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\Util\JsonLD;
  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                         ['vcard' => 'http://www.w3.org/2006/vcard/ns#', 'uuid' => 'http://schema.org/identifier',
 129                         'sensitive' => 'as:sensitive', 'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers']]];
 130
 131                 $data['id'] = $contact['url'];
 132                 $data['uuid'] = $user['guid'];
 133                 $data['type'] = $accounttype[$user['account-type']];
 134                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 135                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 136                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 137                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 138                 $data['preferredUsername'] = $user['nickname'];
 139                 $data['name'] = $contact['name'];
 140                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 141                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 142                 $data['summary'] = $contact['about'];
 143                 $data['url'] = $contact['url'];
 144                 $data['manuallyApprovesFollowers'] = in_array($profile['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 145                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 146                         'owner' => $contact['url'],
 147                         'publicKeyPem' => $user['pubkey']];
 148                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 149                 $data['icon'] = ['type' => 'Image',
 150                         'url' => $contact['avatar']];
 151
 152                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 153                 return $data;
 154         }
 155
 156         public static function createPermissionBlockForItem($item)
 157         {
 158                 $data = ['to' => [], 'cc' => []];
 159
 160                 $terms = Term::tagArrayFromItemId($item['id']);
 161
 162                 if (!$item['private']) {
 163                         $data['to'][] = self::PUBLIC;
 164                         $data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 165
 166                         foreach ($terms as $term) {
 167                                 if ($term['type'] != TERM_MENTION) {
 168                                         continue;
 169                                 }
 170                                 $profile = self::fetchprofile($term['url']);
 171                                 if (!empty($profile)) {
 172                                         $data['cc'][] = $profile['url'];
 173                                 }
 174                         }
 175                 } else {
 176                         //$data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 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                                 $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' => $item['uid'],
 213                                         'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
 214                         while ($contact = DBA::fetch($contacts)) {
 215                                 $contact = defaults($contact, 'batch', $contact['notify']);
 216                                 $inboxes[$contact] = $contact;
 217                         }
 218                         DBA::close($contacts);
 219
 220                         foreach ($terms as $term) {
 221                                 if ($term['type'] != TERM_MENTION) {
 222                                         continue;
 223                                 }
 224                                 $profile = self::fetchprofile($term['url']);
 225                                 if (!empty($profile)) {
 226                                         $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 227                                         $inboxes[$target] = $target;
 228                                 }
 229                         }
 230                 } else {
 231                         $receiver_list = Item::enumeratePermissions($item);
 232
 233                         $mentioned = [];
 234
 235                         foreach ($terms as $term) {
 236                                 if ($term['type'] != TERM_MENTION) {
 237                                         continue;
 238                                 }
 239                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 240                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 241                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 242                                         $profile = self::fetchprofile($contact['url']);
 243                                         if (!empty($profile['network'])) {
 244                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 245                                                 $inboxes[$target] = $target;
 246                                         }
 247                                 }
 248                         }
 249
 250                         foreach ($receiver_list as $receiver) {
 251                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 252                                 $profile = self::fetchprofile($contact['url']);
 253                                 if (!empty($profile['network'])) {
 254                                         $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 255                                         $inboxes[$target] = $target;
 256                                 }
 257                         }
 258                 }
 259
 260                 $profile = self::fetchprofile($item['author-link']);
 261                 if (!empty($profile['sharedinbox'])) {
 262                         unset($inboxes[$profile['sharedinbox']]);
 263                 }
 264
 265                 if (!empty($profile['inbox'])) {
 266                         unset($inboxes[$profile['inbox']]);
 267                 }
 268
 269                 return $inboxes;
 270         }
 271
 272         public static function createActivityFromItem($item_id)
 273         {
 274                 $item = Item::selectFirst([], ['id' => $item_id]);
 275
 276                 if (!DBA::isResult($item)) {
 277                         return false;
 278                 }
 279
 280                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 281                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 282                 if (DBA::isResult($conversation)) {
 283                         $data = json_decode($conversation['source']);
 284                         if (!empty($data)) {
 285                                 return $data;
 286                         }
 287                 }
 288
