src/Protocol/ActivityPub.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub.php
   4  */
   5 namespace Friendica\Protocol;
   6
   7 use Friendica\Database\DBA;
   8 use Friendica\Core\System;
   9 use Friendica\BaseObject;
  10 use Friendica\Util\Network;
  11 use Friendica\Util\HTTPSignature;
  12 use Friendica\Core\Protocol;
  13 use Friendica\Model\Conversation;
  14 use Friendica\Model\Contact;
  15 use Friendica\Model\Item;
  16 use Friendica\Model\User;
  17 use Friendica\Util\DateTimeFormat;
  18 use Friendica\Util\Crypto;
  19 use Friendica\Content\Text\BBCode;
  20 use Friendica\Content\Text\HTML;
  21 use Friendica\Network\Probe;
  22
  23 /**
  24  * @brief ActivityPub Protocol class
  25  * The ActivityPub Protocol is a message exchange protocol defined by the W3C.
  26  * https://www.w3.org/TR/activitypub/
  27  * https://www.w3.org/TR/activitystreams-core/
  28  * https://www.w3.org/TR/activitystreams-vocabulary/
  29  *
  30  * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
  31  * https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/
  32  *
  33  * Digest: https://tools.ietf.org/html/rfc5843
  34  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
  35  * https://github.com/digitalbazaar/php-json-ld
  36  *
  37  * Part of the code for HTTP signing is taken from the Osada project.
  38  * https://framagit.org/macgirvin/osada
  39  *
  40  * To-do:
  41  *
  42  * Receiver:
  43  * - Activities: Dislike, Update, Delete
  44  * - Object Types: Person, Tombstome
  45  *
  46  * Transmitter:
  47  * - Activities: Like, Dislike, Update, Delete
  48  * - Object Tyoes: Article, Announce, Person, Tombstone
  49  *
  50  * General:
  51  * - Message distribution
  52  * - Endpoints: Outbox, Object, Follower, Following
  53  * - General cleanup
  54  */
  55 class ActivityPub
  56 {
  57         const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
  58
  59         public static function isRequest()
  60         {
  61                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  62                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  63         }
  64
  65         public static function transmit($data, $target, $uid)
  66         {
  67                 $owner = User::getOwnerDataById($uid);
  68
  69                 if (!$owner) {
  70                         return;
  71                 }
  72
  73                 $content = json_encode($data);
  74
  75                 // Header data that is about to be signed.
  76                 $host = parse_url($target, PHP_URL_HOST);
  77                 $path = parse_url($target, PHP_URL_PATH);
  78                 $digest = 'SHA-256=' . base64_encode(hash('sha256', $content, true));
  79                 $content_length = strlen($content);
  80
  81                 $headers = ['Content-Length: ' . $content_length, 'Digest: ' . $digest, 'Host: ' . $host];
  82
  83                 $signed_data = "(request-target): post " . $path . "\ncontent-length: " . $content_length . "\ndigest: " . $digest . "\nhost: " . $host;
  84
  85                 $signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
  86
  87                 $headers[] = 'Signature: keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) content-length digest host",signature="' . $signature . '"';
  88
  89                 $headers[] = 'Content-Type: application/activity+json';
  90
  91                 Network::post($target, $content, $headers);
  92                 $return_code = BaseObject::getApp()->get_curl_code();
  93
  94                 logger('Transmit to ' . $target . ' returned ' . $return_code);
  95         }
  96
  97         /**
  98          * Return the ActivityPub profile of the given user
  99          *
 100          * @param integer $uid User ID
 101          * @return array
 102          */
 103         public static function profile($uid)
 104         {
 105                 $accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application', 'page-flags'];
 106                 $condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
 107                         'account_removed' => false, 'verified' => true];
 108                 $fields = ['guid', 'nickname', 'pubkey', 'account-type'];
 109                 $user = DBA::selectFirst('user', $fields, $condition);
 110                 if (!DBA::isResult($user)) {
 111                         return [];
 112                 }
 113
 114                 $fields = ['locality', 'region', 'country-name'];
 115                 $profile = DBA::selectFirst('profile', $fields, ['uid' => $uid, 'is-default' => true]);
 116                 if (!DBA::isResult($profile)) {
 117                         return [];
 118                 }
 119
 120                 $fields = ['name', 'url', 'location', 'about', 'avatar'];
 121                 $contact = DBA::selectFirst('contact', $fields, ['uid' => $uid, 'self' => true]);
 122                 if (!DBA::isResult($contact)) {
 123                         return [];
 124                 }
 125
 126                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 127                         ['uuid' => 'http://schema.org/identifier', 'sensitive' => 'as:sensitive',
 128                         'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
 129                         'vcard' => 'http://www.w3.org/2006/vcard/ns#']]];
 130
 131                 $data['id'] = $contact['url'];
 132                 $data['uuid'] = $user['guid'];
 133                 $data['type'] = $accounttype[$user['account-type']];
 134                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 135                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 136                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 137                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 138                 $data['preferredUsername'] = $user['nickname'];
 139                 $data['name'] = $contact['name'];
 140                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 141                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 142                 $data['summary'] = $contact['about'];
 143                 $data['url'] = $contact['url'];
 144                 $data['manuallyApprovesFollowers'] = in_array($profile['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 145                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 146                         'owner' => $contact['url'],
 147                         'publicKeyPem' => $user['pubkey']];
 148                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 149                 $data['icon'] = ['type' => 'Image',
 150                         'url' => $contact['avatar']];
 151
 152                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 153                 return $data;
 154         }
 155
 156         public static function createActivityFromItem($item_id)
 157         {
 158                 $item = Item::selectFirst([], ['id' => $item_id]);
 159
 160                 if (!DBA::isResult($item)) {
 161                         return false;
 162                 }
 163
 164                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 165                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 166                 if (DBA::isResult($conversation)) {
