src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   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\Core\Logger;
  27 use Friendica\Core\Protocol;
  28 use Friendica\Database\DBA;
  29 use Friendica\DI;
  30 use Friendica\Model\APContact;
  31 use Friendica\Model\Contact;
  32 use Friendica\Model\Conversation;
  33 use Friendica\Model\Event;
  34 use Friendica\Model\Item;
  35 use Friendica\Model\ItemURI;
  36 use Friendica\Model\Mail;
  37 use Friendica\Model\Tag;
  38 use Friendica\Model\User;
  39 use Friendica\Protocol\Activity;
  40 use Friendica\Protocol\ActivityPub;
  41 use Friendica\Util\DateTimeFormat;
  42 use Friendica\Util\JsonLD;
  43 use Friendica\Util\Strings;
  44
  45 /**
  46  * ActivityPub Processor Protocol class
  47  */
  48 class Processor
  49 {
  50         /**
  51          * Converts mentions from Pleroma into the Friendica format
  52          *
  53          * @param string $body
  54          *
  55          * @return string converted body
  56          */
  57         private static function convertMentions($body)
  58         {
  59                 $URLSearchString = "^\[\]";
  60                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  61
  62                 return $body;
  63         }
  64
  65         /**
  66          * Replaces emojis in the body
  67          *
  68          * @param array $emojis
  69          * @param string $body
  70          *
  71          * @return string with replaced emojis
  72          */
  73         private static function replaceEmojis($body, array $emojis)
  74         {
  75                 foreach ($emojis as $emoji) {
  76                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  77                         $body = str_replace($emoji['name'], $replace, $body);
  78                 }
  79                 return $body;
  80         }
  81
  82         /**
  83          * Add attachment data to the item array
  84          *
  85          * @param array   $activity
  86          * @param array   $item
  87          *
  88          * @return array array
  89          */
  90         private static function constructAttachList($activity, $item)
  91         {
  92                 if (empty($activity['attachments'])) {
  93                         return $item;
  94                 }
  95
  96                 foreach ($activity['attachments'] as $attach) {
  97                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
  98                         if ($filetype == 'image') {
  99                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 100                                         continue;
 101                                 }
 102
 103                                 if (empty($attach['name'])) {
 104                                         $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 105                                 } else {
 106                                         $item['body'] .= "\n[img=" . $attach['url'] . ']' . $attach['name'] . '[/img]';
 107                                 }
 108                         } elseif ($filetype == 'audio') {
 109                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 110                                         continue;
 111                                 }
 112
 113                                 $item['body'] .= "\n[audio]" . $attach['url'] . '[/audio]';
 114                         } elseif ($filetype == 'video') {
 115                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 116                                         continue;
 117                                 }
 118
 119                                 $item['body'] .= "\n[video]" . $attach['url'] . '[/video]';
 120                         } else {
 121                                 if (!empty($item["attach"])) {
 122                                         $item["attach"] .= ',';
 123                                 } else {
 124                                         $item["attach"] = '';
 125                                 }
 126                                 if (!isset($attach['length'])) {
 127                                         $attach['length'] = "0";
 128                                 }
 129                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.($attach['name'] ?? '') .'"[/attach]';
 130                         }
 131                 }
 132
 133                 return $item;
 134         }
 135
 136         /**
 137          * Updates a message
 138          *
 139          * @param array $activity Activity array
 140          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 141          */
 142         public static function updateItem($activity)
 143         {
 144                 $item = Item::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 145                 if (!DBA::isResult($item)) {
 146                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 147                         self::createItem($activity);
 148                         return;
 149                 }
 150
 151                 $item['changed'] = DateTimeFormat::utcNow();
 152                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 153
 154                 $item = self::processContent($activity, $item);
 155                 if (empty($item)) {
 156                         return;
 157                 }
 158
 159                 Item::update($item, ['uri' => $activity['id']]);
 160         }
 161
 162         /**
 163          * Prepares data for a message
 164          *
 165          * @param array $activity Activity array
