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