src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub/Processor.php
   4  */
   5 namespace Friendica\Protocol\ActivityPub;
   6
   7 use Friendica\Content\Text\BBCode;
   8 use Friendica\Content\Text\HTML;
   9 use Friendica\Core\Config;
  10 use Friendica\Core\Logger;
  11 use Friendica\Core\PConfig;
  12 use Friendica\Core\Protocol;
  13 use Friendica\Database\DBA;
  14 use Friendica\Model\APContact;
  15 use Friendica\Model\Contact;
  16 use Friendica\Model\Event;
  17 use Friendica\Model\Item;
  18 use Friendica\Model\Mail;
  19 use Friendica\Model\Term;
  20 use Friendica\Model\User;
  21 use Friendica\Protocol\Activity;
  22 use Friendica\Protocol\ActivityPub;
  23 use Friendica\Util\DateTimeFormat;
  24 use Friendica\Util\JsonLD;
  25 use Friendica\Util\Strings;
  26
  27 /**
  28  * ActivityPub Processor Protocol class
  29  */
  30 class Processor
  31 {
  32         /**
  33          * Converts mentions from Pleroma into the Friendica format
  34          *
  35          * @param string $body
  36          *
  37          * @return string converted body
  38          */
  39         private static function convertMentions($body)
  40         {
  41                 $URLSearchString = "^\[\]";
  42                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  43
  44                 return $body;
  45         }
  46
  47         /**
  48          * Replaces emojis in the body
  49          *
  50          * @param array $emojis
  51          * @param string $body
  52          *
  53          * @return string with replaced emojis
  54          */
  55         private static function replaceEmojis($body, array $emojis)
  56         {
  57                 foreach ($emojis as $emoji) {
  58                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  59                         $body = str_replace($emoji['name'], $replace, $body);
  60                 }
  61                 return $body;
  62         }
  63
  64         /**
  65          * Constructs a string with tags for a given tag array
  66          *
  67          * @param array   $tags
  68          * @param boolean $sensitive
  69          * @return string with tags
  70          */
  71         private static function constructTagString(array $tags = null, $sensitive = false)
  72         {
  73                 if (empty($tags)) {
  74                         return '';
  75                 }
  76
  77                 $tag_text = '';
  78                 foreach ($tags as $tag) {
  79                         if (in_array($tag['type'] ?? '', ['Mention', 'Hashtag'])) {
  80                                 if (!empty($tag_text)) {
  81                                         $tag_text .= ',';
  82                                 }
  83
  84                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
  85                         }
  86                 }
  87
  88                 /// @todo add nsfw for $sensitive
  89
  90                 return $tag_text;
  91         }
  92
  93         /**
  94          * Add attachment data to the item array
  95          *
  96          * @param array   $activity
  97          * @param array   $item
  98          *
  99          * @return array array
 100          */
 101         private static function constructAttachList($activity, $item)
 102         {
 103                 if (empty($activity['attachments'])) {
 104                         return $item;
 105                 }
 106
 107                 foreach ($activity['attachments'] as $attach) {
 108                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 109                         if ($filetype == 'image') {
 110                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 111                                         continue;
 112                                 }
 113
 114                                 if (empty($attach['name'])) {
 115                                         $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 116                                 } else {
 117                                         $item['body'] .= "\n[img=" . $attach['url'] . ']' . $attach['name'] . '[/img]';
 118                                 }
 119                         } else {
 120                                 if (!empty($item["attach"])) {
 121                                         $item["attach"] .= ',';
 122                                 } else {
 123                                         $item["attach"] = '';
 124                                 }
 125                                 if (!isset($attach['length'])) {
 126                                         $attach['length'] = "0";
 127                                 }
 128                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.($attach['name'] ?? '') .'"[/attach]';
 129                         }
 130                 }
 131
 132                 return $item;
 133         }
 134
 135         /**
 136          * Updates a message
 137          *