 166          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 167          * @throws \ImagickException
 168          */
 169         public static function createItem($activity)
 170         {
 171                 $item = [];
 172                 $item['verb'] = Activity::POST;
 173                 $item['thr-parent'] = $activity['reply-to-id'];
 174
 175                 if ($activity['reply-to-id'] == $activity['id']) {
 176                         $item['gravity'] = GRAVITY_PARENT;
 177                         $item['object-type'] = Activity\ObjectType::NOTE;
 178                 } else {
 179                         $item['gravity'] = GRAVITY_COMMENT;
 180                         $item['object-type'] = Activity\ObjectType::COMMENT;
 181
 182                         // Ensure that the comment reaches all receivers of the referring post
 183                         $activity['receiver'] = self::addReceivers($activity);
 184                 }
 185
 186                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 187                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 188                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 189                 }
 190
 191                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 192
 193                 self::postItem($activity, $item);
 194         }
 195
 196         /**
 197          * Delete items
 198          *
 199          * @param array $activity
 200          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 201          * @throws \ImagickException
 202          */
 203         public static function deleteItem($activity)
 204         {
 205                 $owner = Contact::getIdForURL($activity['actor']);
 206
 207                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 208                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 209         }
 210
 211         /**
 212          * Prepare the item array for an activity
 213          *
 214          * @param array $activity Activity array
 215          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 216          * @throws \ImagickException
 217          */
 218         public static function addTag($activity)
 219         {
 220                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 221                         return;
 222                 }
 223
 224                 foreach ($activity['receiver'] as $receiver) {
 225                         $item = Item::selectFirst(['id', 'uri-id', 'tag', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 226                         if (!DBA::isResult($item)) {
 227                                 // We don't fetch missing content for this purpose
 228                                 continue;
 229                         }
 230
 231                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 232                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 233                                 continue;
 234                         }
 235
 236                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 237                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 238                 }
 239         }
 240
 241         /**
 242          * Add users to the receiver list of the given public activity.
 243          * This is used to ensure that the activity will be stored in every thread.
 244          *
 245          * @param array $activity Activity array
 246          * @return array Modified receiver list
 247          */
 248         private static function addReceivers(array $activity)
 249         {
 250                 if (!in_array(0, $activity['receiver'])) {
 251                         // Private activities will not be modified
 252                         return $activity['receiver'];
 253                 }
 254
 255                 // Add all owners of the referring item to the receivers
 256                 $original = $receivers = $activity['receiver'];
 257                 $items = Item::select(['uid'], ['uri' => $activity['object_id']]);
 258                 while ($item = DBA::fetch($items)) {
 259                         $receivers['uid:' . $item['uid']] = $item['uid'];
 260                 }
 261                 DBA::close($items);
 262
 263                 if (count($original) != count($receivers)) {
 264                         Logger::info('Improved data', ['id' => $activity['id'], 'object' => $activity['object_id'], 'original' => $original, 'improved' => $receivers]);
 265                 }
 266
 267                 return $receivers;
 268         }
 269
 270         /**
 271          * Prepare the item array for an activity
 272          *
 273          * @param array  $activity Activity array
 274          * @param string $verb     Activity verb
 275          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 276          * @throws \ImagickException
 277          */
 278         public static function createActivity($activity, $verb)
 279         {
 280                 $item = [];
 281                 $item['verb'] = $verb;
 282                 $item['thr-parent'] = $activity['object_id'];
 283                 $item['gravity'] = GRAVITY_ACTIVITY;
 284                 $item['object-type'] = Activity\ObjectType::NOTE;
 285
 286                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 287
 288                 $activity['receiver'] = self::addReceivers($activity);
 289
 290                 self::postItem($activity, $item);
 291         }
 292
 293         /**
 294          * Create an event
 295          *
 296          * @param array $activity Activity array
 297          * @param array $item
