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 use Friendica\Util\LDSignature;
  24
  25 /**
  26  * @brief ActivityPub Protocol class
  27  * The ActivityPub Protocol is a message exchange protocol defined by the W3C.
  28  * https://www.w3.org/TR/activitypub/
  29  * https://www.w3.org/TR/activitystreams-core/
  30  * https://www.w3.org/TR/activitystreams-vocabulary/
  31  *
  32  * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
  33  * https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/
  34  *
  35  * Digest: https://tools.ietf.org/html/rfc5843
  36  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
  37  * https://github.com/digitalbazaar/php-json-ld
  38  *
  39  * Part of the code for HTTP signing is taken from the Osada project.
  40  * https://framagit.org/macgirvin/osada
  41  *
  42  * To-do:
  43  *
  44  * Receiver:
  45  * - Activities: Dislike, Update, Delete
  46  * - Object Types: Person, Tombstome
  47  *
  48  * Transmitter:
  49  * - Activities: Like, Dislike, Update, Delete, Announce
  50  * - Object Tyoes: Article, Person, Tombstone
  51  *
  52  * General:
  53  * - Endpoints: Outbox, Follower, Following
  54  * - General cleanup
  55  * - Queueing unsucessful deliveries
  56  */
  57 class ActivityPub
  58 {
  59         const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
  60
  61         public static function isRequest()
  62         {
  63                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  64                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  65         }
  66
  67         /**
  68          * Return the ActivityPub profile of the given user
  69          *
  70          * @param integer $uid User ID
  71          * @return array
  72          */
  73         public static function profile($uid)
  74         {
  75                 $accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application'];
  76                 $condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
  77                         'account_removed' => false, 'verified' => true];
  78                 $fields = ['guid', 'nickname', 'pubkey', 'account-type', 'page-flags'];
  79                 $user = DBA::selectFirst('user', $fields, $condition);
  80                 if (!DBA::isResult($user)) {
  81                         return [];
  82                 }
  83
  84                 $fields = ['locality', 'region', 'country-name'];
  85                 $profile = DBA::selectFirst('profile', $fields, ['uid' => $uid, 'is-default' => true]);
  86                 if (!DBA::isResult($profile)) {
  87                         return [];
  88                 }
  89
  90                 $fields = ['name', 'url', 'location', 'about', 'avatar'];
  91                 $contact = DBA::selectFirst('contact', $fields, ['uid' => $uid, 'self' => true]);
  92                 if (!DBA::isResult($contact)) {
  93                         return [];
  94                 }
  95
  96                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
  97                         ['vcard' => 'http://www.w3.org/2006/vcard/ns#', 'uuid' => 'http://schema.org/identifier',
  98                         'sensitive' => 'as:sensitive', 'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers']]];
  99
 100                 $data['id'] = $contact['url'];
 101                 $data['uuid'] = $user['guid'];
 102                 $data['type'] = $accounttype[$user['account-type']];
 103                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 104                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 105                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 106                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 107                 $data['preferredUsername'] = $user['nickname'];
 108                 $data['name'] = $contact['name'];
 109                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 110                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 111                 $data['summary'] = $contact['about'];
 112                 $data['url'] = $contact['url'];
 113                 $data['manuallyApprovesFollowers'] = in_array($user['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 114                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 115                         'owner' => $contact['url'],
 116                         'publicKeyPem' => $user['pubkey']];
 117                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 118                 $data['icon'] = ['type' => 'Image',
 119                         'url' => $contact['avatar']];
 120
 121                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 122                 return $data;
 123         }
 124
 125         private static function fetchPermissionBlockFromConversation($item)
 126         {
 127                 if (empty($item['thr-parent'])) {
 128                         return [];
 129                 }
 130
 131                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 132                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 133                 if (!DBA::isResult($conversation)) {
 134                         return [];
 135                 }
 136
 137                 $activity = json_decode($conversation['source'], true);
 138
 139                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 140                 $profile = ActivityPub::fetchprofile($actor);
 141
 142                 $permissions = [];
 143
 144                 $elements = ['to', 'cc', 'bto', 'bcc'];
 145                 foreach ($elements as $element) {
 146                         if (empty($activity[$element])) {
 147                                 continue;
 148                         }
 149                         if (is_string($activity[$element])) {
 150                                 $activity[$element] = [$activity[$element]];
 151                         }
 152                         foreach ($activity[$element] as $receiver) {
 153                                 if ($receiver == $profile['followers']) {
 154                                         $receiver = System::baseUrl() . '/followers/' . $item['author-nick'];
 155                                 }
 156                                 $permissions[$element][] = $receiver;
 157                         }
 158                 }
 159                 return $permissions;
 160         }
 161
 162         public static function createPermissionBlockForItem($item)
 163         {
 164                 $data = ['to' => [], 'cc' => []];
 165
 166                 $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 167
 168                 $terms = Term::tagArrayFromItemId($item['id']);
 169
 170                 if (!$item['private']) {
 171                         $data['to'][] = self::PUBLIC;
 172                         $data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 173
 174                         foreach ($terms as $term) {
 175                                 if ($term['type'] != TERM_MENTION) {
 176                                         continue;
 177                                 }
 178                                 $profile = self::fetchprofile($term['url']);
 179                                 if (!empty($profile)) {
 180                                         $data['cc'][] = $profile['url'];
 181                                 }
 182                         }
 183                 } else {
 184                         //$data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 185                         $receiver_list = Item::enumeratePermissions($item);
 186
 187                         $mentioned = [];
 188                         $contacts = [];
 189
 190                         foreach ($terms as $term) {
