src/Protocol/ActivityPub/Transmitter.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2021, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Feature;
  25 use Friendica\Content\Text\BBCode;
  26 use Friendica\Core\Cache\Enum\Duration;
  27 use Friendica\Core\Logger;
  28 use Friendica\Core\Protocol;
  29 use Friendica\Core\System;
  30 use Friendica\Database\DBA;
  31 use Friendica\DI;
  32 use Friendica\Model\APContact;
  33 use Friendica\Model\Contact;
  34 use Friendica\Model\Conversation;
  35 use Friendica\Model\GServer;
  36 use Friendica\Model\Item;
  37 use Friendica\Model\Photo;
  38 use Friendica\Model\Post;
  39 use Friendica\Model\Profile;
  40 use Friendica\Model\Tag;
  41 use Friendica\Model\User;
  42 use Friendica\Network\HTTPException;
  43 use Friendica\Protocol\Activity;
  44 use Friendica\Protocol\ActivityPub;
  45 use Friendica\Protocol\Relay;
  46 use Friendica\Util\DateTimeFormat;
  47 use Friendica\Util\HTTPSignature;
  48 use Friendica\Util\JsonLD;
  49 use Friendica\Util\LDSignature;
  50 use Friendica\Util\Map;
  51 use Friendica\Util\Network;
  52 use Friendica\Util\XML;
  53
  54 /**
  55  * ActivityPub Transmitter Protocol class
  56  *
  57  * To-Do:
  58  * @todo Undo Announce
  59  */
  60 class Transmitter
  61 {
  62         /**
  63          * Add relay servers to the list of inboxes
  64          *
  65          * @param array $inboxes
  66          * @return array inboxes with added relay servers
  67          */
  68         public static function addRelayServerInboxes(array $inboxes = [])
  69         {
  70                 foreach (Relay::getList(['inbox']) as $contact) {
  71                         $inboxes[$contact['inbox']] = $contact['inbox'];
  72                 }
  73
  74                 return $inboxes;
  75         }
  76
  77         /**
  78          * Add relay servers to the list of inboxes
  79          *
  80          * @param array $inboxes
  81          * @return array inboxes with added relay servers
  82          */
  83         public static function addRelayServerInboxesForItem(int $item_id, array $inboxes = [])
  84         {
  85                 $item = Post::selectFirst(['uid'], ['id' => $item_id]);
  86                 if (empty($item)) {
  87                         return $inboxes;
  88                 }
  89
  90                 $relays = Relay::getDirectRelayList($item_id);
  91                 if (empty($relays)) {
  92                         return $inboxes;
  93                 }
  94
  95                 foreach ($relays as $relay) {
  96                         $contact = Contact::getByURLForUser($relay['url'], $item['uid'], false, ['id']);
  97                         $inboxes[$relay['batch']][] = $contact['id'] ?? 0;
  98                 }
  99                 return $inboxes;
 100         }
 101
 102         /**
 103          * Subscribe to a relay
 104          *
 105          * @param string $url Subscribe actor url
 106          * @return bool success
 107          */
 108         public static function sendRelayFollow(string $url)
 109         {
 110                 $contact = Contact::getByURL($url);
 111                 if (empty($contact)) {
 112                         return false;
 113                 }
 114
 115                 $activity_id = ActivityPub\Transmitter::activityIDFromContact($contact['id']);
 116                 $success = ActivityPub\Transmitter::sendActivity('Follow', $url, 0, $activity_id);
 117                 if ($success) {
 118                         Contact::update(['rel' => Contact::FRIEND], ['id' => $contact['id']]);
 119                 }
 120
 121                 return $success;
 122         }
 123
 124         /**
 125          * Unsubscribe from a relay
 126          *
 127          * @param string $url   Subscribe actor url
 128          * @param bool   $force Set the relay status as non follower even if unsubscribe hadn't worked
 129          * @return bool success
 130          */
 131         public static function sendRelayUndoFollow(string $url, bool $force = false)
 132         {
 133                 $contact = Contact::getByURL($url);
 134                 if (empty($contact)) {
 135                         return false;
 136                 }
 137
 138                 $success = self::sendContactUndo($url, $contact['id'], 0);
 139                 if ($success || $force) {
 140                         Contact::update(['rel' => Contact::NOTHING], ['id' => $contact['id']]);
 141                 }
 142
 143                 return $success;
 144         }
 145
 146         /**
 147          * Collects a list of contacts of the given owner
 148          *
 149          * @param array     $owner  Owner array
 150          * @param int|array $rel    The relevant value(s) contact.rel should match
 151          * @param string    $module The name of the relevant AP endpoint module (followers|following)
 152          * @param integer   $page   Page number
 153          *
 154          * @return array of owners
 155          * @throws \Exception
 156          */
 157         public static function getContacts($owner, $rel, $module, $page = null)
 158         {
 159                 $parameters = [
 160                         'rel' => $rel,
 161                         'uid' => $owner['uid'],
 162                         'self' => false,
 163                         'deleted' => false,
 164                         'hidden' => false,
 165                         'archive' => false,
 166                         'pending' => false,
 167                         'blocked' => false,
 168                 ];
 169
 170                 $condition = DBA::mergeConditions($parameters, ["`url` IN (SELECT `url` FROM `apcontact`)"]);
 171
 172                 $total = DBA::count('contact', $condition);
 173
 174                 $modulePath = '/' . $module . '/';
 175
 176                 $data = ['@context' => ActivityPub::CONTEXT];
 177                 $data['id'] = DI::baseUrl() . $modulePath . $owner['nickname'];
 178                 $data['type'] = 'OrderedCollection';
 179                 $data['totalItems'] = $total;
 180
 181                 // When we hide our friends we will only show the pure number but don't allow more.
 182                 $profile = Profile::getByUID($owner['uid']);
 183                 if (!empty($profile['hide-friends'])) {
 184                         return $data;
 185                 }
 186
 187                 if (empty($page)) {
 188                         $data['first'] = DI::baseUrl() . $modulePath . $owner['nickname'] . '?page=1';
 189                 } else {
 190                         $data['type'] = 'OrderedCollectionPage';
 191                         $list = [];
 192
 193                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 194                         while ($contact = DBA::fetch($contacts)) {
 195                                 $list[] = $contact['url'];
 196                         }
 197                         DBA::close($contacts);
 198
 199                         if (!empty($list)) {
 200                                 $data['next'] = DI::baseUrl() . $modulePath . $owner['nickname'] . '?page=' . ($page + 1);
 201                         }
 202
 203                         $data['partOf'] = DI::baseUrl() . $modulePath . $owner['nickname'];
 204
 205                         $data['orderedItems'] = $list;
 206                 }
 207
 208                 return $data;
 209         }
 210
 211         /**
 212          * Public posts for the given owner
 213          *
 214          * @param array   $owner     Owner array
 215          * @param integer $page      Page number
 216          * @param string  $requester URL of requesting account
 217          *
 218          * @return array of posts
 219          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 220          * @throws \ImagickException
 221          */
 222         public static function getOutbox($owner, $page = null, $requester = '')
 223         {
 224                 $condition = ['private' => [Item::PUBLIC, Item::UNLISTED]];
 225
 226                 if (!empty($requester)) {
 227                         $requester_id = Contact::getIdForURL($requester, $owner['uid']);
 228                         if (!empty($requester_id)) {
 229                                 $permissionSets = DI::permissionSet()->selectByContactId($requester_id, $owner['uid']);
 230                                 if (!empty($permissionSets)) {
 231                                         $condition = ['psid' => array_merge($permissionSets->column('id'),
 232                                                         [DI::permissionSet()->selectPublicForUser($owner['uid'])])];
 233                                 }
 234                         }
 235                 }
 236
 237                 $condition = array_merge($condition,
 238                         ['uid'           => $owner['uid'],
 239                         'author-id'      => Contact::getIdForURL($owner['url'], 0, false),
 240                         'gravity'        => [GRAVITY_PARENT, GRAVITY_COMMENT],
 241                         'network'        => Protocol::FEDERATED,
 242                         'parent-network' => Protocol::FEDERATED,
 243                         'origin'         => true,
 244                         'deleted'        => false,
 245                         'visible'        => true]);
 246
 247                 $count = Post::count($condition);
 248
 249                 $data = ['@context' => ActivityPub::CONTEXT];
 250                 $data['id'] = DI::baseUrl() . '/outbox/' . $owner['nickname'];
 251                 $data['type'] = 'OrderedCollection';
 252                 $data['totalItems'] = $count;
 253
 254                 if (empty($page)) {
 255                         $data['first'] = DI::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=1';
 256                 } else {
 257                         $data['type'] = 'OrderedCollectionPage';
 258                         $list = [];
 259
 260                         $items = Post::select(['id'], $condition, ['limit' => [($page - 1) * 20, 20], 'order' => ['created' => true]]);
 261                         while ($item = Post::fetch($items)) {
 262                                 $activity = self::createActivityFromItem($item['id'], true);
 263                                 $activity['type'] = $activity['type'] == 'Update' ? 'Create' : $activity['type'];
 264
 265                                 // Only list "Create" activity objects here, no reshares
 266                                 if (!empty($activity['object']) && ($activity['type'] == 'Create')) {
 267                                         $list[] = $activity['object'];
 268                                 }
 269                         }
 270                         DBA::close($items);
 271
 272                         if (!empty($list)) {
