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\PageInfo;
  25 use Friendica\Content\Text\BBCode;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Core\Logger;
  28 use Friendica\Core\Protocol;
  29 use Friendica\Database\DBA;
  30 use Friendica\DI;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Contact;
  33 use Friendica\Model\Conversation;
  34 use Friendica\Model\Event;
  35 use Friendica\Model\Item;
  36 use Friendica\Model\ItemURI;
  37 use Friendica\Model\Mail;
  38 use Friendica\Model\Tag;
  39 use Friendica\Model\User;
  40 use Friendica\Protocol\Activity;
  41 use Friendica\Protocol\ActivityPub;
  42 use Friendica\Util\DateTimeFormat;
  43 use Friendica\Util\JsonLD;
  44 use Friendica\Util\Strings;
  45
  46 /**
  47  * ActivityPub Processor Protocol class
  48  */
  49 class Processor
  50 {
  51         /**
  52          * Converts mentions from Pleroma into the Friendica format
  53          *
  54          * @param string $body
  55          *
  56          * @return string converted body
  57          */
  58         private static function convertMentions($body)
  59         {
  60                 $URLSearchString = "^\[\]";
  61                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  62
  63                 return $body;
  64         }
  65
  66         /**
  67          * Replaces emojis in the body
  68          *
  69          * @param array $emojis
  70          * @param string $body
  71          *
  72          * @return string with replaced emojis
  73          */
  74         private static function replaceEmojis($body, array $emojis)
  75         {
  76                 foreach ($emojis as $emoji) {
  77                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  78                         $body = str_replace($emoji['name'], $replace, $body);
  79                 }
  80                 return $body;
  81         }
  82
  83         /**
  84          * Add attachment data to the item array
  85          *
  86          * @param array   $activity
  87          * @param array   $item
  88          *
  89          * @return array array
  90          */
  91         private static function constructAttachList($activity, $item)
  92         {
  93                 if (empty($activity['attachments'])) {
  94                         return $item;
  95                 }
  96
  97                 foreach ($activity['attachments'] as $attach) {
  98                         switch ($attach['type']) {
  99                                 case 'link':
 100                                         $data = [
 101                                                 'url'      => $attach['url'],
 102                                                 'type'     => $attach['type'],
 103                                                 'title'    => $attach['title'] ?? '',
 104                                                 'text'     => $attach['desc']  ?? '',
 105                                                 'image'    => $attach['image'] ?? '',
 106                                                 'images'   => [],
 107                                                 'keywords' => [],
 108                                         ];
 109                                         $item['body'] = PageInfo::appendDataToBody($item['body'], $data);
 110                                         break;
 111                                 default:
 112                                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 113                                         if ($filetype == 'image') {
 114                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 115                                                         continue 2;
 116                                                 }
 117
 118                                                 $item['body'] .= "\n";
 119
 120                                                 // image is the preview/thumbnail URL
 121                                                 if (!empty($attach['image'])) {
 122                                                         $item['body'] .= '[url=' . $attach['url'] . ']';
 123                                                         $attach['url'] = $attach['image'];
 124                                                 }
 125
 126                                                 if (empty($attach['name'])) {
 127                                                         $item['body'] .= '[img]' . $attach['url'] . '[/img]';
 128                                                 } else {
 129                                                         $item['body'] .= '[img=' . $attach['url'] . ']' . $attach['name'] . '[/img]';
 130                                                 }
 131
 132                                                 if (!empty($attach['image'])) {
 133                                                         $item['body'] .= '[/url]';
 134                                                 }
 135                                         } elseif ($filetype == 'audio') {
 136                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 137                                                         continue 2;
 138                                                 }
 139
 140                                                 $item['body'] .= "\n[audio]" . $attach['url'] . '[/audio]';
 141                                         } elseif ($filetype == 'video') {
 142                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
 143                                                         continue 2;
 144                                                 }
 145
 146                                                 $item['body'] .= "\n[video]" . $attach['url'] . '[/video]';
 147                                         } else {
 148                                                 if (!empty($item["attach"])) {
 149                                                         $item["attach"] .= ',';
 150                                                 } else {
 151                                                         $item["attach"] = '';
 152                                                 }
 153
 154                                                 $item["attach"] .= '[attach]href="' . $attach['url'] . '" length="' . ($attach['length'] ?? '0') . '" type="' . $attach['mediaType'] . '" title="' . ($attach['name'] ?? '') . '"[/attach]';