 191                                 if ($term['type'] != TERM_MENTION) {
 192                                         continue;
 193                                 }
 194                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 195                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 196                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 197                                         $data['to'][] = $contact['url'];
 198                                         $contacts[$contact['url']] = $contact['url'];
 199                                 }
 200                         }
 201
 202                         foreach ($receiver_list as $receiver) {
 203                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 204                                 if (empty($contacts[$contact['url']])) {
 205                                         $data['cc'][] = $contact['url'];
 206                                         $contacts[$contact['url']] = $contact['url'];
 207                                 }
 208                         }
 209
 210                         if (empty($data['to'])) {
 211                                 $data['to'] = $data['cc'];
 212                                 $data['cc'] = [];
 213                         }
 214                 }
 215
 216                 return $data;
 217         }
 218
 219         private static function fetchTargetInboxesFromConversation($item, $uid)
 220         {
 221                 if (empty($item['thr-parent'])) {
 222                         return [];
 223                 }
 224
 225                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 226                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 227                 if (!DBA::isResult($conversation)) {
 228                         return [];
 229                 }
 230
 231                 $activity = json_decode($conversation['source'], true);
 232
 233                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 234                 $profile = ActivityPub::fetchprofile($actor);
 235
 236                 $inboxes = [];
 237
 238                 $elements = ['to', 'cc', 'bto', 'bcc'];
 239                 foreach ($elements as $element) {
 240                         if (empty($activity[$element])) {
 241                                 continue;
 242                         }
 243                         if (is_string($activity[$element])) {
 244                                 $activity[$element] = [$activity[$element]];
 245                         }
 246                         foreach ($activity[$element] as $receiver) {
 247                                 if ($receiver == $profile['followers']) {
 248                                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
 249                                                 'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
 250                                         while ($contact = DBA::fetch($contacts)) {
 251                                                 $contact = defaults($contact, 'batch', $contact['notify']);
 252                                                 $inboxes[$contact] = $contact;
 253                                         }
 254                                         DBA::close($contacts);
 255                                 } else {
 256                                         $profile = self::fetchprofile($receiver);
 257                                         if (!empty($profile)) {
 258                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 259                                                 $inboxes[$target] = $target;
 260                                         }
 261                                 }
 262                         }
 263                 }
 264                 return $inboxes;
 265         }
 266
 267         public static function fetchTargetInboxes($item, $uid)
 268         {
 269                 $inboxes = self::fetchTargetInboxesFromConversation($item, $uid);
 270
 271                 $parents = Item::select(['author-link', 'owner-link'], ['parent' => $item['parent']]);
 272                 while ($parent = Item::fetch($parents)) {
 273                         $profile = self::fetchprofile($parent['author-link']);
 274                         if (!empty($profile)) {
 275                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 276                                 $inboxes[$target] = $target;
 277                         }
 278                         $profile = self::fetchprofile($parent['owner-link']);
 279                         if (!empty($profile)) {
 280                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 281                                 $inboxes[$target] = $target;
 282                         }
 283                 }
 284                 DBA::close($parents);
 285
 286                 $terms = Term::tagArrayFromItemId($item['id']);
 287                 if (!$item['private']) {
 288                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
 289                                         'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
 290                         while ($contact = DBA::fetch($contacts)) {
 291                                 $contact = defaults($contact, 'batch', $contact['notify']);
 292                                 $inboxes[$contact] = $contact;
 293                         }
 294                         DBA::close($contacts);
 295
 296                         foreach ($terms as $term) {
 297                                 if ($term['type'] != TERM_MENTION) {
 298                                         continue;
 299                                 }
 300                                 $profile = self::fetchprofile($term['url']);
 301                                 if (!empty($profile)) {
 302                                         $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 303                                         $inboxes[$target] = $target;
 304                                 }
 305                         }
 306                 } else {
 307                         $receiver_list = Item::enumeratePermissions($item);
 308                         $mentioned = [];
 309
 310                         foreach ($terms as $term) {
 311                                 if ($term['type'] != TERM_MENTION) {
 312                                         continue;
 313                                 }
 314                                 $cid = Contact::getIdForURL($term['url'], $uid);
 315                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 316                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 317                                         $profile = self::fetchprofile($contact['url']);
 318                                         if (!empty($profile)) {
 319                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 320                                                 $inboxes[$target] = $target;
 321                                         }
 322                                 }
 323                         }
 324
 325                         foreach ($receiver_list as $receiver) {
 326                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 327                                 $profile = self::fetchprofile($contact['url']);
 328                                 if (!empty($profile)) {
 329                                         $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 330                                         $inboxes[$target] = $target;
 331                                 }
 332                         }
 333                 }
 334
 335                 $profile = self::fetchprofile($item['author-link']);