 273                                 $data['next'] = DI::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=' . ($page + 1);
 274                         }
 275
 276                         $data['partOf'] = DI::baseUrl() . '/outbox/' . $owner['nickname'];
 277
 278                         $data['orderedItems'] = $list;
 279                 }
 280
 281                 return $data;
 282         }
 283
 284         /**
 285          * Return the service array containing information the used software and it's url
 286          *
 287          * @return array with service data
 288          */
 289         private static function getService()
 290         {
 291                 return ['type' => 'Service',
 292                         'name' =>  FRIENDICA_PLATFORM . " '" . FRIENDICA_CODENAME . "' " . FRIENDICA_VERSION . '-' . DB_UPDATE_VERSION,
 293                         'url' => DI::baseUrl()->get()];
 294         }
 295
 296         /**
 297          * Return the ActivityPub profile of the given user
 298          *
 299          * @param int $uid User ID
 300          * @return array with profile data
 301          * @throws HTTPException\NotFoundException
 302          * @throws HTTPException\InternalServerErrorException
 303          */
 304         public static function getProfile(int $uid): array
 305         {
 306                 $owner = User::getOwnerDataById($uid);
 307                 if (!isset($owner['id'])) {
 308                         DI::logger()->error('Unable to find owner data for uid', ['uid' => $uid, 'callstack' => System::callstack(20)]);
 309                         throw new HTTPException\NotFoundException('User not found.');
 310                 }
 311
 312                 $data = ['@context' => ActivityPub::CONTEXT];
 313                 $data['id'] = $owner['url'];
 314
 315                 if (!empty($owner['guid'])) {
 316                         $data['diaspora:guid'] = $owner['guid'];
 317                 }
 318
 319                 $data['type'] = ActivityPub::ACCOUNT_TYPES[$owner['account-type']];
 320
 321                 if ($uid != 0) {
 322                         $data['following'] = DI::baseUrl() . '/following/' . $owner['nick'];
 323                         $data['followers'] = DI::baseUrl() . '/followers/' . $owner['nick'];
 324                         $data['inbox'] = DI::baseUrl() . '/inbox/' . $owner['nick'];
 325                         $data['outbox'] = DI::baseUrl() . '/outbox/' . $owner['nick'];
 326                 } else {
 327                         $data['inbox'] = DI::baseUrl() . '/friendica/inbox';
 328                 }
 329
 330                 $data['preferredUsername'] = $owner['nick'];
 331                 $data['name'] = $owner['name'];
 332
 333                 if (!empty($owner['country-name'] . $owner['region'] . $owner['locality'])) {
 334                         $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $owner['country-name'],
 335                                 'vcard:region' => $owner['region'], 'vcard:locality' => $owner['locality']];
 336                 }
 337
 338                 if (!empty($owner['about'])) {
 339                         $data['summary'] = BBCode::convertForUriId($owner['uri-id'] ?? 0, $owner['about'], BBCode::EXTERNAL);
 340                 }
 341
 342                 if (!empty($owner['xmpp']) || !empty($owner['matrix'])) {
 343                         $data['vcard:hasInstantMessage'] = [];
 344
 345                         if (!empty($owner['xmpp'])) {
 346                                 $data['vcard:hasInstantMessage'][] = 'xmpp:' . $owner['xmpp'];
 347                         }
 348                         if (!empty($owner['matrix'])) {
 349                                 $data['vcard:hasInstantMessage'][] = 'matrix:' . $owner['matrix'];
 350                         }
 351                 }
 352
 353                 $data['url'] = $owner['url'];
 354                 $data['manuallyApprovesFollowers'] = in_array($owner['page-flags'], [User::PAGE_FLAGS_NORMAL, User::PAGE_FLAGS_PRVGROUP]);
 355                 $data['discoverable'] = (bool)$owner['net-publish'];
 356                 $data['publicKey'] = ['id' => $owner['url'] . '#main-key',
 357                         'owner' => $owner['url'],
 358                         'publicKeyPem' => $owner['pubkey']];
 359                 $data['endpoints'] = ['sharedInbox' => DI::baseUrl() . '/inbox'];
 360                 $data['icon'] = ['type' => 'Image', 'url' => User::getAvatarUrl($owner)];
 361
 362                 $resourceid = Photo::ridFromURI($owner['photo']);
 363                 if (!empty($resourceid)) {
 364                         $photo = Photo::selectFirst(['type'], ["resource-id" => $resourceid]);
 365                         if (!empty($photo['type'])) {
 366                                 $data['icon']['mediaType'] = $photo['type'];
 367                         }
 368                 }
 369
 370                 if (!empty($owner['header'])) {
 371                         $data['image'] = ['type' => 'Image', 'url' => Contact::getHeaderUrlForId($owner['id'], '', $owner['updated'])];
 372
 373                         $resourceid = Photo::ridFromURI($owner['header']);
 374                         if (!empty($resourceid)) {
 375                                 $photo = Photo::selectFirst(['type'], ["resource-id" => $resourceid]);
 376                                 if (!empty($photo['type'])) {
 377                                         $data['image']['mediaType'] = $photo['type'];
 378                                 }
 379                         }
 380                 }
 381
 382                 $custom_fields = [];
 383
 384                 foreach (DI::profileField()->selectByContactId(0, $uid) as $profile_field) {
 385                         $custom_fields[] = [
 386                                 'type' => 'PropertyValue',
 387                                 'name' => $profile_field->label,
 388                                 'value' => BBCode::convertForUriId($owner['uri-id'], $profile_field->value)
 389                         ];
 390                 };
 391
 392                 if (!empty($custom_fields)) {
 393                         $data['attachment'] = $custom_fields;
 394                 }
 395
 396                 $data['generator'] = self::getService();
 397
 398                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 399                 return $data;
 400         }
 401
 402         /**
 403          * @param string $username
 404          * @return array
 405          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 406          */
 407         public static function getDeletedUser($username)
 408         {
 409                 return [
 410                         '@context' => ActivityPub::CONTEXT,
 411                         'id' => DI::baseUrl() . '/profile/' . $username,
 412                         'type' => 'Tombstone',
 413                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 414                         'updated' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 415                         'deleted' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 416                 ];
 417         }
 418
 419         /**
 420          * Returns an array with permissions of a given item array
 421          *
 422          * @param array $item
 423          *
 424          * @return array with permissions
 425          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 426          * @throws \ImagickException
 427          */
 428         private static function fetchPermissionBlockFromConversation($item)
 429         {
 430                 if (empty($item['thr-parent'])) {
 431                         return [];
 432                 }
 433
 434                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 435                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 436                 if (!DBA::isResult($conversation)) {
 437                         return [];
 438                 }
 439
 440                 $permissions = [
 441                         'to' => [],
 442                         'cc' => [],
 443                         'bto' => [],
 444                         'bcc' => [],
 445                 ];
 446
 447                 $activity = json_decode($conversation['source'], true);
 448
 449                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 450                 if (!empty($actor)) {
 451                         $permissions['to'][] = $actor;
 452                         $profile = APContact::getByURL($actor);
 453                 } else {
 454                         $profile = [];
 455                 }
 456
 457                 $item_profile = APContact::getByURL($item['author-link']);
 458                 $exclude[] = $item['author-link'];
 459
 460                 if ($item['gravity'] == GRAVITY_PARENT) {
 461                         $exclude[] = $item['owner-link'];
 462                 }
 463
 464                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 465                         if (empty($activity[$element])) {
 466                                 continue;
 467                         }
 468                         if (is_string($activity[$element])) {
 469                                 $activity[$element] = [$activity[$element]];
 470                         }
 471
 472                         foreach ($activity[$element] as $receiver) {
 473                                 if (empty($receiver)) {
 474                                         continue;
 475                                 }
 476
 477                                 if (!empty($profile['followers']) && $receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 478                                         $permissions[$element][] = $item_profile['followers'];
 479                                 } elseif (!in_array($receiver, $exclude)) {
 480                                         $permissions[$element][] = $receiver;
 481                                 }
 482                         }
 483                 }
 484                 return $permissions;
 485         }
 486
 487         /**
 488          * Check if the given item id is from ActivityPub
 489          *
 490          * @param integer $item_id
 491          * @return boolean "true" if the post is from ActivityPub
 492          */
 493         private static function isAPPost(int $item_id)
 494         {
 495                 if (empty($item_id)) {
 496                         return false;
 497                 }
 498
 499                 return Post::exists(['id' => $item_id, 'network' => Protocol::ACTIVITYPUB]);
 500         }
 501
 502         /**
 503          * Creates an array of permissions from an item thread
 504          *
 505          * @param array   $item       Item array
 506          * @param boolean $blindcopy  addressing via "bcc" or "cc"?
