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\Term;
  17 use Friendica\Model\User;
  18 use Friendica\Util\DateTimeFormat;
  19 use Friendica\Util\Crypto;
  20 use Friendica\Content\Text\BBCode;
  21 use Friendica\Content\Text\HTML;
  22 use Friendica\Network\Probe;
  23
  24 /**
  25  * @brief ActivityPub Protocol class
  26  * The ActivityPub Protocol is a message exchange protocol defined by the W3C.
  27  * https://www.w3.org/TR/activitypub/
  28  * https://www.w3.org/TR/activitystreams-core/
  29  * https://www.w3.org/TR/activitystreams-vocabulary/
  30  *
  31  * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
  32  * https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/
  33  *
  34  * Digest: https://tools.ietf.org/html/rfc5843
  35  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
  36  * https://github.com/digitalbazaar/php-json-ld
  37  *
  38  * Part of the code for HTTP signing is taken from the Osada project.
  39  * https://framagit.org/macgirvin/osada
  40  *
  41  * To-do:
  42  *
  43  * Receiver:
  44  * - Activities: Dislike, Update, Delete
  45  * - Object Types: Person, Tombstome
  46  *
  47  * Transmitter:
  48  * - Activities: Like, Dislike, Update, Delete
  49  * - Object Tyoes: Article, Announce, Person, Tombstone
  50  *
  51  * General:
  52  * - Message distribution
  53  * - Endpoints: Outbox, Object, Follower, Following
  54  * - General cleanup
  55  */
  56 class ActivityPub
  57 {
  58         const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
  59
  60         public static function isRequest()
  61         {
  62                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  63                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  64         }
  65
  66         public static function transmit($data, $target, $uid)
  67         {
  68                 $owner = User::getOwnerDataById($uid);
  69
  70                 if (!$owner) {
  71                         return;
  72                 }
  73
  74                 $content = json_encode($data);
  75
  76                 // Header data that is about to be signed.
  77                 $host = parse_url($target, PHP_URL_HOST);
  78                 $path = parse_url($target, PHP_URL_PATH);
  79                 $digest = 'SHA-256=' . base64_encode(hash('sha256', $content, true));
  80                 $content_length = strlen($content);
  81
  82                 $headers = ['Content-Length: ' . $content_length, 'Digest: ' . $digest, 'Host: ' . $host];
  83
  84                 $signed_data = "(request-target): post " . $path . "\ncontent-length: " . $content_length . "\ndigest: " . $digest . "\nhost: " . $host;
  85
  86                 $signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
  87
  88                 $headers[] = 'Signature: keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) content-length digest host",signature="' . $signature . '"';
  89
  90                 $headers[] = 'Content-Type: application/activity+json';
  91
  92                 Network::post($target, $content, $headers);
  93                 $return_code = BaseObject::getApp()->get_curl_code();
  94
  95                 logger('Transmit to ' . $target . ' returned ' . $return_code);
  96         }
  97
  98         /**
  99          * Return the ActivityPub profile of the given user
 100          *
 101          * @param integer $uid User ID
 102          * @return array
 103          */
 104         public static function profile($uid)
 105         {
 106                 $accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application', 'page-flags'];
 107                 $condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
 108                         'account_removed' => false, 'verified' => true];
 109                 $fields = ['guid', 'nickname', 'pubkey', 'account-type'];
 110                 $user = DBA::selectFirst('user', $fields, $condition);
 111                 if (!DBA::isResult($user)) {
 112                         return [];
 113                 }
 114
 115                 $fields = ['locality', 'region', 'country-name'];
 116                 $profile = DBA::selectFirst('profile', $fields, ['uid' => $uid, 'is-default' => true]);
 117                 if (!DBA::isResult($profile)) {
 118                         return [];
 119                 }
 120
 121                 $fields = ['name', 'url', 'location', 'about', 'avatar'];
 122                 $contact = DBA::selectFirst('contact', $fields, ['uid' => $uid, 'self' => true]);
 123                 if (!DBA::isResult($contact)) {
 124                         return [];
 125                 }
 126
 127                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 128                         ['uuid' => 'http://schema.org/identifier', 'sensitive' => 'as:sensitive',
 129                         'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
 130                         'vcard' => 'http://www.w3.org/2006/vcard/ns#']]];
 131
 132                 $data['id'] = $contact['url'];
 133                 $data['uuid'] = $user['guid'];
 134                 $data['type'] = $accounttype[$user['account-type']];
 135                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 136                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 137                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 138                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 139                 $data['preferredUsername'] = $user['nickname'];
 140                 $data['name'] = $contact['name'];
 141                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 142                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 143                 $data['summary'] = $contact['about'];
 144                 $data['url'] = $contact['url'];
 145                 $data['manuallyApprovesFollowers'] = in_array($profile['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 146                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 147                         'owner' => $contact['url'],
 148                         'publicKeyPem' => $user['pubkey']];
 149                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 150                 $data['icon'] = ['type' => 'Image',
 151                         'url' => $contact['avatar']];
 152
 153                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 154                 return $data;
 155         }
 156
 157         public static function createPermissionBlockForItem($item)
 158         {
 159                 $data = ['to' => [], 'cc' => []];
 160
 161                 $terms = Term::tagArrayFromItemId($item['id']);
 162
 163                 if (!$item['private']) {
 164                         $data['to'][] = self::PUBLIC;
 165                         $data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 166
 167                         foreach ($terms as $term) {
 168                                 if ($term['type'] != TERM_MENTION) {
 169                                         continue;
 170                                 }
 171                                 $profile = Probe::uri($term['url'], Protocol::ACTIVITYPUB);
 172                                 if ($profile['network'] == Protocol::ACTIVITYPUB) {
 173                                         $data['cc'][] = $profile['url'];
 174                                 }