 336                 if (!empty($profile['sharedinbox'])) {
 337                         unset($inboxes[$profile['sharedinbox']]);
 338                 }
 339
 340                 if (!empty($profile['inbox'])) {
 341                         unset($inboxes[$profile['inbox']]);
 342                 }
 343
 344                 return $inboxes;
 345         }
 346
 347         public static function createActivityFromItem($item_id)
 348         {
 349                 $item = Item::selectFirst([], ['id' => $item_id]);
 350
 351                 if (!DBA::isResult($item)) {
 352                         return false;
 353                 }
 354
 355                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 356                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 357                 if (DBA::isResult($conversation)) {
 358                         $data = json_decode($conversation['source']);
 359                         if (!empty($data)) {
 360                                 return $data;
 361                         }
 362                 }
 363
 364                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 365                         ['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 366                         'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 367                         'conversation' => 'ostatus:conversation',
 368                         'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
 369
 370                 $data['id'] = $item['uri'] . '#activity';
 371                 $data['type'] = 'Create';
 372                 $data['actor'] = $item['author-link'];
 373
 374                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 375
 376                 if ($item["created"] != $item["edited"]) {
 377                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 378                 }
 379
 380                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 381
 382                 $data['object'] = self::createNote($item);
 383
 384                 $owner = User::getOwnerDataById($item['uid']);
 385
 386                 return LDSignature::sign($data, $owner);
 387         }
 388
 389         public static function createObjectFromItemID($item_id)
 390         {
 391                 $item = Item::selectFirst([], ['id' => $item_id]);
 392
 393                 if (!DBA::isResult($item)) {
 394                         return false;
 395                 }
 396
 397                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 398                         ['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
 399                         'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
 400                         'conversation' => 'ostatus:conversation',
 401                         'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
 402
 403                 $data = array_merge($data, self::createNote($item));
 404
 405
 406                 return $data;
 407         }
 408
 409         private static function createTagList($item)
 410         {
 411                 $tags = [];
 412
 413                 $terms = Term::tagArrayFromItemId($item['id']);
 414                 foreach ($terms as $term) {
 415                         if ($term['type'] == TERM_MENTION) {
 416                                 $contact = Contact::getDetailsByURL($term['url']);
 417                                 if (!empty($contact['addr'])) {
 418                                         $mention = '@' . $contact['addr'];
 419                                 } else {
 420                                         $mention = '@' . $term['url'];
 421                                 }
 422
 423                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 424                         }
 425                 }
 426
 427                 return $tags;
 428         }
 429
 430         public static function createNote($item)
 431         {
 432                 $data = [];
 433                 $data['id'] = $item['uri'];
 434                 $data['type'] = 'Note';
 435                 $data['summary'] = null; // Ignore by now
 436
 437                 if ($item['uri'] != $item['thr-parent']) {
 438                         $data['inReplyTo'] = $item['thr-parent'];
 439                 } else {
 440                         $data['inReplyTo'] = null;
 441                 }
 442
 443                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 444
 445                 if ($item["created"] != $item["edited"]) {
 446                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 447                 }
 448
 449                 $data['url'] = $item['uri'];
 450                 $data['attributedTo'] = $item['author-link'];
 451                 $data['actor'] = $item['author-link'];
 452                 $data['sensitive'] = false; // - Query NSFW
 453
 454                 $conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
 455                 if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 456                         $conversation_uri = $conversation['conversation-uri'];
 457                 } else {
 458                         $conversation_uri = $item['parent-uri'];
 459                 }
 460
 461                 $data['conversation'] = $conversation_uri;
 462
 463                 if (!empty($item['title'])) {
 464                         $data['name'] = BBCode::convert($item['title'], false, 7);
 465                 }
 466
 467                 $data['content'] = BBCode::convert($item['body'], false, 7);
 468                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 469                 $data['attachment'] = []; // @ToDo
 470                 $data['tag'] = self::createTagList($item);
 471                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 472
 473                 //$data['emoji'] = []; // Ignore by now
 474                 return $data;
 475         }
 476
 477         public static function transmitActivity($activity, $target, $uid)
 478         {
 479                 $profile = self::fetchprofile($target);
 480
 481                 $owner = User::getOwnerDataById($uid);
 482
 483                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 484                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 485                         'type' => $activity,
 486                         'actor' => $owner['url'],
 487                         'object' => $profile['url'],
 488                         'to' => $profile['url']];
 489
 490                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 491
 492                 $signed = LDSignature::sign($data, $owner);
 493                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 494         }
 495
 496         public static function transmitContactAccept($target, $id, $uid)
 497         {
 498                 $profile = self::fetchprofile($target);
 499
 500                 $owner = User::getOwnerDataById($uid);
 501                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 502                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 503                         'type' => 'Accept',
 504                         'actor' => $owner['url'],
 505                         'object' => ['id' => $id, 'type' => 'Follow',
 506                                 'actor' => $profile['url'],
 507                                 'object' => $owner['url']],
 508                         'to' => $profile['url']];
 509
 510                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 511
 512                 $signed = LDSignature::sign($data, $owner);
 513                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 514         }
 515
 516         public static function transmitContactReject($target, $id, $uid)