 298          * @throws \Exception
 299          */
 300         public static function createEvent($activity, $item)
 301         {
 302                 $event['summary']  = HTML::toBBCode($activity['name']);
 303                 $event['desc']     = HTML::toBBCode($activity['content']);
 304                 $event['start']    = $activity['start-time'];
 305                 $event['finish']   = $activity['end-time'];
 306                 $event['nofinish'] = empty($event['finish']);
 307                 $event['location'] = $activity['location'];
 308                 $event['adjust']   = true;
 309                 $event['cid']      = $item['contact-id'];
 310                 $event['uid']      = $item['uid'];
 311                 $event['uri']      = $item['uri'];
 312                 $event['edited']   = $item['edited'];
 313                 $event['private']  = $item['private'];
 314                 $event['guid']     = $item['guid'];
 315                 $event['plink']    = $item['plink'];
 316
 317                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 318                 $ev = DBA::selectFirst('event', ['id'], $condition);
 319                 if (DBA::isResult($ev)) {
 320                         $event['id'] = $ev['id'];
 321                 }
 322
 323                 $event_id = Event::store($event);
 324                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 325         }
 326
 327         /**
 328          * Process the content
 329          *
 330          * @param array $activity Activity array
 331          * @param array $item
 332          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 333          * @throws \Exception
 334          */
 335         private static function processContent($activity, $item)
 336         {
 337                 $item['title'] = HTML::toBBCode($activity['name']);
 338
 339                 if (!empty($activity['source'])) {
 340                         $item['body'] = $activity['source'];
 341                 } else {
 342                         $content = HTML::toBBCode($activity['content']);
 343
 344                         if (!empty($activity['emojis'])) {
 345                                 $content = self::replaceEmojis($content, $activity['emojis']);
 346                         }
 347
 348                         $content = self::convertMentions($content);
 349
 350                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 351                                 $item_private = !in_array(0, $activity['item_receiver']);
 352                                 $parent = Item::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 353                                 if (!DBA::isResult($parent)) {
 354                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 355                                         return false;
 356                                 }
 357                                 if ($item_private && ($parent['private'] == Item::PRIVATE)) {
 358                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 359                                         return false;
 360                                 }
 361
 362                                 $potential_implicit_mentions = self::getImplicitMentionList($parent);
 363                                 $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 364                                 $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 365                         }
 366                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 367                         $item['body'] = $content;
 368                 }
 369
 370                 self::storeFromBody($item);
 371                 self::storeTags($item['uri-id'], $activity['tags']);
 372
 373                 $item['location'] = $activity['location'];
 374
 375                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 376                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 377                 }
 378
 379                 $item['app'] = $activity['generator'];
 380
 381                 return $item;
 382         }
 383
 384         /**
 385          * Store hashtags and mentions
 386          *
 387          * @param array $item
 388          */
 389         private static function storeFromBody(array $item)
 390         {
 391                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 392                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 393
 394                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 395         }
 396
 397         /**
 398          * Generate a GUID out of an URL
 399          *
 400          * @param string $url message URL
 401          * @return string with GUID
 402          */
 403         private static function getGUIDByURL(string $url)
 404         {
 405                 $parsed = parse_url($url);
 406
 407                 $host_hash = hash('crc32', $parsed['host']);
 408
 409                 unset($parsed["scheme"]);
 410                 unset($parsed["host"]);
 411
 412                 $path = implode("/", $parsed);
 413
 414                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 415         }
 416
 417         /**
 418          * Creates an item post
 419          *
 420          * @param array $activity Activity data
 421          * @param array $item     item array
 422          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 423          * @throws \ImagickException
 424          */
 425         private static function postItem($activity, $item)
 426         {
 427                 /// @todo What to do with $activity['context']?