 138          * @param array $activity Activity array
 139          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 140          */
 141         public static function updateItem($activity)
 142         {
 143                 $item = Item::selectFirst(['uri', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 144                 if (!DBA::isResult($item)) {
 145                         Logger::warning('Unknown item', ['uri' => $activity['id']]);
 146                         return;
 147                 }
 148
 149                 $item['changed'] = DateTimeFormat::utcNow();
 150                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 151
 152                 $item = self::processContent($activity, $item);
 153                 if (empty($item)) {
 154                         return;
 155                 }
 156
 157                 Item::update($item, ['uri' => $activity['id']]);
 158         }
 159
 160         /**
 161          * Prepares data for a message
 162          *
 163          * @param array $activity Activity array
 164          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 165          * @throws \ImagickException
 166          */
 167         public static function createItem($activity)
 168         {
 169                 $item = [];
 170                 $item['verb'] = Activity::POST;
 171                 $item['thr-parent'] = $activity['reply-to-id'];
 172
 173                 if ($activity['reply-to-id'] == $activity['id']) {
 174                         $item['gravity'] = GRAVITY_PARENT;
 175                         $item['object-type'] = Activity\ObjectType::NOTE;
 176                 } else {
 177                         $item['gravity'] = GRAVITY_COMMENT;
 178                         $item['object-type'] = Activity\ObjectType::COMMENT;
 179
 180                         // Ensure that the comment reaches all receivers of the referring post
 181                         $activity['receiver'] = self::addReceivers($activity);
 182                 }
 183
 184                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 185                         Logger::log('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
 186                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 187                 }
 188
 189                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 190
 191                 self::postItem($activity, $item);
 192         }
 193
 194         /**
 195          * Delete items
 196          *
 197          * @param array $activity
 198          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 199          * @throws \ImagickException
 200          */
 201         public static function deleteItem($activity)
 202         {
 203                 $owner = Contact::getIdForURL($activity['actor']);
 204
 205                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 206                 Item::delete(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 207         }
 208
 209         /**
 210          * Prepare the item array for an activity
 211          *
 212          * @param array $activity Activity array
 213          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 214          * @throws \ImagickException
 215          */
 216         public static function addTag($activity)
 217         {
 218                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 219                         return;
 220                 }
 221
 222                 foreach ($activity['receiver'] as $receiver) {
 223                         $item = Item::selectFirst(['id', 'tag', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 224                         if (!DBA::isResult($item)) {
 225                                 // We don't fetch missing content for this purpose
 226                                 continue;
 227                         }
 228
 229                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 230                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 231                                 continue;
 232                         }
 233
 234                         // To-Do:
 235                         // - Check if "blocktag" is set
 236                         // - Check if actor is a contact
 237
 238                         if (!stristr($item['tag'], trim($activity['object_content']))) {
 239                                 $tag = $item['tag'] . (strlen($item['tag']) ? ',' : '') . '#[url=' . $activity['object_id'] . ']'. $activity['object_content'] . '[/url]';
 240                                 Item::update(['tag' => $tag], ['id' => $item['id']]);
 241                                 Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 242                         }
 243                 }
 244         }
 245
 246         /**
 247          * Add users to the receiver list of the given public activity.
 248          * This is used to ensure that the activity will be stored in every thread.