 155                                         }
 156                         }
 157                 }
 158
 159                 return $item;
 160         }
 161
 162         /**
 163          * Updates a message
 164          *
 165          * @param array $activity Activity array
 166          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 167          */
 168         public static function updateItem($activity)
 169         {
 170                 $item = Item::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
 171                 if (!DBA::isResult($item)) {
 172                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 173                         $item = self::createItem($activity);
 174                         self::postItem($activity, $item);
 175                         return;
 176                 }
 177
 178                 $item['changed'] = DateTimeFormat::utcNow();
 179                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 180
 181                 $item = self::processContent($activity, $item);
 182                 if (empty($item)) {
 183                         return;
 184                 }
 185
 186                 Item::update($item, ['uri' => $activity['id']]);
 187         }
 188
 189         /**
 190          * Prepares data for a message
 191          *
 192          * @param array $activity Activity array
 193          * @return array Internal item
 194          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 195          * @throws \ImagickException
 196          */
 197         public static function createItem($activity)
 198         {
 199                 $item = [];
 200                 $item['verb'] = Activity::POST;
 201                 $item['thr-parent'] = $activity['reply-to-id'];
 202
 203                 if ($activity['reply-to-id'] == $activity['id']) {
 204                         $item['gravity'] = GRAVITY_PARENT;
 205                         $item['object-type'] = Activity\ObjectType::NOTE;
 206                 } else {
 207                         $item['gravity'] = GRAVITY_COMMENT;
 208                         $item['object-type'] = Activity\ObjectType::COMMENT;
 209                 }
 210
 211                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 212                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 213                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 214                 }
 215
 216                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 217
 218                 /// @todo What to do with $activity['context']?
 219                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
 220                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 221                         return [];
 222                 }
 223
 224                 $item['network'] = Protocol::ACTIVITYPUB;
 225                 $item['author-link'] = $activity['author'];
 226                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 227                 $item['owner-link'] = $activity['actor'];
 228                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 229
 230                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 231                         $item['private'] = Item::UNLISTED;
 232                 } elseif (in_array(0, $activity['receiver'])) {
 233                         $item['private'] = Item::PUBLIC;
 234                 } else {
 235                         $item['private'] = Item::PRIVATE;
 236                 }
 237
 238                 if (!empty($activity['raw'])) {
 239                         $item['source'] = $activity['raw'];
 240                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 241                         $item['conversation-href'] = $activity['context'] ?? '';
 242                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 243
 244                         if (isset($activity['push'])) {
 245                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 246                         }
 247                 }
 248
 249                 $item['isForum'] = false;
 250
 251                 if (!empty($activity['thread-completion'])) {
 252                         // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 253                         $item['causer-link'] = $item['owner-link'];
 254                         $item['causer-id'] = $item['owner-id'];
 255
 256                         Logger::info('Ignoring actor because of thread completion.', ['actor' => $item['owner-link']]);
 257                         $item['owner-link'] = $item['author-link'];
 258                         $item['owner-id'] = $item['author-id'];
 259                 } else {
 260                         $actor = APContact::getByURL($item['owner-link'], false);
 261                         $item['isForum'] = ($actor['type'] == 'Group');
 262                 }
 263
 264                 $item['uri'] = $activity['id'];
 265
 266                 $item['created'] = DateTimeFormat::utc($activity['published']);
 267                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 268                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 269                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 270
 271                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 272
 273                 $item = self::processContent($activity, $item);
 274                 if (empty($item)) {
 275                         Logger::info('Message was not processed');
 276                         return [];
 277                 }
 278
 279                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 280
 281                 $item = self::constructAttachList($activity, $item);
 282
 283                 return $item;
 284         }
 285
 286         /**
 287          * Delete items
 288          *
 289          * @param array $activity
 290          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 291          * @throws \ImagickException
 292          */
 293         public static function deleteItem($activity)
 294         {
 295                 $owner = Contact::getIdForURL($activity['actor']);
 296
 297                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 298                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 299         }
 300
 301         /**
 302          * Prepare the item array for an activity