 167                         $data = json_decode($conversation['source']);
 168                         if (!empty($data)) {
 169                                 return $data;
 170                         }
 171                 }
 172
 173                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 174                         ['Emoji' => 'toot:Emoji', 'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 175                         'conversation' => 'ostatus:conversation', 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri',
 176                         'ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 177                         'toot' => 'http://joinmastodon.org/ns#']]];
 178
 179                 $data['type'] = 'Create';
 180                 $data['id'] = $item['uri'] . '/activity';
 181                 $data['actor'] = $item['author-link'];
 182                 $data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
 183                 $data['object'] = self::createNote($item);
 184                 return $data;
 185         }
 186
 187         public static function createNote($item)
 188         {
 189                 $data = [];
 190                 $data['type'] = 'Note';
 191                 $data['id'] = $item['uri'];
 192
 193                 if ($item['uri'] != $item['thr-parent']) {
 194                         $data['inReplyTo'] = $item['thr-parent'];
 195                 }
 196
 197                 $conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
 198                 if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 199                         $conversation_uri = $conversation['conversation-uri'];
 200                 } else {
 201                         $conversation_uri = $item['parent-uri'];
 202                 }
 203
 204                 $data['context'] = $data['conversation'] = $conversation_uri;
 205                 $data['actor'] = $item['author-link'];
 206                 if (!$item['private']) {
 207                         $data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
 208                 }
 209                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 210                 $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 211                 $data['attributedTo'] = $item['author-link'];
 212                 $data['name'] = BBCode::convert($item['title'], false, 7);
 213                 $data['content'] = BBCode::convert($item['body'], false, 7);
 214                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 215                 //$data['summary'] = ''; // Ignore by now
 216                 //$data['sensitive'] = false; // - Query NSFW
 217                 //$data['emoji'] = []; // Ignore by now
 218                 //$data['tag'] = []; /// @ToDo
 219                 //$data['attachment'] = []; // @ToDo
 220                 return $data;
 221         }
 222
 223         public static function transmitActivity($activity, $target, $uid)
 224         {
 225                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 226
 227                 $owner = User::getOwnerDataById($uid);
 228
 229                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 230                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 231                         'type' => $activity,
 232                         'actor' => $owner['url'],
 233                         'object' => $profile['url'],
 234                         'to' => $profile['url']];
 235
 236                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 237                 return self::transmit($data,  $profile['notify'], $uid);
 238         }
 239
 240         public static function transmitContactAccept($target, $id, $uid)
 241         {
 242                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 243
 244                 $owner = User::getOwnerDataById($uid);
 245                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 246                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 247                         'type' => 'Accept',
 248                         'actor' => $owner['url'],
 249                         'object' => ['id' => $id, 'type' => 'Follow',
 250                                 'actor' => $profile['url'],
 251                                 'object' => $owner['url']],
 252                         'to' => $profile['url']];
 253
 254                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 255                 return self::transmit($data,  $profile['notify'], $uid);
 256         }
 257
 258         public static function transmitContactReject($target, $id, $uid)
 259         {
 260                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 261
 262                 $owner = User::getOwnerDataById($uid);
 263                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 264                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 265                         'type' => 'Reject',
 266                         'actor' => $owner['url'],
 267                         'object' => ['id' => $id, 'type' => 'Follow',
 268                                 'actor' => $profile['url'],
 269                                 'object' => $owner['url']],
 270                         'to' => $profile['url']];
 271
 272                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 273                 return self::transmit($data,  $profile['notify'], $uid);
 274         }
 275
 276         public static function transmitContactUndo($target, $uid)
 277         {
 278                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 279
 280                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 281
 282                 $owner = User::getOwnerDataById($uid);
 283                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 284                         'id' => $id,
 285                         'type' => 'Undo',
 286                         'actor' => $owner['url'],
 287                         'object' => ['id' => $id, 'type' => 'Follow',
 288                                 'actor' => $owner['url'],
 289                                 'object' => $profile['url']],
 290                         'to' => $profile['url']];
 291
 292                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 293                 return self::transmit($data,  $profile['notify'], $uid);
 294         }
 295
 296         /**
 297          * Fetches ActivityPub content from the given url
 298          *
 299          * @param string $url content url
 300          * @return array
 301          */
 302         public static function fetchContent($url)
 303         {
 304                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 305                 if (!$ret['success'] || empty($ret['body'])) {
 306                         return;
 307                 }
 308
 309                 return json_decode($ret['body'], true);
 310         }
 311
 312         /**
 313          * Resolves the profile url from the address by using webfinger
 314          *
 315          * @param string $addr profile address (user@domain.tld)
 316          * @return string url