 507          * @param integer $last_id    Last item id for adding receivers
 508          * @param boolean $forum_mode "true" means that we are sending content to a forum
 509          *
 510          * @return array with permission data
 511          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 512          * @throws \ImagickException
 513          */
 514         private static function createPermissionBlockForItem($item, $blindcopy, $last_id = 0, $forum_mode = false)
 515         {
 516                 if ($last_id == 0) {
 517                         $last_id = $item['id'];
 518                 }
 519
 520                 $always_bcc = false;
 521
 522                 // Check if we should always deliver our stuff via BCC
 523                 if (!empty($item['uid'])) {
 524                         $profile = User::getOwnerDataById($item['uid']);
 525                         if (!empty($profile)) {
 526                                 $always_bcc = $profile['hide-friends'];
 527                         }
 528                 }
 529
 530                 if (DI::config()->get('system', 'ap_always_bcc')) {
 531                         $always_bcc = true;
 532                 }
 533
 534                 if (self::isAnnounce($item) || DI::config()->get('debug', 'total_ap_delivery') || self::isAPPost($last_id)) {
 535                         // Will be activated in a later step
 536                         $networks = Protocol::FEDERATED;
 537                 } else {
 538                         // For now only send to these contacts:
 539                         $networks = [Protocol::ACTIVITYPUB, Protocol::OSTATUS];
 540                 }
 541
 542                 $data = ['to' => [], 'cc' => [], 'bcc' => []];
 543
 544                 if ($item['gravity'] == GRAVITY_PARENT) {
 545                         $actor_profile = APContact::getByURL($item['owner-link']);
 546                 } else {
 547                         $actor_profile = APContact::getByURL($item['author-link']);
 548                 }
 549
 550                 $exclusive = false;
 551
 552                 $terms = Tag::getByURIId($item['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
 553
 554                 if ($item['private'] != Item::PRIVATE) {
 555                         // Directly mention the original author upon a quoted reshare.
 556                         // Else just ensure that the original author receives the reshare.
 557                         $announce = self::getAnnounceArray($item);
 558                         if (!empty($announce['comment'])) {
 559                                 $data['to'][] = $announce['actor']['url'];
 560                         } elseif (!empty($announce)) {
 561                                 $data['cc'][] = $announce['actor']['url'];
 562                         }
 563
 564                         $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 565
 566                         // Check if the item is completely public or unlisted
 567                         if ($item['private'] == Item::PUBLIC) {
 568                                 $data['to'][] = ActivityPub::PUBLIC_COLLECTION;
 569                         } else {
 570                                 $data['cc'][] = ActivityPub::PUBLIC_COLLECTION;
 571                         }
 572
 573                         foreach ($terms as $term) {
 574                                 $profile = APContact::getByURL($term['url'], false);
 575                                 if (!empty($profile)) {
 576                                         if ($term['type'] == Tag::EXCLUSIVE_MENTION) {
 577                                                 $exclusive = true;
 578                                                 if (!empty($profile['followers']) && ($profile['type'] == 'Group')) {
 579                                                         $data['cc'][] = $profile['followers'];
 580                                                 }
 581                                         }
 582                                         $data['to'][] = $profile['url'];
 583                                 }
 584                         }
 585                 } else {
 586                         $receiver_list = Item::enumeratePermissions($item, true);
 587
 588                         foreach ($terms as $term) {
 589                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 590                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 591                                         $contact = DBA::selectFirst('contact', ['url', 'network', 'protocol', 'gsid'], ['id' => $cid, 'network' => Protocol::FEDERATED]);
 592                                         if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
 593                                                 continue;
 594                                         }
 595
 596                                         if (!empty($profile = APContact::getByURL($contact['url'], false))) {
 597                                                 $data['to'][] = $profile['url'];
 598                                         }
 599                                 }
 600                         }
 601
 602                         foreach ($receiver_list as $receiver) {
 603                                 $contact = DBA::selectFirst('contact', ['url', 'hidden', 'network', 'protocol', 'gsid'], ['id' => $receiver, 'network' => Protocol::FEDERATED]);
 604                                 if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
 605                                         continue;
 606                                 }
 607
 608                                 if (!empty($profile = APContact::getByURL($contact['url'], false))) {
 609                                         if ($contact['hidden'] || $always_bcc) {
 610                                                 $data['bcc'][] = $profile['url'];
 611                                         } else {
 612                                                 $data['cc'][] = $profile['url'];
 613                                         }
 614                                 }
 615                         }
 616                 }
 617
 618                 if (!empty($item['parent'])) {
 619                         $parents = Post::select(['id', 'author-link', 'owner-link', 'gravity', 'uri'], ['parent' => $item['parent']]);
 620                         while ($parent = Post::fetch($parents)) {
 621                                 if ($parent['gravity'] == GRAVITY_PARENT) {
 622                                         $profile = APContact::getByURL($parent['owner-link'], false);
 623                                         if (!empty($profile)) {
 624                                                 if ($item['gravity'] != GRAVITY_PARENT) {
 625                                                         // Comments to forums are directed to the forum
 626                                                         // But comments to forums aren't directed to the followers collection
 627                                                         // This rule is only valid when the actor isn't the forum.
 628                                                         // The forum needs to transmit their content to their followers.
 629                                                         if (($profile['type'] == 'Group') && ($profile['url'] != ($actor_profile['url'] ?? ''))) {
 630                                                                 $data['to'][] = $profile['url'];
 631                                                         } else {
 632                                                                 $data['cc'][] = $profile['url'];
 633                                                                 if (($item['private'] != Item::PRIVATE) && !empty($actor_profile['followers'])) {
 634                                                                         $data['cc'][] = $actor_profile['followers'];
 635                                                                 }
 636                                                         }
 637                                                 } elseif (!$exclusive) {
 638                                                         // Public thread parent post always are directed to the followers.
 639                                                         // This mustn't be done by posts that are directed to forum servers via the exclusive mention.
 640                                                         // But possibly in that case we could add the "followers" collection of the forum to the message.
 641                                                         if (($item['private'] != Item::PRIVATE) && !$forum_mode) {
 642                                                                 $data['cc'][] = $actor_profile['followers'];
 643                                                         }
 644                                                 }
 645                                         }
 646                                 }
 647
 648                                 // Don't include data from future posts
 649                                 if ($parent['id'] >= $last_id) {
 650                                         continue;
 651                                 }
 652
 653                                 $profile = APContact::getByURL($parent['author-link'], false);
 654                                 if (!empty($profile)) {
 655                                         if (($profile['type'] == 'Group') || ($parent['uri'] == $item['thr-parent'])) {
 656                                                 $data['to'][] = $profile['url'];
 657                                         } else {
 658                                                 $data['cc'][] = $profile['url'];
 659                                         }
 660                                 }
 661                         }
 662                         DBA::close($parents);
 663                 }
 664
 665                 $data['to'] = array_unique($data['to']);
 666                 $data['cc'] = array_unique($data['cc']);
 667                 $data['bcc'] = array_unique($data['bcc']);
 668
 669                 if (($key = array_search($item['author-link'], $data['to'])) !== false) {
 670                         unset($data['to'][$key]);
 671                 }
 672
 673                 if (($key = array_search($item['author-link'], $data['cc'])) !== false) {
 674                         unset($data['cc'][$key]);
 675                 }
 676
 677                 if (($key = array_search($item['author-link'], $data['bcc'])) !== false) {
 678                         unset($data['bcc'][$key]);
 679                 }
 680
 681                 foreach ($data['to'] as $to) {
 682                         if (($key = array_search($to, $data['cc'])) !== false) {
 683                                 unset($data['cc'][$key]);
 684                         }
 685
 686                         if (($key = array_search($to, $data['bcc'])) !== false) {
 687                                 unset($data['bcc'][$key]);
 688                         }
 689                 }
 690
 691                 foreach ($data['cc'] as $cc) {
 692                         if (($key = array_search($cc, $data['bcc'])) !== false) {
 693                                 unset($data['bcc'][$key]);
 694                         }
 695                 }
 696
 697                 $receivers = ['to' => array_values($data['to']), 'cc' => array_values($data['cc']), 'bcc' => array_values($data['bcc'])];
 698
 699                 if (!$blindcopy) {
 700                         unset($receivers['bcc']);
 701                 }
 702
 703                 return $receivers;
 704         }
 705
 706         /**
 707          * Check if an inbox is archived
 708          *
 709          * @param string $url Inbox url
 710          *
 711          * @return boolean "true" if inbox is archived
 712          */
 713         public static function archivedInbox($url)
 714         {
 715                 return DBA::exists('inbox-status', ['url' => $url, 'archive' => true]);
 716         }
 717
 718         /**
 719          * Check if a given contact should be delivered via AP
 720          *
 721          * @param array $contact
 722          * @param array $networks
 723          * @return bool
 724          * @throws Exception
 725          */
 726         private static function isAPContact(array $contact, array $networks)
 727         {
 728                 if (in_array($contact['network'], $networks) || ($contact['protocol'] == Protocol::ACTIVITYPUB)) {
 729                         return true;
 730                 }
 731
 732                 return GServer::getProtocol($contact['gsid'] ?? 0) == Post\DeliveryData::ACTIVITYPUB;
 733         }
 734
 735         /**
 736          * Fetches a list of inboxes of followers of a given user
 737          *
 738          * @param integer $uid      User ID
 739          * @param boolean $personal fetch personal inboxes
 740          * @param boolean $all_ap   Retrieve all AP enabled inboxes
 741          *
 742          * @return array of follower inboxes
 743          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 744          * @throws \ImagickException
 745          */
 746         public static function fetchTargetInboxesforUser($uid, $personal = false, bool $all_ap = false)
 747         {
 748                 $inboxes = [];
 749
 750                 $isforum = false;
 751
 752                 if (!empty($item['uid'])) {
 753                         $profile = User::getOwnerDataById($item['uid']);
 754                         if (!empty($profile)) {
 755                                 $isforum = $profile['account-type'] == User::ACCOUNT_TYPE_COMMUNITY;
 756                         }
 757                 }
 758
 759                 if (DI::config()->get('debug', 'total_ap_delivery') || $all_ap) {
 760                         // Will be activated in a later step