 303          *
 304          * @param array $activity Activity array
 305          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 306          * @throws \ImagickException
 307          */
 308         public static function addTag($activity)
 309         {
 310                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 311                         return;
 312                 }
 313
 314                 foreach ($activity['receiver'] as $receiver) {
 315                         $item = Item::selectFirst(['id', 'uri-id', 'tag', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 316                         if (!DBA::isResult($item)) {
 317                                 // We don't fetch missing content for this purpose
 318                                 continue;
 319                         }
 320
 321                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 322                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 323                                 continue;
 324                         }
 325
 326                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 327                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 328                 }
 329         }
 330
 331         /**
 332          * Prepare the item array for an activity
 333          *
 334          * @param array  $activity Activity array
 335          * @param string $verb     Activity verb
 336          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 337          * @throws \ImagickException
 338          */
 339         public static function createActivity($activity, $verb)
 340         {
 341                 $item = self::createItem($activity);
 342                 $item['verb'] = $verb;
 343                 $item['thr-parent'] = $activity['object_id'];
 344                 $item['gravity'] = GRAVITY_ACTIVITY;
 345                 $item['object-type'] = Activity\ObjectType::NOTE;
 346
 347                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 348
 349                 self::postItem($activity, $item);
 350         }
 351
 352         /**
 353          * Create an event
 354          *
 355          * @param array $activity Activity array
 356          * @param array $item
 357          * @throws \Exception
 358          */
 359         public static function createEvent($activity, $item)
 360         {
 361                 $event['summary']  = HTML::toBBCode($activity['name']);
 362                 $event['desc']     = HTML::toBBCode($activity['content']);
 363                 $event['start']    = $activity['start-time'];
 364                 $event['finish']   = $activity['end-time'];
 365                 $event['nofinish'] = empty($event['finish']);
 366                 $event['location'] = $activity['location'];
 367                 $event['adjust']   = true;
 368                 $event['cid']      = $item['contact-id'];
 369                 $event['uid']      = $item['uid'];
 370                 $event['uri']      = $item['uri'];
 371                 $event['edited']   = $item['edited'];
 372                 $event['private']  = $item['private'];
 373                 $event['guid']     = $item['guid'];
 374                 $event['plink']    = $item['plink'];
 375
 376                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 377                 $ev = DBA::selectFirst('event', ['id'], $condition);
 378                 if (DBA::isResult($ev)) {
 379                         $event['id'] = $ev['id'];
 380                 }
 381
 382                 $event_id = Event::store($event);
 383                 Logger::info('Event was stored', ['id' => $event_id]);
 384         }
 385
 386         /**
 387          * Process the content
 388          *
 389          * @param array $activity Activity array
 390          * @param array $item
 391          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 392          * @throws \Exception
 393          */
 394         private static function processContent($activity, $item)
 395         {
 396                 $item['title'] = HTML::toBBCode($activity['name']);
 397
 398                 if (!empty($activity['source'])) {
 399                         $item['body'] = $activity['source'];
 400                 } else {
 401                         $content = HTML::toBBCode($activity['content']);
 402
 403                         if (!empty($activity['emojis'])) {
 404                                 $content = self::replaceEmojis($content, $activity['emojis']);
 405                         }
 406
 407                         $content = self::convertMentions($content);
 408
 409                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 410                                 $item_private = !in_array(0, $activity['item_receiver']);
 411                                 $parent = Item::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 412                                 if (!DBA::isResult($parent)) {
 413                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 414                                         return false;
 415                                 }
 416                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 417                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 418                                         return false;
 419                                 }
 420
 421                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 422                         }
 423                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 424                         $item['body'] = $content;
 425                 }
 426
 427                 self::storeFromBody($item);
 428                 self::storeTags($item['uri-id'], $activity['tags']);
 429
 430                 $item['location'] = $activity['location'];
 431
 432                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 433                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 434                 }
 435
 436                 $item['app'] = $activity['generator'];
 437
 438                 return $item;
 439         }
 440
 441         /**
 442          * Store hashtags and mentions
 443          *
 444          * @param array $item
 445          */
 446         private static function storeFromBody(array $item)
 447         {
 448                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 449                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 450
