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