 175                         }
 176                 } else {
 177                         $receiver_list = Item::enumeratePermissions($item);
 178
 179                         $mentioned = [];
 180
 181                         foreach ($terms as $term) {
 182                                 if ($term['type'] != TERM_MENTION) {
 183                                         continue;
 184                                 }
 185                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 186                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 187                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 188                                         $data['to'][] = $contact['url'];
 189                                 }
 190                         }
 191
 192                         foreach ($receiver_list as $receiver) {
 193                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 194                                 $data['cc'][] = $contact['url'];
 195                         }
 196
 197                         if (empty($data['to'])) {
 198                                 $data['to'] = $data['cc'];
 199                                 unset($data['cc']);
 200                         }
 201                 }
 202
 203                 return $data;
 204         }
 205
 206         public static function fetchTargetInboxes($item)
 207         {
 208                 $inboxes = [];
 209
 210                 $terms = Term::tagArrayFromItemId($item['id']);
 211                 if (!$item['private']) {
 212                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $item['uid'], 'network' => Protocol::ACTIVITYPUB]);
 213                         while ($contact = DBA::fetch($contacts)) {
 214                                 $contact = defaults($contact, 'batch', $contact['notify']);
 215                                 $inboxes[$contact] = $contact;
 216                         }
 217                         DBA::close($contacts);
 218
 219                         foreach ($terms as $term) {
 220                                 if ($term['type'] != TERM_MENTION) {
 221                                         continue;
 222                                 }
 223                                 $profile = Probe::uri($term['url'], Protocol::ACTIVITYPUB);
 224                                 if ($profile['network'] == Protocol::ACTIVITYPUB) {
 225                                         $target = defaults($profile, 'batch', $profile['notify']);
 226                                         $inboxes[$target] = $target;
 227                                 }
 228                         }
 229                 } else {
 230                         $receiver_list = Item::enumeratePermissions($item);
 231
 232                         $mentioned = [];
 233
 234                         foreach ($terms as $term) {
 235                                 if ($term['type'] != TERM_MENTION) {
 236                                         continue;
 237                                 }
 238                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 239                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 240                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 241                                         $profile = Probe::uri($contact['url'], Protocol::ACTIVITYPUB);
 242                                         if ($profile['network'] == Protocol::ACTIVITYPUB) {
 243                                                 $target = defaults($profile, 'batch', $profile['notify']);
 244                                                 $inboxes[$target] = $target;
 245                                         }
 246                                 }
 247                         }
 248
 249                         foreach ($receiver_list as $receiver) {
 250                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 251                                 $profile = Probe::uri($contact['url'], Protocol::ACTIVITYPUB);
 252                                 if ($profile['network'] == Protocol::ACTIVITYPUB) {
 253                                         $target = defaults($profile, 'batch', $profile['notify']);
 254                                         $inboxes[$target] = $target;
 255                                 }
 256                         }
 257                 }
 258
 259                 return $inboxes;
 260         }
 261
 262         public static function createActivityFromItem($item_id)
 263         {
 264                 $item = Item::selectFirst([], ['id' => $item_id]);
 265
 266                 if (!DBA::isResult($item)) {
 267                         return false;
 268                 }
 269
 270                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 271                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 272                 if (DBA::isResult($conversation)) {
 273                         $data = json_decode($conversation['source']);
 274                         if (!empty($data)) {
 275                                 return $data;
 276                         }
 277                 }
 278
 279                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 280                         ['Emoji' => 'toot:Emoji', 'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 281                         'conversation' => 'ostatus:conversation', 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri',
 282                         'ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 283                         'toot' => 'http://joinmastodon.org/ns#']]];
 284
 285                 $data['type'] = 'Create';
 286                 $data['id'] = $item['uri'] . '#activity';
 287                 $data['actor'] = $item['author-link'];
 288                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 289
 290                 $data['object'] = self::createNote($item);
 291                 return $data;
 292         }
 293
 294         public static function createObjectFromItemID($item_id)
 295         {
 296                 $item = Item::selectFirst([], ['id' => $item_id]);
 297
 298                 if (!DBA::isResult($item)) {
 299                         return false;
 300                 }
 301
 302                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 303                         ['Emoji' => 'toot:Emoji', 'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 304                         'conversation' => 'ostatus:conversation', 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri',
 305                         'ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 306                         'toot' => 'http://joinmastodon.org/ns#']]];
 307
 308                 $data = array_merge($data, self::createNote($item));
 309
 310
 311                 return $data;
 312         }
 313
 314         public static function createNote($item)
 315         {
 316                 $data = [];
 317                 $data['type'] = 'Note';
 318                 $data['id'] = $item['uri'];
 319
 320                 if ($item['uri'] != $item['thr-parent']) {
 321                         $data['inReplyTo'] = $item['thr-parent'];
 322                 }
 323
 324                 $conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
 325                 if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 326                         $conversation_uri = $conversation['conversation-uri'];