 249          *
 250          * @param array $activity Activity array
 251          * @return array Modified receiver list
 252          */
 253         private static function addReceivers(array $activity)
 254         {
 255                 if (!in_array(0, $activity['receiver'])) {
 256                         // Private activities will not be modified
 257                         return $activity['receiver'];
 258                 }
 259
 260                 // Add all owners of the referring item to the receivers
 261                 $original = $receivers = $activity['receiver'];
 262                 $items = Item::select(['uid'], ['uri' => $activity['object_id']]);
 263                 while ($item = DBA::fetch($items)) {
 264                         $receivers['uid:' . $item['uid']] = $item['uid'];
 265                 }
 266                 DBA::close($items);
 267
 268                 if (count($original) != count($receivers)) {
 269                         Logger::info('Improved data', ['id' => $activity['id'], 'object' => $activity['object_id'], 'original' => $original, 'improved' => $receivers]);
 270                 }
 271
 272                 return $receivers;
 273         }
 274
 275         /**
 276          * Prepare the item array for an activity
 277          *
 278          * @param array  $activity Activity array
 279          * @param string $verb     Activity verb
 280          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 281          * @throws \ImagickException
 282          */
 283         public static function createActivity($activity, $verb)
 284         {
 285                 $item = [];
 286                 $item['verb'] = $verb;
 287                 $item['thr-parent'] = $activity['object_id'];
 288                 $item['gravity'] = GRAVITY_ACTIVITY;
 289                 $item['object-type'] = Activity\ObjectType::NOTE;
 290
 291                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 292
 293                 $activity['receiver'] = self::addReceivers($activity);
 294
 295                 self::postItem($activity, $item);
 296         }
 297
 298         /**
 299          * Create an event
 300          *
 301          * @param array $activity Activity array
 302          * @param array $item
 303          * @throws \Exception
 304          */
 305         public static function createEvent($activity, $item)
 306         {
 307                 $event['summary']  = HTML::toBBCode($activity['name']);
 308                 $event['desc']     = HTML::toBBCode($activity['content']);
 309                 $event['start']    = $activity['start-time'];
 310                 $event['finish']   = $activity['end-time'];
 311                 $event['nofinish'] = empty($event['finish']);
 312                 $event['location'] = $activity['location'];
 313                 $event['adjust']   = true;
 314                 $event['cid']      = $item['contact-id'];
 315                 $event['uid']      = $item['uid'];
 316                 $event['uri']      = $item['uri'];
 317                 $event['edited']   = $item['edited'];
 318                 $event['private']  = $item['private'];
 319                 $event['guid']     = $item['guid'];
 320                 $event['plink']    = $item['plink'];
 321
 322                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 323                 $ev = DBA::selectFirst('event', ['id'], $condition);
 324                 if (DBA::isResult($ev)) {
 325                         $event['id'] = $ev['id'];
 326                 }
 327
 328                 $event_id = Event::store($event);
 329                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 330         }
 331
 332         /**
 333          * Process the content
 334          *
 335          * @param array $activity Activity array
 336          * @param array $item
 337          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 338          * @throws \Exception
 339          */
 340         private static function processContent($activity, $item)
 341         {
 342                 $item['title'] = HTML::toBBCode($activity['name']);
 343
 344                 if (!empty($activity['source'])) {
 345                         $item['body'] = $activity['source'];
 346                 } else {
 347                         $content = HTML::toBBCode($activity['content']);
 348
 349                         if (!empty($activity['emojis'])) {
 350                                 $content = self::replaceEmojis($content, $activity['emojis']);
 351                         }
 352
 353                         $content = self::convertMentions($content);
 354
 355                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 356                                 $item_private = !in_array(0, $activity['item_receiver']);
 357                                 $parent = Item::selectFirst(['id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 358                                 if (!DBA::isResult($parent)) {
 359                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 360                                         return false;
 361                                 }
 362                                 if ($item_private && !$parent['private']) {
 363                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 364                                         return false;
 365                                 }
 366
 367                                 $potential_implicit_mentions = self::getImplicitMentionList($parent);
 368                                 $content = self::removeImplicitMentionsFromBody($content, $potential_implicit_mentions);
 369                                 $activity['tags'] = self::convertImplicitMentionsInTags($activity['tags'], $potential_implicit_mentions);
 370                         }
 371                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 372                         $item['body'] = $content;
 373
 374                         if (($activity['object_type'] == 'as:Video') && !empty($activity['alternate-url'])) {
 375                                 $item['body'] .= "\n[video]" . $activity['alternate-url'] . '[/video]';
 376                         }
 377                 }
 378
 379                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive']);
 380
 381                 $item['location'] = $activity['location'];
 382
 383                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 384                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 385                 }
 386
 387                 $item['app'] = $activity['generator'];
 388
 389                 return $item;
 390         }
 391
 392         /**
 393          * Creates an item post
 394          *
 395          * @param array $activity Activity data
 396          * @param array $item     item array
 397          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 398          * @throws \ImagickException
 399          */
 400         private static function postItem($activity, $item)
 401         {
 402                 /// @todo What to do with $activity['context']?
