src/Protocol/ActivityPub/Transmitter.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, 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\Tag;
  40 use Friendica\Model\User;
  41 use Friendica\Network\HTTPException;
  42 use Friendica\Protocol\Activity;
  43 use Friendica\Protocol\ActivityPub;
  44 use Friendica\Protocol\Relay;
  45 use Friendica\Util\DateTimeFormat;
  46 use Friendica\Util\HTTPSignature;
  47 use Friendica\Util\JsonLD;
  48 use Friendica\Util\LDSignature;
  49 use Friendica\Util\Map;
  50 use Friendica\Util\Network;
  51 use Friendica\Util\Strings;
  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          * @param string    $requester URL of the requester
 154          *
 155          * @return array of owners
 156          * @throws \Exception
 157          */
 158         public static function getContacts($owner, $rel, $module, $page = null, string $requester = null)
 159         {
 160                 $parameters = [
 161                         'rel' => $rel,
 162                         'uid' => $owner['uid'],
 163                         'self' => false,
 164                         'deleted' => false,
 165                         'hidden' => false,
 166                         'archive' => false,
 167                         'pending' => false,
 168                         'blocked' => false,
 169                 ];
 170
 171                 $condition = DBA::mergeConditions($parameters, ["`url` IN (SELECT `url` FROM `apcontact`)"]);
 172
 173                 $total = DBA::count('contact', $condition);
 174
 175                 $modulePath = '/' . $module . '/';
 176
 177                 $data = ['@context' => ActivityPub::CONTEXT];
 178                 $data['id'] = DI::baseUrl() . $modulePath . $owner['nickname'];
 179                 $data['type'] = 'OrderedCollection';
 180                 $data['totalItems'] = $total;
 181
 182                 // When we hide our friends we will only show the pure number but don't allow more.
 183                 $show_contacts = empty($owner['hide-friends']);
 184
 185                 // Allow fetching the contact list when the requester is part of the list.
 186                 if (($owner['page-flags'] == User::PAGE_FLAGS_PRVGROUP) && !empty($requester)) {
 187                         $show_contacts = DBA::exists('contact', ['nurl' => Strings::normaliseLink($requester), 'uid' => $owner['uid'], 'blocked' => false]);
 188                 }
 189
 190                 if (!$show_contacts) {
 191                         return $data;
 192                 }
 193
 194                 if (empty($page)) {
 195                         $data['first'] = DI::baseUrl() . $modulePath . $owner['nickname'] . '?page=1';
 196                 } else {
 197                         $data['type'] = 'OrderedCollectionPage';
 198                         $list = [];
 199
 200                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 201                         while ($contact = DBA::fetch($contacts)) {
 202                                 $list[] = $contact['url'];
 203                         }
 204                         DBA::close($contacts);
 205
 206                         if (!empty($list)) {
 207                                 $data['next'] = DI::baseUrl() . $modulePath . $owner['nickname'] . '?page=' . ($page + 1);
 208                         }
 209
 210                         $data['partOf'] = DI::baseUrl() . $modulePath . $owner['nickname'];
 211
 212                         $data['orderedItems'] = $list;
 213                 }
 214
 215                 return $data;
 216         }
 217
 218         /**
 219          * Public posts for the given owner
 220          *
 221          * @param array   $owner     Owner array
 222          * @param integer $page      Page number
 223          * @param string  $requester URL of requesting account
 224          *
 225          * @return array of posts
 226          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 227          * @throws \ImagickException
 228          */
 229         public static function getOutbox($owner, $page = null, $requester = '')
 230         {
 231                 $condition = ['private' => [Item::PUBLIC, Item::UNLISTED]];
 232
 233                 if (!empty($requester)) {
 234                         $requester_id = Contact::getIdForURL($requester, $owner['uid']);
 235                         if (!empty($requester_id)) {
 236                                 $permissionSets = DI::permissionSet()->selectByContactId($requester_id, $owner['uid']);
 237                                 if (!empty($permissionSets)) {
 238                                         $condition = ['psid' => array_merge($permissionSets->column('id'),
 239                                                         [DI::permissionSet()->selectPublicForUser($owner['uid'])])];
 240                                 }
 241                         }
 242                 }
 243
 244                 $condition = array_merge($condition,
 245                         ['uid'           => $owner['uid'],
 246                         'author-id'      => Contact::getIdForURL($owner['url'], 0, false),
 247                         'gravity'        => [GRAVITY_PARENT, GRAVITY_COMMENT],
 248                         'network'        => Protocol::FEDERATED,
 249                         'parent-network' => Protocol::FEDERATED,
 250                         'origin'         => true,
 251                         'deleted'        => false,
 252                         'visible'        => true]);
 253
 254                 $count = Post::count($condition);
 255
 256                 $data = ['@context' => ActivityPub::CONTEXT];
 257                 $data['id'] = DI::baseUrl() . '/outbox/' . $owner['nickname'];
 258                 $data['type'] = 'OrderedCollection';
 259                 $data['totalItems'] = $count;
 260
 261                 if (empty($page)) {
 262                         $data['first'] = DI::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=1';
 263                 } else {
 264                         $data['type'] = 'OrderedCollectionPage';
 265                         $list = [];
 266
 267                         $items = Post::select(['id'], $condition, ['limit' => [($page - 1) * 20, 20], 'order' => ['created' => true]]);
 268                         while ($item = Post::fetch($items)) {
 269                                 $activity = self::createActivityFromItem($item['id'], true);
 270                                 $activity['type'] = $activity['type'] == 'Update' ? 'Create' : $activity['type'];
 271
 272                                 // Only list "Create" activity objects here, no reshares
 273                                 if (!empty($activity['object']) && ($activity['type'] == 'Create')) {
 274                                         $list[] = $activity['object'];
 275                                 }
 276                         }
 277                         DBA::close($items);
 278
 279                         if (!empty($list)) {
 280                                 $data['next'] = DI::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=' . ($page + 1);
 281                         }
 282
 283                         $data['partOf'] = DI::baseUrl() . '/outbox/' . $owner['nickname'];
 284
 285                         $data['orderedItems'] = $list;
 286                 }
 287
 288                 return $data;
 289         }
 290
 291         /**
 292          * Return the service array containing information the used software and it's url
 293          *
 294          * @return array with service data
 295          */
 296         private static function getService()
 297         {
 298                 return ['type' => 'Service',
 299                         'name' =>  FRIENDICA_PLATFORM . " '" . FRIENDICA_CODENAME . "' " . FRIENDICA_VERSION . '-' . DB_UPDATE_VERSION,
 300                         'url' => DI::baseUrl()->get()];
 301         }
 302
 303         /**
 304          * Return the ActivityPub profile of the given user
 305          *
 306          * @param int $uid User ID
 307          * @return array with profile data
 308          * @throws HTTPException\NotFoundException
 309          * @throws HTTPException\InternalServerErrorException
 310          */
 311         public static function getProfile(int $uid): array
 312         {
 313                 $owner = User::getOwnerDataById($uid);
 314                 if (!isset($owner['id'])) {
 315                         DI::logger()->error('Unable to find owner data for uid', ['uid' => $uid, 'callstack' => System::callstack(20)]);
 316                         throw new HTTPException\NotFoundException('User not found.');
 317                 }
 318
 319                 $data = ['@context' => ActivityPub::CONTEXT];
 320                 $data['id'] = $owner['url'];
 321
 322                 if (!empty($owner['guid'])) {
 323                         $data['diaspora:guid'] = $owner['guid'];
 324                 }
 325
 326                 $data['type'] = ActivityPub::ACCOUNT_TYPES[$owner['account-type']];
 327
 328                 if ($uid != 0) {
 329                         $data['following'] = DI::baseUrl() . '/following/' . $owner['nick'];
 330                         $data['followers'] = DI::baseUrl() . '/followers/' . $owner['nick'];
 331                         $data['inbox'] = DI::baseUrl() . '/inbox/' . $owner['nick'];
 332                         $data['outbox'] = DI::baseUrl() . '/outbox/' . $owner['nick'];
 333                 } else {
 334                         $data['inbox'] = DI::baseUrl() . '/friendica/inbox';
 335                 }
 336
 337                 $data['preferredUsername'] = $owner['nick'];
 338                 $data['name'] = $owner['name'];
 339
 340                 if (!empty($owner['country-name'] . $owner['region'] . $owner['locality'])) {
 341                         $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $owner['country-name'],
 342                                 'vcard:region' => $owner['region'], 'vcard:locality' => $owner['locality']];
 343                 }
 344
 345                 if (!empty($owner['about'])) {