 327                 } else {
 328                         $conversation_uri = $item['parent-uri'];
 329                 }
 330
 331                 $data['context'] = $data['conversation'] = $conversation_uri;
 332                 $data['actor'] = $item['author-link'];
 333                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 334                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 335                 $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 336                 $data['attributedTo'] = $item['author-link'];
 337                 $data['name'] = BBCode::convert($item['title'], false, 7);
 338                 $data['content'] = BBCode::convert($item['body'], false, 7);
 339                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 340                 //$data['summary'] = ''; // Ignore by now
 341                 //$data['sensitive'] = false; // - Query NSFW
 342                 //$data['emoji'] = []; // Ignore by now
 343                 //$data['tag'] = []; /// @ToDo
 344                 //$data['attachment'] = []; // @ToDo
 345                 return $data;
 346         }
 347
 348         public static function transmitActivity($activity, $target, $uid)
 349         {
 350                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 351
 352                 $owner = User::getOwnerDataById($uid);
 353
 354                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 355                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 356                         'type' => $activity,
 357                         'actor' => $owner['url'],
 358                         'object' => $profile['url'],
 359                         'to' => $profile['url']];
 360
 361                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 362                 return self::transmit($data,  $profile['notify'], $uid);
 363         }
 364
 365         public static function transmitContactAccept($target, $id, $uid)
 366         {
 367                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 368
 369                 $owner = User::getOwnerDataById($uid);
 370                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 371                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 372                         'type' => 'Accept',
 373                         'actor' => $owner['url'],
 374                         'object' => ['id' => $id, 'type' => 'Follow',
 375                                 'actor' => $profile['url'],
 376                                 'object' => $owner['url']],
 377                         'to' => $profile['url']];
 378
 379                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 380                 return self::transmit($data,  $profile['notify'], $uid);
 381         }
 382
 383         public static function transmitContactReject($target, $id, $uid)
 384         {
 385                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 386
 387                 $owner = User::getOwnerDataById($uid);
 388                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 389                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 390                         'type' => 'Reject',
 391                         'actor' => $owner['url'],
 392                         'object' => ['id' => $id, 'type' => 'Follow',
 393                                 'actor' => $profile['url'],
 394                                 'object' => $owner['url']],
 395                         'to' => $profile['url']];
 396
 397                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 398                 return self::transmit($data,  $profile['notify'], $uid);
 399         }
 400
 401         public static function transmitContactUndo($target, $uid)
 402         {
 403                 $profile = Probe::uri($target, Protocol::ACTIVITYPUB);
 404
 405                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 406
 407                 $owner = User::getOwnerDataById($uid);
 408                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 409                         'id' => $id,
 410                         'type' => 'Undo',
 411                         'actor' => $owner['url'],
 412                         'object' => ['id' => $id, 'type' => 'Follow',
 413                                 'actor' => $owner['url'],
 414                                 'object' => $profile['url']],
 415                         'to' => $profile['url']];
 416
 417                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 418                 return self::transmit($data,  $profile['notify'], $uid);
 419         }
 420
 421         /**
 422          * Fetches ActivityPub content from the given url
 423          *
 424          * @param string $url content url
 425          * @return array
 426          */
 427         public static function fetchContent($url)
 428         {
 429                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 430                 if (!$ret['success'] || empty($ret['body'])) {
 431                         return;
 432                 }
 433
 434                 return json_decode($ret['body'], true);
 435         }
 436
 437         /**
 438          * Resolves the profile url from the address by using webfinger
 439          *
 440          * @param string $addr profile address (user@domain.tld)
 441          * @return string url
 442          */
 443         private static function addrToUrl($addr)
 444         {
 445                 $addr_parts = explode('@', $addr);
 446                 if (count($addr_parts) != 2) {
 447                         return false;
 448                 }
 449
 450                 $webfinger = 'https://' . $addr_parts[1] . '/.well-known/webfinger?resource=acct:' . urlencode($addr);
 451
 452                 $ret = Network::curl($webfinger, false, $redirects, ['accept_content' => 'application/jrd+json,application/json']);
 453                 if (!$ret['success'] || empty($ret['body'])) {
 454                         return false;
 455                 }
 456
 457                 $data = json_decode($ret['body'], true);
 458
 459                 if (empty($data['links'])) {
 460                         return false;
 461                 }
 462
 463                 foreach ($data['links'] as $link) {
 464                         if (empty($link['href']) || empty($link['rel']) || empty($link['type'])) {
 465                                 continue;
 466                         }
 467
 468                         if (($link['rel'] == 'self') && ($link['type'] == 'application/activity+json')) {
 469                                 return $link['href'];
 470                         }
 471                 }
 472
 473                 return false;
 474         }
 475
 476         public static function verifySignature($content, $http_headers)
 477         {
 478                 $object = json_decode($content, true);
 479
 480                 if (empty($object)) {
 481                         return false;
 482                 }
 483
 484                 $actor = self::processElement($object, 'actor', 'id');
 485
 486                 $headers = [];
 487                 $headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . $http_headers['REQUEST_URI'];
 488
 489                 // First take every header