 289                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 290                         ['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 291                         'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 292                         'conversation' => 'ostatus:conversation',
 293                         'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
 294
 295                 $data['type'] = 'Create';
 296                 $data['id'] = $item['uri'] . '#activity';
 297                 $data['actor'] = $item['author-link'];
 298
 299                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 300
 301                 if ($item["created"] != $item["edited"]) {
 302                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 303                 }
 304
 305                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 306
 307                 $data['object'] = self::createNote($item);
 308                 return $data;
 309         }
 310
 311         public static function createObjectFromItemID($item_id)
 312         {
 313                 $item = Item::selectFirst([], ['id' => $item_id]);
 314
 315                 if (!DBA::isResult($item)) {
 316                         return false;
 317                 }
 318
 319                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 320                         ['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 321                         'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 322                         'conversation' => 'ostatus:conversation',
 323                         'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
 324
 325                 $data = array_merge($data, self::createNote($item));
 326
 327
 328                 return $data;
 329         }
 330
 331         private static function createTagList($item)
 332         {
 333                 $tags = [];
 334
 335                 $terms = Term::tagArrayFromItemId($item['id']);
 336                 foreach ($terms as $term) {
 337                         if ($term['type'] == TERM_MENTION) {
 338                                 $contact = Contact::getDetailsByURL($term['url']);
 339                                 if (!empty($contact['addr'])) {
 340                                         $mention = '@' . $contact['addr'];
 341                                 } else {
 342                                         $mention = '@' . $term['url'];
 343                                 }
 344
 345                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 346                         }
 347                 }
 348
 349                 return $tags;
 350         }
 351
 352         public static function createNote($item)
 353         {
 354                 $data = [];
 355                 $data['type'] = 'Note';
 356                 $data['id'] = $item['uri'];
 357
 358                 if ($item['uri'] != $item['thr-parent']) {
 359                         $data['inReplyTo'] = $item['thr-parent'];
 360                 }
 361
 362                 $conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
 363                 if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 364                         $conversation_uri = $conversation['conversation-uri'];
 365                 } else {
 366                         $conversation_uri = $item['parent-uri'];
 367                 }
 368
 369                 $data['context'] = $data['conversation'] = $conversation_uri;
 370                 $data['actor'] = $item['author-link'];
 371                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 372                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 373
 374                 if ($item["created"] != $item["edited"]) {
 375                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 376                 }
 377
 378                 $data['attributedTo'] = $item['author-link'];
 379                 $data['name'] = BBCode::convert($item['title'], false, 7);
 380                 $data['content'] = BBCode::convert($item['body'], false, 7);
 381                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 382                 $data['summary'] = ''; // Ignore by now
 383                 $data['sensitive'] = false; // - Query NSFW
 384                 //$data['emoji'] = []; // Ignore by now
 385                 $data['tag'] = self::createTagList($item);
 386                 $data['attachment'] = []; // @ToDo
 387                 return $data;
 388         }
 389
 390         public static function transmitActivity($activity, $target, $uid)
 391         {
 392                 $profile = self::fetchprofile($target);
 393
 394                 $owner = User::getOwnerDataById($uid);
 395
 396                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 397                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 398                         'type' => $activity,
 399                         'actor' => $owner['url'],
 400                         'object' => $profile['url'],
 401                         'to' => $profile['url']];
 402
 403                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 404                 return self::transmit($data,  $profile['inbox'], $uid);
 405         }
 406
 407         public static function transmitContactAccept($target, $id, $uid)
 408         {
 409                 $profile = self::fetchprofile($target);
 410
 411                 $owner = User::getOwnerDataById($uid);
 412                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 413                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 414                         'type' => 'Accept',
 415                         'actor' => $owner['url'],
 416                         'object' => ['id' => $id, 'type' => 'Follow',
 417                                 'actor' => $profile['url'],
 418                                 'object' => $owner['url']],
 419                         'to' => $profile['url']];
 420
 421                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 422                 return self::transmit($data,  $profile['inbox'], $uid);
 423         }
 424
 425         public static function transmitContactReject($target, $id, $uid)
 426         {
 427                 $profile = self::fetchprofile($target);
 428
 429                 $owner = User::getOwnerDataById($uid);
 430                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 431                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 432                         'type' => 'Reject',
 433                         'actor' => $owner['url'],
 434                         'object' => ['id' => $id, 'type' => 'Follow',
 435                                 'actor' => $profile['url'],
 436                                 'object' => $owner['url']],
 437                         'to' => $profile['url']];
 438
 439                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 440                 return self::transmit($data,  $profile['inbox'], $uid);
 441         }