 317          */
 318         private static function addrToUrl($addr)
 319         {
 320                 $addr_parts = explode('@', $addr);
 321                 if (count($addr_parts) != 2) {
 322                         return false;
 323                 }
 324
 325                 $webfinger = 'https://' . $addr_parts[1] . '/.well-known/webfinger?resource=acct:' . urlencode($addr);
 326
 327                 $ret = Network::curl($webfinger, false, $redirects, ['accept_content' => 'application/jrd+json,application/json']);
 328                 if (!$ret['success'] || empty($ret['body'])) {
 329                         return false;
 330                 }
 331
 332                 $data = json_decode($ret['body'], true);
 333
 334                 if (empty($data['links'])) {
 335                         return false;
 336                 }
 337
 338                 foreach ($data['links'] as $link) {
 339                         if (empty($link['href']) || empty($link['rel']) || empty($link['type'])) {
 340                                 continue;
 341                         }
 342
 343                         if (($link['rel'] == 'self') && ($link['type'] == 'application/activity+json')) {
 344                                 return $link['href'];
 345                         }
 346                 }
 347
 348                 return false;
 349         }
 350
 351         public static function verifySignature($content, $http_headers)
 352         {
 353                 $object = json_decode($content, true);
 354
 355                 if (empty($object)) {
 356                         return false;
 357                 }
 358
 359                 $actor = self::processElement($object, 'actor', 'id');
 360
 361                 $headers = [];
 362                 $headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . $http_headers['REQUEST_URI'];
 363
 364                 // First take every header
 365                 foreach ($http_headers as $k => $v) {
 366                         $field = str_replace('_', '-', strtolower($k));
 367                         $headers[$field] = $v;
 368                 }
 369
 370                 // Now add every http header
 371                 foreach ($http_headers as $k => $v) {
 372                         if (strpos($k, 'HTTP_') === 0) {
 373                                 $field = str_replace('_', '-', strtolower(substr($k, 5)));
 374                                 $headers[$field] = $v;
 375                         }
 376                 }
 377
 378                 $sig_block = ActivityPub::parseSigHeader($http_headers['HTTP_SIGNATURE']);
 379
 380                 if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
 381                         return false;
 382                 }
 383
 384                 $signed_data = '';
 385                 foreach ($sig_block['headers'] as $h) {
 386                         if (array_key_exists($h, $headers)) {
 387                                 $signed_data .= $h . ': ' . $headers[$h] . "\n";
 388                         }
 389                 }
 390                 $signed_data = rtrim($signed_data, "\n");
 391
 392                 if (empty($signed_data)) {
 393                         return false;
 394                 }
 395
 396                 $algorithm = null;
 397
 398                 if ($sig_block['algorithm'] === 'rsa-sha256') {
 399                         $algorithm = 'sha256';
 400                 }
 401
 402                 if ($sig_block['algorithm'] === 'rsa-sha512') {
 403                         $algorithm = 'sha512';
 404                 }
 405
 406                 if (empty($algorithm)) {
 407                         return false;
 408                 }
 409
 410                 $key = self::fetchKey($sig_block['keyId'], $actor);
 411
 412                 if (empty($key)) {
 413                         return false;
 414                 }
 415
 416                 if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
 417                         return false;
 418                 }
 419
 420                 // Check the digest when it is part of the signed data
 421                 if (in_array('digest', $sig_block['headers'])) {
 422                         $digest = explode('=', $headers['digest'], 2);
 423                         if ($digest[0] === 'SHA-256') {
 424                                 $hashalg = 'sha256';
 425                         }
 426                         if ($digest[0] === 'SHA-512') {
 427                                 $hashalg = 'sha512';
 428                         }
 429
 430                         /// @todo add all hashes from the rfc
 431
 432                         if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
 433                                 return false;
 434                         }
 435                 }
 436
 437                 // Check the content-length when it is part of the signed data
 438                 if (in_array('content-length', $sig_block['headers'])) {
 439                         if (strlen($content) != $headers['content-length']) {
 440                                 return false;
 441                         }
 442                 }
 443
 444                 return true;
 445
 446         }
 447
 448         private static function fetchKey($id, $actor)
 449         {
 450                 $url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
 451
 452                 $profile = Probe::uri($url, Protocol::ACTIVITYPUB);
 453                 if (!empty($profile)) {
 454                         return $profile['pubkey'];
 455                 } elseif ($url != $actor) {
 456                         $profile = Probe::uri($actor, Protocol::ACTIVITYPUB);
 457                         if (!empty($profile)) {
 458                                 return $profile['pubkey'];
 459                         }
 460                 }
 461
 462                 return false;
 463         }
 464
 465         /**
 466          * @brief
 467          *
 468          * @param string $header
 469          * @return array associate array with
 470          *   - \e string \b keyID
 471          *   - \e string \b algorithm
 472          *   - \e array  \b headers
 473          *   - \e string \b signature
 474          */
 475         private static function parseSigHeader($header)
 476         {
 477                 $ret = [];
 478                 $matches = [];
 479
 480                 if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
 481                         $ret['keyId'] = $matches[1];
 482                 }
 483
 484                 if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
 485                         $ret['algorithm'] = $matches[1];
 486                 }
 487
 488                 if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
 489                         $ret['headers'] = explode(' ', $matches[1]);
 490                 }
 491
 492                 if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
 493                         $ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
 494                 }
 495
 496                 return $ret;
 497         }
 498
 499         /**
 500          * Fetches a profile from the given url
 501          *