 517         {
 518                 $profile = self::fetchprofile($target);
 519
 520                 $owner = User::getOwnerDataById($uid);
 521                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 522                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 523                         'type' => 'Reject',
 524                         'actor' => $owner['url'],
 525                         'object' => ['id' => $id, 'type' => 'Follow',
 526                                 'actor' => $profile['url'],
 527                                 'object' => $owner['url']],
 528                         'to' => $profile['url']];
 529
 530                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 531
 532                 $signed = LDSignature::sign($data, $owner);
 533                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 534         }
 535
 536         public static function transmitContactUndo($target, $uid)
 537         {
 538                 $profile = self::fetchprofile($target);
 539
 540                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 541
 542                 $owner = User::getOwnerDataById($uid);
 543                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 544                         'id' => $id,
 545                         'type' => 'Undo',
 546                         'actor' => $owner['url'],
 547                         'object' => ['id' => $id, 'type' => 'Follow',
 548                                 'actor' => $owner['url'],
 549                                 'object' => $profile['url']],
 550                         'to' => $profile['url']];
 551
 552                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 553
 554                 $signed = LDSignature::sign($data, $owner);
 555                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 556         }
 557
 558         /**
 559          * Fetches ActivityPub content from the given url
 560          *
 561          * @param string $url content url
 562          * @return array
 563          */
 564         public static function fetchContent($url)
 565         {
 566                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 567                 if (!$ret['success'] || empty($ret['body'])) {
 568                         return;
 569                 }
 570
 571                 return json_decode($ret['body'], true);
 572         }
 573
 574         /**
 575          * Resolves the profile url from the address by using webfinger
 576          *
 577          * @param string $addr profile address (user@domain.tld)
 578          * @return string url
 579          */
 580         private static function addrToUrl($addr)
 581         {
 582                 $addr_parts = explode('@', $addr);
 583                 if (count($addr_parts) != 2) {
 584                         return false;
 585                 }
 586
 587                 $webfinger = 'https://' . $addr_parts[1] . '/.well-known/webfinger?resource=acct:' . urlencode($addr);
 588
 589                 $ret = Network::curl($webfinger, false, $redirects, ['accept_content' => 'application/jrd+json,application/json']);
 590                 if (!$ret['success'] || empty($ret['body'])) {
 591                         return false;
 592                 }
 593
 594                 $data = json_decode($ret['body'], true);
 595
 596                 if (empty($data['links'])) {
 597                         return false;
 598                 }
 599
 600                 foreach ($data['links'] as $link) {
 601                         if (empty($link['href']) || empty($link['rel']) || empty($link['type'])) {
 602                                 continue;
 603                         }
 604
 605                         if (($link['rel'] == 'self') && ($link['type'] == 'application/activity+json')) {
 606                                 return $link['href'];
 607                         }
 608                 }
 609
 610                 return false;
 611         }
 612
 613         public static function fetchprofile($url, $update = false)
 614         {
 615                 if (empty($url)) {
 616                         return false;
 617                 }
 618
 619                 if (!$update) {
 620                         $apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
 621                         if (DBA::isResult($apcontact)) {
 622                                 return $apcontact;
 623                         }
 624
 625                         $apcontact = DBA::selectFirst('apcontact', [], ['alias' => $url]);
 626                         if (DBA::isResult($apcontact)) {
 627                                 return $apcontact;
 628                         }
 629
 630                         $apcontact = DBA::selectFirst('apcontact', [], ['addr' => $url]);
 631                         if (DBA::isResult($apcontact)) {
 632                                 return $apcontact;
 633                         }
 634                 }
 635
 636                 if (empty(parse_url($url, PHP_URL_SCHEME))) {
 637                         $url = self::addrToUrl($url);
 638                         if (empty($url)) {
 639                                 return false;
 640                         }
 641                 }
 642
 643                 $data = self::fetchContent($url);
 644
 645                 if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 646                         return false;
 647                 }
 648
 649                 $apcontact = [];
 650                 $apcontact['url'] = $data['id'];
 651                 $apcontact['uuid'] = defaults($data, 'uuid', null);
 652                 $apcontact['type'] = defaults($data, 'type', null);
 653                 $apcontact['following'] = defaults($data, 'following', null);
 654                 $apcontact['followers'] = defaults($data, 'followers', null);
 655                 $apcontact['inbox'] = defaults($data, 'inbox', null);
 656                 $apcontact['outbox'] = defaults($data, 'outbox', null);
 657                 $apcontact['sharedinbox'] = JsonLD::fetchElement($data, 'endpoints', 'sharedInbox');
 658                 $apcontact['nick'] = defaults($data, 'preferredUsername', null);
 659                 $apcontact['name'] = defaults($data, 'name', $apcontact['nick']);
 660                 $apcontact['about'] = defaults($data, 'summary', '');
 661                 $apcontact['photo'] = JsonLD::fetchElement($data, 'icon', 'url');
 662                 $apcontact['alias'] = JsonLD::fetchElement($data, 'url', 'href');
 663
 664                 $parts = parse_url($apcontact['url']);
 665                 unset($parts['scheme']);
 666                 unset($parts['path']);
 667                 $apcontact['addr'] = $apcontact['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 668
 669                 $apcontact['pubkey'] = trim(JsonLD::fetchElement($data, 'publicKey', 'publicKeyPem'));
 670
 671                 // To-Do
 672                 // manuallyApprovesFollowers
 673
 674                 // Unhandled
 675                 // @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 676
 677                 // Unhandled from Misskey
 678                 // sharedInbox, isCat
 679
 680                 // Unhandled from Kroeg
 681                 // kroeg:blocks, updated
 682
 683                 // Check if the address is resolvable
 684                 if (self::addrToUrl($apcontact['addr']) == $apcontact['url']) {
 685                         $parts = parse_url($apcontact['url']);
 686                         unset($parts['path']);
 687                         $apcontact['baseurl'] = Network::unparseURL($parts);
 688                 } else {
 689                         $apcontact['addr'] = null;