 442
 443         public static function transmitContactUndo($target, $uid)
 444         {
 445                 $profile = self::fetchprofile($target);
 446
 447                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 448
 449                 $owner = User::getOwnerDataById($uid);
 450                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 451                         'id' => $id,
 452                         'type' => 'Undo',
 453                         'actor' => $owner['url'],
 454                         'object' => ['id' => $id, 'type' => 'Follow',
 455                                 'actor' => $owner['url'],
 456                                 'object' => $profile['url']],
 457                         'to' => $profile['url']];
 458
 459                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 460                 return self::transmit($data,  $profile['inbox'], $uid);
 461         }
 462
 463         /**
 464          * Fetches ActivityPub content from the given url
 465          *
 466          * @param string $url content url
 467          * @return array
 468          */
 469         public static function fetchContent($url)
 470         {
 471                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 472                 if (!$ret['success'] || empty($ret['body'])) {
 473                         return;
 474                 }
 475
 476                 return json_decode($ret['body'], true);
 477         }
 478
 479         /**
 480          * Resolves the profile url from the address by using webfinger
 481          *
 482          * @param string $addr profile address (user@domain.tld)
 483          * @return string url
 484          */
 485         private static function addrToUrl($addr)
 486         {
 487                 $addr_parts = explode('@', $addr);
 488                 if (count($addr_parts) != 2) {
 489                         return false;
 490                 }
 491
 492                 $webfinger = 'https://' . $addr_parts[1] . '/.well-known/webfinger?resource=acct:' . urlencode($addr);
 493
 494                 $ret = Network::curl($webfinger, false, $redirects, ['accept_content' => 'application/jrd+json,application/json']);
 495                 if (!$ret['success'] || empty($ret['body'])) {
 496                         return false;
 497                 }
 498
 499                 $data = json_decode($ret['body'], true);
 500
 501                 if (empty($data['links'])) {
 502                         return false;
 503                 }
 504
 505                 foreach ($data['links'] as $link) {
 506                         if (empty($link['href']) || empty($link['rel']) || empty($link['type'])) {
 507                                 continue;
 508                         }
 509
 510                         if (($link['rel'] == 'self') && ($link['type'] == 'application/activity+json')) {
 511                                 return $link['href'];
 512                         }
 513                 }
 514
 515                 return false;
 516         }
 517
 518         public static function verifySignature($content, $http_headers)
 519         {
 520                 $object = json_decode($content, true);
 521
 522                 if (empty($object)) {
 523                         return false;
 524                 }
 525
 526                 $actor = JsonLD::fetchElement($object, 'actor', 'id');
 527
 528                 $headers = [];
 529                 $headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . $http_headers['REQUEST_URI'];
 530
 531                 // First take every header
 532                 foreach ($http_headers as $k => $v) {
 533                         $field = str_replace('_', '-', strtolower($k));
 534                         $headers[$field] = $v;
 535                 }
 536
 537                 // Now add every http header
 538                 foreach ($http_headers as $k => $v) {
 539                         if (strpos($k, 'HTTP_') === 0) {
 540                                 $field = str_replace('_', '-', strtolower(substr($k, 5)));
 541                                 $headers[$field] = $v;
 542                         }
 543                 }
 544
 545                 $sig_block = ActivityPub::parseSigHeader($http_headers['HTTP_SIGNATURE']);
 546
 547                 if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
 548                         return false;
 549                 }
 550
 551                 $signed_data = '';
 552                 foreach ($sig_block['headers'] as $h) {
 553                         if (array_key_exists($h, $headers)) {
 554                                 $signed_data .= $h . ': ' . $headers[$h] . "\n";
 555                         }
 556                 }
 557                 $signed_data = rtrim($signed_data, "\n");
 558
 559                 if (empty($signed_data)) {
 560                         return false;
 561                 }
 562
 563                 $algorithm = null;
 564
 565                 if ($sig_block['algorithm'] === 'rsa-sha256') {
 566                         $algorithm = 'sha256';
 567                 }
 568
 569                 if ($sig_block['algorithm'] === 'rsa-sha512') {
 570                         $algorithm = 'sha512';
 571                 }
 572
 573                 if (empty($algorithm)) {
 574                         return false;
 575                 }
 576
 577                 $key = self::fetchKey($sig_block['keyId'], $actor);
 578
 579                 if (empty($key)) {
 580                         return false;
 581                 }
 582
 583                 if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
 584                         return false;
 585                 }
 586
 587                 // Check the digest when it is part of the signed data
 588                 if (in_array('digest', $sig_block['headers'])) {
 589                         $digest = explode('=', $headers['digest'], 2);
 590                         if ($digest[0] === 'SHA-256') {
 591                                 $hashalg = 'sha256';
 592                         }
 593                         if ($digest[0] === 'SHA-512') {
 594                                 $hashalg = 'sha512';
 595                         }
 596
 597                         /// @todo add all hashes from the rfc
 598
 599                         if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
 600                                 return false;
 601                         }
 602                 }
 603
 604                 // Check the content-length when it is part of the signed data
 605                 if (in_array('content-length', $sig_block['headers'])) {
 606                         if (strlen($content) != $headers['content-length']) {
 607                                 return false;
 608                         }
 609                 }
 610
 611                 return true;
 612
 613         }
 614
