'] == 'as:Image') {
 258                         $item['post-type'] = Item::PT_IMAGE;
 259                 } elseif ($activity['object_type'] == 'as:Page') {
 260                         $item['post-type'] = Item::PT_PAGE;
 261                 } elseif ($activity['object_type'] == 'as:Video') {
 262                         $item['post-type'] = Item::PT_VIDEO;
 263                 } else {
 264                         $item['post-type'] = Item::PT_NOTE;
 265                 }
 266
 267                 $item['isForum'] = false;
 268
 269                 if (!empty($activity['thread-completion'])) {
 270                         if ($activity['thread-completion'] != $item['owner-id']) {
 271                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 272                                 $item['causer-link'] = $actor['url'];
 273                                 $item['causer-id'] = $activity['thread-completion'];
 274                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 275                         } else {
 276                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 277                                 $item['causer-link'] = $item['owner-link'];
 278                                 $item['causer-id'] = $item['owner-id'];
 279                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 280                         }
 281
 282                         $item['owner-link'] = $item['author-link'];
 283                         $item['owner-id'] = $item['author-id'];
 284                 } else {
 285                         $actor = APContact::getByURL($item['owner-link'], false);
 286                         $item['isForum'] = ($actor['type'] == 'Group');
 287                 }
 288
 289                 $item['uri'] = $activity['id'];
 290
 291                 if (empty($activity['published']) || empty($activity['updated'])) {
 292                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 293                 }
 294
 295                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 296                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 297                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 298                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 299
 300                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 301                 if (empty($item['uri-id'])) {
 302                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 303                         return [];
 304                 }
 305
 306                 $item = self::processContent($activity, $item);
 307                 if (empty($item)) {
 308                         Logger::info('Message was not processed');
 309                         return [];
 310                 }
 311
 312                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 313
 314                 self::storeAttachments($activity, $item);
 315
 316                 // We received the post via AP, so we set the protocol of the server to AP
 317                 $contact = Contact::getById($item['author-id'], ['gsid']);
 318                 if (!empty($contact['gsid'])) {
 319                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 320                 }
 321
 322                 if ($item['author-id'] != $item['owner-id']) {
 323                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 324                         if (!empty($contact['gsid'])) {
 325                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 326                         }
 327                 }
 328
 329                 return $item;
 330         }
 331
 332         /**
 333          * Delete items
 334          *
 335          * @param array $activity
 336          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 337          * @throws \ImagickException
 338          */
 339         public static function deleteItem($activity)
 340         {
 341                 $owner = Contact::getIdForURL($activity['actor']);
 342
 343                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 344                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 345         }
 346
 347         /**
 348          * Prepare the item array for an activity
 349          *
 350          * @param array $activity Activity array
 351          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 352          * @throws \ImagickException
 353          */
 354         public static function addTag($activity)
 355         {
 356                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 357                         return;
 358                 }
 359
 360                 foreach ($activity['receiver'] as $receiver) {
 361                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 362                         if (!DBA::isResult($item)) {
 363                                 // We don't fetch missing content for this purpose
 364                                 continue;
 365                         }
 366
 367                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 368                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 369                                 continue;
 370                         }
 371
 372                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 373                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 374                 }
 375         }
 376
 377         /**
 378          * Prepare the item array for an activity
 379          *
 380          * @param array  $activity Activity array
 381          * @param string $verb     Activity verb
 382          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 383          * @throws \ImagickException
 384          */
 385         public static function createActivity($activity, $verb)
 386         {
 387                 $item = self::createItem($activity);
 388                 $item['verb'] = $verb;
 389                 $item['thr-parent'] = $activity['object_id'];
 390                 $item['gravity'] = GRAVITY_ACTIVITY;
 391                 unset($item['post-type']);
 392                 $item['object-type'] = Activity\ObjectType::NOTE;
 393
 394                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 395
 396                 self::postItem($activity, $item);
 397         }
 398
 399         /**
 400          * Create an event
 401          *
 402          * @param array $activity Activity array
 403          * @param array $item
 404          *
 405          * @return int event id
 406          * @throws \Exception
 407          */
 408         public static function createEvent($activity, $item)
 409         {
 410                 $event['summary']   = HTML::toBBCode($activity['name']);
 411                 $event['desc']      = HTML::toBBCode($activity['content']);
 412                 $event['start']     = $activity['start-time'];
 413                 $event['finish']    = $activity['end-time'];
 414                 $event['nofinish']  = empty($event['finish']);