 690                 }
 691
 692                 if ($apcontact['url'] == $apcontact['alias']) {
 693                         $apcontact['alias'] = null;
 694                 }
 695
 696                 $apcontact['updated'] = DateTimeFormat::utcNow();
 697
 698                 DBA::update('apcontact', $apcontact, ['url' => $url], true);
 699
 700                 return $apcontact;
 701         }
 702
 703         /**
 704          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 705          *
 706          * @param string $url profile url
 707          * @return array
 708          */
 709         public static function probeProfile($url)
 710         {
 711                 $apcontact = self::fetchprofile($url, true);
 712                 if (empty($apcontact)) {
 713                         return false;
 714                 }
 715
 716                 $profile = ['network' => Protocol::ACTIVITYPUB];
 717                 $profile['nick'] = $apcontact['nick'];
 718                 $profile['name'] = $apcontact['name'];
 719                 $profile['guid'] = $apcontact['uuid'];
 720                 $profile['url'] = $apcontact['url'];
 721                 $profile['addr'] = $apcontact['addr'];
 722                 $profile['alias'] = $apcontact['alias'];
 723                 $profile['photo'] = $apcontact['photo'];
 724                 // $profile['community']
 725                 // $profile['keywords']
 726                 // $profile['location']
 727                 $profile['about'] = $apcontact['about'];
 728                 $profile['batch'] = $apcontact['sharedinbox'];
 729                 $profile['notify'] = $apcontact['inbox'];
 730                 $profile['poll'] = $apcontact['outbox'];
 731                 $profile['pubkey'] = $apcontact['pubkey'];
 732                 $profile['baseurl'] = $apcontact['baseurl'];
 733
 734                 // Remove all "null" fields
 735                 foreach ($profile as $field => $content) {
 736                         if (is_null($content)) {
 737                                 unset($profile[$field]);
 738                         }
 739                 }
 740
 741                 return $profile;
 742         }
 743
 744         public static function processInbox($body, $header, $uid)
 745         {
 746                 $http_signer = HTTPSignature::getSigner($body, $header);
 747                 if (empty($http_signer)) {
 748                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 749                         return;
 750                 } else {
 751                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 752                 }
 753
 754                 $activity = json_decode($body, true);
 755
 756                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 757                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
 758
 759                 if (empty($activity)) {
 760                         logger('Invalid body.', LOGGER_DEBUG);
 761                         return;
 762                 }
 763
 764                 if (LDSignature::isSigned($activity)) {
 765                         $ld_signer = LDSignature::getSigner($activity);
 766                         if (!empty($ld_signer)) {
 767                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
 768                                 $trust_source = true;
 769                         } elseif ($actor == $http_signer) {
 770                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
 771                                 $trust_source = true;
 772                         } else {
 773                                 logger('Invalid JSON-LD signature.', LOGGER_DEBUG);
 774                                 $trust_source = false;
 775                         }
 776                 } elseif ($actor == $http_signer) {
 777                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 778                         $trust_source = true;
 779                 } else {
 780                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 781                         $trust_source = false;
 782                 }
 783
 784                 self::processActivity($activity, $body, $uid, $trust_source);
 785         }
 786
 787         public static function fetchOutbox($url, $uid)
 788         {
 789                 $data = self::fetchContent($url);
 790                 if (empty($data)) {
 791                         return;
 792                 }
 793
 794                 if (!empty($data['orderedItems'])) {
 795                         $items = $data['orderedItems'];
 796                 } elseif (!empty($data['first']['orderedItems'])) {
 797                         $items = $data['first']['orderedItems'];
 798                 } elseif (!empty($data['first'])) {
 799                         self::fetchOutbox($data['first'], $uid);
 800                         return;
 801                 } else {
 802                         $items = [];
 803                 }
 804
 805                 foreach ($items as $activity) {
 806                         self::processActivity($activity, '', $uid, true);
 807                 }
 808         }
 809
 810         private static function prepareObjectData($activity, $uid, $trust_source)
 811         {
 812                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 813                 if (empty($actor)) {
 814                         logger('Empty actor', LOGGER_DEBUG);
 815                         return [];
 816                 }
 817
 818                 // Fetch all receivers from to, cc, bto and bcc
 819                 $receivers = self::getReceivers($activity, $actor);
 820
 821                 // When it is a delivery to a personal inbox we add that user to the receivers
 822                 if (!empty($uid)) {
 823                         $owner = User::getOwnerDataById($uid);
 824                         $additional = ['uid:' . $uid => $uid];
 825                         $receivers = array_merge($receivers, $additional);
 826                 }
 827
 828                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 829
 830                 if (is_string($activity['object'])) {
 831                         $object_url = $activity['object'];
 832                 } elseif (!empty($activity['object']['id'])) {
 833                         $object_url = $activity['object']['id'];
 834                 } else {
 835                         logger('No object found', LOGGER_DEBUG);
 836                         return [];
 837                 }
 838
 839                 // Fetch the content only on activities where this matters
 840                 if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
 841                         $object_data = self::fetchObject($object_url, $activity['object'], $trust_source);
 842                         if (empty($object_data)) {
 843                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 844                                 return [];
 845                         }
 846                 } elseif ($activity['type'] == 'Accept') {
 847                         $object_data = [];
 848                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
 849                         $object_data['object'] = JsonLD::fetchElement($activity, 'object', 'actor');
 850                 } elseif ($activity['type'] == 'Undo') {
 851                         $object_data = [];
 852                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
 853                         $object_data['object'] = JsonLD::fetchElement($activity, 'object', 'object');
 854                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 855                         // Create a mostly empty array out of the activity data (instead of the object).