 490                 foreach ($http_headers as $k => $v) {
 491                         $field = str_replace('_', '-', strtolower($k));
 492                         $headers[$field] = $v;
 493                 }
 494
 495                 // Now add every http header
 496                 foreach ($http_headers as $k => $v) {
 497                         if (strpos($k, 'HTTP_') === 0) {
 498                                 $field = str_replace('_', '-', strtolower(substr($k, 5)));
 499                                 $headers[$field] = $v;
 500                         }
 501                 }
 502
 503                 $sig_block = ActivityPub::parseSigHeader($http_headers['HTTP_SIGNATURE']);
 504
 505                 if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
 506                         return false;
 507                 }
 508
 509                 $signed_data = '';
 510                 foreach ($sig_block['headers'] as $h) {
 511                         if (array_key_exists($h, $headers)) {
 512                                 $signed_data .= $h . ': ' . $headers[$h] . "\n";
 513                         }
 514                 }
 515                 $signed_data = rtrim($signed_data, "\n");
 516
 517                 if (empty($signed_data)) {
 518                         return false;
 519                 }
 520
 521                 $algorithm = null;
 522
 523                 if ($sig_block['algorithm'] === 'rsa-sha256') {
 524                         $algorithm = 'sha256';
 525                 }
 526
 527                 if ($sig_block['algorithm'] === 'rsa-sha512') {
 528                         $algorithm = 'sha512';
 529                 }
 530
 531                 if (empty($algorithm)) {
 532                         return false;
 533                 }
 534
 535                 $key = self::fetchKey($sig_block['keyId'], $actor);
 536
 537                 if (empty($key)) {
 538                         return false;
 539                 }
 540
 541                 if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
 542                         return false;
 543                 }
 544
 545                 // Check the digest when it is part of the signed data
 546                 if (in_array('digest', $sig_block['headers'])) {
 547                         $digest = explode('=', $headers['digest'], 2);
 548                         if ($digest[0] === 'SHA-256') {
 549                                 $hashalg = 'sha256';
 550                         }
 551                         if ($digest[0] === 'SHA-512') {
 552                                 $hashalg = 'sha512';
 553                         }
 554
 555                         /// @todo add all hashes from the rfc
 556
 557                         if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
 558                                 return false;
 559                         }
 560                 }
 561
 562                 // Check the content-length when it is part of the signed data
 563                 if (in_array('content-length', $sig_block['headers'])) {
 564                         if (strlen($content) != $headers['content-length']) {
 565                                 return false;
 566                         }
 567                 }
 568
 569                 return true;
 570
 571         }
 572
 573         private static function fetchKey($id, $actor)
 574         {
 575                 $url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
 576
 577                 $profile = Probe::uri($url, Protocol::ACTIVITYPUB);
 578                 if (!empty($profile)) {
 579                         return $profile['pubkey'];
 580                 } elseif ($url != $actor) {
 581                         $profile = Probe::uri($actor, Protocol::ACTIVITYPUB);
 582                         if (!empty($profile)) {
 583                                 return $profile['pubkey'];
 584                         }
 585                 }
 586
 587                 return false;
 588         }
 589
 590         /**
 591          * @brief
 592          *
 593          * @param string $header
 594          * @return array associate array with
 595          *   - \e string \b keyID
 596          *   - \e string \b algorithm
 597          *   - \e array  \b headers
 598          *   - \e string \b signature
 599          */
 600         private static function parseSigHeader($header)
 601         {
 602                 $ret = [];
 603                 $matches = [];
 604
 605                 if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
 606                         $ret['keyId'] = $matches[1];
 607                 }
 608
 609                 if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
 610                         $ret['algorithm'] = $matches[1];
 611                 }
 612
 613                 if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
 614                         $ret['headers'] = explode(' ', $matches[1]);
 615                 }
 616
 617                 if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
 618                         $ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
 619                 }
 620
 621                 return $ret;
 622         }
 623
 624         /**
 625          * Fetches a profile from the given url
 626          *
 627          * @param string $url profile url
 628          * @return array
 629          */
 630         public static function fetchProfile($url)
 631         {
 632                 if (empty(parse_url($url, PHP_URL_SCHEME))) {
 633                         $url = self::addrToUrl($url);
 634                         if (empty($url)) {
 635                                 return false;
 636                         }
 637                 }
 638
 639                 $data = self::fetchContent($url);
 640
 641                 if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 642                         return false;
 643                 }
 644
 645                 $profile = ['network' => Protocol::ACTIVITYPUB];
 646                 $profile['nick'] = $data['preferredUsername'];
 647                 $profile['name'] = defaults($data, 'name', $profile['nick']);
 648                 $profile['guid'] = defaults($data, 'uuid', null);
 649                 $profile['url'] = $data['id'];
 650
 651                 $parts = parse_url($profile['url']);
 652                 unset($parts['scheme']);
 653                 unset($parts['path']);
 654                 $profile['addr'] = $profile['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 655                 $profile['alias'] = self::processElement($data, 'url', 'href');
 656                 $profile['photo'] = self::processElement($data, 'icon', 'url');
 657                 // $profile['community']
 658                 // $profile['keywords']
 659                 // $profile['location']
 660                 $profile['about'] = defaults($data, 'summary', '');
 661                 $profile['batch'] = self::processElement($data, 'endpoints', 'sharedInbox');
 662                 $profile['notify'] = $data['inbox'];
 663                 $profile['poll'] = $data['outbox'];
 664                 $profile['pubkey'] = self::processElement($data, 'publicKey', 'publicKeyPem');
 665
 666                 // Check if the address is resolvable
 667                 if (self::addrToUrl($profile['addr']) == $profile['url']) {