 415                 $event['location']  = $activity['location'];
 416                 $event['cid']       = $item['contact-id'];
 417                 $event['uid']       = $item['uid'];
 418                 $event['uri']       = $item['uri'];
 419                 $event['edited']    = $item['edited'];
 420                 $event['private']   = $item['private'];
 421                 $event['guid']      = $item['guid'];
 422                 $event['plink']     = $item['plink'];
 423                 $event['network']   = $item['network'];
 424                 $event['protocol']  = $item['protocol'];
 425                 $event['direction'] = $item['direction'];
 426                 $event['source']    = $item['source'];
 427
 428                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 429                 if (DBA::isResult($ev)) {
 430                         $event['id'] = $ev['id'];
 431                 }
 432
 433                 $event_id = Event::store($event);
 434
 435                 Logger::info('Event was stored', ['id' => $event_id]);
 436
 437                 return $event_id;
 438         }
 439
 440         /**
 441          * Process the content
 442          *
 443          * @param array $activity Activity array
 444          * @param array $item
 445          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 446          * @throws \Exception
 447          */
 448         private static function processContent($activity, $item)
 449         {
 450                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 451                         $item['title'] = Markdown::toBBCode($activity['name']);
 452                         $content = Markdown::toBBCode($activity['content']);
 453                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 454                         $item['title'] = $activity['name'];
 455                         $content = $activity['content'];
 456                 } else {
 457                         // By default assume "text/html"
 458                         $item['title'] = HTML::toBBCode($activity['name']);
 459                         $content = HTML::toBBCode($activity['content']);
 460                 }
 461
 462                 if (!empty($activity['languages'])) {
 463                         $item['language'] = self::processLanguages($activity['languages']);
 464                 }
 465
 466                 if (!empty($activity['emojis'])) {
 467                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 468                 }
 469
 470                 $content = self::addMentionLinks($content, $activity['tags']);
 471
 472                 if (!empty($activity['source'])) {
 473                         $item['body'] = $activity['source'];
 474                         $item['raw-body'] = $content;
 475                         $item['body'] = Item::improveSharedDataInBody($item);
 476                 } else {
 477                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 478                                 $item_private = !in_array(0, $activity['item_receiver']);
 479                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 480                                 if (!DBA::isResult($parent)) {
 481                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 482                                         return false;
 483                                 }
 484                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 485                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 486                                         return false;
 487                                 }
 488
 489                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 490                         }
 491                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 492                         $item['raw-body'] = $item['body'] = $content;
 493                 }
 494
 495                 self::storeFromBody($item);
 496                 self::storeTags($item['uri-id'], $activity['tags']);
 497
 498                 $item['location'] = $activity['location'];
 499
 500                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 501                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 502                 }
 503
 504                 $item['app'] = $activity['generator'];
 505
 506                 return $item;
 507         }
 508
 509         /**
 510          * Store hashtags and mentions
 511          *
 512          * @param array $item
 513          */
 514         private static function storeFromBody(array $item)
 515         {
 516                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 517                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 518
 519                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 520         }
 521
 522         /**
 523          * Generate a GUID out of an URL
 524          *
 525          * @param string $url message URL
 526          * @return string with GUID
 527          */
 528         private static function getGUIDByURL(string $url)
 529         {
 530                 $parsed = parse_url($url);
 531
 532                 $host_hash = hash('crc32', $parsed['host']);
 533
 534                 unset($parsed["scheme"]);
 535                 unset($parsed["host"]);
 536
 537                 $path = implode("/", $parsed);
 538
 539                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 540         }
 541
 542         /**
 543          * Creates an item post
 544          *
 545          * @param array $activity Activity data
 546          * @param array $item     item array
 547          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 548          * @throws \ImagickException
 549          */
 550         public static function postItem(array $activity, array $item)
 551         {
 552                 if (empty($item)) {
 553                         return;
 554                 }
 555
 556                 $stored = false;
 557                 ksort($activity['receiver']);
 558
 559                 foreach ($activity['receiver'] as $receiver) {
 560                         if ($receiver == -1) {
 561                                 continue;
 562                         }
 563
 564                         $item['uid'] = $receiver;
 565
 566                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 567                         switch($type) {
 568                                 case Receiver::TARGET_TO:
 569                                         $item['post-reason'] = Item::PR_TO;
 570                                         break;
 571                                 case Receiver::TARGET_CC:
 572                                         $item['post-reason'] = Item::PR_CC;
 573                                         break;
 574                                 case Receiver::TARGET_BTO:
 575                                         $item['post-reason'] = Item::PR_BTO;