 856                         // This way we later don't have to check for the existence of ech individual array element.
 857                         $object_data = self::processCommonData($activity);
 858                         $object_data['name'] = $activity['type'];
 859                         $object_data['author'] = $activity['actor'];
 860                         $object_data['object'] = $object_url;
 861                 } elseif ($activity['type'] == 'Follow') {
 862                         $object_data['id'] = $activity['id'];
 863                         $object_data['object'] = $object_url;
 864                 } else {
 865                         $object_data = [];
 866                 }
 867
 868                 $object_data = self::addActivityFields($object_data, $activity);
 869
 870                 $object_data['type'] = $activity['type'];
 871                 $object_data['owner'] = $actor;
 872                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 873
 874                 return $object_data;
 875         }
 876
 877         private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 878         {
 879                 if (empty($activity['type'])) {
 880                         logger('Empty type', LOGGER_DEBUG);
 881                         return;
 882                 }
 883
 884                 if (empty($activity['object'])) {
 885                         logger('Empty object', LOGGER_DEBUG);
 886                         return;
 887                 }
 888
 889                 if (empty($activity['actor'])) {
 890                         logger('Empty actor', LOGGER_DEBUG);
 891                         return;
 892
 893                 }
 894
 895                 // Non standard
 896                 // title, atomUri, context_id, statusnetConversationId
 897
 898                 // To-Do?
 899                 // context, location, signature;
 900
 901                 logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
 902
 903                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 904                 if (empty($object_data)) {
 905                         logger('No object data found', LOGGER_DEBUG);
 906                         return;
 907                 }
 908
 909                 switch ($activity['type']) {
 910                         case 'Create':
 911                         case 'Announce':
 912                                 self::createItem($object_data, $body);
 913                                 break;
 914
 915                         case 'Like':
 916                                 self::likeItem($object_data, $body);
 917                                 break;
 918
 919                         case 'Dislike':
 920                                 break;
 921
 922                         case 'Update':
 923                                 break;
 924
 925                         case 'Delete':
 926                                 break;
 927
 928                         case 'Follow':
 929                                 self::followUser($object_data);
 930                                 break;
 931
 932                         case 'Accept':
 933                                 if ($object_data['object_type'] == 'Follow') {
 934                                         self::acceptFollowUser($object_data);
 935                                 }
 936                                 break;
 937
 938                         case 'Undo':
 939                                 if ($object_data['object_type'] == 'Follow') {
 940                                         self::undoFollowUser($object_data);
 941                                 }
 942                                 break;
 943
 944                         default:
 945                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 946                                 break;
 947                 }
 948         }
 949
 950         private static function getReceivers($activity, $actor)
 951         {
 952                 $receivers = [];
 953
 954                 // When it is an answer, we inherite the receivers from the parent
 955                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
 956                 if (!empty($replyto)) {
 957                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 958                         while ($parent = Item::fetch($parents)) {
 959                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 960                         }
 961                 }
 962
 963                 if (!empty($actor)) {
 964                         $profile = self::fetchprofile($actor);
 965                         $followers = defaults($profile, 'followers', '');
 966
 967                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 968                 } else {
 969                         logger('Empty actor', LOGGER_DEBUG);
 970                         $followers = '';
 971                 }
 972
 973                 $elements = ['to', 'cc', 'bto', 'bcc'];
 974                 foreach ($elements as $element) {
 975                         if (empty($activity[$element])) {
 976                                 continue;
 977                         }
 978
 979                         // The receiver can be an arror or a string
 980                         if (is_string($activity[$element])) {
 981                                 $activity[$element] = [$activity[$element]];
 982                         }
 983
 984                         foreach ($activity[$element] as $receiver) {
 985                                 if ($receiver == self::PUBLIC) {
 986                                         $receivers['uid:0'] = 0;
 987                                 }
 988
 989                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
 990                                         // This will most likely catch all OStatus connections to Mastodon
 991                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
 992                                         $contacts = DBA::select('contact', ['uid'], $condition);
 993                                         while ($contact = DBA::fetch($contacts)) {
 994                                                 if ($contact['uid'] != 0) {
 995                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 996                                                 }
 997                                         }
 998                                         DBA::close($contacts);
 999                                 }
1000
1001                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
1002                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1003                                                 'network' => Protocol::ACTIVITYPUB];
1004                                         $contacts = DBA::select('contact', ['uid'], $condition);
1005                                         while ($contact = DBA::fetch($contacts)) {
1006                                                 if ($contact['uid'] != 0) {
1007                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1008                                                 }
1009                                         }
1010                                         DBA::close($contacts);
1011                                         continue;
1012                                 }
1013
1014                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1015                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1016                                 if (!DBA::isResult($contact)) {