 502          * @param string $url profile url
 503          * @return array
 504          */
 505         public static function fetchProfile($url)
 506         {
 507                 if (empty(parse_url($url, PHP_URL_SCHEME))) {
 508                         $url = self::addrToUrl($url);
 509                         if (empty($url)) {
 510                                 return false;
 511                         }
 512                 }
 513
 514                 $data = self::fetchContent($url);
 515
 516                 if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 517                         return false;
 518                 }
 519
 520                 $profile = ['network' => Protocol::ACTIVITYPUB];
 521                 $profile['nick'] = $data['preferredUsername'];
 522                 $profile['name'] = defaults($data, 'name', $profile['nick']);
 523                 $profile['guid'] = defaults($data, 'uuid', null);
 524                 $profile['url'] = $data['id'];
 525
 526                 $parts = parse_url($profile['url']);
 527                 unset($parts['scheme']);
 528                 unset($parts['path']);
 529                 $profile['addr'] = $profile['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 530                 $profile['alias'] = self::processElement($data, 'url', 'href');
 531                 $profile['photo'] = self::processElement($data, 'icon', 'url');
 532                 // $profile['community']
 533                 // $profile['keywords']
 534                 // $profile['location']
 535                 $profile['about'] = defaults($data, 'summary', '');
 536                 $profile['batch'] = self::processElement($data, 'endpoints', 'sharedInbox');
 537                 $profile['notify'] = $data['inbox'];
 538                 $profile['poll'] = $data['outbox'];
 539                 $profile['pubkey'] = self::processElement($data, 'publicKey', 'publicKeyPem');
 540
 541                 // Check if the address is resolvable
 542                 if (self::addrToUrl($profile['addr']) == $profile['url']) {
 543                         $parts = parse_url($profile['url']);
 544                         unset($parts['path']);
 545                         $profile['baseurl'] = Network::unparseURL($parts);
 546                 } else {
 547                         unset($profile['addr']);
 548                 }
 549
 550                 if ($profile['url'] == $profile['alias']) {
 551                         unset($profile['alias']);
 552                 }
 553
 554                 // Remove all "null" fields
 555                 foreach ($profile as $field => $content) {
 556                         if (is_null($content)) {
 557                                 unset($profile[$field]);
 558                         }
 559                 }
 560
 561                 // To-Do
 562                 // type, manuallyApprovesFollowers
 563
 564                 // Unhandled
 565                 // @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 566
 567                 // Unhandled from Misskey
 568                 // sharedInbox, isCat
 569
 570                 // Unhandled from Kroeg
 571                 // kroeg:blocks, updated
 572
 573                 return $profile;
 574         }
 575
 576         public static function processInbox($body, $header, $uid)
 577         {
 578                 logger('Incoming message for user ' . $uid, LOGGER_DEBUG);
 579
 580                 if (!self::verifySignature($body, $header)) {
 581                         logger('Invalid signature, message will be discarded.', LOGGER_DEBUG);
 582                         return;
 583                 }
 584
 585                 $activity = json_decode($body, true);
 586
 587                 if (!is_array($activity)) {
 588                         logger('Invalid body.', LOGGER_DEBUG);
 589                         return;
 590                 }
 591
 592                 self::processActivity($activity, $body, $uid);
 593         }
 594
 595         public static function fetchOutbox($url)
 596         {
 597                 $data = self::fetchContent($url);
 598                 if (empty($data)) {
 599                         return;
 600                 }
 601
 602                 if (!empty($data['orderedItems'])) {
 603                         $items = $data['orderedItems'];
 604                 } elseif (!empty($data['first']['orderedItems'])) {
 605                         $items = $data['first']['orderedItems'];
 606                 } elseif (!empty($data['first'])) {
 607                         self::fetchOutbox($data['first']);
 608                         return;
 609                 } else {
 610                         $items = [];
 611                 }
 612
 613                 foreach ($items as $activity) {
 614                         self::processActivity($activity);
 615                 }
 616         }
 617
 618         private static function prepareObjectData($activity, $uid)
 619         {
 620                 $actor = self::processElement($activity, 'actor', 'id');
 621                 if (empty($actor)) {
 622                         logger('Empty actor', LOGGER_DEBUG);
 623                         return [];
 624                 }
 625
 626                 // Fetch all receivers from to, cc, bto and bcc
 627                 $receivers = self::getReceivers($activity, $actor);
 628
 629                 // When it is a delivery to a personal inbox we add that user to the receivers
 630                 if (!empty($uid)) {
 631                         $owner = User::getOwnerDataById($uid);
 632                         $additional = ['uid:' . $uid => $uid];
 633                         $receivers = array_merge($receivers, $additional);
 634                 }
 635
 636                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 637
 638                 $public = in_array(0, $receivers);
 639
 640                 if (is_string($activity['object'])) {
 641                         $object_url = $activity['object'];
 642                 } elseif (!empty($activity['object']['id'])) {
 643                         $object_url = $activity['object']['id'];
 644                 } else {
 645                         logger('No object found', LOGGER_DEBUG);
 646                         return [];
 647                 }
 648
 649                 // Fetch the content only on activities where this matters
 650                 if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
 651                         $object_data = self::fetchObject($object_url, $activity['object']);
 652                         if (empty($object_data)) {
 653                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 654                                 return [];
 655                         }
 656                 } elseif ($activity['type'] == 'Accept') {
 657                         $object_data = [];
 658                         $object_data['object_type'] = self::processElement($activity, 'object', 'type');
 659                         $object_data['object'] = self::processElement($activity, 'object', 'actor');
 660                 } elseif ($activity['type'] == 'Undo') {
 661                         $object_data = [];