 761                         $networks = Protocol::FEDERATED;
 762                 } else {
 763                         // For now only send to these contacts:
 764                         $networks = [Protocol::ACTIVITYPUB, Protocol::OSTATUS];
 765                 }
 766
 767                 $condition = ['uid' => $uid, 'archive' => false, 'pending' => false, 'blocked' => false, 'network' => Protocol::FEDERATED];
 768
 769                 if (!empty($uid)) {
 770                         $condition['rel'] = [Contact::FOLLOWER, Contact::FRIEND];
 771                 }
 772
 773                 $contacts = DBA::select('contact', ['id', 'url', 'network', 'protocol', 'gsid'], $condition);
 774                 while ($contact = DBA::fetch($contacts)) {
 775                         if (!self::isAPContact($contact, $networks)) {
 776                                 continue;
 777                         }
 778
 779                         if ($isforum && ($contact['network'] == Protocol::DFRN)) {
 780                                 continue;
 781                         }
 782
 783                         if (Network::isUrlBlocked($contact['url'])) {
 784                                 continue;
 785                         }
 786
 787                         $profile = APContact::getByURL($contact['url'], false);
 788                         if (!empty($profile)) {
 789                                 if (empty($profile['sharedinbox']) || $personal || Contact::isLocal($contact['url'])) {
 790                                         $target = $profile['inbox'];
 791                                 } else {
 792                                         $target = $profile['sharedinbox'];
 793                                 }
 794                                 if (!self::archivedInbox($target)) {
 795                                         $inboxes[$target][] = $contact['id'];
 796                                 }
 797                         }
 798                 }
 799                 DBA::close($contacts);
 800
 801                 return $inboxes;
 802         }
 803
 804         /**
 805          * Fetches an array of inboxes for the given item and user
 806          *
 807          * @param array   $item       Item array
 808          * @param integer $uid        User ID
 809          * @param boolean $personal   fetch personal inboxes
 810          * @param integer $last_id    Last item id for adding receivers
 811          * @param boolean $forum_mode "true" means that we are sending content to a forum
 812          * @return array with inboxes
 813          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 814          * @throws \ImagickException
 815          */
 816         public static function fetchTargetInboxes($item, $uid, $personal = false, $last_id = 0, $forum_mode = false)
 817         {
 818                 $permissions = self::createPermissionBlockForItem($item, true, $last_id, $forum_mode);
 819                 if (empty($permissions)) {
 820                         return [];
 821                 }
 822
 823                 $inboxes = [];
 824
 825                 if ($item['gravity'] == GRAVITY_ACTIVITY) {
 826                         $item_profile = APContact::getByURL($item['author-link'], false);
 827                 } else {
 828                         $item_profile = APContact::getByURL($item['owner-link'], false);
 829                 }
 830
 831                 if (empty($item_profile)) {
 832                         return [];
 833                 }
 834
 835                 $profile_uid = User::getIdForURL($item_profile['url']);
 836
 837                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 838                         if (empty($permissions[$element])) {
 839                                 continue;
 840                         }
 841
 842                         $blindcopy = in_array($element, ['bto', 'bcc']);
 843
 844                         foreach ($permissions[$element] as $receiver) {
 845                                 if (empty($receiver) || Network::isUrlBlocked($receiver)) {
 846                                         continue;
 847                                 }
 848
 849                                 if ($item_profile && ($receiver == $item_profile['followers']) && ($uid == $profile_uid)) {
 850                                         $inboxes = array_merge($inboxes, self::fetchTargetInboxesforUser($uid, $personal, self::isAPPost($last_id)));
 851                                 } else {
 852                                         $profile = APContact::getByURL($receiver, false);
 853                                         if (!empty($profile)) {
 854                                                 $contact = Contact::getByURLForUser($receiver, $uid, false, ['id']);
 855
 856                                                 if (empty($profile['sharedinbox']) || $personal || $blindcopy || Contact::isLocal($receiver)) {
 857                                                         $target = $profile['inbox'];
 858                                                 } else {
 859                                                         $target = $profile['sharedinbox'];
 860                                                 }
 861                                                 if (!self::archivedInbox($target)) {
 862                                                         $inboxes[$target][] = $contact['id'] ?? 0;
 863                                                 }
 864                                         }
 865                                 }
 866                         }
 867                 }
 868
 869                 return $inboxes;
 870         }
 871
 872         /**
 873          * Creates an array in the structure of the item table for a given mail id
 874          *
 875          * @param integer $mail_id
 876          *
 877          * @return array
 878          * @throws \Exception
 879          */
 880         public static function ItemArrayFromMail($mail_id, $use_title = false)
 881         {
 882                 $mail = DBA::selectFirst('mail', [], ['id' => $mail_id]);
 883                 if (!DBA::isResult($mail)) {
 884                         return [];
 885                 }
 886
 887                 $reply = DBA::selectFirst('mail', ['uri', 'uri-id', 'from-url'], ['parent-uri' => $mail['parent-uri'], 'reply' => false]);
 888                 if (!DBA::isResult($reply)) {
 889                         $reply = $mail;
 890                 }
 891
 892                 // Making the post more compatible for Mastodon by:
 893                 // - Making it a note and not an article (no title)
 894                 // - Moving the title into the "summary" field that is used as a "content warning"
 895
 896                 if (!$use_title) {
 897                         $mail['body']         = '[abstract]' . $mail['title'] . "[/abstract]\n" . $mail['body'];
 898                         $mail['title']        = '';
 899                 }
 900
 901                 $mail['author-link']      = $mail['owner-link'] = $mail['from-url'];
 902                 $mail['owner-id']         = $mail['author-id'];
 903                 $mail['allow_cid']        = '<'.$mail['contact-id'].'>';
 904                 $mail['allow_gid']        = '';
 905                 $mail['deny_cid']         = '';
 906                 $mail['deny_gid']         = '';
 907                 $mail['private']          = Item::PRIVATE;
 908                 $mail['deleted']          = false;
 909                 $mail['edited']           = $mail['created'];
 910                 $mail['plink']            = DI::baseUrl() . '/message/' . $mail['id'];
 911                 $mail['parent-uri']       = $reply['uri'];
 912                 $mail['parent-uri-id']    = $reply['uri-id'];
 913                 $mail['parent-author-id'] = Contact::getIdForURL($reply['from-url'], 0, false);
 914                 $mail['gravity']          = ($mail['reply'] ? GRAVITY_COMMENT: GRAVITY_PARENT);
 915                 $mail['event-type']       = '';
 916                 $mail['language']         = '';
 917                 $mail['parent']           = 0;
 918
 919                 return $mail;
 920         }
 921
 922         /**
 923          * Creates an activity array for a given mail id
 924          *
 925          * @param integer $mail_id
 926          * @param boolean $object_mode Is the activity item is used inside another object?
 927          *
 928          * @return array of activity
 929          * @throws \Exception
 930          */
 931         public static function createActivityFromMail($mail_id, $object_mode = false)
 932         {
 933                 $mail = self::ItemArrayFromMail($mail_id);
 934                 if (empty($mail)) {
 935                         return [];
 936                 }
 937                 $object = self::createNote($mail);
 938
 939                 if (!$object_mode) {
 940                         $data = ['@context' => ActivityPub::CONTEXT];
 941                 } else {
 942                         $data = [];
 943                 }
 944
 945                 $data['id'] = $mail['uri'] . '/Create';
 946                 $data['type'] = 'Create';
 947                 $data['actor'] = $mail['author-link'];
 948                 $data['published'] = DateTimeFormat::utc($mail['created'] . '+00:00', DateTimeFormat::ATOM);
 949                 $data['instrument'] = self::getService();
 950                 $data = array_merge($data, self::createPermissionBlockForItem($mail, true));
 951
 952                 if (empty($data['to']) && !empty($data['cc'])) {
 953                         $data['to'] = $data['cc'];
 954                 }
 955
 956                 if (empty($data['to']) && !empty($data['bcc'])) {
 957                         $data['to'] = $data['bcc'];
 958                 }
 959
 960                 unset($data['cc']);
 961                 unset($data['bcc']);
 962
 963                 $object['to'] = $data['to'];
 964                 $object['tag'] = [['type' => 'Mention', 'href' => $object['to'][0], 'name' => '']];
 965
 966                 unset($object['cc']);
 967                 unset($object['bcc']);
 968
 969                 $data['directMessage'] = true;
 970
 971                 $data['object'] = $object;
 972
 973                 $owner = User::getOwnerDataById($mail['uid']);
 974
 975                 if (!$object_mode && !empty($owner)) {
 976                         return LDSignature::sign($data, $owner);
 977                 } else {
 978                         return $data;
 979                 }
 980         }
 981
 982         /**
 983          * Returns the activity type of a given item
 984          *
 985          * @param array $item
 986          *
 987          * @return string with activity type
 988          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 989          * @throws \ImagickException
 990          */
 991         private static function getTypeOfItem($item)
 992         {
 993                 $reshared = false;
 994
 995                 // Only check for a reshare, if it is a real reshare and no quoted reshare
 996                 if (strpos($item['body'], "[share") === 0) {
 997                         $announce = self::getAnnounceArray($item);
 998                         $reshared = !empty($announce);
 999                 }
1000
1001                 if ($reshared) {
1002                         $type = 'Announce';
1003                 } elseif ($item['verb'] == Activity::POST) {
1004                         if ($item['created'] == $item['edited']) {
1005                                 $type = 'Create';
1006                         } else {
1007                                 $type = 'Update';
1008                         }
1009                 } elseif ($item['verb'] == Activity::LIKE) {
1010                         $type = 'Like';
1011                 } elseif ($item['verb'] == Activity::DISLIKE) {
1012                         $type = 'Dislike';
1013                 } elseif ($item['verb'] == Activity::ATTEND) {
1014                         $type = 'Accept';
1015                 } elseif ($item['verb'] == Activity::ATTENDNO) {
1016                         $type = 'Reject';
1017                 } elseif ($item['verb'] == Activity::ATTENDMAYBE) {
1018                         $type = 'TentativeAccept';
1019                 } elseif ($item['verb'] == Activity::FOLLOW) {
1020                         $type = 'Follow';
1021                 } elseif ($item['verb'] == Activity::TAG) {
1022                         $type = 'Add';
1023                 } elseif ($item['verb'] == Activity::ANNOUNCE) {
1024                         $type = 'Announce';
1025                 } else {
1026                         $type = '';
1027                 }
1028
1029                 return $type;
1030         }
1031
1032         /**
1033          * Creates the activity or fetches it from the cache
1034          *
1035          * @param integer $item_id
1036          * @param boolean $force Force new cache entry
1037          *
1038          * @return array with the activity
1039          * @throws \Exception
1040          */
1041         public static function createCachedActivityFromItem($item_id, $force = false)
1042         {
1043                 $cachekey = 'APDelivery:createActivity:' . $item_id;
1044
1045                 if (!$force) {
1046                         $data = DI::cache()->get($cachekey);
1047                         if (!is_null($data)) {
1048                                 return $data;
1049                         }
1050                 }
1051
1052                 $data = self::createActivityFromItem($item_id);
1053
1054                 DI::cache()->set($cachekey, $data, Duration::QUARTER_HOUR);
1055                 return $data;
1056         }
1057
1058         /**
1059          * Creates an activity array for a given item id
1060          *
1061          * @param integer $item_id
1062          * @param boolean $object_mode Is the activity item is used inside another object?