1017                                         continue;
1018                                 }
1019                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1020                         }
1021                 }
1022                 return $receivers;
1023         }
1024
1025         private static function addActivityFields($object_data, $activity)
1026         {
1027                 if (!empty($activity['published']) && empty($object_data['published'])) {
1028                         $object_data['published'] = $activity['published'];
1029                 }
1030
1031                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1032                         $object_data['updated'] = $activity['updated'];
1033                 }
1034
1035                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1036                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1037                 }
1038
1039                 if (!empty($activity['instrument'])) {
1040                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1041                 }
1042                 return $object_data;
1043         }
1044
1045         private static function fetchObject($object_url, $object = [], $trust_source = false)
1046         {
1047                 if (!$trust_source || is_string($object)) {
1048                         $data = self::fetchContent($object_url);
1049                         if (empty($data)) {
1050                                 logger('Empty content for ' . $object_url . ', check if content is available locally.', LOGGER_DEBUG);
1051                                 $data = $object_url;
1052                         } else {
1053                                 logger('Fetched content for ' . $object_url, LOGGER_DEBUG);
1054                         }
1055                 } else {
1056                         logger('Using original object for url ' . $object_url, LOGGER_DEBUG);
1057                         $data = $object;
1058                 }
1059
1060                 if (is_string($data)) {
1061                         $item = Item::selectFirst([], ['uri' => $data]);
1062                         if (!DBA::isResult($item)) {
1063                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1064                                 return false;
1065                         }
1066                         logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
1067                         $data = self::createNote($item);
1068                 }
1069
1070                 if (empty($data['type'])) {
1071                         logger('Empty type', LOGGER_DEBUG);
1072                         return false;
1073                 } else {
1074                         $type = $data['type'];
1075                         logger('Type ' . $type, LOGGER_DEBUG);
1076                 }
1077
1078                 if (in_array($type, ['Note', 'Article', 'Video'])) {
1079                         $common = self::processCommonData($data);
1080                 }
1081
1082                 switch ($type) {
1083                         case 'Note':
1084                                 return array_merge($common, self::processNote($data));
1085                         case 'Article':
1086                                 return array_merge($common, self::processArticle($data));
1087                         case 'Video':
1088                                 return array_merge($common, self::processVideo($data));
1089
1090                         case 'Announce':
1091                                 if (empty($data['object'])) {
1092                                         return false;
1093                                 }
1094                                 return self::fetchObject($data['object']);
1095
1096                         case 'Person':
1097                         case 'Tombstone':
1098                                 break;
1099
1100                         default:
1101                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1102                                 break;
1103                 }
1104         }
1105
1106         private static function processCommonData(&$object)
1107         {
1108                 if (empty($object['id'])) {
1109                         return false;
1110                 }
1111
1112                 $object_data = [];
1113                 $object_data['type'] = $object['type'];
1114                 $object_data['uri'] = $object['id'];
1115
1116                 if (!empty($object['inReplyTo'])) {
1117                         $object_data['reply-to-uri'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1118                 } else {
1119                         $object_data['reply-to-uri'] = $object_data['uri'];
1120                 }
1121
1122                 $object_data['published'] = defaults($object, 'published', null);
1123                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1124
1125                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1126                         $object_data['published'] = $object_data['updated'];
1127                 }
1128
1129                 $object_data['uuid'] = defaults($object, 'uuid', null);
1130                 $object_data['owner'] = $object_data['author'] = JsonLD::fetchElement($object, 'attributedTo', 'id');
1131                 $object_data['context'] = defaults($object, 'context', null);
1132                 $object_data['conversation'] = defaults($object, 'conversation', null);
1133                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1134                 $object_data['name'] = defaults($object, 'title', null);
1135                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1136                 $object_data['summary'] = defaults($object, 'summary', null);
1137                 $object_data['content'] = defaults($object, 'content', null);
1138                 $object_data['source'] = defaults($object, 'source', null);
1139                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1140                 $object_data['attachments'] = defaults($object, 'attachment', null);
1141                 $object_data['tags'] = defaults($object, 'tag', null);
1142                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1143                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1144                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1145
1146                 // Unhandled
1147                 // @context, type, actor, signature, mediaType, duration, replies, icon
1148
1149                 // Also missing: (Defined in the standard, but currently unused)
1150                 // audience, preview, endTime, startTime, generator, image
1151
1152                 return $object_data;
1153         }
1154
1155         private static function processNote($object)
1156         {
1157                 $object_data = [];
1158
1159                 // To-Do?
1160                 // emoji, atomUri, inReplyToAtomUri
1161
1162                 // Unhandled
1163                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1164                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1165
1166                 return $object_data;
1167         }
1168
1169         private static function processArticle($object)
1170         {
1171                 $object_data = [];
1172
1173                 return $object_data;
1174         }
1175
1176         private static function processVideo($object)
1177         {
1178                 $object_data = [];
1179
1180                 // To-Do?