 662                         $object_data['object_type'] = self::processElement($activity, 'object', 'type');
 663                         $object_data['object'] = self::processElement($activity, 'object', 'object');
 664                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 665                         // Create a mostly empty array out of the activity data (instead of the object).
 666                         // This way we later don't have to check for the existence of ech individual array element.
 667                         $object_data = self::processCommonData($activity);
 668                         $object_data['name'] = $activity['type'];
 669                         $object_data['author'] = $activity['actor'];
 670                         $object_data['object'] = $object_url;
 671                 } elseif ($activity['type'] == 'Follow') {
 672                         $object_data['id'] = $activity['id'];
 673                         $object_data['object'] = $object_url;
 674                 } else {
 675                         $object_data = [];
 676                 }
 677
 678                 $object_data = self::addActivityFields($object_data, $activity);
 679
 680                 $object_data['type'] = $activity['type'];
 681                 $object_data['owner'] = $actor;
 682                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 683
 684                 return $object_data;
 685         }
 686
 687         private static function processActivity($activity, $body = '', $uid = null)
 688         {
 689                 if (empty($activity['type'])) {
 690                         logger('Empty type', LOGGER_DEBUG);
 691                         return;
 692                 }
 693
 694                 if (empty($activity['object'])) {
 695                         logger('Empty object', LOGGER_DEBUG);
 696                         return;
 697                 }
 698
 699                 if (empty($activity['actor'])) {
 700                         logger('Empty actor', LOGGER_DEBUG);
 701                         return;
 702
 703                 }
 704
 705                 // Non standard
 706                 // title, atomUri, context_id, statusnetConversationId
 707
 708                 // To-Do?
 709                 // context, location, signature;
 710
 711                 logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
 712
 713                 $object_data = self::prepareObjectData($activity, $uid);
 714                 if (empty($object_data)) {
 715                         logger('No object data found', LOGGER_DEBUG);
 716                         return;
 717                 }
 718
 719                 switch ($activity['type']) {
 720                         case 'Create':
 721                         case 'Announce':
 722                                 self::createItem($object_data, $body);
 723                                 break;
 724
 725                         case 'Like':
 726                                 self::likeItem($object_data, $body);
 727                                 break;
 728
 729                         case 'Dislike':
 730                                 break;
 731
 732                         case 'Update':
 733                                 break;
 734
 735                         case 'Delete':
 736                                 break;
 737
 738                         case 'Follow':
 739                                 self::followUser($object_data);
 740                                 break;
 741
 742                         case 'Accept':
 743                                 if ($object_data['object_type'] == 'Follow') {
 744                                         self::acceptFollowUser($object_data);
 745                                 }
 746                                 break;
 747
 748                         case 'Undo':
 749                                 if ($object_data['object_type'] == 'Follow') {
 750                                         self::undoFollowUser($object_data);
 751                                 }
 752                                 break;
 753
 754                         default:
 755                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 756                                 break;
 757                 }
 758         }
 759
 760         private static function getReceivers($activity, $actor)
 761         {
 762                 $receivers = [];
 763
 764                 if (!empty($actor)) {
 765                         $data = self::fetchContent($actor);
 766                         $followers = defaults($data, 'followers', '');
 767
 768                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 769                 } else {
 770                         logger('Empty actor', LOGGER_DEBUG);
 771                         $followers = '';
 772                 }
 773
 774                 $elements = ['to', 'cc', 'bto', 'bcc'];
 775                 foreach ($elements as $element) {
 776                         if (empty($activity[$element])) {
 777                                 continue;
 778                         }
 779
 780                         // The receiver can be an arror or a string
 781                         if (is_string($activity[$element])) {
 782                                 $activity[$element] = [$activity[$element]];
 783                         }
 784
 785                         foreach ($activity[$element] as $receiver) {
 786                                 if ($receiver == self::PUBLIC) {
 787                                         $receivers['uid:0'] = 0;
 788                                 }
 789
 790                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
 791                                         // This will most likely catch all OStatus connections to Mastodon
 792                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
 793                                         $contacts = DBA::select('contact', ['uid'], $condition);
 794                                         while ($contact = DBA::fetch($contacts)) {
 795                                                 if ($contact['uid'] != 0) {
 796                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 797                                                 }
 798                                         }
 799                                         DBA::close($contacts);
 800                                 }
 801
 802                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
 803                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 804                                                 'network' => Protocol::ACTIVITYPUB];
 805                                         $contacts = DBA::select('contact', ['uid'], $condition);
 806                                         while ($contact = DBA::fetch($contacts)) {
 807                                                 if ($contact['uid'] != 0) {
 808                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 809                                                 }
 810                                         }
 811                                         DBA::close($contacts);
 812                                         continue;
