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          * Converts mentions from Pleroma into the Friendica format
  57          *
  58          * @param string $body
  59          *
  60          * @return string converted body
  61          */
  62         private static function convertMentions($body)
  63         {
  64                 $URLSearchString = "^\[\]";
  65                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  66
  67                 return $body;
  68         }
  69
  70         /**
  71          * Convert the language array into a language JSON
  72          *
  73          * @param array $languages
  74          * @return string language JSON
  75          */
  76         private static function processLanguages(array $languages)
  77         {
  78                 $codes = array_keys($languages);
  79                 $lang = [];
  80                 foreach ($codes as $code) {
  81                         $lang[$code] = 1;
  82                 }
  83
  84                 if (empty($lang)) {
  85                         return '';
  86                 }
  87
  88                 return json_encode($lang);
  89         }
  90         /**
  91          * Replaces emojis in the body
  92          *
  93          * @param array $emojis
  94          * @param string $body
  95          *
  96          * @return string with replaced emojis
  97          */
  98         private static function replaceEmojis($body, array $emojis)
  99         {
 100                 $body = strtr($body,
 101                         array_combine(
 102                                 array_column($emojis, 'name'),
 103                                 array_map(function ($emoji) {
 104                                         return '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
 105                                 }, $emojis)
 106                         )
 107                 );
 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                 $item['created'] = DateTimeFormat::utc($activity['published']);
 292                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 293                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 294                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 295
 296                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 297                 if (empty($item['uri-id'])) {
 298                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 299                         return [];
 300                 }
 301
 302                 $item = self::processContent($activity, $item);
 303                 if (empty($item)) {
 304                         Logger::info('Message was not processed');
 305                         return [];
 306                 }
 307
 308                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 309
 310                 self::storeAttachments($activity, $item);
 311
 312                 // We received the post via AP, so we set the protocol of the server to AP
 313                 $contact = Contact::getById($item['author-id'], ['gsid']);
 314                 if (!empty($contact['gsid'])) {
 315                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 316                 }
 317
 318                 if ($item['author-id'] != $item['owner-id']) {
 319                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 320                         if (!empty($contact['gsid'])) {
 321                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 322                         }
 323                 }
 324
 325                 return $item;
 326         }
 327
 328         /**
 329          * Delete items
 330          *
 331          * @param array $activity
 332          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 333          * @throws \ImagickException
 334          */
 335         public static function deleteItem($activity)
 336         {
 337                 $owner = Contact::getIdForURL($activity['actor']);
 338
 339                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 340                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 341         }
 342
 343         /**
 344          * Prepare the item array for an activity
 345          *
 346          * @param array $activity Activity array
 347          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 348          * @throws \ImagickException
 349          */
 350         public static function addTag($activity)
 351         {
 352                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 353                         return;
 354                 }
 355
 356                 foreach ($activity['receiver'] as $receiver) {
 357                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 358                         if (!DBA::isResult($item)) {
 359                                 // We don't fetch missing content for this purpose
 360                                 continue;
 361                         }
 362
 363                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 364                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 365                                 continue;
 366                         }
 367
 368                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 369                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 370                 }
 371         }
 372
 373         /**
 374          * Prepare the item array for an activity
 375          *
 376          * @param array  $activity Activity array
 377          * @param string $verb     Activity verb
 378          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 379          * @throws \ImagickException
 380          */
 381         public static function createActivity($activity, $verb)
 382         {
 383                 $item = self::createItem($activity);
 384                 $item['verb'] = $verb;
 385                 $item['thr-parent'] = $activity['object_id'];
 386                 $item['gravity'] = GRAVITY_ACTIVITY;
 387                 unset($item['post-type']);
 388                 $item['object-type'] = Activity\ObjectType::NOTE;
 389
 390                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 391
 392                 self::postItem($activity, $item);
 393         }
 394
 395         /**
 396          * Create an event
 397          *
 398          * @param array $activity Activity array
 399          * @param array $item
 400          * @throws \Exception
 401          */
 402         public static function createEvent($activity, $item)
 403         {
 404                 $event['summary']   = HTML::toBBCode($activity['name']);