 346                         $data['summary'] = BBCode::convertForUriId($owner['uri-id'] ?? 0, $owner['about'], BBCode::EXTERNAL);
 347                 }
 348
 349                 if (!empty($owner['xmpp']) || !empty($owner['matrix'])) {
 350                         $data['vcard:hasInstantMessage'] = [];
 351
 352                         if (!empty($owner['xmpp'])) {
 353                                 $data['vcard:hasInstantMessage'][] = 'xmpp:' . $owner['xmpp'];
 354                         }
 355                         if (!empty($owner['matrix'])) {
 356                                 $data['vcard:hasInstantMessage'][] = 'matrix:' . $owner['matrix'];
 357                         }
 358                 }
 359
 360                 $data['url'] = $owner['url'];
 361                 $data['manuallyApprovesFollowers'] = in_array($owner['page-flags'], [User::PAGE_FLAGS_NORMAL, User::PAGE_FLAGS_PRVGROUP]);
 362                 $data['discoverable'] = (bool)$owner['net-publish'];
 363                 $data['publicKey'] = ['id' => $owner['url'] . '#main-key',
 364                         'owner' => $owner['url'],
 365                         'publicKeyPem' => $owner['pubkey']];
 366                 $data['endpoints'] = ['sharedInbox' => DI::baseUrl() . '/inbox'];
 367                 $data['icon'] = ['type' => 'Image', 'url' => User::getAvatarUrl($owner)];
 368
 369                 $resourceid = Photo::ridFromURI($owner['photo']);
 370                 if (!empty($resourceid)) {
 371                         $photo = Photo::selectFirst(['type'], ["resource-id" => $resourceid]);
 372                         if (!empty($photo['type'])) {
 373                                 $data['icon']['mediaType'] = $photo['type'];
 374                         }
 375                 }
 376
 377                 if (!empty($owner['header'])) {
 378                         $data['image'] = ['type' => 'Image', 'url' => Contact::getHeaderUrlForId($owner['id'], '', $owner['updated'])];
 379
 380                         $resourceid = Photo::ridFromURI($owner['header']);
 381                         if (!empty($resourceid)) {
 382                                 $photo = Photo::selectFirst(['type'], ["resource-id" => $resourceid]);
 383                                 if (!empty($photo['type'])) {
 384                                         $data['image']['mediaType'] = $photo['type'];
 385                                 }
 386                         }
 387                 }
 388
 389                 $custom_fields = [];
 390
 391                 foreach (DI::profileField()->selectByContactId(0, $uid) as $profile_field) {
 392                         $custom_fields[] = [
 393                                 'type' => 'PropertyValue',
 394                                 'name' => $profile_field->label,
 395                                 'value' => BBCode::convertForUriId($owner['uri-id'], $profile_field->value)
 396                         ];
 397                 };
 398
 399                 if (!empty($custom_fields)) {
 400                         $data['attachment'] = $custom_fields;
 401                 }
 402
 403                 $data['generator'] = self::getService();
 404
 405                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 406                 return $data;
 407         }
 408
 409         /**
 410          * @param string $username
 411          * @return array
 412          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 413          */
 414         public static function getDeletedUser($username)
 415         {
 416                 return [
 417                         '@context' => ActivityPub::CONTEXT,
 418                         'id' => DI::baseUrl() . '/profile/' . $username,
 419                         'type' => 'Tombstone',
 420                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 421                         'updated' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 422                         'deleted' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
 423                 ];
 424         }
 425
 426         /**
 427          * Returns an array with permissions of a given item array
 428          *
 429          * @param array $item
 430          *
 431          * @return array with permissions
 432          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 433          * @throws \ImagickException
 434          */
 435         private static function fetchPermissionBlockFromConversation($item)
 436         {
 437                 if (empty($item['thr-parent'])) {
 438                         return [];
 439                 }
 440
 441                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 442                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 443                 if (!DBA::isResult($conversation)) {
 444                         return [];
 445                 }
 446
 447                 $permissions = [
 448                         'to' => [],
 449                         'cc' => [],
 450                         'bto' => [],
 451                         'bcc' => [],
 452                 ];
 453
 454                 $activity = json_decode($conversation['source'], true);
 455
 456                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 457                 if (!empty($actor)) {
 458                         $permissions['to'][] = $actor;
 459                         $profile = APContact::getByURL($actor);
 460                 } else {
 461                         $profile = [];
 462                 }
 463
 464                 $item_profile = APContact::getByURL($item['author-link']);
 465                 $exclude[] = $item['author-link'];
 466
 467                 if ($item['gravity'] == GRAVITY_PARENT) {
 468                         $exclude[] = $item['owner-link'];
 469                 }
 470
 471                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 472                         if (empty($activity[$element])) {
 473                                 continue;
 474                         }
 475                         if (is_string($activity[$element])) {
 476                                 $activity[$element] = [$activity[$element]];
 477                         }
 478
 479                         foreach ($activity[$element] as $receiver) {
 480                                 if (empty($receiver)) {
 481                                         continue;
 482                                 }
 483
 484                                 if (!empty($profile['followers']) && $receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 485                                         $permissions[$element][] = $item_profile['followers'];
 486                                 } elseif (!in_array($receiver, $exclude)) {
 487                                         $permissions[$element][] = $receiver;
 488                                 }
 489                         }
 490                 }
 491                 return $permissions;
 492         }
 493
 494         /**
 495          * Check if the given item id is from ActivityPub
 496          *
 497          * @param integer $item_id
 498          * @return boolean "true" if the post is from ActivityPub
 499          */
 500         private static function isAPPost(int $item_id)
 501         {
 502                 if (empty($item_id)) {
 503                         return false;
 504                 }
 505
 506                 return Post::exists(['id' => $item_id, 'network' => Protocol::ACTIVITYPUB]);
 507         }
 508
 509         /**
 510          * Creates an array of permissions from an item thread
 511          *
 512          * @param array   $item       Item array
 513          * @param boolean $blindcopy  addressing via "bcc" or "cc"?
 514          * @param integer $last_id    Last item id for adding receivers
 515          * @param boolean $forum_post "true" means that we are sending content to a forum
 516          *
 517          * @return array with permission data
 518          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 519          * @throws \ImagickException
 520          */
 521         private static function createPermissionBlockForItem($item, $blindcopy, $last_id = 0, $forum_post = false)
 522         {
 523                 if ($last_id == 0) {
 524                         $last_id = $item['id'];
 525                 }
 526
 527                 $always_bcc = false;
 528
 529                 // Check if we should always deliver our stuff via BCC
 530                 if (!empty($item['uid'])) {
 531                         $profile = User::getOwnerDataById($item['uid']);
 532                         if (!empty($profile)) {
 533                                 $always_bcc = $profile['hide-friends'];
 534                         }
 535                 }
 536
 537                 if (DI::config()->get('system', 'ap_always_bcc')) {
 538                         $always_bcc = true;
 539                 }
 540
 541                 if (self::isAnnounce($item) || DI::config()->get('debug', 'total_ap_delivery') || self::isAPPost($last_id)) {
 542                         // Will be activated in a later step
 543                         $networks = Protocol::FEDERATED;
 544                 } else {
 545                         // For now only send to these contacts:
 546                         $networks = [Protocol::ACTIVITYPUB, Protocol::OSTATUS];
 547                 }
 548
 549                 $data = ['to' => [], 'cc' => [], 'bcc' => []];
 550
 551                 if ($item['gravity'] == GRAVITY_PARENT) {
 552                         $actor_profile = APContact::getByURL($item['owner-link']);
 553                 } else {
 554                         $actor_profile = APContact::getByURL($item['author-link']);
 555                 }
 556
 557                 $exclusive = false;
 558
 559                 $terms = Tag::getByURIId($item['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
 560
 561                 if ($item['private'] != Item::PRIVATE) {
 562                         // Directly mention the original author upon a quoted reshare.
 563                         // Else just ensure that the original author receives the reshare.