 451                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 452         }
 453
 454         /**
 455          * Generate a GUID out of an URL
 456          *
 457          * @param string $url message URL
 458          * @return string with GUID
 459          */
 460         private static function getGUIDByURL(string $url)
 461         {
 462                 $parsed = parse_url($url);
 463
 464                 $host_hash = hash('crc32', $parsed['host']);
 465
 466                 unset($parsed["scheme"]);
 467                 unset($parsed["host"]);
 468
 469                 $path = implode("/", $parsed);
 470
 471                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 472         }
 473
 474         /**
 475          * Creates an item post
 476          *
 477          * @param array $activity Activity data
 478          * @param array $item     item array
 479          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 480          * @throws \ImagickException
 481          */
 482         public static function postItem(array $activity, array $item)
 483         {
 484                 if (empty($item)) {
 485                         return;
 486                 }
 487
 488                 $stored = false;
 489
 490                 foreach ($activity['receiver'] as $receiver) {
 491                         if ($receiver == -1) {
 492                                 continue;
 493                         }
 494
 495                         $item['uid'] = $receiver;
 496
 497                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 498                         switch($type) {
 499                                 case Receiver::TARGET_TO:
 500                                         $item['post-type'] = Item::PT_TO;
 501                                         break;
 502                                 case Receiver::TARGET_CC:
 503                                         $item['post-type'] = Item::PT_CC;
 504                                         break;
 505                                 case Receiver::TARGET_BTO:
 506                                         $item['post-type'] = Item::PT_BTO;
 507                                         break;
 508                                 case Receiver::TARGET_BCC:
 509                                         $item['post-type'] = Item::PT_BCC;
 510                                         break;
 511                                 case Receiver::TARGET_FOLLOWER:
 512                                         $item['post-type'] = Item::PT_FOLLOWER;
 513                                         break;
 514                                 case Receiver::TARGET_ANSWER:
 515                                         $item['post-type'] = Item::PT_COMMENT;
 516                                         break;
 517                                 case Receiver::TARGET_GLOBAL:
 518                                         $item['post-type'] = Item::PT_GLOBAL;
 519                                         break;
 520                                 default:
 521                                         $item['post-type'] = Item::PT_ARTICLE;
 522                         }
 523
 524                         if ($item['isForum'] ?? false) {
 525                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 526                         } else {
 527                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 528                         }
 529
 530                         if (($receiver != 0) && empty($item['contact-id'])) {
 531                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 532                         }
 533
 534                         if (!empty($activity['directmessage'])) {
 535                                 self::postMail($activity, $item);
 536                                 continue;
 537                         }
 538
 539                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 540                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 541
 542                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 543                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 544                                 }
 545
 546                                 if ($skip) {
 547                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 548                                         continue;
 549                                 }
 550
 551                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 552                         }
 553
 554                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 555                                 self::createEvent($activity, $item);
 556                         }
 557
 558                         $item_id = Item::insert($item);
 559                         if ($item_id) {
 560                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 561                         } else {
 562                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 563                         }
 564
 565                         if ($item['uid'] == 0) {
 566                                 $stored = $item_id;
 567                         }
 568                 }
 569
 570                 // Store send a follow request for every reshare - but only when the item had been stored
 571                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 572                         $author = APContact::getByURL($item['owner-link'], false);
 573                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 574                         if ($author['type'] != 'Group') {
 575                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 576                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 577                         }
 578                 }
 579         }
 580
 581         /**
 582          * Store tags and mentions into the tag table
 583          *
 584          * @param integer $uriid
 585          * @param array $tags
 586          */
 587         private static function storeTags(int $uriid, array $tags = null)
 588         {
 589                 foreach ($tags as $tag) {
 590                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 591                                 continue;
 592                         }
 593
 594                         $hash = substr($tag['name'], 0, 1);
