src/Protocol/ActivityPub/Transmitter.php

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