 405                 $event['desc']      = HTML::toBBCode($activity['content']);
 406                 $event['start']     = $activity['start-time'];
 407                 $event['finish']    = $activity['end-time'];
 408                 $event['nofinish']  = empty($event['finish']);
 409                 $event['location']  = $activity['location'];
 410                 $event['adjust']    = $activity['adjust'] ?? true;
 411                 $event['cid']       = $item['contact-id'];
 412                 $event['uid']       = $item['uid'];
 413                 $event['uri']       = $item['uri'];
 414                 $event['edited']    = $item['edited'];
 415                 $event['private']   = $item['private'];
 416                 $event['guid']      = $item['guid'];
 417                 $event['plink']     = $item['plink'];
 418                 $event['network']   = $item['network'];
 419                 $event['protocol']  = $item['protocol'];
 420                 $event['direction'] = $item['direction'];
 421                 $event['source']    = $item['source'];
 422
 423                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 424                 $ev = DBA::selectFirst('event', ['id'], $condition);
 425                 if (DBA::isResult($ev)) {
 426                         $event['id'] = $ev['id'];
 427                 }
 428
 429                 $event_id = Event::store($event);
 430                 Logger::info('Event was stored', ['id' => $event_id]);
 431         }
 432
 433         /**
 434          * Process the content
 435          *
 436          * @param array $activity Activity array
 437          * @param array $item
 438          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 439          * @throws \Exception
 440          */
 441         private static function processContent($activity, $item)
 442         {
 443                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 444                         $item['title'] = Markdown::toBBCode($activity['name']);
 445                         $content = Markdown::toBBCode($activity['content']);
 446                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 447                         $item['title'] = $activity['name'];
 448                         $content = $activity['content'];
 449                 } else {
 450                         // By default assume "text/html"
 451                         $item['title'] = HTML::toBBCode($activity['name']);
 452                         $content = HTML::toBBCode($activity['content']);
 453                 }
 454
 455                 if (!empty($activity['languages'])) {
 456                         $item['language'] = self::processLanguages($activity['languages']);
 457                 }
 458
 459                 if (!empty($activity['emojis'])) {
 460                         $content = self::replaceEmojis($content, $activity['emojis']);
 461                 }
 462
 463                 $content = self::convertMentions($content);
 464
 465                 if (!empty($activity['source'])) {
 466                         $item['body'] = $activity['source'];
 467                         $item['raw-body'] = $content;
 468                         $item['body'] = Item::improveSharedDataInBody($item);
 469                 } else {
 470                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 471                                 $item_private = !in_array(0, $activity['item_receiver']);
 472                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 473                                 if (!DBA::isResult($parent)) {
 474                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 475                                         return false;
 476                                 }
 477                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 478                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 479                                         return false;
 480                                 }
 481
 482                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 483                         }
 484                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 485                         $item['raw-body'] = $item['body'] = $content;
 486                 }
 487
 488                 self::storeFromBody($item);
 489                 self::storeTags($item['uri-id'], $activity['tags']);
 490
 491                 $item['location'] = $activity['location'];
 492
 493                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 494                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 495                 }
 496
 497                 $item['app'] = $activity['generator'];
 498
 499                 return $item;
 500         }
 501
 502         /**
 503          * Store hashtags and mentions
 504          *
 505          * @param array $item
 506          */
 507         private static function storeFromBody(array $item)
 508         {
 509                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 510                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 511
 512                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 513         }
 514
 515         /**
 516          * Generate a GUID out of an URL
 517          *
 518          * @param string $url message URL
 519          * @return string with GUID
 520          */
 521         private static function getGUIDByURL(string $url)
 522         {
 523                 $parsed = parse_url($url);
 524
 525                 $host_hash = hash('crc32', $parsed['host']);
 526
 527                 unset($parsed["scheme"]);
 528                 unset($parsed["host"]);
 529
 530                 $path = implode("/", $parsed);
 531
 532                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 533         }
 534
 535         /**
 536          * Creates an item post
 537          *
 538          * @param array $activity Activity data
 539          * @param array $item     item array
 540          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 541          * @throws \ImagickException
 542          */
 543         public static function postItem(array $activity, array $item)
 544         {
 545                 if (empty($item)) {
 546                         return;
 547                 }
 548
 549                 $stored = false;
 550                 ksort($activity['receiver']);
 551
 552                 foreach ($activity['receiver'] as $receiver) {
 553                         if ($receiver == -1) {
 554                                 continue;
 555                         }
 556
 557                         $item['uid'] = $receiver;
 558
 559                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 560                         switch($type) {