 403                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 404                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 405                         return;
 406                 }
 407
 408                 $item['network'] = Protocol::ACTIVITYPUB;
 409                 $item['private'] = !in_array(0, $activity['receiver']);
 410                 $item['author-link'] = $activity['author'];
 411                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 412                 $item['owner-link'] = $activity['actor'];
 413                 $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 414
 415                 $isForum = false;
 416
 417                 if (!empty($activity['thread-completion'])) {
 418                         // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 419                         $item['causer-link'] = $item['owner-link'];
 420                         $item['causer-id'] = $item['owner-id'];
 421
 422                         Logger::info('Ignoring actor because of thread completion.', ['actor' => $item['owner-link']]);
 423                         $item['owner-link'] = $item['author-link'];
 424                         $item['owner-id'] = $item['author-id'];
 425                 } else {
 426                         $actor = APContact::getByURL($item['owner-link'], false);
 427                         $isForum = ($actor['type'] == 'Group');
 428                 }
 429
 430                 $item['uri'] = $activity['id'];
 431
 432                 $item['created'] = DateTimeFormat::utc($activity['published']);
 433                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 434                 $item['guid'] = $activity['diaspora:guid'];
 435
 436                 $item = self::processContent($activity, $item);
 437                 if (empty($item)) {
 438                         return;
 439                 }
 440
 441                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 442
 443                 $item = self::constructAttachList($activity, $item);
 444
 445                 $stored = false;
 446
 447                 foreach ($activity['receiver'] as $receiver) {
 448                         $item['uid'] = $receiver;
 449
 450                         if ($isForum) {
 451                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver, true);
 452                         } else {
 453                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 454                         }
 455
 456                         if (($receiver != 0) && empty($item['contact-id'])) {
 457                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 458                         }
 459
 460                         if (!empty($activity['directmessage'])) {
 461                                 self::postMail($activity, $item);
 462                                 continue;
 463                         }
 464
 465                         if (PConfig::get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 466                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 467
 468                                 if ($skip && (($activity['type'] == 'as:Announce') || $isForum)) {
 469                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 470                                 }
 471
 472                                 if ($skip) {
 473                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 474                                         continue;
 475                                 }
 476
 477                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 478                         }
 479
 480                         if ($activity['object_type'] == 'as:Event') {
 481                                 self::createEvent($activity, $item);
 482                         }
 483
 484                         $item_id = Item::insert($item);
 485                         if ($item_id) {
 486                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 487                         } else {
 488                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 489                         }
 490
 491                         if ($item['uid'] == 0) {
 492                                 $stored = $item_id;
 493                         }
 494                 }
 495
 496                 // Store send a follow request for every reshare - but only when the item had been stored
 497                 if ($stored && !$item['private'] && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 498                         $author = APContact::getByURL($item['owner-link'], false);
 499                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 500                         if ($author['type'] != 'Group') {
 501                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 502                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 503                         }
 504                 }
 505         }
 506
 507         /**
 508          * Creates an mail post
 509          *
 510          * @param array $activity Activity data
 511          * @param array $item     item array
 512          * @return int|bool New mail table row id or false on error
 513          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 514          */
 515         private static function postMail($activity, $item)
 516         {
 517                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 518                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 519                         return false;
 520                 }
 521
 522                 Logger::info('Direct Message', $item);
 523
 524                 $msg = [];
 525                 $msg['uid'] = $item['uid'];
 526
 527                 $msg['contact-id'] = $item['contact-id'];
 528