 668                         $parts = parse_url($profile['url']);
 669                         unset($parts['path']);
 670                         $profile['baseurl'] = Network::unparseURL($parts);
 671                 } else {
 672                         unset($profile['addr']);
 673                 }
 674
 675                 if ($profile['url'] == $profile['alias']) {
 676                         unset($profile['alias']);
 677                 }
 678
 679                 // Remove all "null" fields
 680                 foreach ($profile as $field => $content) {
 681                         if (is_null($content)) {
 682                                 unset($profile[$field]);
 683                         }
 684                 }
 685
 686                 // To-Do
 687                 // type, manuallyApprovesFollowers
 688
 689                 // Unhandled
 690                 // @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 691
 692                 // Unhandled from Misskey
 693                 // sharedInbox, isCat
 694
 695                 // Unhandled from Kroeg
 696                 // kroeg:blocks, updated
 697
 698                 return $profile;
 699         }
 700
 701         public static function processInbox($body, $header, $uid)
 702         {
 703                 logger('Incoming message for user ' . $uid, LOGGER_DEBUG);
 704
 705                 if (!self::verifySignature($body, $header)) {
 706                         logger('Invalid signature, message will be discarded.', LOGGER_DEBUG);
 707                         return;
 708                 }
 709
 710                 $activity = json_decode($body, true);
 711
 712                 if (!is_array($activity)) {
 713                         logger('Invalid body.', LOGGER_DEBUG);
 714                         return;
 715                 }
 716
 717                 self::processActivity($activity, $body, $uid);
 718         }
 719
 720         public static function fetchOutbox($url)
 721         {
 722                 $data = self::fetchContent($url);
 723                 if (empty($data)) {
 724                         return;
 725                 }
 726
 727                 if (!empty($data['orderedItems'])) {
 728                         $items = $data['orderedItems'];
 729                 } elseif (!empty($data['first']['orderedItems'])) {
 730                         $items = $data['first']['orderedItems'];
 731                 } elseif (!empty($data['first'])) {
 732                         self::fetchOutbox($data['first']);
 733                         return;
 734                 } else {
 735                         $items = [];
 736                 }
 737
 738                 foreach ($items as $activity) {
 739                         self::processActivity($activity);
 740                 }
 741         }
 742
 743         private static function prepareObjectData($activity, $uid)
 744         {
 745                 $actor = self::processElement($activity, 'actor', 'id');
 746                 if (empty($actor)) {
 747                         logger('Empty actor', LOGGER_DEBUG);
 748                         return [];
 749                 }
 750
 751                 // Fetch all receivers from to, cc, bto and bcc
 752                 $receivers = self::getReceivers($activity, $actor);
 753
 754                 // When it is a delivery to a personal inbox we add that user to the receivers
 755                 if (!empty($uid)) {
 756                         $owner = User::getOwnerDataById($uid);
 757                         $additional = ['uid:' . $uid => $uid];
 758                         $receivers = array_merge($receivers, $additional);
 759                 }
 760
 761                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 762
 763                 $public = in_array(0, $receivers);
 764
 765                 if (is_string($activity['object'])) {
 766                         $object_url = $activity['object'];
 767                 } elseif (!empty($activity['object']['id'])) {
 768                         $object_url = $activity['object']['id'];
 769                 } else {
 770                         logger('No object found', LOGGER_DEBUG);
 771                         return [];
 772                 }
 773
 774                 // Fetch the content only on activities where this matters
 775                 if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
 776                         $object_data = self::fetchObject($object_url, $activity['object']);
 777                         if (empty($object_data)) {
 778                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 779                                 return [];
 780                         }
 781                 } elseif ($activity['type'] == 'Accept') {
 782                         $object_data = [];
 783                         $object_data['object_type'] = self::processElement($activity, 'object', 'type');
 784                         $object_data['object'] = self::processElement($activity, 'object', 'actor');
 785                 } elseif ($activity['type'] == 'Undo') {
 786                         $object_data = [];
 787                         $object_data['object_type'] = self::processElement($activity, 'object', 'type');
 788                         $object_data['object'] = self::processElement($activity, 'object', 'object');
 789                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 790                         // Create a mostly empty array out of the activity data (instead of the object).
 791                         // This way we later don't have to check for the existence of ech individual array element.
 792                         $object_data = self::processCommonData($activity);
 793                         $object_data['name'] = $activity['type'];
 794                         $object_data['author'] = $activity['actor'];
 795                         $object_data['object'] = $object_url;
 796                 } elseif ($activity['type'] == 'Follow') {
 797                         $object_data['id'] = $activity['id'];
 798                         $object_data['object'] = $object_url;
 799                 } else {
 800                         $object_data = [];
 801                 }
 802
 803                 $object_data = self::addActivityFields($object_data, $activity);
 804
 805                 $object_data['type'] = $activity['type'];
 806                 $object_data['owner'] = $actor;
 807                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 808
 809                 return $object_data;
 810         }
 811
 812         private static function processActivity($activity, $body = '', $uid = null)
 813         {
 814                 if (empty($activity['type'])) {
 815                         logger('Empty type', LOGGER_DEBUG);
 816                         return;
 817                 }
 818
 819                 if (empty($activity['object'])) {
 820                         logger('Empty object', LOGGER_DEBUG);
 821                         return;
 822                 }
 823
 824                 if (empty($activity['actor'])) {
 825                         logger('Empty actor', LOGGER_DEBUG);
 826                         return;
 827
 828                 }
 829
 830                 // Non standard
 831                 // title, atomUri, context_id, statusnetConversationId
 832
 833                 // To-Do?