 595
 596                         if ($tag['type'] == 'Mention') {
 597                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 598                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 599                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 600                                         $tag['name'] = substr($tag['name'], 1);
 601                                 }
 602                                 $type = Tag::IMPLICIT_MENTION;
 603
 604                                 if (!empty($tag['href'])) {
 605                                         $apcontact = APContact::getByURL($tag['href']);
 606                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 607                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 608                                         }
 609                                 }
 610                         } elseif ($tag['type'] == 'Hashtag') {
 611                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 612                                         $tag['name'] = substr($tag['name'], 1);
 613                                 }
 614                                 $type = Tag::HASHTAG;
 615                         }
 616
 617                         if (empty($tag['name'])) {
 618                                 continue;
 619                         }
 620
 621                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 622                 }
 623         }
 624
 625         /**
 626          * Creates an mail post
 627          *
 628          * @param array $activity Activity data
 629          * @param array $item     item array
 630          * @return int|bool New mail table row id or false on error
 631          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 632          */
 633         private static function postMail($activity, $item)
 634         {
 635                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 636                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 637                         return false;
 638                 }
 639
 640                 Logger::info('Direct Message', $item);
 641
 642                 $msg = [];
 643                 $msg['uid'] = $item['uid'];
 644
 645                 $msg['contact-id'] = $item['contact-id'];
 646
 647                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 648                 $msg['from-name'] = $contact['name'];
 649                 $msg['from-url'] = $contact['url'];
 650                 $msg['from-photo'] = $contact['photo'];
 651
 652                 $msg['uri'] = $item['uri'];
 653                 $msg['created'] = $item['created'];
 654
 655                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 656                 if (DBA::isResult($parent)) {
 657                         $msg['parent-uri'] = $parent['parent-uri'];
 658                         $msg['title'] = $parent['title'];
 659                 } else {
 660                         $msg['parent-uri'] = $item['thr-parent'];
 661
 662                         if (!empty($item['title'])) {
 663                                 $msg['title'] = $item['title'];
 664                         } elseif (!empty($item['content-warning'])) {
 665                                 $msg['title'] = $item['content-warning'];
 666                         } else {
 667                                 // Trying to generate a title out of the body
 668                                 $title = $item['body'];
 669
 670                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 671                                         $title = $matches[3];
 672                                 }
 673
 674                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, BBCode::API, true), 0));
 675
 676                                 if (strlen($title) > 20) {
 677                                         $title = substr($title, 0, 20) . '...';
 678                                 }
 679
 680                                 $msg['title'] = $title;
 681                         }
 682                 }
 683                 $msg['body'] = $item['body'];
 684
 685                 return Mail::insert($msg);
 686         }
 687
 688         /**
 689          * Fetches missing posts
 690          *
 691          * @param string $url message URL
 692          * @param array $child activity array with the child of this message
 693          * @return string fetched message URL
 694          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 695          */
 696         public static function fetchMissingActivity(string $url, array $child = [])
 697         {
 698                 if (!empty($child['receiver'])) {
 699                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 700                 } else {
 701                         $uid = 0;
 702                 }
 703
 704                 $object = ActivityPub::fetchContent($url, $uid);
 705                 if (empty($object)) {
 706                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 707                         return '';
 708                 }
 709
 710                 if (empty($object['id'])) {
 711                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 712                         return '';
 713                 }
 714
 715                 if (!empty($object['actor'])) {
 716                         $object_actor = $object['actor'];
 717                 } elseif (!empty($object['attributedTo'])) {
 718                         $object_actor = $object['attributedTo'];
 719                 } else {
 720                         // Shouldn't happen
 721                         $object_actor = '';
 722                 }
 723
 724                 $signer = [$object_actor];
 725
 726                 if (!empty($child['author'])) {
 727                         $actor = $child['author'];
 728                         $signer[] = $actor;
 729                 } else {
 730                         $actor = $object_actor;
 731                 }
 732
 733                 if (!empty($object['published'])) {
 734                         $published = $object['published'];
 735                 } elseif (!empty($child['published'])) {
 736                         $published = $child['published'];
 737                 } else {
 738                         $published = DateTimeFormat::utcNow();