 529                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 530                 $msg['from-name'] = $contact['name'];
 531                 $msg['from-url'] = $contact['url'];
 532                 $msg['from-photo'] = $contact['photo'];
 533
 534                 $msg['uri'] = $item['uri'];
 535                 $msg['created'] = $item['created'];
 536
 537                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 538                 if (DBA::isResult($parent)) {
 539                         $msg['parent-uri'] = $parent['parent-uri'];
 540                         $msg['title'] = $parent['title'];
 541                 } else {
 542                         $msg['parent-uri'] = $item['thr-parent'];
 543
 544                         if (!empty($item['title'])) {
 545                                 $msg['title'] = $item['title'];
 546                         } elseif (!empty($item['content-warning'])) {
 547                                 $msg['title'] = $item['content-warning'];
 548                         } else {
 549                                 // Trying to generate a title out of the body
 550                                 $title = $item['body'];
 551
 552                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 553                                         $title = $matches[3];
 554                                 }
 555
 556                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, 2, true), 0));
 557
 558                                 if (strlen($title) > 20) {
 559                                         $title = substr($title, 0, 20) . '...';
 560                                 }
 561
 562                                 $msg['title'] = $title;
 563                         }
 564                 }
 565                 $msg['body'] = $item['body'];
 566
 567                 return Mail::insert($msg);
 568         }
 569
 570         /**
 571          * Fetches missing posts
 572          *
 573          * @param string $url message URL
 574          * @param array $child activity array with the child of this message
 575          * @return boolean success
 576          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 577          */
 578         public static function fetchMissingActivity($url, $child = [])
 579         {
 580                 if (!empty($child['receiver'])) {
 581                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 582                 } else {
 583                         $uid = 0;
 584                 }
 585
 586                 $object = ActivityPub::fetchContent($url, $uid);
 587                 if (empty($object)) {
 588                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 589                         return false;
 590                 }
 591
 592                 if (empty($object['id'])) {
 593                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 594                         return false;
 595                 }
 596
 597                 if (!empty($child['author'])) {
 598                         $actor = $child['author'];
 599                 } elseif (!empty($object['actor'])) {
 600                         $actor = $object['actor'];
 601                 } elseif (!empty($object['attributedTo'])) {
 602                         $actor = $object['attributedTo'];
 603                 } else {
 604                         // Shouldn't happen
 605                         $actor = '';
 606                 }
 607
 608                 if (!empty($object['published'])) {
 609                         $published = $object['published'];
 610                 } elseif (!empty($child['published'])) {
 611                         $published = $child['published'];
 612                 } else {
 613                         $published = DateTimeFormat::utcNow();
 614                 }
 615
 616                 $activity = [];
 617                 $activity['@context'] = $object['@context'];
 618                 unset($object['@context']);
 619                 $activity['id'] = $object['id'];
 620                 $activity['to'] = $object['to'] ?? [];
 621                 $activity['cc'] = $object['cc'] ?? [];
 622                 $activity['actor'] = $actor;
 623                 $activity['object'] = $object;
 624                 $activity['published'] = $published;
 625                 $activity['type'] = 'Create';
 626
 627                 $ldactivity = JsonLD::compact($activity);
 628
 629                 $ldactivity['thread-completion'] = true;
 630
 631                 ActivityPub\Receiver::processActivity($ldactivity);
 632                 Logger::log('Activity ' . $url . ' had been fetched and processed.');
 633
 634                 return true;
 635         }
 636
 637         /**
 638          * perform a "follow" request
 639          *
 640          * @param array $activity
 641          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 642          * @throws \ImagickException
 643          */
 644         public static function followUser($activity)
 645         {
 646                 $uid = User::getIdForURL($activity['object_id']);
 647                 if (empty($uid)) {
 648                         return;
 649                 }
 650
 651                 $owner = User::getOwnerDataById($uid);
 652
 653                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 654                 if (!empty($cid)) {
 655                         self::switchContact($cid);
 656                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 657                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 658                 } else {
 659                         $contact = [];
 660                 }
 661
 662                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 663                         'author-link' => $activity['actor']];
 664
 665                 $note = Strings::escapeTags(trim($activity['content'] ?? ''));