 834                 // context, location, signature;
 835
 836                 logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
 837
 838                 $object_data = self::prepareObjectData($activity, $uid);
 839                 if (empty($object_data)) {
 840                         logger('No object data found', LOGGER_DEBUG);
 841                         return;
 842                 }
 843
 844                 switch ($activity['type']) {
 845                         case 'Create':
 846                         case 'Announce':
 847                                 self::createItem($object_data, $body);
 848                                 break;
 849
 850                         case 'Like':
 851                                 self::likeItem($object_data, $body);
 852                                 break;
 853
 854                         case 'Dislike':
 855                                 break;
 856
 857                         case 'Update':
 858                                 break;
 859
 860                         case 'Delete':
 861                                 break;
 862
 863                         case 'Follow':
 864                                 self::followUser($object_data);
 865                                 break;
 866
 867                         case 'Accept':
 868                                 if ($object_data['object_type'] == 'Follow') {
 869                                         self::acceptFollowUser($object_data);
 870                                 }
 871                                 break;
 872
 873                         case 'Undo':
 874                                 if ($object_data['object_type'] == 'Follow') {
 875                                         self::undoFollowUser($object_data);
 876                                 }
 877                                 break;
 878
 879                         default:
 880                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 881                                 break;
 882                 }
 883         }
 884
 885         private static function getReceivers($activity, $actor)
 886         {
 887                 $receivers = [];
 888
 889                 if (!empty($actor)) {
 890                         $data = self::fetchContent($actor);
 891                         $followers = defaults($data, 'followers', '');
 892
 893                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 894                 } else {
 895                         logger('Empty actor', LOGGER_DEBUG);
 896                         $followers = '';
 897                 }
 898
 899                 $elements = ['to', 'cc', 'bto', 'bcc'];
 900                 foreach ($elements as $element) {
 901                         if (empty($activity[$element])) {
 902                                 continue;
 903                         }
 904
 905                         // The receiver can be an arror or a string
 906                         if (is_string($activity[$element])) {
 907                                 $activity[$element] = [$activity[$element]];
 908                         }
 909
 910                         foreach ($activity[$element] as $receiver) {
 911                                 if ($receiver == self::PUBLIC) {
 912                                         $receivers['uid:0'] = 0;
 913                                 }
 914
 915                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
 916                                         // This will most likely catch all OStatus connections to Mastodon
 917                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
 918                                         $contacts = DBA::select('contact', ['uid'], $condition);
 919                                         while ($contact = DBA::fetch($contacts)) {
 920                                                 if ($contact['uid'] != 0) {
 921                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 922                                                 }
 923                                         }
 924                                         DBA::close($contacts);
 925                                 }
 926
 927                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
 928                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 929                                                 'network' => Protocol::ACTIVITYPUB];
 930                                         $contacts = DBA::select('contact', ['uid'], $condition);
 931                                         while ($contact = DBA::fetch($contacts)) {
 932                                                 if ($contact['uid'] != 0) {
 933                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 934                                                 }
 935                                         }
 936                                         DBA::close($contacts);
 937                                         continue;
 938                                 }
 939
 940                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
 941                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
 942                                 if (!DBA::isResult($contact)) {
 943                                         continue;
 944                                 }
 945                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 946                         }
 947                 }
 948                 return $receivers;
 949         }
 950
 951         private static function addActivityFields($object_data, $activity)
 952         {
 953                 if (!empty($activity['published']) && empty($object_data['published'])) {
 954                         $object_data['published'] = $activity['published'];
 955                 }
 956
 957                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
 958                         $object_data['updated'] = $activity['updated'];
 959                 }
 960
 961                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
 962                         $object_data['parent-uri'] = self::processElement($activity, 'inReplyTo', 'id');
 963                 }
 964
 965                 if (!empty($activity['instrument'])) {
 966                         $object_data['service'] = self::processElement($activity, 'instrument', 'name', 'type', 'Service');
 967                 }
 968                 return $object_data;
 969         }
 970
 971         private static function fetchObject($object_url, $object = [], $public = true)
 972         {
 973                 if ($public) {
 974                         $data = self::fetchContent($object_url);
 975                         if (empty($data)) {
 976                                 logger('Empty content for ' . $object_url . ', check if content is available locally.', LOGGER_DEBUG);
 977                                 $data = $object_url;
 978                                 $data = $object;
 979                         }
 980                 } else {
 981                         logger('Using original object for url ' . $object_url, LOGGER_DEBUG);
 982                         $data = $object;
 983                 }
 984
 985                 if (is_string($data)) {
 986                         $item = Item::selectFirst([], ['uri' => $data]);
 987                         if (!DBA::isResult($item)) {
 988                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
 989                                 return false;
 990                         }
 991                         logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
 992                         $data = self::createNote($item);
 993                 }
 994
 995                 if (empty($data['type'])) {
 996                         logger('Empty type', LOGGER_DEBUG);
 997                         return false;
 998                 } else {
 999                         $type = $data['type'];
1000                         logger('Type ' . $type, LOGGER_DEBUG);
1001                 }
1002
1003                 if (in_array($type, ['Note', 'Article', 'Video'])) {
1004                         $common = self::processCommonData($data);
1005                 }
1006
1007                 switch ($type) {
1008                         case 'Note':
1009                                 return array_merge($common, self::processNote($data));
1010                         case 'Article':
1011                                 return array_merge($common, self::processArticle($data));
1012                         case 'Video':
1013                                 return array_merge($common, self::processVideo($data));
1014
1015                         case 'Announce':
1016                                 if (empty($data['object'])) {
1017                                         return false;
1018                                 }
1019                                 return self::fetchObject($data['object']);
1020
1021                         case 'Person':
1022                         case 'Tombstone':
1023                                 break;
1024
1025                         default:
1026                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1027                                 break;
1028                 }