 561                                 case Receiver::TARGET_TO:
 562                                         $item['post-reason'] = Item::PR_TO;
 563                                         break;
 564                                 case Receiver::TARGET_CC:
 565                                         $item['post-reason'] = Item::PR_CC;
 566                                         break;
 567                                 case Receiver::TARGET_BTO:
 568                                         $item['post-reason'] = Item::PR_BTO;
 569                                         break;
 570                                 case Receiver::TARGET_BCC:
 571                                         $item['post-reason'] = Item::PR_BCC;
 572                                         break;
 573                                 case Receiver::TARGET_FOLLOWER:
 574                                         $item['post-reason'] = Item::PR_FOLLOWER;
 575                                         break;
 576                                 case Receiver::TARGET_ANSWER:
 577                                         $item['post-reason'] = Item::PR_COMMENT;
 578                                         break;
 579                                 case Receiver::TARGET_GLOBAL:
 580                                         $item['post-reason'] = Item::PR_GLOBAL;
 581                                         break;
 582                                 default:
 583                                         $item['post-reason'] = Item::PR_NONE;
 584                         }
 585
 586                         if (!empty($activity['from-relay'])) {
 587                                 $item['post-reason'] = Item::PR_RELAY;
 588                         } elseif (!empty($activity['thread-completion'])) {
 589                                 $item['post-reason'] = Item::PR_FETCHED;
 590                         }
 591
 592                         if ($item['isForum'] ?? false) {
 593                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 594                         } else {
 595                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 596                         }
 597
 598                         if (($receiver != 0) && empty($item['contact-id'])) {
 599                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 600                         }
 601
 602                         if (!empty($activity['directmessage'])) {
 603                                 self::postMail($activity, $item);
 604                                 continue;
 605                         }
 606
 607                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) &&
 608                                 ($item['post-reason'] == Item::PR_BCC) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 609                                 Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 610                                 continue;
 611                         }
 612
 613                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 614                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 615
 616                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 617                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 618                                 }
 619
 620                                 if ($skip) {
 621                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 622                                         continue;
 623                                 }
 624
 625                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 626                         }
 627
 628                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 629                                 self::createEvent($activity, $item);
 630                         }
 631
 632                         $item_id = Item::insert($item);
 633                         if ($item_id) {
 634                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 635                         } else {
 636                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 637                         }
 638
 639                         if ($item['uid'] == 0) {
 640                                 $stored = $item_id;
 641                         }
 642                 }
 643
 644                 // Store send a follow request for every reshare - but only when the item had been stored
 645                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 646                         $author = APContact::getByURL($item['owner-link'], false);
 647                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 648                         if ($author['type'] != 'Group') {
 649                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 650                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 651                         }
 652                 }
 653         }
 654
 655         /**
 656          * Store tags and mentions into the tag table
 657          *
 658          * @param integer $uriid
 659          * @param array $tags
 660          */
 661         private static function storeTags(int $uriid, array $tags = null)
 662         {
 663                 foreach ($tags as $tag) {
 664                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 665                                 continue;
 666                         }
 667
 668                         $hash = substr($tag['name'], 0, 1);
 669
 670                         if ($tag['type'] == 'Mention') {
 671                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 672                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 673                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 674                                         $tag['name'] = substr($tag['name'], 1);
 675                                 }
 676                                 $type = Tag::IMPLICIT_MENTION;
 677
 678                                 if (!empty($tag['href'])) {
 679                                         $apcontact = APContact::getByURL($tag['href']);
 680                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 681                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 682                                         }
 683                                 }
 684                         } elseif ($tag['type'] == 'Hashtag') {
 685                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 686                                         $tag['name'] = substr($tag['name'], 1);
 687                                 }
 688                                 $type = Tag::HASHTAG;
 689                         }
 690