 428                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 429                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 430                         return;
 431                 }
 432
 433                 $item['network'] = Protocol::ACTIVITYPUB;
 434                 $item['author-link'] = $activity['author'];
 435                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 436                 $item['owner-link'] = $activity['actor'];
 437                 $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 438
 439                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 440                         $item['private'] = Item::UNLISTED;
 441                 } elseif (in_array(0, $activity['receiver'])) {
 442                         $item['private'] = Item::PUBLIC;
 443                 } else {
 444                         $item['private'] = Item::PRIVATE;
 445                 }
 446
 447                 if (!empty($activity['raw'])) {
 448                         $item['source'] = $activity['raw'];
 449                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 450                         $item['conversation-href'] = $activity['context'] ?? '';
 451                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 452
 453                         if (isset($activity['push'])) {
 454                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 455                         }
 456                 }
 457
 458                 $isForum = false;
 459
 460                 if (!empty($activity['thread-completion'])) {
 461                         // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 462                         $item['causer-link'] = $item['owner-link'];
 463                         $item['causer-id'] = $item['owner-id'];
 464
 465                         Logger::info('Ignoring actor because of thread completion.', ['actor' => $item['owner-link']]);
 466                         $item['owner-link'] = $item['author-link'];
 467                         $item['owner-id'] = $item['author-id'];
 468                 } else {
 469                         $actor = APContact::getByURL($item['owner-link'], false);
 470                         $isForum = ($actor['type'] == 'Group');
 471                 }
 472
 473                 $item['uri'] = $activity['id'];
 474
 475                 $item['created'] = DateTimeFormat::utc($activity['published']);
 476                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 477                 $item['guid'] = $activity['diaspora:guid'] ?: $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 478
 479                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 480
 481                 $item = self::processContent($activity, $item);
 482                 if (empty($item)) {
 483                         return;
 484                 }
 485
 486                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 487
 488                 $item = self::constructAttachList($activity, $item);
 489
 490                 $stored = false;
 491
 492                 foreach ($activity['receiver'] as $receiver) {
 493                         if ($receiver == -1) {
 494                                 continue;
 495                         }
 496
 497                         $item['uid'] = $receiver;
 498
 499                         if ($isForum) {
 500                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver, true);
 501                         } else {
 502                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 503                         }
 504
 505                         if (($receiver != 0) && empty($item['contact-id'])) {
 506                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 507                         }
 508
 509                         if (!empty($activity['directmessage'])) {
 510                                 self::postMail($activity, $item);
 511                                 continue;
 512                         }
 513
 514                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 515                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 516
 517                                 if ($skip && (($activity['type'] == 'as:Announce') || $isForum)) {
 518                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 519                                 }
 520
 521                                 if ($skip) {
 522                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 523                                         continue;
 524                                 }
 525
 526                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 527                         }
 528
 529                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 530                                 self::createEvent($activity, $item);
 531                         }
 532
 533                         $item_id = Item::insert($item);
 534                         if ($item_id) {
 535                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 536                         } else {
 537                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 538                         }
 539
 540                         if ($item['uid'] == 0) {
 541                                 $stored = $item_id;
 542                         }
 543                 }
 544
 545                 // Store send a follow request for every reshare - but only when the item had been stored
 546                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 547                         $author = APContact::getByURL($item['owner-link'], false);
 548                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 549                         if ($author['type'] != 'Group') {
 550                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 551                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 552                         }
 553                 }
 554         }
 555
 556         /**
 557          * Store tags and mentions into the tag table
 558          *
 559          * @param integer $uriid
 560          * @param array $tags
 561          */
 562         private static function storeTags(int $uriid, array $tags = null)
 563         {
 564                 foreach ($tags as $tag) {
 565                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 566                                 continue;
 567                         }
 568
 569                         $hash = substr($tag['name'], 0, 1);
 570