 564                         $announce = self::getAnnounceArray($item);
 565                         if (!empty($announce['comment'])) {
 566                                 $data['to'][] = $announce['actor']['url'];
 567                         } elseif (!empty($announce)) {
 568                                 $data['cc'][] = $announce['actor']['url'];
 569                         }
 570
 571                         $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 572
 573                         // Check if the item is completely public or unlisted
 574                         if ($item['private'] == Item::PUBLIC) {
 575                                 $data['to'][] = ActivityPub::PUBLIC_COLLECTION;
 576                         } else {
 577                                 $data['cc'][] = ActivityPub::PUBLIC_COLLECTION;
 578                         }
 579
 580                         foreach ($terms as $term) {
 581                                 $profile = APContact::getByURL($term['url'], false);
 582                                 if (!empty($profile)) {
 583                                         if ($term['type'] == Tag::EXCLUSIVE_MENTION) {
 584                                                 $exclusive = true;
 585                                                 if (!empty($profile['followers']) && ($profile['type'] == 'Group')) {
 586                                                         $data['cc'][] = $profile['followers'];
 587                                                 }
 588                                         }
 589                                         $data['to'][] = $profile['url'];
 590                                 }
 591                         }
 592                 } else {
 593                         $receiver_list = Item::enumeratePermissions($item, true);
 594
 595                         foreach ($terms as $term) {
 596                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 597                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 598                                         $contact = DBA::selectFirst('contact', ['url', 'network', 'protocol', 'gsid'], ['id' => $cid, 'network' => Protocol::FEDERATED]);
 599                                         if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
 600                                                 continue;
 601                                         }
 602
 603                                         $profile = APContact::getByURL($term['url'], false);
 604                                         if (!empty($profile)) {
 605                                                 if ($term['type'] == Tag::EXCLUSIVE_MENTION) {
 606                                                         $exclusive = true;
 607                                                         if (!empty($profile['followers']) && ($profile['type'] == 'Group')) {
 608                                                                 $data['cc'][] = $profile['followers'];
 609                                                         }
 610                                                 }
 611                                                 $data['to'][] = $profile['url'];
 612                                         }
 613                                 }
 614                         }
 615
 616                         if (!$exclusive) {
 617                                 foreach ($receiver_list as $receiver) {
 618                                         $contact = DBA::selectFirst('contact', ['url', 'hidden', 'network', 'protocol', 'gsid'], ['id' => $receiver, 'network' => Protocol::FEDERATED]);
 619                                         if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
 620                                                 continue;
 621                                         }
 622
 623                                         if (!empty($profile = APContact::getByURL($contact['url'], false))) {
 624                                                 if ($contact['hidden'] || $always_bcc) {
 625                                                         $data['bcc'][] = $profile['url'];
 626                                                 } else {
 627                                                         $data['cc'][] = $profile['url'];
 628                                                 }
 629                                         }
 630                                 }
 631                         }
 632                 }
 633
 634                 if (!empty($item['parent'])) {
 635                         $parents = Post::select(['id', 'author-link', 'owner-link', 'gravity', 'uri'], ['parent' => $item['parent']]);
 636                         while ($parent = Post::fetch($parents)) {
 637                                 if ($parent['gravity'] == GRAVITY_PARENT) {
 638                                         $profile = APContact::getByURL($parent['owner-link'], false);
 639                                         if (!empty($profile)) {
 640                                                 if ($item['gravity'] != GRAVITY_PARENT) {
 641                                                         // Comments to forums are directed to the forum
 642                                                         // But comments to forums aren't directed to the followers collection
 643                                                         // This rule is only valid when the actor isn't the forum.
 644                                                         // The forum needs to transmit their content to their followers.
 645                                                         if (($profile['type'] == 'Group') && ($profile['url'] != ($actor_profile['url'] ?? ''))) {
 646                                                                 $data['to'][] = $profile['url'];
 647                                                         } else {
 648                                                                 $data['cc'][] = $profile['url'];
 649                                                                 if (($item['private'] != Item::PRIVATE) && !empty($actor_profile['followers'])) {
 650                                                                         $data['cc'][] = $actor_profile['followers'];
 651                                                                 }
 652                                                         }
 653                                                 } elseif (!$exclusive) {
 654                                                         // Public thread parent post always are directed to the followers.
 655                                                         // This mustn't be done by posts that are directed to forum servers via the exclusive mention.
 656                                                         // But possibly in that case we could add the "followers" collection of the forum to the message.
 657                                                         if (($item['private'] != Item::PRIVATE) && !$forum_post) {
 658                                                                 $data['cc'][] = $actor_profile['followers'];
 659                                                         }
 660                                                 }
 661                                         }
 662                                 }
 663
 664                                 // Don't include data from future posts
 665                                 if ($parent['id'] >= $last_id) {
 666                                         continue;
 667                                 }
 668
 669                                 $profile = APContact::getByURL($parent['author-link'], false);
 670                                 if (!empty($profile)) {
 671                                         if (($profile['type'] == 'Group') || ($parent['uri'] == $item['thr-parent'])) {
 672                                                 $data['to'][] = $profile['url'];
 673                                         } else {
 674                                                 $data['cc'][] = $profile['url'];
 675                                         }
 676                                 }
 677                         }
 678                         DBA::close($parents);
 679                 }
 680
 681                 $data['to'] = array_unique($data['to']);
 682                 $data['cc'] = array_unique($data['cc']);
 683                 $data['bcc'] = array_unique($data['bcc']);
 684
 685                 if (($key = array_search($item['author-link'], $data['to'])) !== false) {
 686                         unset($data['to'][$key]);
 687                 }
 688
 689                 if (($key = array_search($item['author-link'], $data['cc'])) !== false) {
 690                         unset($data['cc'][$key]);
 691                 }
 692
 693                 if (($key = array_search($item['author-link'], $data['bcc'])) !== false) {
 694                         unset($data['bcc'][$key]);
 695                 }
 696
 697                 foreach ($data['to'] as $to) {
 698                         if (($key = array_search($to, $data['cc'])) !== false) {
 699                                 unset($data['cc'][$key]);
 700                         }
 701
 702                         if (($key = array_search($to, $data['bcc'])) !== false) {
 703                                 unset($data['bcc'][$key]);
 704                         }
 705                 }
 706
 707                 foreach ($data['cc'] as $cc) {
 708                         if (($key = array_search($cc, $data['bcc'])) !== false) {
 709                                 unset($data['bcc'][$key]);
 710                         }
 711                 }
 712
 713                 $receivers = ['to' => array_values($data['to']), 'cc' => array_values($data['cc']), 'bcc' => array_values($data['bcc'])];
 714
 715                 if (!$blindcopy) {
 716                         unset($receivers['bcc']);
 717                 }
 718
 719                 return $receivers;
 720         }
 721
 722         /**
 723          * Check if an inbox is archived
 724          *
 725          * @param string $url Inbox url
 726          *
 727          * @return boolean "true" if inbox is archived
 728          */
 729         public static function archivedInbox($url)
 730         {
 731                 return DBA::exists('inbox-status', ['url' => $url, 'archive' => true]);
 732         }
 733
 734         /**
 735          * Check if a given contact should be delivered via AP
 736          *
 737          * @param array $contact
 738          * @param array $networks
 739          * @return bool
 740          * @throws Exception
 741          */
 742         private static function isAPContact(array $contact, array $networks)
 743         {
 744                 if (in_array($contact['network'], $networks) || ($contact['protocol'] == Protocol::ACTIVITYPUB)) {
 745                         return true;
 746                 }
 747
 748                 return GServer::getProtocol($contact['gsid'] ?? 0) == Post\DeliveryData::ACTIVITYPUB;
 749         }
 750
 751         /**
 752          * Fetches a list of inboxes of followers of a given user
 753          *
 754          * @param integer $uid      User ID
 755          * @param boolean $personal fetch personal inboxes
 756          * @param boolean $all_ap   Retrieve all AP enabled inboxes
 757          *
 758          * @return array of follower inboxes
 759          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 760          * @throws \ImagickException
 761          */
 762         public static function fetchTargetInboxesforUser($uid, $personal = false, bool $all_ap = false)
 763         {
 764                 $inboxes = [];
 765
 766                 $isforum = false;
 767
 768                 if (!empty($item['uid'])) {
 769                         $profile = User::getOwnerDataById($item['uid']);
 770                         if (!empty($profile)) {
 771                                 $isforum = $profile['account-type'] == User::ACCOUNT_TYPE_COMMUNITY;
 772                         }
 773                 }
 774
 775                 if (DI::config()->get('debug', 'total_ap_delivery') || $all_ap) {
 776                         // Will be activated in a later step
 777                         $networks = Protocol::FEDERATED;
 778                 } else {
 779                         // For now only send to these contacts:
 780                         $networks = [Protocol::ACTIVITYPUB, Protocol::OSTATUS];
 781                 }
 782
 783                 $condition = ['uid' => $uid, 'archive' => false, 'pending' => false, 'blocked' => false, 'network' => Protocol::FEDERATED];
 784
 785                 if (!empty($uid)) {
 786                         $condition['rel'] = [Contact::FOLLOWER, Contact::FRIEND];
 787                 }
 788
 789                 $contacts = DBA::select('contact', ['id', 'url', 'network', 'protocol', 'gsid'], $condition);
 790                 while ($contact = DBA::fetch($contacts)) {
 791                         if (!self::isAPContact($contact, $networks)) {
 792                                 continue;