 691                         if (empty($tag['name'])) {
 692                                 continue;
 693                         }
 694
 695                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 696                 }
 697         }
 698
 699         /**
 700          * Creates an mail post
 701          *
 702          * @param array $activity Activity data
 703          * @param array $item     item array
 704          * @return int|bool New mail table row id or false on error
 705          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 706          */
 707         private static function postMail($activity, $item)
 708         {
 709                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 710                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 711                         return false;
 712                 }
 713
 714                 Logger::info('Direct Message', $item);
 715
 716                 $msg = [];
 717                 $msg['uid'] = $item['uid'];
 718
 719                 $msg['contact-id'] = $item['contact-id'];
 720
 721                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 722                 $msg['from-name'] = $contact['name'];
 723                 $msg['from-url'] = $contact['url'];
 724                 $msg['from-photo'] = $contact['photo'];
 725
 726                 $msg['uri'] = $item['uri'];
 727                 $msg['created'] = $item['created'];
 728
 729                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 730                 if (DBA::isResult($parent)) {
 731                         $msg['parent-uri'] = $parent['parent-uri'];
 732                         $msg['title'] = $parent['title'];
 733                 } else {
 734                         $msg['parent-uri'] = $item['thr-parent'];
 735
 736                         if (!empty($item['title'])) {
 737                                 $msg['title'] = $item['title'];
 738                         } elseif (!empty($item['content-warning'])) {
 739                                 $msg['title'] = $item['content-warning'];
 740                         } else {
 741                                 // Trying to generate a title out of the body
 742                                 $title = $item['body'];
 743
 744                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 745                                         $title = $matches[3];
 746                                 }
 747
 748                                 $title = trim(BBCode::toPlaintext($title));
 749
 750                                 if (strlen($title) > 20) {
 751                                         $title = substr($title, 0, 20) . '...';
 752                                 }
 753
 754                                 $msg['title'] = $title;
 755                         }
 756                 }
 757                 $msg['body'] = $item['body'];
 758
 759                 return Mail::insert($msg);
 760         }
 761
 762         /**
 763          * Fetches missing posts
 764          *
 765          * @param string $url         message URL
 766          * @param array  $child       activity array with the child of this message
 767          * @param string $relay_actor Relay actor
 768          * @return string fetched message URL
 769          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 770          */
 771         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '')
 772         {
 773                 if (!empty($child['receiver'])) {
 774                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 775                 } else {
 776                         $uid = 0;
 777                 }
 778
 779                 $object = ActivityPub::fetchContent($url, $uid);
 780                 if (empty($object)) {
 781                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
 782                         return '';
 783                 }
 784
 785                 if (empty($object['id'])) {
 786                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
 787                         return '';
 788                 }
 789
 790                 if (!empty($object['actor'])) {
 791                         $object_actor = $object['actor'];
 792                 } elseif (!empty($object['attributedTo'])) {
 793                         $object_actor = $object['attributedTo'];
 794                         if (is_array($object_actor)) {
 795                                 $compacted = JsonLD::compact($object);
 796                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
 797                         }
 798                 } else {
 799                         // Shouldn't happen
 800                         $object_actor = '';
 801                 }
 802
 803                 $signer = [$object_actor];
 804
 805                 if (!empty($child['author'])) {
 806                         $actor = $child['author'];
 807                         $signer[] = $actor;
 808                 } else {
 809                         $actor = $object_actor;
 810                 }
 811
 812                 if (!empty($object['published'])) {
 813                         $published = $object['published'];
 814                 } elseif (!empty($child['published'])) {
 815                         $published = $child['published'];
 816                 } else {
 817                         $published = DateTimeFormat::utcNow();
 818                 }
 819
 820                 $activity = [];
 821                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
 822                 unset($object['@context']);
 823                 $activity['id'] = $object['id'];
 824                 $activity['to'] = $object['to'] ?? [];
 825                 $activity['cc'] = $object['cc'] ?? [];
 826                 $activity['actor'] = $actor;
 827                 $activity['object'] = $object;
 828                 $activity['published'] = $published;
 829                 $activity['type'] = 'Create';
 830
 831                 $ldactivity = JsonLD::compact($activity);
 832
 833                 if (!empty($relay_actor)) {
 834                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
 835                 } elseif (!empty($child['thread-completion'])) {
 836                         $ldactivity['thread-completion'] = $child['thread-completion'];
 837                 } else {
 838                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
 839                 }
 840
 841                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
 842                         return '';
 843                 }
 844
 845                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
 846