 813                                 }
 814
 815                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
 816                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
 817                                 if (!DBA::isResult($contact)) {
 818                                         continue;
 819                                 }
 820                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 821                         }
 822                 }
 823                 return $receivers;
 824         }
 825
 826         private static function addActivityFields($object_data, $activity)
 827         {
 828                 if (!empty($activity['published']) && empty($object_data['published'])) {
 829                         $object_data['published'] = $activity['published'];
 830                 }
 831
 832                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
 833                         $object_data['updated'] = $activity['updated'];
 834                 }
 835
 836                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
 837                         $object_data['parent-uri'] = self::processElement($activity, 'inReplyTo', 'id');
 838                 }
 839
 840                 if (!empty($activity['instrument'])) {
 841                         $object_data['service'] = self::processElement($activity, 'instrument', 'name', 'type', 'Service');
 842                 }
 843                 return $object_data;
 844         }
 845
 846         private static function fetchObject($object_url, $object = [], $public = true)
 847         {
 848                 if ($public) {
 849                         $data = self::fetchContent($object_url);
 850                         if (empty($data)) {
 851                                 logger('Empty content for ' . $object_url . ', check if content is available locally.', LOGGER_DEBUG);
 852                                 $data = $object_url;
 853                                 $data = $object;
 854                         }
 855                 } else {
 856                         logger('Using original object for url ' . $object_url, LOGGER_DEBUG);
 857                         $data = $object;
 858                 }
 859
 860                 if (is_string($data)) {
 861                         $item = Item::selectFirst([], ['uri' => $data]);
 862                         if (!DBA::isResult($item)) {
 863                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
 864                                 return false;
 865                         }
 866                         logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
 867                         $data = self::createNote($item);
 868                 }
 869
 870                 if (empty($data['type'])) {
 871                         logger('Empty type', LOGGER_DEBUG);
 872                         return false;
 873                 } else {
 874                         $type = $data['type'];
 875                         logger('Type ' . $type, LOGGER_DEBUG);
 876                 }
 877
 878                 if (in_array($type, ['Note', 'Article', 'Video'])) {
 879                         $common = self::processCommonData($data);
 880                 }
 881
 882                 switch ($type) {
 883                         case 'Note':
 884                                 return array_merge($common, self::processNote($data));
 885                         case 'Article':
 886                                 return array_merge($common, self::processArticle($data));
 887                         case 'Video':
 888                                 return array_merge($common, self::processVideo($data));
 889
 890                         case 'Announce':
 891                                 if (empty($data['object'])) {
 892                                         return false;
 893                                 }
 894                                 return self::fetchObject($data['object']);
 895
 896                         case 'Person':
 897                         case 'Tombstone':
 898                                 break;
 899
 900                         default:
 901                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
 902                                 break;
 903                 }
 904         }
 905
 906         private static function processCommonData(&$object)
 907         {
 908                 if (empty($object['id'])) {
 909                         return false;
 910                 }
 911
 912                 $object_data = [];
 913                 $object_data['type'] = $object['type'];
 914                 $object_data['uri'] = $object['id'];
 915
 916                 if (!empty($object['inReplyTo'])) {
 917                         $object_data['reply-to-uri'] = self::processElement($object, 'inReplyTo', 'id');
 918                 } else {
 919                         $object_data['reply-to-uri'] = $object_data['uri'];
 920                 }
 921
 922                 $object_data['published'] = defaults($object, 'published', null);
 923                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
 924
 925                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 926                         $object_data['published'] = $object_data['updated'];
 927                 }
 928
 929                 $object_data['uuid'] = defaults($object, 'uuid', null);
 930                 $object_data['owner'] = $object_data['author'] = self::processElement($object, 'attributedTo', 'id');
 931                 $object_data['context'] = defaults($object, 'context', null);
 932                 $object_data['conversation'] = defaults($object, 'conversation', null);
 933                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
 934                 $object_data['name'] = defaults($object, 'title', null);
 935                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
 936                 $object_data['summary'] = defaults($object, 'summary', null);
 937                 $object_data['content'] = defaults($object, 'content', null);
 938                 $object_data['source'] = defaults($object, 'source', null);
 939                 $object_data['location'] = self::processElement($object, 'location', 'name', 'type', 'Place');
 940                 $object_data['attachments'] = defaults($object, 'attachment', null);
 941                 $object_data['tags'] = defaults($object, 'tag', null);
 942                 $object_data['service'] = self::processElement($object, 'instrument', 'name', 'type', 'Service');
 943                 $object_data['alternate-url'] = self::processElement($object, 'url', 'href');
 944                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
 945
 946                 // Unhandled
 947                 // @context, type, actor, signature, mediaType, duration, replies, icon
 948
 949                 // Also missing: (Defined in the standard, but currently unused)
 950                 // audience, preview, endTime, startTime, generator, image
 951
 952                 return $object_data;
 953         }
 954
 955         private static function processNote($object)
 956         {
 957                 $object_data = [];
 958
 959                 // To-Do?