1063          *
1064          * @return false|array
1065          * @throws \Exception
1066          */
1067         public static function createActivityFromItem(int $item_id, bool $object_mode = false)
1068         {
1069                 Logger::info('Fetching activity', ['item' => $item_id]);
1070                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
1071                 if (!DBA::isResult($item)) {
1072                         return false;
1073                 }
1074
1075                 // In case of a forum post ensure to return the original post if author and forum are on the same machine
1076                 if (($item['gravity'] == GRAVITY_PARENT) && !empty($item['forum_mode'])) {
1077                         $author = Contact::getById($item['author-id'], ['nurl']);
1078                         if (!empty($author['nurl'])) {
1079                                 $self = Contact::selectFirst(['uid'], ['nurl' => $author['nurl'], 'self' => true]);
1080                                 if (!empty($self['uid'])) {
1081                                         $forum_item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri-id' => $item['uri-id'], 'uid' => $self['uid']]);
1082                                         if (DBA::isResult($forum_item)) {
1083                                                 $item = $forum_item;
1084                                         }
1085                                 }
1086                         }
1087                 }
1088
1089                 if (empty($item['uri-id'])) {
1090                         Logger::warning('Item without uri-id', ['item' => $item]);
1091                         return false;
1092                 }
1093
1094                 if (!$item['deleted']) {
1095                         $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
1096                         $conversation = DBA::selectFirst('conversation', ['source'], $condition);
1097                         if (!$item['origin'] && DBA::isResult($conversation)) {
1098                                 $data = json_decode($conversation['source'], true);
1099                                 if (!empty($data['type'])) {
1100                                         if (in_array($data['type'], ['Create', 'Update'])) {
1101                                                 if ($object_mode) {
1102                                                         unset($data['@context']);
1103                                                         unset($data['signature']);
1104                                                 }
1105                                                 Logger::info('Return stored conversation', ['item' => $item_id]);
1106                                                 return $data;
1107                                         } elseif (in_array('as:' . $data['type'], Receiver::CONTENT_TYPES)) {
1108                                                 if (!empty($data['@context'])) {
1109                                                         $context = $data['@context'];
1110                                                         unset($data['@context']);
1111                                                 }
1112                                                 unset($data['actor']);
1113                                                 $object = $data;
1114                                         }
1115                                 }
1116                         }
1117                 }
1118
1119                 $type = self::getTypeOfItem($item);
1120
1121                 if (!$object_mode) {
1122                         $data = ['@context' => $context ?? ActivityPub::CONTEXT];
1123
1124                         if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
1125                                 $type = 'Undo';
1126                         } elseif ($item['deleted']) {
1127                                 $type = 'Delete';
1128                         }
1129                 } else {
1130                         $data = [];
1131                 }
1132
1133                 if ($type == 'Delete') {
1134                         $data['id'] = Item::newURI($item['uid'], $item['guid']) . '/' . $type;;
1135                 } elseif (($item['gravity'] == GRAVITY_ACTIVITY) && ($type != 'Undo')) {
1136                         $data['id'] = $item['uri'];
1137                 } else {
1138                         $data['id'] = $item['uri'] . '/' . $type;
1139                 }
1140
1141                 $data['type'] = $type;
1142
1143                 if (($type != 'Announce') || ($item['gravity'] != GRAVITY_PARENT)) {
1144                         $data['actor'] = $item['author-link'];
1145                 } else {
1146                         $data['actor'] = $item['owner-link'];
1147                 }
1148
1149                 $data['published'] = DateTimeFormat::utc($item['created'] . '+00:00', DateTimeFormat::ATOM);
1150
1151                 $data['instrument'] = self::getService();
1152
1153                 $data = array_merge($data, self::createPermissionBlockForItem($item, false));
1154
1155                 if (in_array($data['type'], ['Create', 'Update', 'Delete'])) {
1156                         $data['object'] = $object ?? self::createNote($item);
1157                 } elseif ($data['type'] == 'Add') {
1158                         $data = self::createAddTag($item, $data);
1159                 } elseif ($data['type'] == 'Announce') {
1160                         if ($item['verb'] == ACTIVITY::ANNOUNCE) {
1161                                 $data['object'] = $item['thr-parent'];
1162                         } else {
1163                                 $data = self::createAnnounce($item, $data);
1164                         }
1165                 } elseif ($data['type'] == 'Follow') {
1166                         $data['object'] = $item['parent-uri'];
1167                 } elseif ($data['type'] == 'Undo') {
1168                         $data['object'] = self::createActivityFromItem($item_id, true);
1169                 } else {
1170                         $data['diaspora:guid'] = $item['guid'];
1171                         if (!empty($item['signed_text'])) {
1172                                 $data['diaspora:like'] = $item['signed_text'];
1173                         }
1174                         $data['object'] = $item['thr-parent'];
1175                 }
1176
1177                 if (!empty($item['contact-uid'])) {
1178                         $uid = $item['contact-uid'];
1179                 } else {
1180                         $uid = $item['uid'];
1181                 }
1182
1183                 $owner = User::getOwnerDataById($uid);
1184
1185                 Logger::info('Fetched activity', ['item' => $item_id, 'uid' => $uid]);
1186
1187                 // We don't sign if we aren't the actor. This is important for relaying content especially for forums
1188                 if (!$object_mode && !empty($owner) && ($data['actor'] == $owner['url'])) {
1189                         return LDSignature::sign($data, $owner);
1190                 } else {
1191                         return $data;
1192                 }
1193
1194                 /// @todo Create "conversation" entry
1195         }
1196
1197         /**
1198          * Creates a location entry for a given item array
1199          *
1200          * @param array $item
1201          *
1202          * @return array with location array
1203          */
1204         private static function createLocation($item)
1205         {
1206                 $location = ['type' => 'Place'];
1207
1208                 if (!empty($item['location'])) {
1209                         $location['name'] = $item['location'];
1210                 }
1211
1212                 $coord = [];
1213
1214                 if (empty($item['coord'])) {
1215                         $coord = Map::getCoordinates($item['location']);
1216                 } else {
1217                         $coords = explode(' ', $item['coord']);
1218                         if (count($coords) == 2) {
1219                                 $coord = ['lat' => $coords[0], 'lon' => $coords[1]];
1220                         }
1221                 }
1222
1223                 if (!empty($coord['lat']) && !empty($coord['lon'])) {
1224                         $location['latitude'] = $coord['lat'];
1225                         $location['longitude'] = $coord['lon'];
1226                 }
1227
1228                 return $location;
1229         }
1230
1231         /**
1232          * Returns a tag array for a given item array
1233          *
1234          * @param array $item
1235          *
1236          * @return array of tags
1237          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1238          */
1239         private static function createTagList($item)
1240         {
1241                 $tags = [];
1242
1243                 $terms = Tag::getByURIId($item['uri-id'], [Tag::HASHTAG, Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1244                 foreach ($terms as $term) {
1245                         if ($term['type'] == Tag::HASHTAG) {
1246                                 $url = DI::baseUrl() . '/search?tag=' . urlencode($term['name']);
1247                                 $tags[] = ['type' => 'Hashtag', 'href' => $url, 'name' => '#' . $term['name']];
1248                         } else {
1249                                 $contact = Contact::getByURL($term['url'], false, ['addr']);
1250                                 if (empty($contact)) {
1251                                         continue;
1252                                 }
1253                                 if (!empty($contact['addr'])) {
1254                                         $mention = '@' . $contact['addr'];
1255                                 } else {
1256                                         $mention = '@' . $term['url'];
1257                                 }
1258
1259                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
1260                         }
1261                 }
1262
1263                 $announce = self::getAnnounceArray($item);
1264                 // Mention the original author upon commented reshares
1265                 if (!empty($announce['comment'])) {
1266                         $tags[] = ['type' => 'Mention', 'href' => $announce['actor']['url'], 'name' => '@' . $announce['actor']['addr']];
1267                 }
1268
1269                 return $tags;
1270         }
1271
1272         /**
1273          * Adds attachment data to the JSON document
1274          *
1275          * @param array  $item Data of the item that is to be posted
1276          * @param string $type Object type
1277          *
1278          * @return array with attachment data
1279          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1280          */
1281         private static function createAttachmentList($item, $type)
1282         {
1283                 $attachments = [];
1284
1285                 $uriids = [$item['uri-id']];
1286                 $shared = BBCode::fetchShareAttributes($item['body']);
1287                 if (!empty($shared['guid'])) {