 615         private static function fetchKey($id, $actor)
 616         {
 617                 $url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
 618
 619                 $profile = self::fetchprofile($url);
 620                 if (!empty($profile)) {
 621                         return $profile['pubkey'];
 622                 } elseif ($url != $actor) {
 623                         $profile = self::fetchprofile($actor);
 624                         if (!empty($profile)) {
 625                                 return $profile['pubkey'];
 626                         }
 627                 }
 628
 629                 return false;
 630         }
 631
 632         /**
 633          * @brief
 634          *
 635          * @param string $header
 636          * @return array associate array with
 637          *   - \e string \b keyID
 638          *   - \e string \b algorithm
 639          *   - \e array  \b headers
 640          *   - \e string \b signature
 641          */
 642         private static function parseSigHeader($header)
 643         {
 644                 $ret = [];
 645                 $matches = [];
 646
 647                 if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
 648                         $ret['keyId'] = $matches[1];
 649                 }
 650
 651                 if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
 652                         $ret['algorithm'] = $matches[1];
 653                 }
 654
 655                 if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
 656                         $ret['headers'] = explode(' ', $matches[1]);
 657                 }
 658
 659                 if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
 660                         $ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
 661                 }
 662
 663                 return $ret;
 664         }
 665
 666         public static function fetchprofile($url, $update = false)
 667         {
 668                 if (empty($url)) {
 669                         return false;
 670                 }
 671
 672                 if (!$update) {
 673                         $apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
 674                         if (DBA::isResult($apcontact)) {
 675                                 return $apcontact;
 676                         }
 677
 678                         $apcontact = DBA::selectFirst('apcontact', [], ['alias' => $url]);
 679                         if (DBA::isResult($apcontact)) {
 680                                 return $apcontact;
 681                         }
 682
 683                         $apcontact = DBA::selectFirst('apcontact', [], ['addr' => $url]);
 684                         if (DBA::isResult($apcontact)) {
 685                                 return $apcontact;
 686                         }
 687                 }
 688
 689                 if (empty(parse_url($url, PHP_URL_SCHEME))) {
 690                         $url = self::addrToUrl($url);
 691                         if (empty($url)) {
 692                                 return false;
 693                         }
 694                 }
 695
 696                 $data = self::fetchContent($url);
 697
 698                 if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 699                         return false;
 700                 }
 701
 702                 $apcontact = [];
 703                 $apcontact['url'] = $data['id'];
 704                 $apcontact['uuid'] = defaults($data, 'uuid', null);
 705                 $apcontact['type'] = defaults($data, 'type', null);
 706                 $apcontact['following'] = defaults($data, 'following', null);
 707                 $apcontact['followers'] = defaults($data, 'followers', null);
 708                 $apcontact['inbox'] = defaults($data, 'inbox', null);
 709                 $apcontact['outbox'] = defaults($data, 'outbox', null);
 710                 $apcontact['sharedinbox'] = JsonLD::fetchElement($data, 'endpoints', 'sharedInbox');
 711                 $apcontact['nick'] = defaults($data, 'preferredUsername', null);
 712                 $apcontact['name'] = defaults($data, 'name', $apcontact['nick']);
 713                 $apcontact['about'] = defaults($data, 'summary', '');
 714                 $apcontact['photo'] = JsonLD::fetchElement($data, 'icon', 'url');
 715                 $apcontact['alias'] = JsonLD::fetchElement($data, 'url', 'href');
 716
 717                 $parts = parse_url($apcontact['url']);
 718                 unset($parts['scheme']);
 719                 unset($parts['path']);
 720                 $apcontact['addr'] = $apcontact['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 721
 722                 $apcontact['pubkey'] = trim(JsonLD::fetchElement($data, 'publicKey', 'publicKeyPem'));
 723
 724                 // To-Do
 725                 // manuallyApprovesFollowers
 726
 727                 // Unhandled
 728                 // @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 729
 730                 // Unhandled from Misskey
 731                 // sharedInbox, isCat
 732
 733                 // Unhandled from Kroeg
 734                 // kroeg:blocks, updated
 735
 736                 // Check if the address is resolvable
 737                 if (self::addrToUrl($apcontact['addr']) == $apcontact['url']) {
 738                         $parts = parse_url($apcontact['url']);
 739                         unset($parts['path']);
 740                         $apcontact['baseurl'] = Network::unparseURL($parts);
 741                 } else {
 742                         $apcontact['addr'] = null;
 743                 }
 744
 745                 if ($apcontact['url'] == $apcontact['alias']) {
 746                         $apcontact['alias'] = null;
 747                 }
 748
 749                 $apcontact['updated'] = DateTimeFormat::utcNow();
 750
 751                 DBA::update('apcontact', $apcontact, ['url' => $url], true);
 752
 753                 return $apcontact;
 754         }
 755
 756         /**
 757          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 758          *
 759          * @param string $url profile url
 760          * @return array
 761          */
 762         public static function probeProfile($url)
 763         {
 764                 $apcontact = self::fetchprofile($url, true);
 765                 if (empty($apcontact)) {
 766                         return false;
 767                 }
 768
 769                 $profile = ['network' => Protocol::ACTIVITYPUB];
 770                 $profile['nick'] = $apcontact['nick'];
 771                 $profile['name'] = $apcontact['name'];
 772                 $profile['guid'] = $apcontact['uuid'];
 773                 $profile['url'] = $apcontact['url'];
 774                 $profile['addr'] = $apcontact['addr'];
 775                 $profile['alias'] = $apcontact['alias'];
 776                 $profile['photo'] = $apcontact['photo'];
 777                 // $profile['community']