 847                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 848
 849                 return $activity['id'];
 850         }
 851
 852         /**
 853          * Test if incoming relay messages should be accepted
 854          *
 855          * @param array $activity activity array
 856          * @param string $id      object ID
 857          * @return boolean true if message is accepted
 858          */
 859         private static function acceptIncomingMessage(array $activity, string $id)
 860         {
 861                 if (empty($activity['as:object'])) {
 862                         Logger::info('No object field in activity - accepted', ['id' => $id]);
 863                         return true;
 864                 }
 865
 866                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
 867                 $uriid = ItemURI::getIdByURI($replyto);
 868                 if (Post::exists(['uri-id' => $uriid])) {
 869                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
 870                         return true;
 871                 }
 872
 873                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 874                 $authorid = Contact::getIdForURL($attributed_to);
 875
 876                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
 877
 878                 $messageTags = [];
 879                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
 880                 if (!empty($tags)) {
 881                         foreach ($tags as $tag) {
 882                                 if ($tag['type'] != 'Hashtag') {
 883                                         continue;
 884                                 }
 885                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
 886                         }
 887                 }
 888
 889                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
 890         }
 891
 892         /**
 893          * perform a "follow" request
 894          *
 895          * @param array $activity
 896          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 897          * @throws \ImagickException
 898          */
 899         public static function followUser($activity)
 900         {
 901                 $uid = User::getIdForURL($activity['object_id']);
 902                 if (empty($uid)) {
 903                         return;
 904                 }
 905
 906                 $owner = User::getOwnerDataById($uid);
 907                 if (empty($owner)) {
 908                         return;
 909                 }
 910
 911                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 912                 if (!empty($cid)) {
 913                         self::switchContact($cid);
 914                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 915                 }
 916
 917                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 918                         'author-link' => $activity['actor']];
 919
 920                 // Ensure that the contact has got the right network type
 921                 self::switchContact($item['author-id']);
 922
 923                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
 924                 if ($result === true) {
 925                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
 926                 }
 927
 928                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 929                 if (empty($cid)) {
 930                         return;
 931                 }
 932
 933                 if (empty($contact)) {
 934                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 935                 }
 936
 937                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 938         }
 939
 940         /**
 941          * Update the given profile
 942          *
 943          * @param array $activity
 944          * @throws \Exception
 945          */
 946         public static function updatePerson($activity)
 947         {
 948                 if (empty($activity['object_id'])) {
 949                         return;
 950                 }
 951
 952                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
 953                 Contact::updateFromProbeByURL($activity['object_id']);
 954         }
 955
 956         /**
 957          * Delete the given profile
 958          *
 959          * @param array $activity
 960          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 961          */
 962         public static function deletePerson($activity)
 963         {
 964                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 965                         Logger::info('Empty object id or actor.');
 966                         return;
 967                 }
 968
 969                 if ($activity['object_id'] != $activity['actor']) {
 970                         Logger::info('Object id does not match actor.');
 971                         return;
 972                 }
 973
 974                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 975                 while ($contact = DBA::fetch($contacts)) {
 976                         Contact::remove($contact['id']);
 977                 }
 978                 DBA::close($contacts);
 979
 980                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
 981         }
 982
 983         /**
 984          * Accept a follow request
 985          *
 986          * @param array $activity
 987          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 988          * @throws \ImagickException
 989          */
 990         public static function acceptFollowUser($activity)
 991         {
 992                 $uid = User::getIdForURL($activity['object_actor']);
 993                 if (empty($uid)) {
 994                         return;
 995                 }
 996
 997                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 998                 if (empty($cid)) {
 999                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1000                         return;
1001                 }
1002
1003                 self::switchContact($cid);
1004
1005                 $fields = ['pending' => false];
1006
1007                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1008                 if ($contact['rel'] == Contact::FOLLOWER) {
1009                         $fields['rel'] = Contact::FRIEND;
1010                 }
1011
1012                 $condition = ['id' => $cid];
1013                 DBA::update('contact', $fields, $condition);
1014                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1015         }
1016
1017         /**
1018          * Reject a follow request
1019          *
1020          * @param array $activity