1288                         $shared_item = Post::selectFirst(['uri-id'], ['guid' => $shared['guid']]);
1289                         if (!empty($shared_item['uri-id'])) {
1290                                 $uriids[] = $shared_item['uri-id'];
1291                         }
1292                 }
1293
1294                 $urls = [];
1295                 foreach ($uriids as $uriid) {
1296                         foreach (Post\Media::getByURIId($uriid, [Post\Media::AUDIO, Post\Media::IMAGE, Post\Media::VIDEO, Post\Media::DOCUMENT, Post\Media::TORRENT]) as $attachment) {
1297                                 if (in_array($attachment['url'], $urls)) {
1298                                         continue;
1299                                 }
1300                                 $urls[] = $attachment['url'];
1301
1302                                 $attach = ['type' => 'Document',
1303                                         'mediaType' => $attachment['mimetype'],
1304                                         'url' => $attachment['url'],
1305                                         'name' => $attachment['description']];
1306
1307                                 if (!empty($attachment['height'])) {
1308                                         $attach['height'] = $attachment['height'];
1309                                 }
1310
1311                                 if (!empty($attachment['width'])) {
1312                                         $attach['width'] = $attachment['width'];
1313                                 }
1314
1315                                 if (!empty($attachment['preview'])) {
1316                                         $attach['image'] = $attachment['preview'];
1317                                 }
1318
1319                                 $attachments[] = $attach;
1320                         }
1321                 }
1322
1323                 return $attachments;
1324         }
1325
1326         /**
1327          * Callback function to replace a Friendica style mention in a mention for a summary
1328          *
1329          * @param array $match Matching values for the callback
1330          * @return string Replaced mention
1331          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1332          */
1333         private static function mentionAddrCallback($match)
1334         {
1335                 if (empty($match[1])) {
1336                         return '';
1337                 }
1338
1339                 $data = Contact::getByURL($match[1], false, ['addr']);
1340                 if (empty($data['addr'])) {
1341                         return $match[0];
1342                 }
1343
1344                 return '@' . $data['addr'];
1345         }
1346
1347         /**
1348          * Remove image elements since they are added as attachment
1349          *
1350          * @param string $body
1351          *
1352          * @return string with removed images
1353          */
1354         private static function removePictures($body)
1355         {
1356                 // Simplify image codes
1357                 $body = preg_replace("/\[img\=([0-9]*)x([0-9]*)\](.*?)\[\/img\]/ism", '[img]$3[/img]', $body);
1358                 $body = preg_replace("/\[img\=(.*?)\](.*?)\[\/img\]/ism", '[img]$1[/img]', $body);
1359
1360                 // Now remove local links
1361                 $body = preg_replace_callback(
1362                         '/\[url=([^\[\]]*)\]\[img\](.*)\[\/img\]\[\/url\]/Usi',
1363                         function ($match) {
1364                                 // We remove the link when it is a link to a local photo page
1365                                 if (Photo::isLocalPage($match[1])) {
1366                                         return '';
1367                                 }
1368                                 // otherwise we just return the link
1369                                 return '[url]' . $match[1] . '[/url]';
1370                         },
1371                         $body
1372                 );
1373
1374                 // Remove all pictures
1375                 $body = preg_replace("/\[img\]([^\[\]]*)\[\/img\]/Usi", '', $body);
1376
1377                 return $body;
1378         }
1379
1380         /**
1381          * Fetches the "context" value for a givem item array from the "conversation" table
1382          *
1383          * @param array $item
1384          *
1385          * @return string with context url
1386          * @throws \Exception
1387          */
1388         private static function fetchContextURLForItem($item)
1389         {
1390                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
1391                 if (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
1392                         $context_uri = $conversation['conversation-href'];
1393                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
1394                         $context_uri = $conversation['conversation-uri'];
1395                 } else {
1396                         $context_uri = $item['parent-uri'] . '#context';
1397                 }
1398                 return $context_uri;
1399         }
1400
1401         /**
1402          * Returns if the post contains sensitive content ("nsfw")
1403          *
1404          * @param integer $uri_id
1405          *
1406          * @return boolean
1407          * @throws \Exception
1408          */
1409         private static function isSensitive($uri_id)
1410         {
1411                 return DBA::exists('tag-view', ['uri-id' => $uri_id, 'name' => 'nsfw']);
1412         }
1413
1414         /**
1415          * Creates event data
1416          *
1417          * @param array $item
1418          *
1419          * @return array with the event data
1420          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1421          */
1422         private static function createEvent($item)
1423         {
1424                 $event = [];
1425                 $event['name'] = $item['event-summary'];
1426                 $event['content'] = BBCode::convertForUriId($item['uri-id'], $item['event-desc'], BBCode::ACTIVITYPUB);
1427                 $event['startTime'] = DateTimeFormat::utc($item['event-start'], 'c');
1428
1429                 if (!$item['event-nofinish']) {
1430                         $event['endTime'] = DateTimeFormat::utc($item['event-finish'], 'c');
1431                 }
1432
1433                 if (!empty($item['event-location'])) {
1434                         $item['location'] = $item['event-location'];
1435                         $event['location'] = self::createLocation($item);
1436                 }
1437
1438                 // 2021.12: Backward compatibility value, all the events now "adjust" to the viewer timezone
1439                 $event['dfrn:adjust'] = true;
1440
1441                 return $event;
1442         }
1443
1444         /**
1445          * Creates a note/article object array
1446          *
1447          * @param array $item
1448          *
1449          * @return array with the object data
1450          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1451          * @throws \ImagickException
1452          */
1453         public static function createNote($item)
1454         {
1455                 if (empty($item)) {
1456                         return [];
1457                 }
1458
1459                 if ($item['event-type'] == 'event') {
1460                         $type = 'Event';
1461                 } elseif (!empty($item['title'])) {
1462                         $type = 'Article';
1463                 } else {
1464                         $type = 'Note';
1465                 }
1466
1467                 if ($item['deleted']) {
1468                         $type = 'Tombstone';
1469                 }
1470
1471                 $data = [];
1472                 $data['id'] = $item['uri'];
1473                 $data['type'] = $type;
1474
1475                 if ($item['deleted']) {
1476                         return $data;
1477                 }
1478
1479                 $data['summary'] = BBCode::toPlaintext(BBCode::getAbstract($item['body'], Protocol::ACTIVITYPUB));
1480
1481                 if ($item['uri'] != $item['thr-parent']) {
1482                         $data['inReplyTo'] = $item['thr-parent'];
1483                 } else {
1484                         $data['inReplyTo'] = null;
1485                 }
1486
1487                 $data['diaspora:guid'] = $item['guid'];
1488                 $data['published'] = DateTimeFormat::utc($item['created'] . '+00:00', DateTimeFormat::ATOM);
1489
1490                 if ($item['created'] != $item['edited']) {
1491                         $data['updated'] = DateTimeFormat::utc($item['edited'] . '+00:00', DateTimeFormat::ATOM);
1492                 }
1493
1494                 $data['url'] = $item['plink'];
1495                 $data['attributedTo'] = $item['author-link'];
1496                 $data['sensitive'] = self::isSensitive($item['uri-id']);
1497                 $data['context'] = self::fetchContextURLForItem($item);
1498
1499                 if (!empty($item['title'])) {
1500                         $data['name'] = BBCode::toPlaintext($item['title'], false);
1501                 }
1502
1503                 $permission_block = self::createPermissionBlockForItem($item, false);
1504
1505                 $body = $item['body'];
1506
1507                 if ($type == 'Note') {
1508                         $body = $item['raw-body'] ?? self::removePictures($body);
1509                 }
1510
1511                 /**
1512                  * @todo Improve the automated summary
1513                  * This part is currently deactivated. The automated summary seems to be more
1514                  * confusing than helping. But possibly we will find a better way.
1515                  * So the code is left here for now as a reminder
1516                  *
1517                  * } elseif (($type == 'Article') && empty($data['summary'])) {
1518                  *              $regexp = "/[@!]\[url\=([^\[\]]*)\].*?\[\/url\]/ism";
1519                  *              $summary = preg_replace_callback($regexp, ['self', 'mentionAddrCallback'], $body);
1520                  *              $data['summary'] = BBCode::toPlaintext(Plaintext::shorten(self::removePictures($summary), 1000));
1521                  * }
1522                  */
1523
1524                 if (empty($item['uid']) || !Feature::isEnabled($item['uid'], 'explicit_mentions')) {
1525                         $body = self::prependMentions($body, $item['uri-id'], $item['author-link']);
1526                 }
1527
1528                 if ($type == 'Event') {
1529                         $data = array_merge($data, self::createEvent($item));
1530                 } else {
1531                         $body = BBCode::setMentionsToNicknames($body);
1532
1533                         $data['content'] = BBCode::convertForUriId($item['uri-id'], $body, BBCode::ACTIVITYPUB);
1534                 }
1535
1536                 // The regular "content" field does contain a minimized HTML. This is done since systems like
1537                 // Mastodon has got problems with - for example - embedded pictures.