 576                                         break;
 577                                 case Receiver::TARGET_BCC:
 578                                         $item['post-reason'] = Item::PR_BCC;
 579                                         break;
 580                                 case Receiver::TARGET_FOLLOWER:
 581                                         $item['post-reason'] = Item::PR_FOLLOWER;
 582                                         break;
 583                                 case Receiver::TARGET_ANSWER:
 584                                         $item['post-reason'] = Item::PR_COMMENT;
 585                                         break;
 586                                 case Receiver::TARGET_GLOBAL:
 587                                         $item['post-reason'] = Item::PR_GLOBAL;
 588                                         break;
 589                                 default:
 590                                         $item['post-reason'] = Item::PR_NONE;
 591                         }
 592
 593                         if (!empty($activity['from-relay'])) {
 594                                 $item['post-reason'] = Item::PR_RELAY;
 595                         } elseif (!empty($activity['thread-completion'])) {
 596                                 $item['post-reason'] = Item::PR_FETCHED;
 597                         }
 598
 599                         if ($item['isForum'] ?? false) {
 600                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 601                         } else {
 602                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 603                         }
 604
 605                         if (($receiver != 0) && empty($item['contact-id'])) {
 606                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 607                         }
 608
 609                         if (!empty($activity['directmessage'])) {
 610                                 self::postMail($activity, $item);
 611                                 continue;
 612                         }
 613
 614                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) &&
 615                                 ($item['post-reason'] == Item::PR_BCC) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 616                                 Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 617                                 continue;
 618                         }
 619
 620                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 621                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 622
 623                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 624                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 625                                 }
 626
 627                                 if ($skip) {
 628                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 629                                         continue;
 630                                 }
 631
 632                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 633                         }
 634
 635                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 636                                 $event_id = self::createEvent($activity, $item);
 637
 638                                 $item = Event::getItemArrayForImportedId($event_id, $item);
 639                         }
 640
 641                         $item_id = Item::insert($item);
 642                         if ($item_id) {
 643                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 644                         } else {
 645                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 646                         }
 647
 648                         if ($item['uid'] == 0) {
 649                                 $stored = $item_id;
 650                         }
 651                 }
 652
 653                 // Store send a follow request for every reshare - but only when the item had been stored
 654                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 655                         $author = APContact::getByURL($item['owner-link'], false);
 656                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 657                         if ($author['type'] != 'Group') {
 658                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 659                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 660                         }
 661                 }
 662         }
 663
 664         /**
 665          * Store tags and mentions into the tag table
 666          *
 667          * @param integer $uriid
 668          * @param array $tags
 669          */
 670         private static function storeTags(int $uriid, array $tags = null)
 671         {
 672                 foreach ($tags as $tag) {
 673                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 674                                 continue;
 675                         }
 676
 677                         $hash = substr($tag['name'], 0, 1);
 678
 679                         if ($tag['type'] == 'Mention') {
 680                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 681                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 682                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 683                                         $tag['name'] = substr($tag['name'], 1);
 684                                 }
 685                                 $type = Tag::IMPLICIT_MENTION;
 686
 687                                 if (!empty($tag['href'])) {
 688                                         $apcontact = APContact::getByURL($tag['href']);
 689                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 690                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 691                                         }
 692                                 }
 693                         } elseif ($tag['type'] == 'Hashtag') {
 694                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 695                                         $tag['name'] = substr($tag['name'], 1);
 696                                 }
 697                                 $type = Tag::HASHTAG;
 698                         }
 699
 700                         if (empty($tag['name'])) {
 701                                 continue;
 702                         }
 703
 704                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 705                 }
 706         }
 707
 708         /**
 709          * Creates an mail post
 710          *
 711          * @param array $activity Activity data
 712          * @param array $item     item array
 713          * @return int|bool New mail table row id or false on error
 714          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 715          */
 716         private static function postMail($activity, $item)
 717         {