 666
 667                 // Ensure that the contact has got the right network type
 668                 self::switchContact($item['author-id']);
 669
 670                 $result = Contact::addRelationship($owner, $contact, $item, false, $note);
 671                 if ($result === true) {
 672                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $item['author-id'], $owner['uid']);
 673                 }
 674
 675                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 676                 if (empty($cid)) {
 677                         return;
 678                 }
 679
 680                 if (empty($contact)) {
 681                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 682                 }
 683
 684                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 685         }
 686
 687         /**
 688          * Update the given profile
 689          *
 690          * @param array $activity
 691          * @throws \Exception
 692          */
 693         public static function updatePerson($activity)
 694         {
 695                 if (empty($activity['object_id'])) {
 696                         return;
 697                 }
 698
 699                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 700                 Contact::updateFromProbeByURL($activity['object_id'], true);
 701         }
 702
 703         /**
 704          * Delete the given profile
 705          *
 706          * @param array $activity
 707          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 708          */
 709         public static function deletePerson($activity)
 710         {
 711                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 712                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 713                         return;
 714                 }
 715
 716                 if ($activity['object_id'] != $activity['actor']) {
 717                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 718                         return;
 719                 }
 720
 721                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 722                 while ($contact = DBA::fetch($contacts)) {
 723                         Contact::remove($contact['id']);
 724                 }
 725                 DBA::close($contacts);
 726
 727                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 728         }
 729
 730         /**
 731          * Accept a follow request
 732          *
 733          * @param array $activity
 734          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 735          * @throws \ImagickException
 736          */
 737         public static function acceptFollowUser($activity)
 738         {
 739                 $uid = User::getIdForURL($activity['object_actor']);
 740                 if (empty($uid)) {
 741                         return;
 742                 }
 743
 744                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 745                 if (empty($cid)) {
 746                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 747                         return;
 748                 }
 749
 750                 self::switchContact($cid);
 751
 752                 $fields = ['pending' => false];
 753
 754                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 755                 if ($contact['rel'] == Contact::FOLLOWER) {
 756                         $fields['rel'] = Contact::FRIEND;
 757                 }
 758
 759                 $condition = ['id' => $cid];
 760                 DBA::update('contact', $fields, $condition);
 761                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 762         }
 763
 764         /**
 765          * Reject a follow request
 766          *
 767          * @param array $activity
 768          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 769          * @throws \ImagickException
 770          */
 771         public static function rejectFollowUser($activity)
 772         {
 773                 $uid = User::getIdForURL($activity['object_actor']);
 774                 if (empty($uid)) {
 775                         return;
 776                 }
 777
 778                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 779                 if (empty($cid)) {
 780                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 781                         return;
 782                 }
 783
 784                 self::switchContact($cid);
 785
 786                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
 787                         Contact::remove($cid);
 788                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 789                 } else {
 790                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 791                 }
 792         }
 793
 794         /**
 795          * Undo activity like "like" or "dislike"
 796          *
 797          * @param array $activity
 798          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 799          * @throws \ImagickException
 800          */
 801         public static function undoActivity($activity)
 802         {
 803                 if (empty($activity['object_id'])) {
 804                         return;
 805                 }
 806
 807                 if (empty($activity['object_actor'])) {
 808                         return;
 809                 }
 810
 811                 $author_id = Contact::getIdForURL($activity['object_actor']);
 812                 if (empty($author_id)) {
 813                         return;
 814                 }
 815
 816                 Item::delete(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 817         }
 818
 819         /**
 820          * Activity to remove a follower
 821          *
 822          * @param array $activity