 960                 // emoji, atomUri, inReplyToAtomUri
 961
 962                 // Unhandled
 963                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 964                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 965
 966                 return $object_data;
 967         }
 968
 969         private static function processArticle($object)
 970         {
 971                 $object_data = [];
 972
 973                 return $object_data;
 974         }
 975
 976         private static function processVideo($object)
 977         {
 978                 $object_data = [];
 979
 980                 // To-Do?
 981                 // category, licence, language, commentsEnabled
 982
 983                 // Unhandled
 984                 // views, waitTranscoding, state, support, subtitleLanguage
 985                 // likes, dislikes, shares, comments
 986
 987                 return $object_data;
 988         }
 989
 990         private static function processElement($array, $element, $key, $type = null, $type_value = null)
 991         {
 992                 if (empty($array)) {
 993                         return false;
 994                 }
 995
 996                 if (empty($array[$element])) {
 997                         return false;
 998                 }
 999
1000                 if (is_string($array[$element])) {
1001                         return $array[$element];
1002                 }
1003
1004                 if (is_null($type_value)) {
1005                         if (!empty($array[$element][$key])) {
1006                                 return $array[$element][$key];
1007                         }
1008
1009                         if (!empty($array[$element][0][$key])) {
1010                                 return $array[$element][0][$key];
1011                         }
1012
1013                         return false;
1014                 }
1015
1016                 if (!empty($array[$element][$key]) && !empty($array[$element][$type]) && ($array[$element][$type] == $type_value)) {
1017                         return $array[$element][$key];
1018                 }
1019
1020                 /// @todo Add array search
1021
1022                 return false;
1023         }
1024
1025         private static function convertMentions($body)
1026         {
1027                 $URLSearchString = "^\[\]";
1028                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1029
1030                 return $body;
1031         }
1032
1033         private static function constructTagList($tags, $sensitive)
1034         {
1035                 if (empty($tags)) {
1036                         return '';
1037                 }
1038
1039                 $tag_text = '';
1040                 foreach ($tags as $tag) {
1041                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1042                                 if (!empty($tag_text)) {
1043                                         $tag_text .= ',';
1044                                 }
1045
1046                                 if (empty($tag['href'])) {
1047                                         //$tag['href']
1048                                         logger('Blubb!');
1049                                 }
1050
1051                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1052                         }
1053                 }
1054
1055                 /// @todo add nsfw for $sensitive
1056
1057                 return $tag_text;
1058         }
1059
1060         private static function constructAttachList($attachments, $item)
1061         {
1062                 if (empty($attachments)) {
1063                         return $item;
1064                 }
1065
1066                 foreach ($attachments as $attach) {
1067                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1068                         if ($filetype == 'image') {
1069                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1070                         } else {
1071                                 if (!empty($item["attach"])) {
1072                                         $item["attach"] .= ',';
1073                                 } else {
1074                                         $item["attach"] = '';
1075                                 }
1076                                 if (!isset($attach['length'])) {
1077                                         $attach['length'] = "0";
1078                                 }
1079                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1080                         }
1081                 }
1082
1083                 return $item;
1084         }
1085
1086         private static function createItem($activity, $body)
1087         {
1088                 $item = [];
1089                 $item['verb'] = ACTIVITY_POST;
1090                 $item['parent-uri'] = $activity['reply-to-uri'];
1091
1092                 if ($activity['reply-to-uri'] == $activity['uri']) {
1093                         $item['gravity'] = GRAVITY_PARENT;
1094                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1095                 } else {
1096                         $item['gravity'] = GRAVITY_COMMENT;
1097                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1098                 }
1099
1100                 if (($activity['uri'] != $activity['reply-to-uri']) && !Item::exists(['uri' => $activity['reply-to-uri']])) {
1101                         logger('Parent ' . $activity['reply-to-uri'] . ' not found. Try to refetch it.');
1102                         self::fetchMissingActivity($activity['reply-to-uri'], $activity);
1103                 }
1104
1105                 self::postItem($activity, $item, $body);
1106         }
1107
1108         private static function likeItem($activity, $body)
1109         {
1110                 $item = [];
1111                 $item['verb'] = ACTIVITY_LIKE;
1112                 $item['parent-uri'] = $activity['object'];
1113                 $item['gravity'] = GRAVITY_ACTIVITY;
1114                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1115
1116                 self::postItem($activity, $item, $body);
1117         }
1118
1119         private static function postItem($activity, $item, $body)
1120         {
1121                 /// @todo What to do with $activity['context']?