 793                         }
 794
 795                         if ($isforum && ($contact['network'] == Protocol::DFRN)) {
 796                                 continue;
 797                         }
 798
 799                         if (Network::isUrlBlocked($contact['url'])) {
 800                                 continue;
 801                         }
 802
 803                         $profile = APContact::getByURL($contact['url'], false);
 804                         if (!empty($profile)) {
 805                                 if (empty($profile['sharedinbox']) || $personal || Contact::isLocal($contact['url'])) {
 806                                         $target = $profile['inbox'];
 807                                 } else {
 808                                         $target = $profile['sharedinbox'];
 809                                 }
 810                                 if (!self::archivedInbox($target)) {
 811                                         $inboxes[$target][] = $contact['id'];
 812                                 }
 813                         }
 814                 }
 815                 DBA::close($contacts);
 816
 817                 return $inboxes;
 818         }
 819
 820         /**
 821          * Fetches an array of inboxes for the given item and user
 822          *
 823          * @param array   $item       Item array
 824          * @param integer $uid        User ID
 825          * @param boolean $personal   fetch personal inboxes
 826          * @param integer $last_id    Last item id for adding receivers
 827          * @param boolean $forum_post "true" means that we are sending content to a forum
 828          * @return array with inboxes
 829          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 830          * @throws \ImagickException
 831          */
 832         public static function fetchTargetInboxes($item, $uid, $personal = false, $last_id = 0, $forum_post = false)
 833         {
 834                 $permissions = self::createPermissionBlockForItem($item, true, $last_id, $forum_post);
 835                 if (empty($permissions)) {
 836                         return [];
 837                 }
 838
 839                 $inboxes = [];
 840
 841                 if ($item['gravity'] == GRAVITY_ACTIVITY) {
 842                         $item_profile = APContact::getByURL($item['author-link'], false);
 843                 } else {
 844                         $item_profile = APContact::getByURL($item['owner-link'], false);
 845                 }
 846
 847                 if (empty($item_profile)) {
 848                         return [];
 849                 }
 850
 851                 $profile_uid = User::getIdForURL($item_profile['url']);
 852
 853                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 854                         if (empty($permissions[$element])) {
 855                                 continue;
 856                         }
 857
 858                         $blindcopy = in_array($element, ['bto', 'bcc']);
 859
 860                         foreach ($permissions[$element] as $receiver) {
 861                                 if (empty($receiver) || Network::isUrlBlocked($receiver)) {
 862                                         continue;
 863                                 }
 864
 865                                 if ($item_profile && ($receiver == $item_profile['followers']) && ($uid == $profile_uid)) {
 866                                         $inboxes = array_merge($inboxes, self::fetchTargetInboxesforUser($uid, $personal, self::isAPPost($last_id)));
 867                                 } else {
 868                                         $profile = APContact::getByURL($receiver, false);
 869                                         if (!empty($profile)) {
 870                                                 $contact = Contact::getByURLForUser($receiver, $uid, false, ['id']);
 871
 872                                                 if (empty($profile['sharedinbox']) || $personal || $blindcopy || Contact::isLocal($receiver)) {
 873                                                         $target = $profile['inbox'];
 874                                                 } else {
 875                                                         $target = $profile['sharedinbox'];
 876                                                 }
 877                                                 if (!self::archivedInbox($target)) {
 878                                                         $inboxes[$target][] = $contact['id'] ?? 0;
 879                                                 }
 880                                         }
 881                                 }
 882                         }
 883                 }
 884
 885                 return $inboxes;
 886         }
 887
 888         /**
 889          * Creates an array in the structure of the item table for a given mail id
 890          *
 891          * @param integer $mail_id
 892          *
 893          * @return array
 894          * @throws \Exception
 895          */
 896         public static function ItemArrayFromMail($mail_id, $use_title = false)
 897         {
 898                 $mail = DBA::selectFirst('mail', [], ['id' => $mail_id]);
 899                 if (!DBA::isResult($mail)) {
 900                         return [];
 901                 }
 902
 903                 $reply = DBA::selectFirst('mail', ['uri', 'uri-id', 'from-url'], ['parent-uri' => $mail['parent-uri'], 'reply' => false]);
 904                 if (!DBA::isResult($reply)) {
 905                         $reply = $mail;
 906                 }
 907
 908                 // Making the post more compatible for Mastodon by:
 909                 // - Making it a note and not an article (no title)
 910                 // - Moving the title into the "summary" field that is used as a "content warning"
 911
 912                 if (!$use_title) {
 913                         $mail['body']         = '[abstract]' . $mail['title'] . "[/abstract]\n" . $mail['body'];
 914                         $mail['title']        = '';
 915                 }
 916
 917                 $mail['author-link']      = $mail['owner-link'] = $mail['from-url'];
 918                 $mail['owner-id']         = $mail['author-id'];
 919                 $mail['allow_cid']        = '<'.$mail['contact-id'].'>';
 920                 $mail['allow_gid']        = '';
 921                 $mail['deny_cid']         = '';
 922                 $mail['deny_gid']         = '';
 923                 $mail['private']          = Item::PRIVATE;
 924                 $mail['deleted']          = false;
 925                 $mail['edited']           = $mail['created'];
 926                 $mail['plink']            = DI::baseUrl() . '/message/' . $mail['id'];
 927                 $mail['parent-uri']       = $reply['uri'];
 928                 $mail['parent-uri-id']    = $reply['uri-id'];
 929                 $mail['parent-author-id'] = Contact::getIdForURL($reply['from-url'], 0, false);
 930                 $mail['gravity']          = ($mail['reply'] ? GRAVITY_COMMENT: GRAVITY_PARENT);
 931                 $mail['event-type']       = '';
 932                 $mail['language']         = '';
 933                 $mail['parent']           = 0;
 934
 935                 return $mail;
 936         }
 937
 938         /**
 939          * Creates an activity array for a given mail id
 940          *
 941          * @param integer $mail_id
 942          * @param boolean $object_mode Is the activity item is used inside another object?
 943          *
 944          * @return array of activity
 945          * @throws \Exception
 946          */
 947         public static function createActivityFromMail($mail_id, $object_mode = false)
 948         {
 949                 $mail = self::ItemArrayFromMail($mail_id);
 950                 if (empty($mail)) {
 951                         return [];
 952                 }
 953                 $object = self::createNote($mail);
 954
 955                 if (!$object_mode) {
 956                         $data = ['@context' => ActivityPub::CONTEXT];
 957                 } else {
 958                         $data = [];
 959                 }
 960
 961                 $data['id'] = $mail['uri'] . '/Create';
 962                 $data['type'] = 'Create';
 963                 $data['actor'] = $mail['author-link'];
 964                 $data['published'] = DateTimeFormat::utc($mail['created'] . '+00:00', DateTimeFormat::ATOM);
 965                 $data['instrument'] = self::getService();
 966                 $data = array_merge($data, self::createPermissionBlockForItem($mail, true));
 967
 968                 if (empty($data['to']) && !empty($data['cc'])) {
 969                         $data['to'] = $data['cc'];
 970                 }
 971
 972                 if (empty($data['to']) && !empty($data['bcc'])) {
 973                         $data['to'] = $data['bcc'];
 974                 }
 975
 976                 unset($data['cc']);
 977                 unset($data['bcc']);
 978
 979                 $object['to'] = $data['to'];
 980                 $object['tag'] = [['type' => 'Mention', 'href' => $object['to'][0], 'name' => '']];
 981
 982                 unset($object['cc']);
 983                 unset($object['bcc']);
 984
 985                 $data['directMessage'] = true;
 986
 987                 $data['object'] = $object;
 988
 989                 $owner = User::getOwnerDataById($mail['uid']);
 990
 991                 if (!$object_mode && !empty($owner)) {
 992                         return LDSignature::sign($data, $owner);
 993                 } else {
 994                         return $data;
 995                 }
 996         }
 997
 998         /**
 999          * Returns the activity type of a given item
1000          *
1001          * @param array $item
1002          *
1003          * @return string with activity type
1004          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1005          * @throws \ImagickException
1006          */
1007         private static function getTypeOfItem($item)
1008         {
1009                 $reshared = false;
1010
1011                 // Only check for a reshare, if it is a real reshare and no quoted reshare
1012                 if (strpos($item['body'], "[share") === 0) {
1013                         $announce = self::getAnnounceArray($item);
1014                         $reshared = !empty($announce);
1015                 }
1016
1017                 if ($reshared) {
1018                         $type = 'Announce';
1019                 } elseif ($item['verb'] == Activity::POST) {
1020                         if ($item['created'] == $item['edited']) {
1021                                 $type = 'Create';
1022                         } else {
1023                                 $type = 'Update';
1024                         }
1025                 } elseif ($item['verb'] == Activity::LIKE) {
1026                         $type = 'Like';
1027                 } elseif ($item['verb'] == Activity::DISLIKE) {
1028                         $type = 'Dislike';
1029                 } elseif ($item['verb'] == Activity::ATTEND) {
1030                         $type = 'Accept';
1031                 } elseif ($item['verb'] == Activity::ATTENDNO) {
1032                         $type = 'Reject';
1033                 } elseif ($item['verb'] == Activity::ATTENDMAYBE) {
1034                         $type = 'TentativeAccept';
1035                 } elseif ($item['verb'] == Activity::FOLLOW) {
1036                         $type = 'Follow';
1037                 } elseif ($item['verb'] == Activity::TAG) {
1038                         $type = 'Add';
1039                 } elseif ($item['verb'] == Activity::ANNOUNCE) {
1040                         $type = 'Announce';
1041                 } else {
1042                         $type = '';
1043                 }
1044
1045                 return $type;
1046         }
1047
1048         /**
1049          * Creates the activity or fetches it from the cache
1050          *
1051          * @param integer $item_id
1052          * @param boolean $force Force new cache entry
1053          *
1054          * @return array with the activity
1055          * @throws \Exception
1056          */
1057         public static function createCachedActivityFromItem($item_id, $force = false)
1058         {
1059                 $cachekey = 'APDelivery:createActivity:' . $item_id;
1060
1061                 if (!$force) {
1062                         $data = DI::cache()->get($cachekey);
1063                         if (!is_null($data)) {
1064                                 return $data;
1065                         }
1066                 }
1067
1068                 $data = self::createActivityFromItem($item_id);
1069
1070                 DI::cache()->set($cachekey, $data, Duration::QUARTER_HOUR);
1071                 return $data;
1072         }
1073
1074         /**
1075          * Creates an activity array for a given item id
1076          *
1077          * @param integer $item_id
1078          * @param boolean $object_mode Is the activity item is used inside another object?