 778                 // $profile['keywords']
 779                 // $profile['location']
 780                 $profile['about'] = $apcontact['about'];
 781                 $profile['batch'] = $apcontact['sharedinbox'];
 782                 $profile['notify'] = $apcontact['inbox'];
 783                 $profile['poll'] = $apcontact['outbox'];
 784                 $profile['pubkey'] = $apcontact['pubkey'];
 785                 $profile['baseurl'] = $apcontact['baseurl'];
 786
 787                 // Remove all "null" fields
 788                 foreach ($profile as $field => $content) {
 789                         if (is_null($content)) {
 790                                 unset($profile[$field]);
 791                         }
 792                 }
 793
 794                 return $profile;
 795         }
 796
 797         public static function processInbox($body, $header, $uid)
 798         {
 799                 logger('Incoming message for user ' . $uid, LOGGER_DEBUG);
 800
 801                 if (!self::verifySignature($body, $header)) {
 802                         logger('Invalid signature, message will be discarded.', LOGGER_DEBUG);
 803                         return;
 804                 }
 805
 806                 $activity = json_decode($body, true);
 807
 808                 if (!is_array($activity)) {
 809                         logger('Invalid body.', LOGGER_DEBUG);
 810                         return;
 811                 }
 812
 813                 self::processActivity($activity, $body, $uid);
 814         }
 815
 816         public static function fetchOutbox($url)
 817         {
 818                 $data = self::fetchContent($url);
 819                 if (empty($data)) {
 820                         return;
 821                 }
 822
 823                 if (!empty($data['orderedItems'])) {
 824                         $items = $data['orderedItems'];
 825                 } elseif (!empty($data['first']['orderedItems'])) {
 826                         $items = $data['first']['orderedItems'];
 827                 } elseif (!empty($data['first'])) {
 828                         self::fetchOutbox($data['first']);
 829                         return;
 830                 } else {
 831                         $items = [];
 832                 }
 833
 834                 foreach ($items as $activity) {
 835                         self::processActivity($activity);
 836                 }
 837         }
 838
 839         private static function prepareObjectData($activity, $uid)
 840         {
 841                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 842                 if (empty($actor)) {
 843                         logger('Empty actor', LOGGER_DEBUG);
 844                         return [];
 845                 }
 846
 847                 // Fetch all receivers from to, cc, bto and bcc
 848                 $receivers = self::getReceivers($activity, $actor);
 849
 850                 // When it is a delivery to a personal inbox we add that user to the receivers
 851                 if (!empty($uid)) {
 852                         $owner = User::getOwnerDataById($uid);
 853                         $additional = ['uid:' . $uid => $uid];
 854                         $receivers = array_merge($receivers, $additional);
 855                 }
 856
 857                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 858
 859                 $public = in_array(0, $receivers);
 860
 861                 if (is_string($activity['object'])) {
 862                         $object_url = $activity['object'];
 863                 } elseif (!empty($activity['object']['id'])) {
 864                         $object_url = $activity['object']['id'];
 865                 } else {
 866                         logger('No object found', LOGGER_DEBUG);
 867                         return [];
 868                 }
 869
 870                 // Fetch the content only on activities where this matters
 871                 if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
 872                         $object_data = self::fetchObject($object_url, $activity['object']);
 873                         if (empty($object_data)) {
 874                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 875                                 return [];
 876                         }
 877                 } elseif ($activity['type'] == 'Accept') {
 878                         $object_data = [];
 879                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
 880                         $object_data['object'] = JsonLD::fetchElement($activity, 'object', 'actor');
 881                 } elseif ($activity['type'] == 'Undo') {
 882                         $object_data = [];
 883                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
 884                         $object_data['object'] = JsonLD::fetchElement($activity, 'object', 'object');
 885                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 886                         // Create a mostly empty array out of the activity data (instead of the object).
 887                         // This way we later don't have to check for the existence of ech individual array element.
 888                         $object_data = self::processCommonData($activity);
 889                         $object_data['name'] = $activity['type'];
 890                         $object_data['author'] = $activity['actor'];
 891                         $object_data['object'] = $object_url;
 892                 } elseif ($activity['type'] == 'Follow') {
 893                         $object_data['id'] = $activity['id'];
 894                         $object_data['object'] = $object_url;
 895                 } else {
 896                         $object_data = [];
 897                 }
 898
 899                 $object_data = self::addActivityFields($object_data, $activity);
 900
 901                 $object_data['type'] = $activity['type'];
 902                 $object_data['owner'] = $actor;
 903                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 904
 905                 return $object_data;
 906         }
 907
 908         private static function processActivity($activity, $body = '', $uid = null)
 909         {
 910                 if (empty($activity['type'])) {
 911                         logger('Empty type', LOGGER_DEBUG);
 912                         return;
 913                 }
 914
 915                 if (empty($activity['object'])) {
 916                         logger('Empty object', LOGGER_DEBUG);
 917                         return;
 918                 }
 919
 920                 if (empty($activity['actor'])) {
 921                         logger('Empty actor', LOGGER_DEBUG);
 922                         return;
 923
 924                 }
 925
 926                 // Non standard
 927                 // title, atomUri, context_id, statusnetConversationId
 928
 929                 // To-Do?
