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