1079          *
1080          * @return false|array
1081          * @throws \Exception
1082          */
1083         public static function createActivityFromItem(int $item_id, bool $object_mode = false)
1084         {
1085                 Logger::info('Fetching activity', ['item' => $item_id]);
1086                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
1087                 if (!DBA::isResult($item)) {
1088                         return false;
1089                 }
1090
1091                 if (empty($item['uri-id'])) {
1092                         Logger::warning('Item without uri-id', ['item' => $item]);
1093                         return false;
1094                 }
1095
1096                 if (!$item['deleted']) {
1097                         $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
1098                         $conversation = DBA::selectFirst('conversation', ['source'], $condition);
1099                         if (!$item['origin'] && DBA::isResult($conversation)) {
1100                                 $data = json_decode($conversation['source'], true);
1101                                 if (!empty($data['type'])) {
1102                                         if (in_array($data['type'], ['Create', 'Update'])) {
1103                                                 if ($object_mode) {
1104                                                         unset($data['@context']);
1105                                                         unset($data['signature']);
1106                                                 }
1107                                                 Logger::info('Return stored conversation', ['item' => $item_id]);
1108                                                 return $data;
1109                                         } elseif (in_array('as:' . $data['type'], Receiver::CONTENT_TYPES)) {
1110                                                 if (!empty($data['@context'])) {
1111                                                         $context = $data['@context'];
1112                                                         unset($data['@context']);
1113                                                 }
1114                                                 unset($data['actor']);
1115                                                 $object = $data;
1116                                         }
1117                                 }
1118                         }
1119                 }
1120
1121                 $type = self::getTypeOfItem($item);
1122
1123                 if (!$object_mode) {
1124                         $data = ['@context' => $context ?? ActivityPub::CONTEXT];
1125
1126                         if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
1127                                 $type = 'Undo';
1128                         } elseif ($item['deleted']) {
1129                                 $type = 'Delete';
1130                         }
1131                 } else {
1132                         $data = [];
1133                 }
1134
1135                 if ($type == 'Delete') {
1136                         $data['id'] = Item::newURI($item['uid'], $item['guid']) . '/' . $type;;
1137                 } elseif (($item['gravity'] == GRAVITY_ACTIVITY) && ($type != 'Undo')) {
1138                         $data['id'] = $item['uri'];
1139                 } else {
1140                         $data['id'] = $item['uri'] . '/' . $type;
1141                 }
1142
1143                 $data['type'] = $type;
1144
1145                 if (($type != 'Announce') || ($item['gravity'] != GRAVITY_PARENT)) {
1146                         $data['actor'] = $item['author-link'];
1147                 } else {
1148                         $data['actor'] = $item['owner-link'];
1149                 }
1150
1151                 $data['published'] = DateTimeFormat::utc($item['created'] . '+00:00', DateTimeFormat::ATOM);
1152
1153                 $data['instrument'] = self::getService();
1154
1155                 $data = array_merge($data, self::createPermissionBlockForItem($item, false));
1156
1157                 if (in_array($data['type'], ['Create', 'Update', 'Delete'])) {
1158                         $data['object'] = $object ?? self::createNote($item);
1159                 } elseif ($data['type'] == 'Add') {
1160                         $data = self::createAddTag($item, $data);
1161                 } elseif ($data['type'] == 'Announce') {
1162                         if ($item['verb'] == ACTIVITY::ANNOUNCE) {
1163                                 $data['object'] = $item['thr-parent'];
1164                         } else {
1165                                 $data = self::createAnnounce($item, $data);
1166                         }
1167                 } elseif ($data['type'] == 'Follow') {
1168                         $data['object'] = $item['parent-uri'];
1169                 } elseif ($data['type'] == 'Undo') {
1170                         $data['object'] = self::createActivityFromItem($item_id, true);
1171                 } else {
1172                         $data['diaspora:guid'] = $item['guid'];
1173                         if (!empty($item['signed_text'])) {
1174                                 $data['diaspora:like'] = $item['signed_text'];
1175                         }
1176                         $data['object'] = $item['thr-parent'];
1177                 }
1178
1179                 if (!empty($item['contact-uid'])) {
1180                         $uid = $item['contact-uid'];
1181                 } else {
1182                         $uid = $item['uid'];
1183                 }
1184
1185                 $owner = User::getOwnerDataById($uid);
1186
1187                 Logger::info('Fetched activity', ['item' => $item_id, 'uid' => $uid]);
1188
1189                 // We don't sign if we aren't the actor. This is important for relaying content especially for forums
1190                 if (!$object_mode && !empty($owner) && ($data['actor'] == $owner['url'])) {
1191                         return LDSignature::sign($data, $owner);
1192                 } else {
1193                         return $data;
1194                 }
1195
1196                 /// @todo Create "conversation" entry
1197         }
1198
1199         /**
1200          * Creates a location entry for a given item array
1201          *
1202          * @param array $item
1203          *
1204          * @return array with location array
1205          */
1206         private static function createLocation($item)
1207         {
1208                 $location = ['type' => 'Place'];
1209
1210                 if (!empty($item['location'])) {
1211                         $location['name'] = $item['location'];
1212                 }
1213
1214                 $coord = [];
1215
1216                 if (empty($item['coord'])) {
1217                         $coord = Map::getCoordinates($item['location']);
1218                 } else {
1219                         $coords = explode(' ', $item['coord']);
1220                         if (count($coords) == 2) {
1221                                 $coord = ['lat' => $coords[0], 'lon' => $coords[1]];
1222                         }
1223                 }
1224
1225                 if (!empty($coord['lat']) && !empty($coord['lon'])) {
1226                         $location['latitude'] = $coord['lat'];
1227                         $location['longitude'] = $coord['lon'];
1228                 }
1229
1230                 return $location;
1231         }
1232
1233         /**
1234          * Returns a tag array for a given item array
1235          *
1236          * @param array $item
1237          *
1238          * @return array of tags
1239          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1240          */
1241         private static function createTagList($item)
1242         {
1243                 $tags = [];
1244
1245                 $terms = Tag::getByURIId($item['uri-id'], [Tag::HASHTAG, Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1246                 foreach ($terms as $term) {
1247                         if ($term['type'] == Tag::HASHTAG) {
1248                                 $url = DI::baseUrl() . '/search?tag=' . urlencode($term['name']);
1249                                 $tags[] = ['type' => 'Hashtag', 'href' => $url, 'name' => '#' . $term['name']];
1250                         } else {
1251                                 $contact = Contact::getByURL($term['url'], false, ['addr']);
1252                                 if (empty($contact)) {
1253                                         continue;
1254                                 }
1255                                 if (!empty($contact['addr'])) {
1256                                         $mention = '@' . $contact['addr'];
1257                                 } else {
1258                                         $mention = '@' . $term['url'];
1259                                 }
1260
1261                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
1262                         }
1263                 }
1264
1265                 $announce = self::getAnnounceArray($item);
1266                 // Mention the original author upon commented reshares
1267                 if (!empty($announce['comment'])) {
1268                         $tags[] = ['type' => 'Mention', 'href' => $announce['actor']['url'], 'name' => '@' . $announce['actor']['addr']];
1269                 }
1270
1271                 return $tags;
1272         }
1273
1274         /**
1275          * Adds attachment data to the JSON document
1276          *
1277          * @param array  $item Data of the item that is to be posted
1278          * @param string $type Object type
1279          *
1280          * @return array with attachment data
1281          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1282          */
1283         private static function createAttachmentList($item, $type)
1284         {
1285                 $attachments = [];
1286
1287                 $uriids = [$item['uri-id']];
1288                 $shared = BBCode::fetchShareAttributes($item['body']);
1289                 if (!empty($shared['guid'])) {
1290                         $shared_item = Post::selectFirst(['uri-id'], ['guid' => $shared['guid']]);
1291                         if (!empty($shared_item['uri-id'])) {
1292                                 $uriids[] = $shared_item['uri-id'];
1293                         }
1294                 }
1295
1296                 $urls = [];
1297                 foreach ($uriids as $uriid) {
1298                         foreach (Post\Media::getByURIId($uriid, [Post\Media::AUDIO, Post\Media::IMAGE, Post\Media::VIDEO, Post\Media::DOCUMENT, Post\Media::TORRENT]) as $attachment) {
1299                                 if (in_array($attachment['url'], $urls)) {
1300                                         continue;
1301                                 }
1302                                 $urls[] = $attachment['url'];
1303
1304                                 $attach = ['type' => 'Document',
1305                                         'mediaType' => $attachment['mimetype'],
1306                                         'url' => $attachment['url'],
1307                                         'name' => $attachment['description']];
1308
1309                                 if (!empty($attachment['height'])) {
1310                                         $attach['height'] = $attachment['height'];