 930                 // context, location, signature;
 931
 932                 logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
 933
 934                 $object_data = self::prepareObjectData($activity, $uid);
 935                 if (empty($object_data)) {
 936                         logger('No object data found', LOGGER_DEBUG);
 937                         return;
 938                 }
 939
 940                 switch ($activity['type']) {
 941                         case 'Create':
 942                         case 'Announce':
 943                                 self::createItem($object_data, $body);
 944                                 break;
 945
 946                         case 'Like':
 947                                 self::likeItem($object_data, $body);
 948                                 break;
 949
 950                         case 'Dislike':
 951                                 break;
 952
 953                         case 'Update':
 954                                 break;
 955
 956                         case 'Delete':
 957                                 break;
 958
 959                         case 'Follow':
 960                                 self::followUser($object_data);
 961                                 break;
 962
 963                         case 'Accept':
 964                                 if ($object_data['object_type'] == 'Follow') {
 965                                         self::acceptFollowUser($object_data);
 966                                 }
 967                                 break;
 968
 969                         case 'Undo':
 970                                 if ($object_data['object_type'] == 'Follow') {
 971                                         self::undoFollowUser($object_data);
 972                                 }
 973                                 break;
 974
 975                         default:
 976                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 977                                 break;
 978                 }
 979         }
 980
 981         private static function getReceivers($activity, $actor)
 982         {
 983                 $receivers = [];
 984
 985                 if (!empty($actor)) {
 986                         $profile = self::fetchprofile($actor);
 987                         $followers = defaults($profile, 'followers', '');
 988
 989                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 990                 } else {
 991                         logger('Empty actor', LOGGER_DEBUG);
 992                         $followers = '';
 993                 }
 994
 995                 $elements = ['to', 'cc', 'bto', 'bcc'];
 996                 foreach ($elements as $element) {
 997                         if (empty($activity[$element])) {
 998                                 continue;
 999                         }
1000
1001                         // The receiver can be an arror or a string
1002                         if (is_string($activity[$element])) {
1003                                 $activity[$element] = [$activity[$element]];
1004                         }
1005
1006                         foreach ($activity[$element] as $receiver) {
1007                                 if ($receiver == self::PUBLIC) {
1008                                         $receivers['uid:0'] = 0;
1009                                 }
1010
1011                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
1012                                         // This will most likely catch all OStatus connections to Mastodon
1013                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
1014                                         $contacts = DBA::select('contact', ['uid'], $condition);
1015                                         while ($contact = DBA::fetch($contacts)) {
1016                                                 if ($contact['uid'] != 0) {
1017                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1018                                                 }
1019                                         }
1020                                         DBA::close($contacts);
1021                                 }
1022
1023                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
1024                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1025                                                 'network' => Protocol::ACTIVITYPUB];
1026                                         $contacts = DBA::select('contact', ['uid'], $condition);
1027                                         while ($contact = DBA::fetch($contacts)) {
1028                                                 if ($contact['uid'] != 0) {
1029                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1030                                                 }
1031                                         }
1032                                         DBA::close($contacts);
1033                                         continue;
1034                                 }
1035
1036                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1037                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1038                                 if (!DBA::isResult($contact)) {
1039                                         continue;
1040                                 }
1041                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1042                         }
1043                 }
1044                 return $receivers;
1045         }
1046
1047         private static function addActivityFields($object_data, $activity)
1048         {
1049                 if (!empty($activity['published']) && empty($object_data['published'])) {
1050                         $object_data['published'] = $activity['published'];
1051                 }
1052
1053                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1054                         $object_data['updated'] = $activity['updated'];
1055                 }
1056
1057                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1058                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1059                 }
1060
1061                 if (!empty($activity['instrument'])) {
1062                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1063                 }
1064                 return $object_data;
1065         }
1066
1067         private static function fetchObject($object_url, $object = [], $public = true)
1068         {
1069                 if ($public) {
1070                         $data = self::fetchContent($object_url);
1071                         if (empty($data)) {
1072                                 logger('Empty content for ' . $object_url . ', check if content is available locally.', LOGGER_DEBUG);
1073                                 $data = $object_url;
1074                                 $data = $object;
1075                         }
1076                 } else {
1077                         logger('Using original object for url ' . $object_url, LOGGER_DEBUG);
1078                         $data = $object;
1079                 }
1080
1081                 if (is_string($data)) {
1082                         $item = Item::selectFirst([], ['uri' => $data]);
1083                         if (!DBA::isResult($item)) {
1084                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1085                                 return false;
1086                         }
1087                         logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
1088                         $data = self::createNote($item);
1089                 }
1090
1091                 if (empty($data['type'])) {
1092                         logger('Empty type', LOGGER_DEBUG);
1093                         return false;
1094                 } else {
1095                         $type = $data['type'];
1096                         logger('Type ' . $type, LOGGER_DEBUG);
1097                 }
1098
1099                 if (in_array($type, ['Note', 'Article', 'Video'])) {
1100                         $common = self::processCommonData($data);
1101                 }
1102
1103                 switch ($type) {
1104                         case 'Note':
1105                                 return array_merge($common, self::processNote($data));
1106                         case 'Article':
1107                                 return array_merge($common, self::processArticle($data));
1108                         case 'Video':