1021          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1022          * @throws \ImagickException
1023          */
1024         public static function rejectFollowUser($activity)
1025         {
1026                 $uid = User::getIdForURL($activity['object_actor']);
1027                 if (empty($uid)) {
1028                         return;
1029                 }
1030
1031                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1032                 if (empty($cid)) {
1033                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1034                         return;
1035                 }
1036
1037                 self::switchContact($cid);
1038
1039                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
1040                         Contact::remove($cid);
1041                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1042                 } else {
1043                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1044                 }
1045         }
1046
1047         /**
1048          * Undo activity like "like" or "dislike"
1049          *
1050          * @param array $activity
1051          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1052          * @throws \ImagickException
1053          */
1054         public static function undoActivity($activity)
1055         {
1056                 if (empty($activity['object_id'])) {
1057                         return;
1058                 }
1059
1060                 if (empty($activity['object_actor'])) {
1061                         return;
1062                 }
1063
1064                 $author_id = Contact::getIdForURL($activity['object_actor']);
1065                 if (empty($author_id)) {
1066                         return;
1067                 }
1068
1069                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1070         }
1071
1072         /**
1073          * Activity to remove a follower
1074          *
1075          * @param array $activity
1076          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1077          * @throws \ImagickException
1078          */
1079         public static function undoFollowUser($activity)
1080         {
1081                 $uid = User::getIdForURL($activity['object_object']);
1082                 if (empty($uid)) {
1083                         return;
1084                 }
1085
1086                 $owner = User::getOwnerDataById($uid);
1087                 if (empty($owner)) {
1088                         return;
1089                 }
1090
1091                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1092                 if (empty($cid)) {
1093                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1094                         return;
1095                 }
1096
1097                 self::switchContact($cid);
1098
1099                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1100                 if (!DBA::isResult($contact)) {
1101                         return;
1102                 }
1103
1104                 Contact::removeFollower($owner, $contact);
1105                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1106         }
1107
1108         /**
1109          * Switches a contact to AP if needed
1110          *
1111          * @param integer $cid Contact ID
1112          * @throws \Exception
1113          */
1114         private static function switchContact($cid)
1115         {
1116                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1117                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1118                         return;
1119                 }
1120
1121                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1122                 Contact::updateFromProbe($cid);
1123         }
1124
1125         /**
1126          * Collects implicit mentions like:
1127          * - the author of the parent item
1128          * - all the mentioned conversants in the parent item
1129          *
1130          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1131          * @return array
1132          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1133          */
1134         private static function getImplicitMentionList(array $parent)
1135         {
1136                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1137
1138                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1139
1140                 $implicit_mentions = [];
1141                 if (empty($parent_author['url'])) {
1142                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1143                 } else {
1144                         $implicit_mentions[] = $parent_author['url'];
1145                         $implicit_mentions[] = $parent_author['nurl'];
1146                         $implicit_mentions[] = $parent_author['alias'];
1147                 }
1148
1149                 if (!empty($parent['alias'])) {
1150                         $implicit_mentions[] = $parent['alias'];
1151                 }
1152
1153                 foreach ($parent_terms as $term) {
1154                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1155                         if (!empty($contact['url'])) {
1156                                 $implicit_mentions[] = $contact['url'];
1157                                 $implicit_mentions[] = $contact['nurl'];
1158                                 $implicit_mentions[] = $contact['alias'];
1159                         }
1160                 }
1161
1162                 return $implicit_mentions;
1163         }
1164
1165         /**
1166          * Strips from the body prepended implicit mentions
1167          *
1168          * @param string $body
1169          * @param array $parent
1170          * @return string
1171          */
1172         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1173         {
1174                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1175                         return $body;
1176                 }
1177
1178                 $potential_mentions = self::getImplicitMentionList($parent);
1179
1180                 $kept_mentions = [];
1181
1182                 // Extract one prepended mention at a time from the body
1183                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1184                         if (!in_array($matches[2], $potential_mentions)) {
1185                                 $kept_mentions[] = $matches[1];
1186                         }
1187
1188                         $body = $matches[3];
1189                 }
1190
1191                 // Re-appending the kept mentions to the body after extraction
1192                 $kept_mentions[] = $body;
1193
1194                 return implode('', $kept_mentions);
1195         }
1196 }