1311                                 }
1312
1313                                 if (!empty($attachment['width'])) {
1314                                         $attach['width'] = $attachment['width'];
1315                                 }
1316
1317                                 if (!empty($attachment['preview'])) {
1318                                         $attach['image'] = $attachment['preview'];
1319                                 }
1320
1321                                 $attachments[] = $attach;
1322                         }
1323                 }
1324
1325                 return $attachments;
1326         }
1327
1328         /**
1329          * Callback function to replace a Friendica style mention in a mention for a summary
1330          *
1331          * @param array $match Matching values for the callback
1332          * @return string Replaced mention
1333          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1334          */
1335         private static function mentionAddrCallback($match)
1336         {
1337                 if (empty($match[1])) {
1338                         return '';
1339                 }
1340
1341                 $data = Contact::getByURL($match[1], false, ['addr']);
1342                 if (empty($data['addr'])) {
1343                         return $match[0];
1344                 }
1345
1346                 return '@' . $data['addr'];
1347         }
1348
1349         /**
1350          * Remove image elements since they are added as attachment
1351          *
1352          * @param string $body
1353          *
1354          * @return string with removed images
1355          */
1356         private static function removePictures($body)
1357         {
1358                 // Simplify image codes
1359                 $body = preg_replace("/\[img\=([0-9]*)x([0-9]*)\](.*?)\[\/img\]/ism", '[img]$3[/img]', $body);
1360                 $body = preg_replace("/\[img\=(.*?)\](.*?)\[\/img\]/ism", '[img]$1[/img]', $body);
1361
1362                 // Now remove local links
1363                 $body = preg_replace_callback(
1364                         '/\[url=([^\[\]]*)\]\[img\](.*)\[\/img\]\[\/url\]/Usi',
1365                         function ($match) {
1366                                 // We remove the link when it is a link to a local photo page
1367                                 if (Photo::isLocalPage($match[1])) {
1368                                         return '';
1369                                 }
1370                                 // otherwise we just return the link
1371                                 return '[url]' . $match[1] . '[/url]';
1372                         },
1373                         $body
1374                 );
1375
1376                 // Remove all pictures
1377                 $body = preg_replace("/\[img\]([^\[\]]*)\[\/img\]/Usi", '', $body);
1378
1379                 return $body;
1380         }
1381
1382         /**
1383          * Fetches the "context" value for a givem item array from the "conversation" table
1384          *
1385          * @param array $item
1386          *
1387          * @return string with context url
1388          * @throws \Exception
1389          */
1390         private static function fetchContextURLForItem($item)
1391         {
1392                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
1393                 if (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
1394                         $context_uri = $conversation['conversation-href'];
1395                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
1396                         $context_uri = $conversation['conversation-uri'];
1397                 } else {
1398                         $context_uri = $item['parent-uri'] . '#context';
1399                 }
1400                 return $context_uri;
1401         }
1402
1403         /**
1404          * Returns if the post contains sensitive content ("nsfw")
1405          *
1406          * @param integer $uri_id
1407          *
1408          * @return boolean
1409          * @throws \Exception
1410          */
1411         private static function isSensitive($uri_id)
1412         {
1413                 return DBA::exists('tag-view', ['uri-id' => $uri_id, 'name' => 'nsfw']);
1414         }
1415
1416         /**
1417          * Creates event data
1418          *
1419          * @param array $item
1420          *
1421          * @return array with the event data
1422          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1423          */
1424         private static function createEvent($item)
1425         {
1426                 $event = [];
1427                 $event['name'] = $item['event-summary'];
1428                 $event['content'] = BBCode::convertForUriId($item['uri-id'], $item['event-desc'], BBCode::ACTIVITYPUB);
1429                 $event['startTime'] = DateTimeFormat::utc($item['event-start'], 'c');
1430
1431                 if (!$item['event-nofinish']) {
1432                         $event['endTime'] = DateTimeFormat::utc($item['event-finish'], 'c');
1433                 }
1434
1435                 if (!empty($item['event-location'])) {
1436                         $item['location'] = $item['event-location'];
1437                         $event['location'] = self::createLocation($item);
1438                 }
1439
1440                 // 2021.12: Backward compatibility value, all the events now "adjust" to the viewer timezone
1441                 $event['dfrn:adjust'] = true;
1442
1443                 return $event;
1444         }
1445
1446         /**
1447          * Creates a note/article object array
1448          *
1449          * @param array $item
1450          *
1451          * @return array with the object data
1452          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1453          * @throws \ImagickException
1454          */
1455         public static function createNote($item)
1456         {
1457                 if (empty($item)) {
1458                         return [];
1459                 }
1460
1461                 if ($item['event-type'] == 'event') {
1462                         $type = 'Event';
1463                 } elseif (!empty($item['title'])) {
1464                         $type = 'Article';
1465                 } else {
1466                         $type = 'Note';
1467                 }
1468
1469                 if ($item['deleted']) {
1470                         $type = 'Tombstone';
1471                 }
1472
1473                 $data = [];
1474                 $data['id'] = $item['uri'];
1475                 $data['type'] = $type;
1476
1477                 if ($item['deleted']) {
1478                         return $data;
1479                 }
1480
1481                 $data['summary'] = BBCode::toPlaintext(BBCode::getAbstract($item['body'], Protocol::ACTIVITYPUB));
1482
1483                 if ($item['uri'] != $item['thr-parent']) {
1484                         $data['inReplyTo'] = $item['thr-parent'];
1485                 } else {
1486                         $data['inReplyTo'] = null;
1487                 }
1488
1489                 $data['diaspora:guid'] = $item['guid'];
1490                 $data['published'] = DateTimeFormat::utc($item['created'] . '+00:00', DateTimeFormat::ATOM);
1491
1492                 if ($item['created'] != $item['edited']) {
1493                         $data['updated'] = DateTimeFormat::utc($item['edited'] . '+00:00', DateTimeFormat::ATOM);
1494                 }
1495
1496                 $data['url'] = $item['plink'];
1497                 $data['attributedTo'] = $item['author-link'];
1498                 $data['sensitive'] = self::isSensitive($item['uri-id']);
1499                 $data['context'] = self::fetchContextURLForItem($item);
1500
1501                 if (!empty($item['title'])) {
1502                         $data['name'] = BBCode::toPlaintext($item['title'], false);
1503                 }
1504
1505                 $permission_block = self::createPermissionBlockForItem($item, false);
1506
1507                 $body = $item['body'];
1508
1509                 if ($type == 'Note') {
1510                         $body = $item['raw-body'] ?? self::removePictures($body);
1511                 }
1512
1513                 /**
1514                  * @todo Improve the automated summary
1515                  * This part is currently deactivated. The automated summary seems to be more
1516                  * confusing than helping. But possibly we will find a better way.
1517                  * So the code is left here for now as a reminder
1518                  *
1519                  * } elseif (($type == 'Article') && empty($data['summary'])) {
1520                  *              $regexp = "/[@!]\[url\=([^\[\]]*)\].*?\[\/url\]/ism";
1521                  *              $summary = preg_replace_callback($regexp, ['self', 'mentionAddrCallback'], $body);
1522                  *              $data['summary'] = BBCode::toPlaintext(Plaintext::shorten(self::removePictures($summary), 1000));
1523                  * }
1524                  */
1525
1526                 if (empty($item['uid']) || !Feature::isEnabled($item['uid'], 'explicit_mentions')) {
1527                         $body = self::prependMentions($body, $item['uri-id'], $item['author-link']);
1528                 }
1529
1530                 if ($type == 'Event') {
1531                         $data = array_merge($data, self::createEvent($item));
1532                 } else {
1533                         $body = BBCode::setMentionsToNicknames($body);
1534
1535                         $data['content'] = BBCode::convertForUriId($item['uri-id'], $body, BBCode::ACTIVITYPUB);
1536                 }
1537
1538                 // The regular "content" field does contain a minimized HTML. This is done since systems like
1539                 // Mastodon has got problems with - for example - embedded pictures.
1540                 // The contentMap does contain the unmodified HTML.
1541                 $language = self::getLanguage($item);
1542                 if (!empty($language)) {
1543                         $richbody = BBCode::setMentionsToNicknames($item['body'] ?? '');
1544                         $richbody = BBCode::removeAttachment($richbody);
1545
1546                         $data['contentMap'][$language] = BBCode::convertForUriId($item['uri-id'], $richbody, BBCode::EXTERNAL);
1547                 }
1548
1549                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
1550
1551                 if (!empty($item['signed_text']) && ($item['uri'] != $item['thr-parent'])) {
1552                         $data['diaspora:comment'] = $item['signed_text'];
1553                 }
1554
1555                 $data['attachment'] = self::createAttachmentList($item, $type);
1556                 $data['tag'] = self::createTagList($item);
1557
1558                 if (empty($data['location']) && (!empty($item['coord']) || !empty($item['location']))) {
1559                         $data['location'] = self::createLocation($item);
1560                 }
1561
1562                 if (!empty($item['app'])) {
1563                         $data['generator'] = ['type' => 'Application', 'name' => $item['app']];
1564                 }
1565
1566                 $data = array_merge($data, $permission_block);
1567
1568                 return $data;
1569         }
1570
1571         /**
1572          * Fetches the language from the post, the user or the system.