 739                 }
 740
 741                 $activity = [];
 742                 $activity['@context'] = $object['@context'];
 743                 unset($object['@context']);
 744                 $activity['id'] = $object['id'];
 745                 $activity['to'] = $object['to'] ?? [];
 746                 $activity['cc'] = $object['cc'] ?? [];
 747                 $activity['actor'] = $actor;
 748                 $activity['object'] = $object;
 749                 $activity['published'] = $published;
 750                 $activity['type'] = 'Create';
 751
 752                 $ldactivity = JsonLD::compact($activity);
 753
 754                 $ldactivity['thread-completion'] = true;
 755
 756                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
 757
 758                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
 759
 760                 return $activity['id'];
 761         }
 762
 763         /**
 764          * perform a "follow" request
 765          *
 766          * @param array $activity
 767          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 768          * @throws \ImagickException
 769          */
 770         public static function followUser($activity)
 771         {
 772                 $uid = User::getIdForURL($activity['object_id']);
 773                 if (empty($uid)) {
 774                         return;
 775                 }
 776
 777                 $owner = User::getOwnerDataById($uid);
 778                 if (empty($owner)) {
 779                         return;
 780                 }
 781
 782                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 783                 if (!empty($cid)) {
 784                         self::switchContact($cid);
 785                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 786                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 787                 } else {
 788                         $contact = [];
 789                 }
 790
 791                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 792                         'author-link' => $activity['actor']];
 793
 794                 $note = Strings::escapeTags(trim($activity['content'] ?? ''));
 795
 796                 // Ensure that the contact has got the right network type
 797                 self::switchContact($item['author-id']);
 798
 799                 $result = Contact::addRelationship($owner, $contact, $item, false, $note);
 800                 if ($result === true) {
 801                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
 802                 }
 803
 804                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 805                 if (empty($cid)) {
 806                         return;
 807                 }
 808
 809                 if (empty($contact)) {
 810                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
 811                 }
 812
 813                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 814         }
 815
 816         /**
 817          * Update the given profile
 818          *
 819          * @param array $activity
 820          * @throws \Exception
 821          */
 822         public static function updatePerson($activity)
 823         {
 824                 if (empty($activity['object_id'])) {
 825                         return;
 826                 }
 827
 828                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
 829                 Contact::updateFromProbeByURL($activity['object_id']);
 830         }
 831
 832         /**
 833          * Delete the given profile
 834          *
 835          * @param array $activity
 836          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 837          */
 838         public static function deletePerson($activity)
 839         {
 840                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 841                         Logger::info('Empty object id or actor.');
 842                         return;
 843                 }
 844
 845                 if ($activity['object_id'] != $activity['actor']) {
 846                         Logger::info('Object id does not match actor.');
 847                         return;
 848                 }
 849
 850                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 851                 while ($contact = DBA::fetch($contacts)) {
 852                         Contact::remove($contact['id']);
 853                 }
 854                 DBA::close($contacts);
 855
 856                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
 857         }
 858
 859         /**
 860          * Accept a follow request
 861          *
 862          * @param array $activity
 863          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 864          * @throws \ImagickException
 865          */
 866         public static function acceptFollowUser($activity)
 867         {
 868                 $uid = User::getIdForURL($activity['object_actor']);
 869                 if (empty($uid)) {
 870                         return;
 871                 }
 872
 873                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 874                 if (empty($cid)) {
 875                         Logger::info('No contact found', ['actor' => $activity['actor']]);
 876                         return;
 877                 }
 878
 879                 self::switchContact($cid);
 880
 881                 $fields = ['pending' => false];
 882
 883                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 884                 if ($contact['rel'] == Contact::FOLLOWER) {
 885                         $fields['rel'] = Contact::FRIEND;
 886                 }
 887
 888                 $condition = ['id' => $cid];
 889                 DBA::update('contact', $fields, $condition);
 890                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
 891         }
 892
 893         /**
 894          * Reject a follow request
 895          *
 896          * @param array $activity
 897          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 898          * @throws \ImagickException
 899          */
 900         public static function rejectFollowUser($activity)
 901         {
 902                 $uid = User::getIdForURL($activity['object_actor']);
 903                 if (empty($uid)) {
 904                         return;
 905                 }
 906