1122
1123                 $item['network'] = Protocol::ACTIVITYPUB;
1124                 $item['private'] = !in_array(0, $activity['receiver']);
1125                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1126                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1127                 $item['uri'] = $activity['uri'];
1128                 $item['created'] = $activity['published'];
1129                 $item['edited'] = $activity['updated'];
1130                 $item['guid'] = $activity['uuid'];
1131                 $item['title'] = HTML::toBBCode($activity['name']);
1132                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1133                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1134                 $item['location'] = $activity['location'];
1135                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1136                 $item['app'] = $activity['service'];
1137                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1138
1139                 $item = self::constructAttachList($activity['attachments'], $item);
1140
1141                 $source = self::processElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1142                 if (!empty($source)) {
1143                         $item['body'] = $source;
1144                 }
1145
1146                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1147                 $item['source'] = $body;
1148                 $item['conversation-uri'] = $activity['conversation'];
1149
1150                 foreach ($activity['receiver'] as $receiver) {
1151                         $item['uid'] = $receiver;
1152                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1153
1154                         if (($receiver != 0) && empty($item['contact-id'])) {
1155                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1156                         }
1157
1158                         $item_id = Item::insert($item);
1159                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1160                 }
1161         }
1162
1163         private static function fetchMissingActivity($url, $child)
1164         {
1165                 $object = ActivityPub::fetchContent($url);
1166                 if (empty($object)) {
1167                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1168                         return;
1169                 }
1170
1171                 $activity = [];
1172                 $activity['@context'] = $object['@context'];
1173                 unset($object['@context']);
1174                 $activity['id'] = $object['id'];
1175                 $activity['to'] = defaults($object, 'to', []);
1176                 $activity['cc'] = defaults($object, 'cc', []);
1177                 $activity['actor'] = $activity['author'];
1178                 $activity['object'] = $object;
1179                 $activity['published'] = $object['published'];
1180                 $activity['type'] = 'Create';
1181                 self::processActivity($activity);
1182                 logger('Activity ' . $url . ' had been fetched and processed.');
1183         }
1184
1185         private static function getUserOfObject($object)
1186         {
1187                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($object), 'self' => true]);
1188                 if (!DBA::isResult($self)) {
1189                         return false;
1190                 } else {
1191                         return $self['uid'];
1192                 }
1193         }
1194
1195         private static function followUser($activity)
1196         {
1197                 $uid = self::getUserOfObject($activity['object']);
1198                 if (empty($uid)) {
1199                         return;
1200                 }
1201
1202                 $owner = User::getOwnerDataById($uid);
1203
1204                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1205                 if (!empty($cid)) {
1206                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1207                 } else {
1208                         $contact = false;
1209                 }
1210
1211                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1212                         'author-link' => $activity['owner']];
1213
1214                 Contact::addRelationship($owner, $contact, $item);
1215                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1216                 if (empty($cid)) {
1217                         return;
1218                 }
1219
1220                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1221                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1222                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1223                 }
1224
1225                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1226                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1227         }
1228
1229         private static function acceptFollowUser($activity)
1230         {
1231                 $uid = self::getUserOfObject($activity['object']);
1232                 if (empty($uid)) {
1233                         return;
1234                 }
1235
1236                 $owner = User::getOwnerDataById($uid);
1237
1238                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1239                 if (empty($cid)) {
1240                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1241                         return;
1242                 }
1243
1244                 $fields = ['pending' => false];
1245
1246                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1247                 if ($contact['rel'] == Contact::FOLLOWER) {
1248                         $fields['rel'] = Contact::FRIEND;
1249                 }
1250
1251                 $condition = ['id' => $cid];
1252                 DBA::update('contact', $fields, $condition);
1253                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1254         }
1255
1256         private static function undoFollowUser($activity)
1257         {
1258                 $uid = self::getUserOfObject($activity['object']);
1259                 if (empty($uid)) {
1260                         return;
1261                 }
1262
1263                 $owner = User::getOwnerDataById($uid);
1264
1265                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1266                 if (empty($cid)) {
1267                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1268                         return;
1269                 }
1270
1271                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1272                 if (!DBA::isResult($contact)) {
1273                         return;
1274                 }
1275
1276                 Contact::removeFollower($owner, $contact);
1277                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1278         }
1279 }