1573          *
1574          * @param array $item
1575          *
1576          * @return string language string
1577          */
1578         private static function getLanguage(array $item)
1579         {
1580                 // Try to fetch the language from the post itself
1581                 if (!empty($item['language'])) {
1582                         $languages = array_keys(json_decode($item['language'], true));
1583                         if (!empty($languages[0])) {
1584                                 return $languages[0];
1585                         }
1586                 }
1587
1588                 // Otherwise use the user's language
1589                 if (!empty($item['uid'])) {
1590                         $user = DBA::selectFirst('user', ['language'], ['uid' => $item['uid']]);
1591                         if (!empty($user['language'])) {
1592                                 return $user['language'];
1593                         }
1594                 }
1595
1596                 // And finally just use the system language
1597                 return DI::config()->get('system', 'language');
1598         }
1599
1600         /**
1601          * Creates an an "add tag" entry
1602          *
1603          * @param array $item
1604          * @param array $data activity data
1605          *
1606          * @return array with activity data for adding tags
1607          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1608          * @throws \ImagickException
1609          */
1610         private static function createAddTag($item, $data)
1611         {
1612                 $object = XML::parseString($item['object']);
1613                 $target = XML::parseString($item["target"]);
1614
1615                 $data['diaspora:guid'] = $item['guid'];
1616                 $data['actor'] = $item['author-link'];
1617                 $data['target'] = (string)$target->id;
1618                 $data['summary'] = BBCode::toPlaintext($item['body']);
1619                 $data['object'] = ['id' => (string)$object->id, 'type' => 'tag', 'name' => (string)$object->title, 'content' => (string)$object->content];
1620
1621                 return $data;
1622         }
1623
1624         /**
1625          * Creates an announce object entry
1626          *
1627          * @param array $item
1628          * @param array $data activity data
1629          *
1630          * @return array with activity data
1631          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1632          * @throws \ImagickException
1633          */
1634         private static function createAnnounce($item, $data)
1635         {
1636                 $orig_body = $item['body'];
1637                 $announce = self::getAnnounceArray($item);
1638                 if (empty($announce)) {
1639                         $data['type'] = 'Create';
1640                         $data['object'] = self::createNote($item);
1641                         return $data;
1642                 }
1643
1644                 if (empty($announce['comment'])) {
1645                         // Pure announce, without a quote
1646                         $data['type'] = 'Announce';
1647                         $data['object'] = $announce['object']['uri'];
1648                         return $data;
1649                 }
1650
1651                 // Quote
1652                 $data['type'] = 'Create';
1653                 $item['body'] = $announce['comment'] . "\n" . $announce['object']['plink'];
1654                 $data['object'] = self::createNote($item);
1655
1656                 /// @todo Finally descide how to implement this in AP. This is a possible way:
1657                 $data['object']['attachment'][] = self::createNote($announce['object']);
1658
1659                 $data['object']['source']['content'] = $orig_body;
1660                 return $data;
1661         }
1662
1663         /**
1664          * Return announce related data if the item is an annunce
1665          *
1666          * @param array $item
1667          *
1668          * @return array
1669          */
1670         public static function getAnnounceArray($item)
1671         {
1672                 $reshared = Item::getShareArray($item);
1673                 if (empty($reshared['guid'])) {
1674                         return [];
1675                 }
1676
1677                 $reshared_item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['guid' => $reshared['guid']]);
1678                 if (!DBA::isResult($reshared_item)) {
1679                         return [];
1680                 }
1681
1682                 if (!in_array($reshared_item['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN])) {
1683                         return [];
1684                 }
1685
1686                 $profile = APContact::getByURL($reshared_item['author-link'], false);
1687                 if (empty($profile)) {
1688                         return [];
1689                 }
1690
1691                 return ['object' => $reshared_item, 'actor' => $profile, 'comment' => $reshared['comment']];
1692         }
1693
1694         /**
1695          * Checks if the provided item array is an announce
1696          *
1697          * @param array $item
1698          *
1699          * @return boolean
1700          */
1701         public static function isAnnounce($item)
1702         {
1703                 if (!empty($item['verb']) && ($item['verb'] == Activity::ANNOUNCE)) {
1704                         return true;
1705                 }
1706
1707                 $announce = self::getAnnounceArray($item);
1708                 if (empty($announce)) {
1709                         return false;
1710                 }
1711
1712                 return empty($announce['comment']);
1713         }
1714
1715         /**
1716          * Creates an activity id for a given contact id
1717          *
1718          * @param integer $cid Contact ID of target
1719          *
1720          * @return bool|string activity id
1721          */
1722         public static function activityIDFromContact($cid)
1723         {
1724                 $contact = DBA::selectFirst('contact', ['uid', 'id', 'created'], ['id' => $cid]);
1725                 if (!DBA::isResult($contact)) {
1726                         return false;
1727                 }
1728
1729                 $hash = hash('ripemd128', $contact['uid'].'-'.$contact['id'].'-'.$contact['created']);
1730                 $uuid = substr($hash, 0, 8). '-' . substr($hash, 8, 4) . '-' . substr($hash, 12, 4) . '-' . substr($hash, 16, 4) . '-' . substr($hash, 20, 12);
1731                 return DI::baseUrl() . '/activity/' . $uuid;
1732         }
1733
1734         /**
1735          * Transmits a contact suggestion to a given inbox
1736          *
1737          * @param integer $uid           User ID
1738          * @param string  $inbox         Target inbox
1739          * @param integer $suggestion_id Suggestion ID
1740          *
1741          * @return boolean was the transmission successful?
1742          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1743          */
1744         public static function sendContactSuggestion($uid, $inbox, $suggestion_id)
1745         {
1746                 $owner = User::getOwnerDataById($uid);
1747
1748                 $suggestion = DI::fsuggest()->selectOneById($suggestion_id);
1749
1750                 $data = ['@context' => ActivityPub::CONTEXT,
1751                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1752                         'type' => 'Announce',
1753                         'actor' => $owner['url'],
1754                         'object' => $suggestion->url,
1755                         'content' => $suggestion->note,
1756                         'instrument' => self::getService(),
1757                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1758                         'cc' => []];
1759
1760                 $signed = LDSignature::sign($data, $owner);
1761
1762                 Logger::info('Deliver profile deletion for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1763                 return HTTPSignature::transmit($signed, $inbox, $uid);
1764         }
1765
1766         /**
1767          * Transmits a profile relocation to a given inbox
1768          *
1769          * @param integer $uid   User ID
1770          * @param string  $inbox Target inbox
1771          *
1772          * @return boolean was the transmission successful?
1773          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1774          */
1775         public static function sendProfileRelocation($uid, $inbox)
1776         {
1777                 $owner = User::getOwnerDataById($uid);
1778
1779                 $data = ['@context' => ActivityPub::CONTEXT,
1780                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1781                         'type' => 'dfrn:relocate',
1782                         'actor' => $owner['url'],
1783                         'object' => $owner['url'],
1784                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1785                         'instrument' => self::getService(),
1786                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1787                         'cc' => []];
1788
1789                 $signed = LDSignature::sign($data, $owner);
1790
1791                 Logger::info('Deliver profile relocation for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1792                 return HTTPSignature::transmit($signed, $inbox, $uid);
1793         }
1794
1795         /**
1796          * Transmits a profile deletion to a given inbox
1797          *
1798          * @param integer $uid   User ID
1799          * @param string  $inbox Target inbox
1800          *
1801          * @return boolean was the transmission successful?
1802          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1803          */
1804         public static function sendProfileDeletion($uid, $inbox)
1805         {
1806                 $owner = User::getOwnerDataById($uid);
1807
1808                 if (empty($owner)) {
1809                         Logger::error('No owner data found, the deletion message cannot be processed.', ['user' => $uid]);
1810                         return false;
1811                 }
1812
1813                 if (empty($owner['uprvkey'])) {
1814                         Logger::error('No private key for owner found, the deletion message cannot be processed.', ['user' => $uid]);
1815                         return false;
1816                 }
1817
1818                 $data = ['@context' => ActivityPub::CONTEXT,
1819                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1820                         'type' => 'Delete',
1821                         'actor' => $owner['url'],
1822                         'object' => $owner['url'],
1823                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1824                         'instrument' => self::getService(),
1825                         'to' => [ActivityPub::PUBLIC_COLLECTION],
1826                         'cc' => []];
1827
1828                 $signed = LDSignature::sign($data, $owner);
1829
1830                 Logger::info('Deliver profile deletion for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1831                 return HTTPSignature::transmit($signed, $inbox, $uid);
1832         }
1833
1834         /**
1835          * Transmits a profile change to a given inbox
1836          *
1837          * @param integer $uid   User ID
1838          * @param string  $inbox Target inbox
1839          *
1840          * @return boolean was the transmission successful?
