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