 718                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 719                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 720                         return false;
 721                 }
 722
 723                 Logger::info('Direct Message', $item);
 724
 725                 $msg = [];
 726                 $msg['uid'] = $item['uid'];
 727
 728                 $msg['contact-id'] = $item['contact-id'];
 729
 730                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 731                 $msg['from-name'] = $contact['name'];
 732                 $msg['from-url'] = $contact['url'];
 733                 $msg['from-photo'] = $contact['photo'];
 734
 735                 $msg['uri'] = $item['uri'];
 736                 $msg['created'] = $item['created'];
 737
 738                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 739                 if (DBA::isResult($parent)) {
 740                         $msg['parent-uri'] = $parent['parent-uri'];
 741                         $msg['title'] = $parent['title'];
 742                 } else {
 743                         $msg['parent-uri'] = $item['thr-parent'];
 744
 745                         if (!empty($item['title'])) {
 746                                 $msg['title'] = $item['title'];
 747                         } elseif (!empty($item['content-warning'])) {
 748                                 $msg['title'] = $item['content-warning'];
 749                         } else {
 750                                 // Trying to generate a title out of the body
 751                                 $title = $item['body'];
 752
 753                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 754                                         $title = $matches[3];
 755                                 }
 756
 757                                 $title = trim(BBCode::toPlaintext($title));
 758
 759                                 if (strlen($title) > 20) {
 760                                         $title = substr($title, 0, 20) . '...';
 761                                 }
 762
 763                                 $msg['title'] = $title;
 764                         }
 765                 }
 766                 $msg['body'] = $item['body'];
 767
 768                 return Mail::insert($msg);
 769         }
 770
 771         /**
 772          * Fetches missing posts
 773          *
 774          * @param string $url         message URL
 775          * @param array  $child       activity array with the child of this message
 776          * @param string $relay_actor Relay actor
 777          * @return string fetched message URL
 778          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 779          */
 780         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '')
 781         {
 782                 if (!empty($child['receiver'])) {
 783                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 784                 } else {
 785                         $uid = 0;
 786                 }
 787
 788                 $object = ActivityPub::fetchContent($url, $uid);
 789                 if (empty($object)) {
 790                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
 791                         return '';
 792                 }
 793
 794                 if (empty($object['id'])) {
 795                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
 796                         return '';
 797                 }
 798
 799                 if (!empty($object['actor'])) {
 800                         $object_actor = $object['actor'];
 801                 } elseif (!empty($object['attributedTo'])) {
 802                         $object_actor = $object['attributedTo'];
 803                         if (is_array($object_actor)) {
 804                                 $compacted = JsonLD::compact($object);
 805                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
 806                         }
 807                 } else {
 808                         // Shouldn't happen
 809                         $object_actor = '';
 810                 }
 811
 812                 $signer = [$object_actor];
 813
 814                 if (!empty($child['author'])) {
 815                         $actor = $child['author'];
 816                         $signer[] = $actor;
 817                 } else {
 818                         $actor = $object_actor;
 819                 }
 820
 821                 if (!empty($object['published'])) {
 822                         $published = $object['published'];
 823                 } elseif (!empty($child['published'])) {
 824                         $published = $child['published'];
 825                 } else {
 826                         $published = DateTimeFormat::utcNow();
 827                 }
 828
 829                 $activity = [];
 830                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
 831                 unset($object['@context']);
 832                 $activity['id'] = $object['id'];
 833                 $activity['to'] = $object['to'] ?? [];
 834                 $activity['cc'] = $object['cc'] ?? [];
 835                 $activity['actor'] = $actor;
 836                 $activity['object'] = $object;
 837                 $activity['published'] = $published;
 838                 $activity['type'] = 'Create';
 839
 840                 $ldactivity = JsonLD::compact($activity);
 841
 842                 if (!empty($relay_actor)) {
 843                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
 844                 } elseif (!empty($child['thread-completion'])) {
 845                         $ldactivity['thread-completion'] = $child['thread-completion'];
 846                 } else {
 847                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
 848                 }
 849
 850                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
 851                         return '';
 852                 }
 853
 854                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
 855
 856                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 857
 858                 return $activity['id'];
 859         }
 860
 861         /**
 862          * Test if incoming relay messages should be accepted
 863          *
 864          * @param array $activity activity array
 865          * @param string $id      object ID
 866          * @return boolean true if message is accepted
 867          */
 868         private static function acceptIncomingMessage(array $activity, string $id)
 869         {
 870                 if (empty($activity['as:object'])) {
 871                         Logger::info('No object field in activity - accepted', ['id' => $id]);
 872                         return true;
 873                 }
 874
 875                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
 876                 $uriid = ItemURI::getIdByURI($replyto);
 877                 if (Post::exists(['uri-id' => $uriid])) {
 878                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
 879                         return true;