1109                                 return array_merge($common, self::processVideo($data));
1110
1111                         case 'Announce':
1112                                 if (empty($data['object'])) {
1113                                         return false;
1114                                 }
1115                                 return self::fetchObject($data['object']);
1116
1117                         case 'Person':
1118                         case 'Tombstone':
1119                                 break;
1120
1121                         default:
1122                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1123                                 break;
1124                 }
1125         }
1126
1127         private static function processCommonData(&$object)
1128         {
1129                 if (empty($object['id'])) {
1130                         return false;
1131                 }
1132
1133                 $object_data = [];
1134                 $object_data['type'] = $object['type'];
1135                 $object_data['uri'] = $object['id'];
1136
1137                 if (!empty($object['inReplyTo'])) {
1138                         $object_data['reply-to-uri'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1139                 } else {
1140                         $object_data['reply-to-uri'] = $object_data['uri'];
1141                 }
1142
1143                 $object_data['published'] = defaults($object, 'published', null);
1144                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1145
1146                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1147                         $object_data['published'] = $object_data['updated'];
1148                 }
1149
1150                 $object_data['uuid'] = defaults($object, 'uuid', null);
1151                 $object_data['owner'] = $object_data['author'] = JsonLD::fetchElement($object, 'attributedTo', 'id');
1152                 $object_data['context'] = defaults($object, 'context', null);
1153                 $object_data['conversation'] = defaults($object, 'conversation', null);
1154                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1155                 $object_data['name'] = defaults($object, 'title', null);
1156                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1157                 $object_data['summary'] = defaults($object, 'summary', null);
1158                 $object_data['content'] = defaults($object, 'content', null);
1159                 $object_data['source'] = defaults($object, 'source', null);
1160                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1161                 $object_data['attachments'] = defaults($object, 'attachment', null);
1162                 $object_data['tags'] = defaults($object, 'tag', null);
1163                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1164                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1165                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1166
1167                 // Unhandled
1168                 // @context, type, actor, signature, mediaType, duration, replies, icon
1169
1170                 // Also missing: (Defined in the standard, but currently unused)
1171                 // audience, preview, endTime, startTime, generator, image
1172
1173                 return $object_data;
1174         }
1175
1176         private static function processNote($object)
1177         {
1178                 $object_data = [];
1179
1180                 // To-Do?
1181                 // emoji, atomUri, inReplyToAtomUri
1182
1183                 // Unhandled
1184                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1185                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1186
1187                 return $object_data;
1188         }
1189
1190         private static function processArticle($object)
1191         {
1192                 $object_data = [];
1193
1194                 return $object_data;
1195         }
1196
1197         private static function processVideo($object)
1198         {
1199                 $object_data = [];
1200
1201                 // To-Do?
1202                 // category, licence, language, commentsEnabled
1203
1204                 // Unhandled
1205                 // views, waitTranscoding, state, support, subtitleLanguage
1206                 // likes, dislikes, shares, comments
1207
1208                 return $object_data;
1209         }
1210
1211         private static function convertMentions($body)
1212         {
1213                 $URLSearchString = "^\[\]";
1214                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1215
1216                 return $body;
1217         }
1218
1219         private static function constructTagList($tags, $sensitive)
1220         {
1221                 if (empty($tags)) {
1222                         return '';
1223                 }
1224
1225                 $tag_text = '';
1226                 foreach ($tags as $tag) {
1227                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1228                                 if (!empty($tag_text)) {
1229                                         $tag_text .= ',';
1230                                 }
1231
1232                                 if (empty($tag['href'])) {
1233                                         //$tag['href']
1234                                         logger('Blubb!');
1235                                 }
1236
1237                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1238                         }
1239                 }
1240
1241                 /// @todo add nsfw for $sensitive
1242
1243                 return $tag_text;
1244         }
1245
1246         private static function constructAttachList($attachments, $item)
1247         {
1248                 if (empty($attachments)) {
1249                         return $item;
1250                 }
1251
1252                 foreach ($attachments as $attach) {
1253                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1254                         if ($filetype == 'image') {
1255                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1256                         } else {
1257                                 if (!empty($item["attach"])) {
1258                                         $item["attach"] .= ',';
1259                                 } else {
1260                                         $item["attach"] = '';
1261                                 }
1262                                 if (!isset($attach['length'])) {
1263                                         $attach['length'] = "0";
1264                                 }
1265                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1266                         }
1267                 }
1268
1269                 return $item;
1270         }
1271
1272         private static function createItem($activity, $body)
1273         {
1274                 $item = [];
1275                 $item['verb'] = ACTIVITY_POST;
1276                 $item['parent-uri'] = $activity['reply-to-uri'];
1277
1278                 if ($activity['reply-to-uri'] == $activity['uri']) {
1279                         $item['gravity'] = GRAVITY_PARENT;
1280                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1281                 } else {
1282                         $item['gravity'] = GRAVITY_COMMENT;
1283                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1284                 }
1285
1286                 if (($activity['uri'] != $activity['reply-to-uri']) && !Item::exists(['uri' => $activity['reply-to-uri']])) {
1287                         logger('Parent ' . $activity['reply-to-uri'] . ' not found. Try to refetch it.');
1288                         self::fetchMissingActivity($activity['reply-to-uri'], $activity);
1289                 }
1290
1291                 self::postItem($activity, $item, $body);
1292         }
1293
1294         private static function likeItem($activity, $body)
1295         {
1296                 $item = [];
1297                 $item['verb'] = ACTIVITY_LIKE;
1298                 $item['parent-uri'] = $activity['object'];
1299                 $item['gravity'] = GRAVITY_ACTIVITY;
1300                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1301
1302                 self::postItem($activity, $item, $body);
1303         }
1304
1305         private static function postItem($activity, $item, $body)
1306         {
1307                 /// @todo What to do with $activity['context']?