1538                 // The contentMap does contain the unmodified HTML.
1539                 $language = self::getLanguage($item);
1540                 if (!empty($language)) {
1541                         $richbody = BBCode::setMentionsToNicknames($item['body'] ?? '');
1542                         $richbody = BBCode::removeAttachment($richbody);
1543
1544                         $data['contentMap'][$language] = BBCode::convertForUriId($item['uri-id'], $richbody, BBCode::EXTERNAL);
1545                 }
1546
1547                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
1548
1549                 if (!empty($item['signed_text']) && ($item['uri'] != $item['thr-parent'])) {
1550                         $data['diaspora:comment'] = $item['signed_text'];
1551                 }
1552
1553                 $data['attachment'] = self::createAttachmentList($item, $type);
1554                 $data['tag'] = self::createTagList($item);
1555
1556                 if (empty($data['location']) && (!empty($item['coord']) || !empty($item['location']))) {
1557                         $data['location'] = self::createLocation($item);
1558                 }
1559
1560                 if (!empty($item['app'])) {
1561                         $data['generator'] = ['type' => 'Application', 'name' => $item['app']];
1562                 }
1563
1564                 $data = array_merge($data, $permission_block);
1565
1566                 return $data;
1567         }
1568
1569         /**
1570          * Fetches the language from the post, the user or the system.
1571          *
1572          * @param array $item
1573          *
1574          * @return string language string
1575          */
1576         private static function getLanguage(array $item)
1577         {
1578                 // Try to fetch the language from the post itself
1579                 if (!empty($item['language'])) {
1580                         $languages = array_keys(json_decode($item['language'], true));
1581                         if (!empty($languages[0])) {
1582                                 return $languages[0];
1583                         }
1584                 }
1585
1586                 // Otherwise use the user's language
1587                 if (!empty($item['uid'])) {
1588                         $user = DBA::selectFirst('user', ['language'], ['uid' => $item['uid']]);
1589                         if (!empty($user['language'])) {
1590                                 return $user['language'];
1591                         }
1592                 }
1593
1594                 // And finally just use the system language
1595                 return DI::config()->get('system', 'language');
1596         }
1597
1598         /**
1599          * Creates an an "add tag" entry
1600          *
1601          * @param array $item
1602          * @param array $data activity data
1603          *
1604          * @return array with activity data for adding tags
1605          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1606          * @throws \ImagickException
1607          */
1608         private static function createAddTag($item, $data)
1609         {
1610                 $object = XML::parseString($item['object']);
1611                 $target = XML::parseString($item["target"]);
1612
1613                 $data['diaspora:guid'] = $item['guid'];
1614                 $data['actor'] = $item['author-link'];
1615                 $data['target'] = (string)$target->id;
1616                 $data['summary'] = BBCode::toPlaintext($item['body']);
1617                 $data['object'] = ['id' => (string)$object->id, 'type' => 'tag', 'name' => (string)$object->title, 'content' => (string)$object->content];
1618
1619                 return $data;
1620         }
1621
1622         /**
1623          * Creates an announce object entry
1624          *
1625          * @param array $item
1626          * @param array $data activity data
1627          *
1628          * @return array with activity data
1629          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1630          * @throws \ImagickException
1631          */
1632         private static function createAnnounce($item, $data)
1633         {
1634                 $orig_body = $item['body'];
1635                 $announce = self::getAnnounceArray($item);
1636                 if (empty($announce)) {
1637                         $data['type'] = 'Create';
1638                         $data['object'] = self::createNote($item);
1639                         return $data;
1640                 }
1641
1642                 if (empty($announce['comment'])) {
1643                         // Pure announce, without a quote
1644                         $data['type'] = 'Announce';
1645                         $data['object'] = $announce['object']['uri'];
1646                         return $data;
1647                 }
1648
1649                 // Quote
1650                 $data['type'] = 'Create';
1651                 $item['body'] = $announce['comment'] . "\n" . $announce['object']['plink'];
1652                 $data['object'] = self::createNote($item);
1653
1654                 /// @todo Finally descide how to implement this in AP. This is a possible way:
1655                 $data['object']['attachment'][] = self::createNote($announce['object']);
1656
1657                 $data['object']['source']['content'] = $orig_body;
1658                 return $data;
1659         }
1660
1661         /**
1662          * Return announce related data if the item is an annunce
1663          *
1664          * @param array $item
1665          *
1666          * @return array
1667          */
1668         public static function getAnnounceArray($item)
1669         {
1670                 $reshared = Item::getShareArray($item);
1671                 if (empty($reshared['guid'])) {
1672                         return [];
1673                 }
1674
1675                 $reshared_item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['guid' => $reshared['guid']]);
1676                 if (!DBA::isResult($reshared_item)) {
1677                         return [];
1678                 }
1679
1680                 if (!in_array($reshared_item['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN])) {
1681                         return [];
1682                 }
1683
1684                 $profile = APContact::getByURL($reshared_item['author-link'], false);
1685                 if (empty($profile)) {
1686                         return [];
1687                 }
1688
1689                 return ['object' => $reshared_item, 'actor' => $profile, 'comment' => $reshared['comment']];
1690         }
1691
1692         /**
1693          * Checks if the provided item array is an announce
1694          *
1695          * @param array $item
1696          *
1697          * @return boolean
1698          */
1699         public static function isAnnounce($item)
1700         {
1701                 if (!empty($item['verb']) && ($item['verb'] == Activity::ANNOUNCE)) {
1702                         return true;
1703                 }
1704
1705                 $announce = self::getAnnounceArray($item);
1706                 if (empty($announce)) {
1707                         return false;
1708                 }
1709
1710                 return empty($announce['comment']);
1711         }
1712
1713         /**
1714          * Creates an activity id for a given contact id
1715          *
1716          * @param integer $cid Contact ID of target
1717          *
1718          * @return bool|string activity id
1719          */
1720         public static function activityIDFromContact($cid)
1721         {
1722                 $contact = DBA::selectFirst('contact', ['uid', 'id', 'created'], ['id' => $cid]);
1723                 if (!DBA::isResult($contact)) {
1724                         return false;
1725                 }
1726
1727                 $hash = hash('ripemd128', $contact['uid'].'-'.$contact['id'].'-'.$contact['created']);
1728                 $uuid = substr($hash, 0, 8). '-' . substr($hash, 8, 4) . '-' . substr($hash, 12, 4) . '-' . substr($hash, 16, 4) . '-' . substr($hash, 20, 12);
1729                 return DI::baseUrl() . '/activity/' . $uuid;
1730         }
1731
1732         /**
1733          * Transmits a contact suggestion to a given inbox
1734          *
1735          * @param integer $uid           User ID
1736          * @param string  $inbox         Target inbox
1737          * @param integer $suggestion_id Suggestion ID
1738          *
1739          * @return boolean was the transmission successful?
1740          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1741          */
1742         public static function sendContactSuggestion($uid, $inbox, $suggestion_id)
1743         {
1744                 $owner = User::getOwnerDataById($uid);
1745
1746                 $suggestion = DI::fsuggest()->selectOneById($suggestion_id);
1747
1748                 $data = ['@context' => ActivityPub::CONTEXT,
1749                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1750                         'type' => 'Announce',
1751                         'actor' => $owner['url'],
1752                         'object' => $suggestion->url,
1753                         'content' => $suggestion->note,
1754                         'instrument' => self::getService(),
1755                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1756                         'cc' => []];
1757
1758                 $signed = LDSignature::sign($data, $owner);
1759
1760                 Logger::info('Deliver profile deletion for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1761                 return HTTPSignature::transmit($signed, $inbox, $uid);
1762         }
1763
1764         /**
1765          * Transmits a profile relocation to a given inbox
1766          *
1767          * @param integer $uid   User ID
1768          * @param string  $inbox Target inbox
1769          *
1770          * @return boolean was the transmission successful?
1771          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1772          */
1773         public static function sendProfileRelocation($uid, $inbox)
1774         {
1775                 $owner = User::getOwnerDataById($uid);
1776
1777                 $data = ['@context' => ActivityPub::CONTEXT,
1778                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1779                         'type' => 'dfrn:relocate',
1780                         'actor' => $owner['url'],
1781                         'object' => $owner['url'],
1782                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1783                         'instrument' => self::getService(),
1784                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1785                         'cc' => []];
1786
1787                 $signed = LDSignature::sign($data, $owner);
1788
1789                 Logger::info('Deliver profile relocation for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1790                 return HTTPSignature::transmit($signed, $inbox, $uid);
1791         }
1792
1793         /**
1794          * Transmits a profile deletion to a given inbox
1795          *
1796          * @param integer $uid   User ID
1797          * @param string  $inbox Target inbox
1798          *
1799          * @return boolean was the transmission successful?