 571                         if ($tag['type'] == 'Mention') {
 572                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 573                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 574                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 575                                         $tag['name'] = substr($tag['name'], 1);
 576                                 }
 577                                 $type = Tag::IMPLICIT_MENTION;
 578
 579                                 if (!empty($tag['href'])) {
 580                                         $apcontact = APContact::getByURL($tag['href']);
 581                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 582                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 583                                         }
 584                                 }
 585                         } elseif ($tag['type'] == 'Hashtag') {
 586                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 587                                         $tag['name'] = substr($tag['name'], 1);
 588                                 }
 589                                 $type = Tag::HASHTAG;
 590                         }
 591
 592                         if (empty($tag['name'])) {
 593                                 continue;
 594                         }
 595
 596                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 597                 }
 598         }
 599
 600         /**
 601          * Creates an mail post
 602          *
 603          * @param array $activity Activity data
 604          * @param array $item     item array
 605          * @return int|bool New mail table row id or false on error
 606          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 607          */
 608         private static function postMail($activity, $item)
 609         {
 610                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 611                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 612                         return false;
 613                 }
 614
 615                 Logger::info('Direct Message', $item);
 616
 617                 $msg = [];
 618                 $msg['uid'] = $item['uid'];
 619
 620                 $msg['contact-id'] = $item['contact-id'];
 621
 622                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 623                 $msg['from-name'] = $contact['name'];
 624                 $msg['from-url'] = $contact['url'];
 625                 $msg['from-photo'] = $contact['photo'];
 626
 627                 $msg['uri'] = $item['uri'];
 628                 $msg['created'] = $item['created'];
 629
 630                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 631                 if (DBA::isResult($parent)) {
 632                         $msg['parent-uri'] = $parent['parent-uri'];
 633                         $msg['title'] = $parent['title'];
 634                 } else {
 635                         $msg['parent-uri'] = $item['thr-parent'];
 636
 637                         if (!empty($item['title'])) {
 638                                 $msg['title'] = $item['title'];
 639                         } elseif (!empty($item['content-warning'])) {
 640                                 $msg['title'] = $item['content-warning'];
 641                         } else {
 642                                 // Trying to generate a title out of the body
 643                                 $title = $item['body'];
 644
 645                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 646                                         $title = $matches[3];
 647                                 }
 648
 649                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, 2, true), 0));
 650
 651                                 if (strlen($title) > 20) {
 652                                         $title = substr($title, 0, 20) . '...';
 653                                 }
 654
 655                                 $msg['title'] = $title;
 656                         }
 657                 }
 658                 $msg['body'] = $item['body'];
 659
 660                 return Mail::insert($msg);
 661         }
 662
 663         /**
 664          * Fetches missing posts
 665          *
 666          * @param string $url message URL
 667          * @param array $child activity array with the child of this message
 668          * @return string fetched message URL
 669          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 670          */
 671         public static function fetchMissingActivity($url, $child = [])
 672         {
 673                 if (!empty($child['receiver'])) {
 674                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 675                 } else {
 676                         $uid = 0;
 677                 }
 678
 679                 $object = ActivityPub::fetchContent($url, $uid);
 680                 if (empty($object)) {
 681                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 682                         return '';
 683                 }
 684
 685                 if (empty($object['id'])) {
 686                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 687                         return '';
 688                 }
 689
 690                 if (!empty($child['author'])) {
 691                         $actor = $child['author'];
 692                 } elseif (!empty($object['actor'])) {
 693                         $actor = $object['actor'];
 694                 } elseif (!empty($object['attributedTo'])) {
 695                         $actor = $object['attributedTo'];
 696                 } else {
 697                         // Shouldn't happen
 698                         $actor = '';
 699                 }
 700
 701                 if (!empty($object['published'])) {
 702                         $published = $object['published'];
 703                 } elseif (!empty($child['published'])) {
 704                         $published = $child['published'];
 705                 } else {
 706                         $published = DateTimeFormat::utcNow();
 707                 }
 708
 709                 $activity = [];
 710                 $activity['@context'] = $object['@context'];
 711                 unset($object['@context']);
 712                 $activity['id'] = $object['id'];
 713                 $activity['to'] = $object['to'] ?? [];
 714                 $activity['cc'] = $object['cc'] ?? [];
 715                 $activity['actor'] = $actor;
 716                 $activity['object'] = $object;
 717                 $activity['published'] = $published;