1841          * @throws HTTPException\InternalServerErrorException
1842          * @throws HTTPException\NotFoundException
1843          * @throws \ImagickException
1844          */
1845         public static function sendProfileUpdate(int $uid, string $inbox): bool
1846         {
1847                 $owner = User::getOwnerDataById($uid);
1848                 $profile = APContact::getByURL($owner['url']);
1849
1850                 $data = ['@context' => ActivityPub::CONTEXT,
1851                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1852                         'type' => 'Update',
1853                         'actor' => $owner['url'],
1854                         'object' => self::getProfile($uid),
1855                         'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
1856                         'instrument' => self::getService(),
1857                         'to' => [$profile['followers']],
1858                         'cc' => []];
1859
1860                 $signed = LDSignature::sign($data, $owner);
1861
1862                 Logger::info('Deliver profile update for user ' . $uid . ' to ' . $inbox . ' via ActivityPub');
1863                 return HTTPSignature::transmit($signed, $inbox, $uid);
1864         }
1865
1866         /**
1867          * Transmits a given activity to a target
1868          *
1869          * @param string  $activity Type name
1870          * @param string  $target   Target profile
1871          * @param integer $uid      User ID
1872          * @return bool
1873          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1874          * @throws \ImagickException
1875          * @throws \Exception
1876          */
1877         public static function sendActivity($activity, $target, $uid, $id = '')
1878         {
1879                 $profile = APContact::getByURL($target);
1880                 if (empty($profile['inbox'])) {
1881                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1882                         return;
1883                 }
1884
1885                 $owner = User::getOwnerDataById($uid);
1886
1887                 if (empty($id)) {
1888                         $id = DI::baseUrl() . '/activity/' . System::createGUID();
1889                 }
1890
1891                 $data = ['@context' => ActivityPub::CONTEXT,
1892                         'id' => $id,
1893                         'type' => $activity,
1894                         'actor' => $owner['url'],
1895                         'object' => $profile['url'],
1896                         'instrument' => self::getService(),
1897                         'to' => [$profile['url']]];
1898
1899                 Logger::info('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid);
1900
1901                 $signed = LDSignature::sign($data, $owner);
1902                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1903         }
1904
1905         /**
1906          * Transmits a "follow object" activity to a target
1907          * This is a preparation for sending automated "follow" requests when receiving "Announce" messages
1908          *
1909          * @param string  $object Object URL
1910          * @param string  $target Target profile
1911          * @param integer $uid    User ID
1912          * @return bool
1913          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1914          * @throws \ImagickException
1915          * @throws \Exception
1916          */
1917         public static function sendFollowObject($object, $target, $uid = 0)
1918         {
1919                 $profile = APContact::getByURL($target);
1920                 if (empty($profile['inbox'])) {
1921                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1922                         return;
1923                 }
1924
1925                 if (empty($uid)) {
1926                         // Fetch the list of administrators
1927                         $admin_mail = explode(',', str_replace(' ', '', DI::config()->get('config', 'admin_email')));
1928
1929                         // We need to use some user as a sender. It doesn't care who it will send. We will use an administrator account.
1930                         $condition = ['verified' => true, 'blocked' => false, 'account_removed' => false, 'account_expired' => false, 'email' => $admin_mail];
1931                         $first_user = DBA::selectFirst('user', ['uid'], $condition);
1932                         $uid = $first_user['uid'];
1933                 }
1934
1935                 $condition = ['verb' => Activity::FOLLOW, 'uid' => 0, 'parent-uri' => $object,
1936                         'author-id' => Contact::getPublicIdByUserId($uid)];
1937                 if (Post::exists($condition)) {
1938                         Logger::info('Follow for ' . $object . ' for user ' . $uid . ' does already exist.');
1939                         return false;
1940                 }
1941
1942                 $owner = User::getOwnerDataById($uid);
1943
1944                 $data = ['@context' => ActivityPub::CONTEXT,
1945                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1946                         'type' => 'Follow',
1947                         'actor' => $owner['url'],
1948                         'object' => $object,
1949                         'instrument' => self::getService(),
1950                         'to' => [$profile['url']]];
1951
1952                 Logger::info('Sending follow ' . $object . ' to ' . $target . ' for user ' . $uid);
1953
1954                 $signed = LDSignature::sign($data, $owner);
1955                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1956         }
1957
1958         /**
1959          * Transmit a message that the contact request had been accepted
1960          *
1961          * @param string  $target Target profile
1962          * @param         $id
1963          * @param integer $uid    User ID
1964          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1965          * @throws \ImagickException
1966          */
1967         public static function sendContactAccept($target, $id, $uid)
1968         {
1969                 $profile = APContact::getByURL($target);
1970                 if (empty($profile['inbox'])) {
1971                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
1972                         return;
1973                 }
1974
1975                 $owner = User::getOwnerDataById($uid);
1976                 $data = ['@context' => ActivityPub::CONTEXT,
1977                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
1978                         'type' => 'Accept',
1979                         'actor' => $owner['url'],
1980                         'object' => [
1981                                 'id' => (string)$id,
1982                                 'type' => 'Follow',
1983                                 'actor' => $profile['url'],
1984                                 'object' => $owner['url']
1985                         ],
1986                         'instrument' => self::getService(),
1987                         'to' => [$profile['url']]];
1988
1989                 Logger::debug('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id);
1990
1991                 $signed = LDSignature::sign($data, $owner);
1992                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
1993         }
1994
1995         /**
1996          * Reject a contact request or terminates the contact relation
1997          *
1998          * @param string  $target Target profile
1999          * @param         $id
2000          * @param integer $uid    User ID
2001          * @return bool Operation success
2002          * @throws HTTPException\InternalServerErrorException
2003          * @throws \ImagickException
2004          */
2005         public static function sendContactReject($target, $id, $uid): bool
2006         {
2007                 $profile = APContact::getByURL($target);
2008                 if (empty($profile['inbox'])) {
2009                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
2010                         return false;
2011                 }
2012
2013                 $owner = User::getOwnerDataById($uid);
2014                 $data = ['@context' => ActivityPub::CONTEXT,
2015                         'id' => DI::baseUrl() . '/activity/' . System::createGUID(),
2016                         'type' => 'Reject',
2017                         'actor' => $owner['url'],
2018                         'object' => [
2019                                 'id' => (string)$id,
2020                                 'type' => 'Follow',
2021                                 'actor' => $profile['url'],
2022                                 'object' => $owner['url']
2023                         ],
2024                         'instrument' => self::getService(),
2025                         'to' => [$profile['url']]];
2026
2027                 Logger::debug('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id);
2028
2029                 $signed = LDSignature::sign($data, $owner);
2030                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
2031         }
2032
2033         /**
2034          * Transmits a message that we don't want to follow this contact anymore
2035          *
2036          * @param string  $target Target profile
2037          * @param integer $uid    User ID
2038          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
2039          * @throws \ImagickException
2040          * @throws \Exception
2041          * @return bool success
2042          */
2043         public static function sendContactUndo($target, $cid, $uid)
2044         {
2045                 $profile = APContact::getByURL($target);
2046                 if (empty($profile['inbox'])) {
2047                         Logger::warning('No inbox found for target', ['target' => $target, 'profile' => $profile]);
2048                         return false;
2049                 }
2050
2051                 $object_id = self::activityIDFromContact($cid);
2052                 if (empty($object_id)) {
2053                         return false;
2054                 }
2055
2056                 $id = DI::baseUrl() . '/activity/' . System::createGUID();
2057
2058                 $owner = User::getOwnerDataById($uid);
2059                 $data = ['@context' => ActivityPub::CONTEXT,
2060                         'id' => $id,
2061                         'type' => 'Undo',
2062                         'actor' => $owner['url'],
2063                         'object' => ['id' => $object_id, 'type' => 'Follow',
2064                                 'actor' => $owner['url'],
2065                                 'object' => $profile['url']],
2066                         'instrument' => self::getService(),
2067                         'to' => [$profile['url']]];
2068
2069                 Logger::info('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id);
2070
2071                 $signed = LDSignature::sign($data, $owner);
2072                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
2073         }
2074
2075         private static function prependMentions($body, int $uriid, string $authorLink)
2076         {
2077                 $mentions = [];
2078
2079                 foreach (Tag::getByURIId($uriid, [Tag::IMPLICIT_MENTION]) as $tag) {
2080                         $profile = Contact::getByURL($tag['url'], false, ['addr', 'contact-type', 'nick']);
2081                         if (!empty($profile['addr'])
2082                                 && $profile['contact-type'] != Contact::TYPE_COMMUNITY
2083                                 && !strstr($body, $profile['addr'])
2084                                 && !strstr($body, $tag['url'])
2085                                 && $tag['url'] !== $authorLink
2086                         ) {
2087                                 $mentions[] = '@[url=' . $tag['url'] . ']' . $profile['nick'] . '[/url]';
2088                         }
2089                 }
2090
2091                 $mentions[] = $body;
2092
2093                 return implode(' ', $mentions);
2094         }
2095 }