1800          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1801          */
1802         public static function sendProfileDeletion($uid, $inbox)
1803         {
1804                 $owner = User::getOwnerDataById($uid);
1805
1806                 if (empty($owner)) {
1807                         Logger::error('No owner data found, the deletion message cannot be processed.', ['user' => $uid]);
1808                         return false;
1809                 }
1810
1811                 if (empty($owner['uprvkey'])) {
1812                         Logger::error('No private key for owner found, the deletion message cannot be processed.', ['user' => $uid]);
1813                         return false;
1814                 }
1815
1816                 $data = ['@context' => ActivityPub::CONTEXT,
1817                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1818                         'type' => 'Delete',
1819                         'actor' => $owner['url'],
1820                         'object' => $owner['url'],
1821                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1822                         'instrument' => self::getService(),
1823                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1824                         'cc' => []];
1825
1826                 $signed = LDSignature::sign($data, $owner);
1827
1828                 Logger::info('Deliver profile deletion for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1829                 return HTTPSignature::transmit($signed, $inbox, $uid);
1830         }
1831
1832         /**
1833          * Transmits a profile change to a given inbox
1834          *
1835          * @param integer $uid   User ID
1836          * @param string  $inbox Target inbox
1837          *
1838          * @return boolean was the transmission successful?
1839          * @throws HTTPException\InternalServerErrorException
1840          * @throws HTTPException\NotFoundException
1841          * @throws \ImagickException
1842          */
1843         public static function sendProfileUpdate(int $uid, string $inbox): bool
1844         {
1845                 $owner = User::getOwnerDataById($uid);
1846                 $profile = APContact::getByURL($owner['url']);
1847
1848                 $data = ['@context' => ActivityPub::CONTEXT,
1849                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1850                         'type' => 'Update',
1851                         'actor' => $owner['url'],
1852                         'object' => self::getProfile($uid),
1853                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1854                         'instrument' => self::getService(),
1855                         'to' => [$profile['followers']],
1856                         'cc' => []];
1857
1858                 $signed = LDSignature::sign($data, $owner);
1859
1860                 Logger::info('Deliver profile update for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1861                 return HTTPSignature::transmit($signed, $inbox, $uid);
1862         }
1863
1864         /**
1865          * Transmits a given activity to a target
1866          *
1867          * @param string  $activity Type name
1868          * @param string  $target   Target profile
1869          * @param integer $uid      User ID
1870          * @return bool
1871          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1872          * @throws \ImagickException
1873          * @throws \Exception
1874          */
1875         public static function sendActivity($activity, $target, $uid, $id = '')
1876         {
1877                 $profile = APContact::getByURL($target);
1878                 if (empty($profile['inbox'])) {
1879                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1880                         return;
1881                 }
1882
1883                 $owner = User::getOwnerDataById($uid);
1884
1885                 if (empty($id)) {
1886                         $id = DI::baseUrl() . '/activity/' . System::createGUID();
1887                 }
1888
1889                 $data = ['@context' => ActivityPub::CONTEXT,
1890                         'id' => $id,
1891                         'type' => $activity,
1892                         'actor' => $owner['url'],
1893                         'object' => $profile['url'],
1894                         'instrument' => self::getService(),
1895                         'to' => [$profile['url']]];
1896
1897                 Logger::info('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid);
1898
1899                 $signed = LDSignature::sign($data, $owner);
1900                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1901         }
1902
1903         /**
1904          * Transmits a "follow object" activity to a target
1905          * This is a preparation for sending automated "follow" requests when receiving "Announce" messages
1906          *
1907          * @param string  $object Object URL
1908          * @param string  $target Target profile
1909          * @param integer $uid    User ID
1910          * @return bool
1911          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1912          * @throws \ImagickException
1913          * @throws \Exception
1914          */
1915         public static function sendFollowObject($object, $target, $uid = 0)
1916         {
1917                 $profile = APContact::getByURL($target);
1918                 if (empty($profile['inbox'])) {
1919                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1920                         return;
1921                 }
1922
1923                 if (empty($uid)) {
1924                         // Fetch the list of administrators
1925                         $admin_mail = explode(',', str_replace(' ', '', DI::config()->get('config', 'admin_email')));
1926
1927                         // We need to use some user as a sender. It doesn't care who it will send. We will use an administrator account.
1928                         $condition = ['verified' => true, 'blocked' => false, 'account_removed' => false, 'account_expired' => false, 'email' => $admin_mail];
1929                         $first_user = DBA::selectFirst('user', ['uid'], $condition);
1930                         $uid = $first_user['uid'];
1931                 }
1932
1933                 $condition = ['verb' => Activity::FOLLOW, 'uid' => 0, 'parent-uri' => $object,
1934                         'author-id' => Contact::getPublicIdByUserId($uid)];
1935                 if (Post::exists($condition)) {
1936                         Logger::info('Follow for ' . $object . ' for user ' . $uid . ' does already exist.');
1937                         return false;
1938                 }
1939
1940                 $owner = User::getOwnerDataById($uid);
1941
1942                 $data = ['@context' => ActivityPub::CONTEXT,
1943                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1944                         'type' => 'Follow',
1945                         'actor' => $owner['url'],
1946                         'object' => $object,
1947                         'instrument' => self::getService(),
1948                         'to' => [$profile['url']]];
1949
1950                 Logger::info('Sending follow ' . $object . ' to ' . $target . ' for user ' . $uid);
1951
1952                 $signed = LDSignature::sign($data, $owner);
1953                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1954         }
1955
1956         /**
1957          * Transmit a message that the contact request had been accepted
1958          *
1959          * @param string  $target Target profile
1960          * @param         $id
1961          * @param integer $uid    User ID
1962          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1963          * @throws \ImagickException
1964          */
1965         public static function sendContactAccept($target, $id, $uid)
1966         {
1967                 $profile = APContact::getByURL($target);
1968                 if (empty($profile['inbox'])) {
1969                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1970                         return;
1971                 }
1972
1973                 $owner = User::getOwnerDataById($uid);
1974                 $data = ['@context' => ActivityPub::CONTEXT,
1975                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1976                         'type' => 'Accept',
1977                         'actor' => $owner['url'],
1978                         'object' => [
1979                                 'id' => (string)$id,
1980                                 'type' => 'Follow',
1981                                 'actor' => $profile['url'],
1982                                 'object' => $owner['url']
1983                         ],
1984                         'instrument' => self::getService(),
1985                         'to' => [$profile['url']]];
1986
1987                 Logger::debug('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id);
1988
1989                 $signed = LDSignature::sign($data, $owner);
1990                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1991         }
1992
1993         /**
1994          * Reject a contact request or terminates the contact relation
1995          *
1996          * @param string  $target Target profile
1997          * @param         $id
1998          * @param integer $uid    User ID
1999          * @return bool Operation success
2000          * @throws HTTPException\InternalServerErrorException
2001          * @throws \ImagickException
2002          */
2003         public static function sendContactReject($target, $id, $uid): bool
2004         {
2005                 $profile = APContact::getByURL($target);
2006                 if (empty($profile['inbox'])) {
2007                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
2008                         return false;
2009                 }
2010
2011                 $owner = User::getOwnerDataById($uid);
2012                 $data = ['@context' => ActivityPub::CONTEXT,
2013                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
2014                         'type' => 'Reject',
2015                         'actor' => $owner['url'],
2016                         'object' => [
2017                                 'id' => (string)$id,
2018                                 'type' => 'Follow',
2019                                 'actor' => $profile['url'],
2020                                 'object' => $owner['url']
2021                         ],
2022                         'instrument' => self::getService(),
2023                         'to' => [$profile['url']]];
2024
2025                 Logger::debug('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id);
2026
2027                 $signed = LDSignature::sign($data, $owner);
2028                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
2029         }
2030
2031         /**
2032          * Transmits a message that we don't want to follow this contact anymore
2033          *
2034          * @param string  $target Target profile
2035          * @param integer $uid    User ID
2036          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
2037          * @throws \ImagickException
2038          * @throws \Exception
2039          * @return bool success
2040          */
2041         public static function sendContactUndo($target, $cid, $uid)
2042         {
2043                 $profile = APContact::getByURL($target);
2044                 if (empty($profile['inbox'])) {
2045                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
2046                         return false;
2047                 }
2048
2049                 $object_id = self::activityIDFromContact($cid);
2050                 if (empty($object_id)) {
2051                         return false;
2052                 }
2053
2054                 $id = DI::baseUrl() . '/activity/' . System::createGUID();
2055
2056                 $owner = User::getOwnerDataById($uid);
2057                 $data = ['@context' => ActivityPub::CONTEXT,
2058                         'id' => $id,
2059                         'type' => 'Undo',
2060                         'actor' => $owner['url'],
2061                         'object' => ['id' => $object_id, 'type' => 'Follow',
2062                                 'actor' => $owner['url'],
2063                                 'object' => $profile['url']],
2064                         'instrument' => self::getService(),
2065                         'to' => [$profile['url']]];
2066
2067                 Logger::info('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id);
2068
2069                 $signed = LDSignature::sign($data, $owner);
2070                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
2071         }
2072
2073         private static function prependMentions($body, int $uriid, string $authorLink)
2074         {
2075                 $mentions = [];
2076
2077                 foreach (Tag::getByURIId($uriid, [Tag::IMPLICIT_MENTION]) as $tag) {
2078                         $profile = Contact::getByURL($tag['url'], false, ['addr', 'contact-type', 'nick']);
2079                         if (!empty($profile['addr'])
2080                                 && $profile['contact-type'] != Contact::TYPE_COMMUNITY
2081                                 && !strstr($body, $profile['addr'])
2082                                 && !strstr($body, $tag['url'])
2083                                 && $tag['url'] !== $authorLink
2084                         ) {
2085                                 $mentions[] = '@[url=' . $tag['url'] . ']' . $profile['nick'] . '[/url]';
2086                         }
2087                 }
2088
2089                 $mentions[] = $body;
2090
2091                 return implode(' ', $mentions);
2092         }
2093 }