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