 718                 $activity['type'] = 'Create';
 719
 720                 $ldactivity = JsonLD::compact($activity);
 721
 722                 $ldactivity['thread-completion'] = true;
 723
 724                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity));
 725
 726                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 727
 728                 return $activity['id'];
 729         }
 730
 731         /**
 732          * perform a "follow" request
 733          *
 734          * @param array $activity
 735          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 736          * @throws \ImagickException
 737          */
 738         public static function followUser($activity)
 739         {
 740                 $uid = User::getIdForURL($activity['object_id']);
 741                 if (empty($uid)) {
 742                         return;
 743                 }
 744
 745                 $owner = User::getOwnerDataById($uid);
 746
 747                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 748                 if (!empty($cid)) {
 749                         self::switchContact($cid);
 750                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 751                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 752                 } else {
 753                         $contact = [];
 754                 }
 755
 756                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 757                         'author-link' => $activity['actor']];
 758
 759                 $note = Strings::escapeTags(trim($activity['content'] ?? ''));
 760
 761                 // Ensure that the contact has got the right network type
 762                 self::switchContact($item['author-id']);
 763
 764                 $result = Contact::addRelationship($owner, $contact, $item, false, $note);
 765                 if ($result === true) {
 766                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $item['author-id'], $owner['uid']);
 767                 }
 768
 769                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 770                 if (empty($cid)) {
 771                         return;
 772                 }
 773
 774                 if (empty($contact)) {
 775                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 776                 }
 777
 778                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 779         }
 780
 781         /**
 782          * Update the given profile
 783          *
 784          * @param array $activity
 785          * @throws \Exception
 786          */
 787         public static function updatePerson($activity)
 788         {
 789                 if (empty($activity['object_id'])) {
 790                         return;
 791                 }
 792
 793                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 794                 Contact::updateFromProbeByURL($activity['object_id'], true);
 795         }
 796
 797         /**
 798          * Delete the given profile
 799          *
 800          * @param array $activity
 801          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 802          */
 803         public static function deletePerson($activity)
 804         {
 805                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 806                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 807                         return;
 808                 }
 809
 810                 if ($activity['object_id'] != $activity['actor']) {
 811                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 812                         return;
 813                 }
 814
 815                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 816                 while ($contact = DBA::fetch($contacts)) {
 817                         Contact::remove($contact['id']);
 818                 }
 819                 DBA::close($contacts);
 820
 821                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 822         }
 823
 824         /**
 825          * Accept a follow request
 826          *
 827          * @param array $activity
 828          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 829          * @throws \ImagickException
 830          */
 831         public static function acceptFollowUser($activity)
 832         {
 833                 $uid = User::getIdForURL($activity['object_actor']);
 834                 if (empty($uid)) {
 835                         return;
 836                 }
 837
 838                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 839                 if (empty($cid)) {
 840                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 841                         return;
 842                 }
 843
 844                 self::switchContact($cid);
 845
 846                 $fields = ['pending' => false];
 847
 848                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 849                 if ($contact['rel'] == Contact::FOLLOWER) {
 850                         $fields['rel'] = Contact::FRIEND;
 851                 }
 852
 853                 $condition = ['id' => $cid];
 854                 DBA::update('contact', $fields, $condition);
 855                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 856         }
 857
 858         /**
 859          * Reject a follow request
 860          *
 861          * @param array $activity
 862          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 863          * @throws \ImagickException
 864          */
 865         public static function rejectFollowUser($activity)
 866         {
 867                 $uid = User::getIdForURL($activity['object_actor']);
 868                 if (empty($uid)) {
 869                         return;
 870                 }
 871
 872                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 873                 if (empty($cid)) {
 874                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 875                         return;
 876                 }
 877
 878                 self::switchContact($cid);
 879
 880                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
 881                         Contact::remove($cid);
 882                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 883                 } else {
 884                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 885                 }
 886         }
 887
 888         /**
 889          * Undo activity like "like" or "dislike"
 890          *
 891          * @param array $activity