 880                 }
 881
 882                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 883                 $authorid = Contact::getIdForURL($attributed_to);
 884
 885                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
 886
 887                 $messageTags = [];
 888                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
 889                 if (!empty($tags)) {
 890                         foreach ($tags as $tag) {
 891                                 if ($tag['type'] != 'Hashtag') {
 892                                         continue;
 893                                 }
 894                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
 895                         }
 896                 }
 897
 898                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
 899         }
 900
 901         /**
 902          * perform a "follow" request
 903          *
 904          * @param array $activity
 905          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 906          * @throws \ImagickException
 907          */
 908         public static function followUser($activity)
 909         {
 910                 $uid = User::getIdForURL($activity['object_id']);
 911                 if (empty($uid)) {
 912                         return;
 913                 }
 914
 915                 $owner = User::getOwnerDataById($uid);
 916                 if (empty($owner)) {
 917                         return;
 918                 }
 919
 920                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 921                 if (!empty($cid)) {
 922                         self::switchContact($cid);
 923                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 924                 }
 925
 926                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 927                         'author-link' => $activity['actor']];
 928
 929                 // Ensure that the contact has got the right network type
 930                 self::switchContact($item['author-id']);
 931
 932                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
 933                 if ($result === true) {
 934                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
 935                 }
 936
 937                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 938                 if (empty($cid)) {
 939                         return;
 940                 }
 941
 942                 if (empty($contact)) {
 943                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 944                 }
 945
 946                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 947         }
 948
 949         /**
 950          * Update the given profile
 951          *
 952          * @param array $activity
 953          * @throws \Exception
 954          */
 955         public static function updatePerson($activity)
 956         {
 957                 if (empty($activity['object_id'])) {
 958                         return;
 959                 }
 960
 961                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
 962                 Contact::updateFromProbeByURL($activity['object_id']);
 963         }
 964
 965         /**
 966          * Delete the given profile
 967          *
 968          * @param array $activity
 969          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 970          */
 971         public static function deletePerson($activity)
 972         {
 973                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 974                         Logger::info('Empty object id or actor.');
 975                         return;
 976                 }
 977
 978                 if ($activity['object_id'] != $activity['actor']) {
 979                         Logger::info('Object id does not match actor.');
 980                         return;
 981                 }
 982
 983                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 984                 while ($contact = DBA::fetch($contacts)) {
 985                         Contact::remove($contact['id']);
 986                 }
 987                 DBA::close($contacts);
 988
 989                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
 990         }
 991
 992         /**
 993          * Accept a follow request
 994          *
 995          * @param array $activity
 996          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 997          * @throws \ImagickException
 998          */
 999         public static function acceptFollowUser($activity)
1000         {
1001                 $uid = User::getIdForURL($activity['object_actor']);
1002                 if (empty($uid)) {
1003                         return;
1004                 }
1005
1006                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1007                 if (empty($cid)) {
1008                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1009                         return;
1010                 }
1011
1012                 self::switchContact($cid);
1013
1014                 $fields = ['pending' => false];
1015
1016                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1017                 if ($contact['rel'] == Contact::FOLLOWER) {
1018                         $fields['rel'] = Contact::FRIEND;
1019                 }
1020
1021                 $condition = ['id' => $cid];
1022                 Contact::update($fields, $condition);
1023                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1024         }
1025
1026         /**
1027          * Reject a follow request
1028          *
1029          * @param array $activity
1030          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1031          * @throws \ImagickException
1032          */
1033         public static function rejectFollowUser($activity)
1034         {
1035                 $uid = User::getIdForURL($activity['object_actor']);
1036                 if (empty($uid)) {
1037                         return;
1038                 }
1039
1040                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1041                 if (empty($cid)) {
1042                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1043                         return;
1044                 }
1045
1046                 self::switchContact($cid);
1047
1048                 $contact = Contact::getById($cid, ['rel']);
1049                 if ($contact['rel'] == Contact::SHARING) {
1050                         Contact::remove($cid);
1051                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1052                 } elseif ($contact['rel'] == Contact::FRIEND) {
1053                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1054                 } else {
1055                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1056                 }
1057         }
1058
1059         /**
1060          * Undo activity like "like" or "dislike"
1061          *