 907                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 908                 if (empty($cid)) {
 909                         Logger::info('No contact found', ['actor' => $activity['actor']]);
 910                         return;
 911                 }
 912
 913                 self::switchContact($cid);
 914
 915                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
 916                         Contact::remove($cid);
 917                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
 918                 } else {
 919                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
 920                 }
 921         }
 922
 923         /**
 924          * Undo activity like "like" or "dislike"
 925          *
 926          * @param array $activity
 927          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 928          * @throws \ImagickException
 929          */
 930         public static function undoActivity($activity)
 931         {
 932                 if (empty($activity['object_id'])) {
 933                         return;
 934                 }
 935
 936                 if (empty($activity['object_actor'])) {
 937                         return;
 938                 }
 939
 940                 $author_id = Contact::getIdForURL($activity['object_actor']);
 941                 if (empty($author_id)) {
 942                         return;
 943                 }
 944
 945                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 946         }
 947
 948         /**
 949          * Activity to remove a follower
 950          *
 951          * @param array $activity
 952          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 953          * @throws \ImagickException
 954          */
 955         public static function undoFollowUser($activity)
 956         {
 957                 $uid = User::getIdForURL($activity['object_object']);
 958                 if (empty($uid)) {
 959                         return;
 960                 }
 961
 962                 $owner = User::getOwnerDataById($uid);
 963                 if (empty($owner)) {
 964                         return;
 965                 }
 966
 967                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 968                 if (empty($cid)) {
 969                         Logger::info('No contact found', ['actor' => $activity['actor']]);
 970                         return;
 971                 }
 972
 973                 self::switchContact($cid);
 974
 975                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 976                 if (!DBA::isResult($contact)) {
 977                         return;
 978                 }
 979
 980                 Contact::removeFollower($owner, $contact);
 981                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
 982         }
 983
 984         /**
 985          * Switches a contact to AP if needed
 986          *
 987          * @param integer $cid Contact ID
 988          * @throws \Exception
 989          */
 990         private static function switchContact($cid)
 991         {
 992                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
 993                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
 994                         return;
 995                 }
 996
 997                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
 998                 Contact::updateFromProbe($cid);
 999         }
1000
1001         /**
1002          * Collects implicit mentions like:
1003          * - the author of the parent item
1004          * - all the mentioned conversants in the parent item
1005          *
1006          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1007          * @return array
1008          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1009          */
1010         private static function getImplicitMentionList(array $parent)
1011         {
1012                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1013
1014                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1015
1016                 $implicit_mentions = [];
1017                 if (empty($parent_author['url'])) {
1018                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
1019                 } else {
1020                         $implicit_mentions[] = $parent_author['url'];
1021                         $implicit_mentions[] = $parent_author['nurl'];
1022                         $implicit_mentions[] = $parent_author['alias'];
1023                 }
1024
1025                 if (!empty($parent['alias'])) {
1026                         $implicit_mentions[] = $parent['alias'];
1027                 }
1028
1029                 foreach ($parent_terms as $term) {
1030                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1031                         if (!empty($contact['url'])) {
1032                                 $implicit_mentions[] = $contact['url'];
1033                                 $implicit_mentions[] = $contact['nurl'];
1034                                 $implicit_mentions[] = $contact['alias'];
1035                         }
1036                 }
1037
1038                 return $implicit_mentions;
1039         }
1040
1041         /**
1042          * Strips from the body prepended implicit mentions
1043          *
1044          * @param string $body
1045          * @param array $parent
1046          * @return string
1047          */
1048         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1049         {
1050                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1051                         return $body;
1052                 }
1053
1054                 $potential_mentions = self::getImplicitMentionList($parent);
1055
1056                 $kept_mentions = [];
1057
1058                 // Extract one prepended mention at a time from the body
1059                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1060                         if (!in_array($matches[2], $potential_mentions)) {
1061                                 $kept_mentions[] = $matches[1];
1062                         }
1063
1064                         $body = $matches[3];
1065                 }
1066
1067                 // Re-appending the kept mentions to the body after extraction
1068                 $kept_mentions[] = $body;
1069
1070                 return implode('', $kept_mentions);
1071         }
1072 }