 892          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 893          * @throws \ImagickException
 894          */
 895         public static function undoActivity($activity)
 896         {
 897                 if (empty($activity['object_id'])) {
 898                         return;
 899                 }
 900
 901                 if (empty($activity['object_actor'])) {
 902                         return;
 903                 }
 904
 905                 $author_id = Contact::getIdForURL($activity['object_actor']);
 906                 if (empty($author_id)) {
 907                         return;
 908                 }
 909
 910                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 911         }
 912
 913         /**
 914          * Activity to remove a follower
 915          *
 916          * @param array $activity
 917          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 918          * @throws \ImagickException
 919          */
 920         public static function undoFollowUser($activity)
 921         {
 922                 $uid = User::getIdForURL($activity['object_object']);
 923                 if (empty($uid)) {
 924                         return;
 925                 }
 926
 927                 $owner = User::getOwnerDataById($uid);
 928
 929                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 930                 if (empty($cid)) {
 931                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 932                         return;
 933                 }
 934
 935                 self::switchContact($cid);
 936
 937                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 938                 if (!DBA::isResult($contact)) {
 939                         return;
 940                 }
 941
 942                 Contact::removeFollower($owner, $contact);
 943                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 944         }
 945
 946         /**
 947          * Switches a contact to AP if needed
 948          *
 949          * @param integer $cid Contact ID
 950          * @throws \Exception
 951          */
 952         private static function switchContact($cid)
 953         {
 954                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
 955                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
 956                         return;
 957                 }
 958
 959                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
 960                 Contact::updateFromProbe($cid);
 961         }
 962
 963         /**
 964          * Collects implicit mentions like:
 965          * - the author of the parent item
 966          * - all the mentioned conversants in the parent item
 967          *
 968          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 969          * @return array
 970          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 971          */
 972         private static function getImplicitMentionList(array $parent)
 973         {
 974                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
 975                         return [];
 976                 }
 977
 978                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
 979
 980                 $parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 981
 982                 $implicit_mentions = [];
 983                 if (empty($parent_author)) {
 984                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 985                 } else {
 986                         $implicit_mentions[] = $parent_author['url'];
 987                         $implicit_mentions[] = $parent_author['nurl'];
 988                         $implicit_mentions[] = $parent_author['alias'];
 989                 }
 990
 991                 if (!empty($parent['alias'])) {
 992                         $implicit_mentions[] = $parent['alias'];
 993                 }
 994
 995                 foreach ($parent_terms as $term) {
 996                         $contact = Contact::getDetailsByURL($term['url'], 0);
 997                         if (!empty($contact)) {
 998                                 $implicit_mentions[] = $contact['url'];
 999                                 $implicit_mentions[] = $contact['nurl'];
1000                                 $implicit_mentions[] = $contact['alias'];
1001                         }
1002                 }
1003
1004                 return $implicit_mentions;
1005         }
1006
1007         /**
1008          * Strips from the body prepended implicit mentions
1009          *
1010          * @param string $body
1011          * @param array $potential_mentions
1012          * @return string
1013          */
1014         private static function removeImplicitMentionsFromBody($body, array $potential_mentions)
1015         {
1016                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1017                         return $body;
1018                 }
1019
1020                 $kept_mentions = [];
1021
1022                 // Extract one prepended mention at a time from the body
1023                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1024                         if (!in_array($matches[2], $potential_mentions)) {
1025                                 $kept_mentions[] = $matches[1];
1026                         }
1027
1028                         $body = $matches[3];
1029                 }
1030
1031                 // Re-appending the kept mentions to the body after extraction
1032                 $kept_mentions[] = $body;
1033
1034                 return implode('', $kept_mentions);
1035         }
1036
1037         private static function convertImplicitMentionsInTags($activity_tags, array $potential_mentions)
1038         {
1039                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1040                         return $activity_tags;
1041                 }
1042
1043                 foreach ($activity_tags as $index => $tag) {
1044                         if (in_array($tag['href'], $potential_mentions)) {
1045                                 $activity_tags[$index]['name'] = preg_replace(
1046                                         '/' . preg_quote(Tag::TAG_CHARACTER[Tag::MENTION], '/') . '/',
1047                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION],
1048                                         $activity_tags[$index]['name'],
1049                                         1
1050                                 );
1051                         }
1052                 }
1053
1054                 return $activity_tags;
1055         }
1056 }