1062          * @param array $activity
1063          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1064          * @throws \ImagickException
1065          */
1066         public static function undoActivity($activity)
1067         {
1068                 if (empty($activity['object_id'])) {
1069                         return;
1070                 }
1071
1072                 if (empty($activity['object_actor'])) {
1073                         return;
1074                 }
1075
1076                 $author_id = Contact::getIdForURL($activity['object_actor']);
1077                 if (empty($author_id)) {
1078                         return;
1079                 }
1080
1081                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1082         }
1083
1084         /**
1085          * Activity to remove a follower
1086          *
1087          * @param array $activity
1088          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1089          * @throws \ImagickException
1090          */
1091         public static function undoFollowUser($activity)
1092         {
1093                 $uid = User::getIdForURL($activity['object_object']);
1094                 if (empty($uid)) {
1095                         return;
1096                 }
1097
1098                 $owner = User::getOwnerDataById($uid);
1099                 if (empty($owner)) {
1100                         return;
1101                 }
1102
1103                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1104                 if (empty($cid)) {
1105                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1106                         return;
1107                 }
1108
1109                 self::switchContact($cid);
1110
1111                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1112                 if (!DBA::isResult($contact)) {
1113                         return;
1114                 }
1115
1116                 Contact::removeFollower($contact);
1117                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1118         }
1119
1120         /**
1121          * Switches a contact to AP if needed
1122          *
1123          * @param integer $cid Contact ID
1124          * @throws \Exception
1125          */
1126         private static function switchContact($cid)
1127         {
1128                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1129                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1130                         return;
1131                 }
1132
1133                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1134                 Contact::updateFromProbe($cid);
1135         }
1136
1137         /**
1138          * Collects implicit mentions like:
1139          * - the author of the parent item
1140          * - all the mentioned conversants in the parent item
1141          *
1142          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1143          * @return array
1144          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1145          */
1146         private static function getImplicitMentionList(array $parent)
1147         {
1148                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1149
1150                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1151
1152                 $implicit_mentions = [];
1153                 if (empty($parent_author['url'])) {
1154                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1155                 } else {
1156                         $implicit_mentions[] = $parent_author['url'];
1157                         $implicit_mentions[] = $parent_author['nurl'];
1158                         $implicit_mentions[] = $parent_author['alias'];
1159                 }
1160
1161                 if (!empty($parent['alias'])) {
1162                         $implicit_mentions[] = $parent['alias'];
1163                 }
1164
1165                 foreach ($parent_terms as $term) {
1166                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1167                         if (!empty($contact['url'])) {
1168                                 $implicit_mentions[] = $contact['url'];
1169                                 $implicit_mentions[] = $contact['nurl'];
1170                                 $implicit_mentions[] = $contact['alias'];
1171                         }
1172                 }
1173
1174                 return $implicit_mentions;
1175         }
1176
1177         /**
1178          * Strips from the body prepended implicit mentions
1179          *
1180          * @param string $body
1181          * @param array $parent
1182          * @return string
1183          */
1184         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1185         {
1186                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1187                         return $body;
1188                 }
1189
1190                 $potential_mentions = self::getImplicitMentionList($parent);
1191
1192                 $kept_mentions = [];
1193
1194                 // Extract one prepended mention at a time from the body
1195                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1196                         if (!in_array($matches[2], $potential_mentions)) {
1197                                 $kept_mentions[] = $matches[1];
1198                         }
1199
1200                         $body = $matches[3];
1201                 }
1202
1203                 // Re-appending the kept mentions to the body after extraction
1204                 $kept_mentions[] = $body;
1205
1206                 return implode('', $kept_mentions);
1207         }
1208
1209         /**
1210          * Adds links to string mentions
1211          *
1212          * @param string $body
1213          * @param array  $tags
1214          * @return string
1215          */
1216         protected static function addMentionLinks(string $body, array $tags): string
1217         {
1218                 // This prevents links to be added again to Pleroma-style mention links
1219                 $body = self::normalizeMentionLinks($body);
1220
1221                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1222                         foreach ($tags as $tag) {
1223                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1224                                         continue;
1225                                 }
1226
1227                                 $hash = substr($tag['name'], 0, 1);
1228                                 $name = substr($tag['name'], 1);
1229                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1230                                         $hash = '';
1231                                         $name = $tag['name'];
1232                                 }
1233
1234                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1235                         }
1236
1237                         return $body;
1238                 });
1239
1240                 return $body;
1241         }
1242 }