 823          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 824          * @throws \ImagickException
 825          */
 826         public static function undoFollowUser($activity)
 827         {
 828                 $uid = User::getIdForURL($activity['object_object']);
 829                 if (empty($uid)) {
 830                         return;
 831                 }
 832
 833                 $owner = User::getOwnerDataById($uid);
 834
 835                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 836                 if (empty($cid)) {
 837                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 838                         return;
 839                 }
 840
 841                 self::switchContact($cid);
 842
 843                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 844                 if (!DBA::isResult($contact)) {
 845                         return;
 846                 }
 847
 848                 Contact::removeFollower($owner, $contact);
 849                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 850         }
 851
 852         /**
 853          * Switches a contact to AP if needed
 854          *
 855          * @param integer $cid Contact ID
 856          * @throws \Exception
 857          */
 858         private static function switchContact($cid)
 859         {
 860                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 861                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN])) {
 862                         return;
 863                 }
 864
 865                 Logger::log('Change existing contact ' . $cid . ' from ' . $contact['network'] . ' to ActivityPub.');
 866                 Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
 867         }
 868
 869         /**
 870          * Collects implicit mentions like:
 871          * - the author of the parent item
 872          * - all the mentioned conversants in the parent item
 873          *
 874          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 875          * @return array
 876          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 877          */
 878         private static function getImplicitMentionList(array $parent)
 879         {
 880                 if (Config::get('system', 'disable_implicit_mentions')) {
 881                         return [];
 882                 }
 883
 884                 $parent_terms = Term::tagArrayFromItemId($parent['id'], [Term::MENTION, Term::IMPLICIT_MENTION]);
 885
 886                 $parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 887
 888                 $implicit_mentions = [];
 889                 if (empty($parent_author)) {
 890                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 891                 } else {
 892                         $implicit_mentions[] = $parent_author['url'];
 893                         $implicit_mentions[] = $parent_author['nurl'];
 894                         $implicit_mentions[] = $parent_author['alias'];
 895                 }
 896
 897                 if (!empty($parent['alias'])) {
 898                         $implicit_mentions[] = $parent['alias'];
 899                 }
 900
 901                 foreach ($parent_terms as $term) {
 902                         $contact = Contact::getDetailsByURL($term['url'], 0);
 903                         if (!empty($contact)) {
 904                                 $implicit_mentions[] = $contact['url'];
 905                                 $implicit_mentions[] = $contact['nurl'];
 906                                 $implicit_mentions[] = $contact['alias'];
 907                         }
 908                 }
 909
 910                 return $implicit_mentions;
 911         }
 912
 913         /**
 914          * Strips from the body prepended implicit mentions
 915          *
 916          * @param string $body
 917          * @param array $potential_mentions
 918          * @return string
 919          */
 920         private static function removeImplicitMentionsFromBody($body, array $potential_mentions)
 921         {
 922                 if (Config::get('system', 'disable_implicit_mentions')) {
 923                         return $body;
 924                 }
 925
 926                 $kept_mentions = [];
 927
 928                 // Extract one prepended mention at a time from the body
 929                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
 930                         if (!in_array($matches[2], $potential_mentions)) {
 931                                 $kept_mentions[] = $matches[1];
 932                         }
 933
 934                         $body = $matches[3];
 935                 }
 936
 937                 // Re-appending the kept mentions to the body after extraction
 938                 $kept_mentions[] = $body;
 939
 940                 return implode('', $kept_mentions);
 941         }
 942
 943         private static function convertImplicitMentionsInTags($activity_tags, array $potential_mentions)
 944         {
 945                 if (Config::get('system', 'disable_implicit_mentions')) {
 946                         return $activity_tags;
 947                 }
 948
 949                 foreach ($activity_tags as $index => $tag) {
 950                         if (in_array($tag['href'], $potential_mentions)) {
 951                                 $activity_tags[$index]['name'] = preg_replace(
 952                                         '/' . preg_quote(Term::TAG_CHARACTER[Term::MENTION], '/') . '/',
 953                                         Term::TAG_CHARACTER[Term::IMPLICIT_MENTION],
 954                                         $activity_tags[$index]['name'],
 955                                         1
 956                                 );
 957                         }
 958                 }
 959
 960                 return $activity_tags;
 961         }
 962 }