1308
1309                 $item['network'] = Protocol::ACTIVITYPUB;
1310                 $item['private'] = !in_array(0, $activity['receiver']);
1311                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1312                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1313                 $item['uri'] = $activity['uri'];
1314                 $item['created'] = $activity['published'];
1315                 $item['edited'] = $activity['updated'];
1316                 $item['guid'] = $activity['uuid'];
1317                 $item['title'] = HTML::toBBCode($activity['name']);
1318                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1319                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1320                 $item['location'] = $activity['location'];
1321                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1322                 $item['app'] = $activity['service'];
1323                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1324
1325                 $item = self::constructAttachList($activity['attachments'], $item);
1326
1327                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1328                 if (!empty($source)) {
1329                         $item['body'] = $source;
1330                 }
1331
1332                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1333                 $item['source'] = $body;
1334                 $item['conversation-uri'] = $activity['conversation'];
1335
1336                 foreach ($activity['receiver'] as $receiver) {
1337                         $item['uid'] = $receiver;
1338                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1339
1340                         if (($receiver != 0) && empty($item['contact-id'])) {
1341                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1342                         }
1343
1344                         $item_id = Item::insert($item);
1345                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1346                 }
1347         }
1348
1349         private static function fetchMissingActivity($url, $child)
1350         {
1351                 $object = ActivityPub::fetchContent($url);
1352                 if (empty($object)) {
1353                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1354                         return;
1355                 }
1356
1357                 $activity = [];
1358                 $activity['@context'] = $object['@context'];
1359                 unset($object['@context']);
1360                 $activity['id'] = $object['id'];
1361                 $activity['to'] = defaults($object, 'to', []);
1362                 $activity['cc'] = defaults($object, 'cc', []);
1363                 $activity['actor'] = $child['author'];
1364                 $activity['object'] = $object;
1365                 $activity['published'] = $object['published'];
1366                 $activity['type'] = 'Create';
1367                 self::processActivity($activity);
1368                 logger('Activity ' . $url . ' had been fetched and processed.');
1369         }
1370
1371         private static function getUserOfObject($object)
1372         {
1373                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($object), 'self' => true]);
1374                 if (!DBA::isResult($self)) {
1375                         return false;
1376                 } else {
1377                         return $self['uid'];
1378                 }
1379         }
1380
1381         private static function followUser($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                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1393                 } else {
1394                         $contact = false;
1395                 }
1396
1397                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1398                         'author-link' => $activity['owner']];
1399
1400                 Contact::addRelationship($owner, $contact, $item);
1401                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1402                 if (empty($cid)) {
1403                         return;
1404                 }
1405
1406                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1407                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1408                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1409                 }
1410
1411                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1412                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1413         }
1414
1415         private static function acceptFollowUser($activity)
1416         {
1417                 $uid = self::getUserOfObject($activity['object']);
1418                 if (empty($uid)) {
1419                         return;
1420                 }
1421
1422                 $owner = User::getOwnerDataById($uid);
1423
1424                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1425                 if (empty($cid)) {
1426                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1427                         return;
1428                 }
1429
1430                 $fields = ['pending' => false];
1431
1432                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1433                 if ($contact['rel'] == Contact::FOLLOWER) {
1434                         $fields['rel'] = Contact::FRIEND;
1435                 }
1436
1437                 $condition = ['id' => $cid];
1438                 DBA::update('contact', $fields, $condition);
1439                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1440         }
1441
1442         private static function undoFollowUser($activity)
1443         {
1444                 $uid = self::getUserOfObject($activity['object']);
1445                 if (empty($uid)) {
1446                         return;
1447                 }
1448
1449                 $owner = User::getOwnerDataById($uid);
1450
1451                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1452                 if (empty($cid)) {
1453                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1454                         return;
1455                 }
1456
1457                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1458                 if (!DBA::isResult($contact)) {
1459                         return;
1460                 }
1461
1462                 Contact::removeFollower($owner, $contact);
1463                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1464         }
1465 }