1029         }
1030
1031         private static function processCommonData(&$object)
1032         {
1033                 if (empty($object['id'])) {
1034                         return false;
1035                 }
1036
1037                 $object_data = [];
1038                 $object_data['type'] = $object['type'];
1039                 $object_data['uri'] = $object['id'];
1040
1041                 if (!empty($object['inReplyTo'])) {
1042                         $object_data['reply-to-uri'] = self::processElement($object, 'inReplyTo', 'id');
1043                 } else {
1044                         $object_data['reply-to-uri'] = $object_data['uri'];
1045                 }
1046
1047                 $object_data['published'] = defaults($object, 'published', null);
1048                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1049
1050                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1051                         $object_data['published'] = $object_data['updated'];
1052                 }
1053
1054                 $object_data['uuid'] = defaults($object, 'uuid', null);
1055                 $object_data['owner'] = $object_data['author'] = self::processElement($object, 'attributedTo', 'id');
1056                 $object_data['context'] = defaults($object, 'context', null);
1057                 $object_data['conversation'] = defaults($object, 'conversation', null);
1058                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1059                 $object_data['name'] = defaults($object, 'title', null);
1060                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1061                 $object_data['summary'] = defaults($object, 'summary', null);
1062                 $object_data['content'] = defaults($object, 'content', null);
1063                 $object_data['source'] = defaults($object, 'source', null);
1064                 $object_data['location'] = self::processElement($object, 'location', 'name', 'type', 'Place');
1065                 $object_data['attachments'] = defaults($object, 'attachment', null);
1066                 $object_data['tags'] = defaults($object, 'tag', null);
1067                 $object_data['service'] = self::processElement($object, 'instrument', 'name', 'type', 'Service');
1068                 $object_data['alternate-url'] = self::processElement($object, 'url', 'href');
1069                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1070
1071                 // Unhandled
1072                 // @context, type, actor, signature, mediaType, duration, replies, icon
1073
1074                 // Also missing: (Defined in the standard, but currently unused)
1075                 // audience, preview, endTime, startTime, generator, image
1076
1077                 return $object_data;
1078         }
1079
1080         private static function processNote($object)
1081         {
1082                 $object_data = [];
1083
1084                 // To-Do?
1085                 // emoji, atomUri, inReplyToAtomUri
1086
1087                 // Unhandled
1088                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1089                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1090
1091                 return $object_data;
1092         }
1093
1094         private static function processArticle($object)
1095         {
1096                 $object_data = [];
1097
1098                 return $object_data;
1099         }
1100
1101         private static function processVideo($object)
1102         {
1103                 $object_data = [];
1104
1105                 // To-Do?
1106                 // category, licence, language, commentsEnabled
1107
1108                 // Unhandled
1109                 // views, waitTranscoding, state, support, subtitleLanguage
1110                 // likes, dislikes, shares, comments
1111
1112                 return $object_data;
1113         }
1114
1115         private static function processElement($array, $element, $key, $type = null, $type_value = null)
1116         {
1117                 if (empty($array)) {
1118                         return false;
1119                 }
1120
1121                 if (empty($array[$element])) {
1122                         return false;
1123                 }
1124
1125                 if (is_string($array[$element])) {
1126                         return $array[$element];
1127                 }
1128
1129                 if (is_null($type_value)) {
1130                         if (!empty($array[$element][$key])) {
1131                                 return $array[$element][$key];
1132                         }
1133
1134                         if (!empty($array[$element][0][$key])) {
1135                                 return $array[$element][0][$key];
1136                         }
1137
1138                         return false;
1139                 }
1140
1141                 if (!empty($array[$element][$key]) && !empty($array[$element][$type]) && ($array[$element][$type] == $type_value)) {
1142                         return $array[$element][$key];
1143                 }
1144
1145                 /// @todo Add array search
1146
1147                 return false;
1148         }
1149
1150         private static function convertMentions($body)
1151         {
1152                 $URLSearchString = "^\[\]";
1153                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1154
1155                 return $body;
1156         }
1157
1158         private static function constructTagList($tags, $sensitive)
1159         {
1160                 if (empty($tags)) {
1161                         return '';
1162                 }
1163
1164                 $tag_text = '';
1165                 foreach ($tags as $tag) {
1166                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1167                                 if (!empty($tag_text)) {
1168                                         $tag_text .= ',';
1169                                 }
1170
1171                                 if (empty($tag['href'])) {
1172                                         //$tag['href']
1173                                         logger('Blubb!');
1174                                 }
1175
1176                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1177                         }
1178                 }
1179
1180                 /// @todo add nsfw for $sensitive
1181
1182                 return $tag_text;
1183         }
1184
1185         private static function constructAttachList($attachments, $item)
1186         {
1187                 if (empty($attachments)) {
1188                         return $item;
1189                 }
1190
1191                 foreach ($attachments as $attach) {
1192                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1193                         if ($filetype == 'image') {
1194                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1195                         } else {
1196                                 if (!empty($item["attach"])) {
1197                                         $item["attach"] .= ',';
1198                                 } else {
1199                                         $item["attach"] = '';
1200                                 }
1201                                 if (!isset($attach['length'])) {
1202                                         $attach['length'] = "0";
1203                                 }
1204                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1205                         }
1206                 }
1207
1208                 return $item;
1209         }
1210
1211         private static function createItem($activity, $body)
1212         {
1213                 $item = [];
1214                 $item['verb'] = ACTIVITY_POST;
1215                 $item['parent-uri'] = $activity['reply-to-uri'];
1216
1217                 if ($activity['reply-to-uri'] == $activity['uri']) {
1218                         $item['gravity'] = GRAVITY_PARENT;
1219                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1220                 } else {
1221                         $item['gravity'] = GRAVITY_COMMENT;
1222                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1223                 }
1224
1225                 if (($activity['uri'] != $activity['reply-to-uri']) && !Item::exists(['uri' => $activity['reply-to-uri']])) {
1226                         logger('Parent ' . $activity['reply-to-uri'] . ' not found. Try to refetch it.');
1227                         self::fetchMissingActivity($activity['reply-to-uri'], $activity);
1228                 }
1229
1230                 self::postItem($activity, $item, $body);
1231         }
1232
1233         private static function likeItem($activity, $body)
1234         {
1235                 $item = [];
1236                 $item['verb'] = ACTIVITY_LIKE;
1237                 $item['parent-uri'] = $activity['object'];
1238                 $item['gravity'] = GRAVITY_ACTIVITY;
1239                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1240
1241                 self::postItem($activity, $item, $body);
1242         }
1243
1244         private static function postItem($activity, $item, $body)
1245         {
1246                 /// @todo What to do with $activity['context']?
1247
1248                 $item['network'] = Protocol::ACTIVITYPUB;
1249                 $item['private'] = !in_array(0, $activity['receiver']);
1250                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1251                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1252                 $item['uri'] = $activity['uri'];
1253                 $item['created'] = $activity['published'];
1254                 $item['edited'] = $activity['updated'];
1255                 $item['guid'] = $activity['uuid'];
1256                 $item['title'] = HTML::toBBCode($activity['name']);
1257                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1258                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1259                 $item['location'] = $activity['location'];
1260                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1261                 $item['app'] = $activity['service'];
1262                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1263
1264                 $item = self::constructAttachList($activity['attachments'], $item);
1265
1266                 $source = self::processElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1267                 if (!empty($source)) {
1268                         $item['body'] = $source;
1269                 }
1270
1271                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1272                 $item['source'] = $body;
1273                 $item['conversation-uri'] = $activity['conversation'];
1274
1275                 foreach ($activity['receiver'] as $receiver) {
1276                         $item['uid'] = $receiver;
1277                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1278
1279                         if (($receiver != 0) && empty($item['contact-id'])) {
1280                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1281                         }
1282
1283                         $item_id = Item::insert($item);
1284                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1285                 }
1286         }
1287
1288         private static function fetchMissingActivity($url, $child)
1289         {
1290                 $object = ActivityPub::fetchContent($url);
1291                 if (empty($object)) {
1292                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1293                         return;
1294                 }
1295
1296                 $activity = [];
1297                 $activity['@context'] = $object['@context'];
1298                 unset($object['@context']);
1299                 $activity['id'] = $object['id'];
1300                 $activity['to'] = defaults($object, 'to', []);
1301                 $activity['cc'] = defaults($object, 'cc', []);
1302                 $activity['actor'] = $activity['author'];
1303                 $activity['object'] = $object;
1304                 $activity['published'] = $object['published'];
1305                 $activity['type'] = 'Create';
1306                 self::processActivity($activity);
1307                 logger('Activity ' . $url . ' had been fetched and processed.');
1308         }
1309
1310         private static function getUserOfObject($object)
1311         {
1312                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($object), 'self' => true]);
1313                 if (!DBA::isResult($self)) {
1314                         return false;
1315                 } else {
1316                         return $self['uid'];
1317                 }
1318         }
1319
1320         private static function followUser($activity)
1321         {
1322                 $uid = self::getUserOfObject($activity['object']);
1323                 if (empty($uid)) {
1324                         return;
1325                 }
1326
1327                 $owner = User::getOwnerDataById($uid);
1328
1329                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1330                 if (!empty($cid)) {
1331                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1332                 } else {
1333                         $contact = false;
1334                 }
1335
1336                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1337                         'author-link' => $activity['owner']];
1338
1339                 Contact::addRelationship($owner, $contact, $item);
1340                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1341                 if (empty($cid)) {
1342                         return;
1343                 }
1344
1345                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1346                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1347                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1348                 }
1349
1350                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1351                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1352         }
1353
1354         private static function acceptFollowUser($activity)
1355         {
1356                 $uid = self::getUserOfObject($activity['object']);
1357                 if (empty($uid)) {
1358                         return;
1359                 }
1360
1361                 $owner = User::getOwnerDataById($uid);
1362
1363                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1364                 if (empty($cid)) {
1365                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1366                         return;
1367                 }
1368
1369                 $fields = ['pending' => false];
1370
1371                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1372                 if ($contact['rel'] == Contact::FOLLOWER) {
1373                         $fields['rel'] = Contact::FRIEND;
1374                 }
1375
1376                 $condition = ['id' => $cid];
1377                 DBA::update('contact', $fields, $condition);
1378                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1379         }
1380
1381         private static function undoFollowUser($activity)
1382         {
1383                 $uid = self::getUserOfObject($activity['object']);
1384                 if (empty($uid)) {
1385                         return;
1386                 }
1387
1388                 $owner = User::getOwnerDataById($uid);
1389
1390                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1391                 if (empty($cid)) {
1392                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1393                         return;
1394                 }
1395
1396                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1397                 if (!DBA::isResult($contact)) {
1398                         return;
1399                 }
1400
1401                 Contact::removeFollower($owner, $contact);
1402                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1403         }
1404 }