1181                 // category, licence, language, commentsEnabled
1182
1183                 // Unhandled
1184                 // views, waitTranscoding, state, support, subtitleLanguage
1185                 // likes, dislikes, shares, comments
1186
1187                 return $object_data;
1188         }
1189
1190         private static function convertMentions($body)
1191         {
1192                 $URLSearchString = "^\[\]";
1193                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1194
1195                 return $body;
1196         }
1197
1198         private static function constructTagList($tags, $sensitive)
1199         {
1200                 if (empty($tags)) {
1201                         return '';
1202                 }
1203
1204                 $tag_text = '';
1205                 foreach ($tags as $tag) {
1206                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1207                                 if (!empty($tag_text)) {
1208                                         $tag_text .= ',';
1209                                 }
1210
1211                                 if (empty($tag['href'])) {
1212                                         //$tag['href']
1213                                         logger('Blubb!');
1214                                 }
1215
1216                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1217                         }
1218                 }
1219
1220                 /// @todo add nsfw for $sensitive
1221
1222                 return $tag_text;
1223         }
1224
1225         private static function constructAttachList($attachments, $item)
1226         {
1227                 if (empty($attachments)) {
1228                         return $item;
1229                 }
1230
1231                 foreach ($attachments as $attach) {
1232                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1233                         if ($filetype == 'image') {
1234                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1235                         } else {
1236                                 if (!empty($item["attach"])) {
1237                                         $item["attach"] .= ',';
1238                                 } else {
1239                                         $item["attach"] = '';
1240                                 }
1241                                 if (!isset($attach['length'])) {
1242                                         $attach['length'] = "0";
1243                                 }
1244                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1245                         }
1246                 }
1247
1248                 return $item;
1249         }
1250
1251         private static function createItem($activity, $body)
1252         {
1253                 $item = [];
1254                 $item['verb'] = ACTIVITY_POST;
1255                 $item['parent-uri'] = $activity['reply-to-uri'];
1256
1257                 if ($activity['reply-to-uri'] == $activity['uri']) {
1258                         $item['gravity'] = GRAVITY_PARENT;
1259                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1260                 } else {
1261                         $item['gravity'] = GRAVITY_COMMENT;
1262                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1263                 }
1264
1265                 if (($activity['uri'] != $activity['reply-to-uri']) && !Item::exists(['uri' => $activity['reply-to-uri']])) {
1266                         logger('Parent ' . $activity['reply-to-uri'] . ' not found. Try to refetch it.');
1267                         self::fetchMissingActivity($activity['reply-to-uri'], $activity);
1268                 }
1269
1270                 self::postItem($activity, $item, $body);
1271         }
1272
1273         private static function likeItem($activity, $body)
1274         {
1275                 $item = [];
1276                 $item['verb'] = ACTIVITY_LIKE;
1277                 $item['parent-uri'] = $activity['object'];
1278                 $item['gravity'] = GRAVITY_ACTIVITY;
1279                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1280
1281                 self::postItem($activity, $item, $body);
1282         }
1283
1284         private static function postItem($activity, $item, $body)
1285         {
1286                 /// @todo What to do with $activity['context']?
1287
1288                 $item['network'] = Protocol::ACTIVITYPUB;
1289                 $item['private'] = !in_array(0, $activity['receiver']);
1290                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1291                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1292                 $item['uri'] = $activity['uri'];
1293                 $item['created'] = $activity['published'];
1294                 $item['edited'] = $activity['updated'];
1295                 $item['guid'] = $activity['uuid'];
1296                 $item['title'] = HTML::toBBCode($activity['name']);
1297                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1298                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1299                 $item['location'] = $activity['location'];
1300                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1301                 $item['app'] = $activity['service'];
1302                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1303
1304                 $item = self::constructAttachList($activity['attachments'], $item);
1305
1306                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1307                 if (!empty($source)) {
1308                         $item['body'] = $source;
1309                 }
1310
1311                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1312                 $item['source'] = $body;
1313                 $item['conversation-uri'] = $activity['conversation'];
1314
1315                 foreach ($activity['receiver'] as $receiver) {
1316                         $item['uid'] = $receiver;
1317                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1318
1319                         if (($receiver != 0) && empty($item['contact-id'])) {
1320                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1321                         }
1322
1323                         $item_id = Item::insert($item);
1324                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1325                 }
1326         }
1327
1328         private static function fetchMissingActivity($url, $child)
1329         {
1330                 $object = ActivityPub::fetchContent($url);
1331                 if (empty($object)) {
1332                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1333                         return;
1334                 }
1335
1336                 $activity = [];
1337                 $activity['@context'] = $object['@context'];
1338                 unset($object['@context']);
1339                 $activity['id'] = $object['id'];
1340                 $activity['to'] = defaults($object, 'to', []);
1341                 $activity['cc'] = defaults($object, 'cc', []);
1342                 $activity['actor'] = $child['author'];
1343                 $activity['object'] = $object;
1344                 $activity['published'] = $object['published'];
1345                 $activity['type'] = 'Create';
1346
1347                 self::processActivity($activity);
1348                 logger('Activity ' . $url . ' had been fetched and processed.');
1349         }
1350
1351         private static function getUserOfObject($object)
1352         {
1353                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($object), 'self' => true]);
1354                 if (!DBA::isResult($self)) {
1355                         return false;
1356                 } else {
1357                         return $self['uid'];
1358                 }
1359         }
1360
1361         private static function followUser($activity)
1362         {
1363                 $uid = self::getUserOfObject($activity['object']);
1364                 if (empty($uid)) {
1365                         return;
1366                 }
1367
1368                 $owner = User::getOwnerDataById($uid);
1369
1370                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1371                 if (!empty($cid)) {
1372                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1373                 } else {
1374                         $contact = false;
1375                 }
1376
1377                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1378                         'author-link' => $activity['owner']];
1379
1380                 Contact::addRelationship($owner, $contact, $item);
1381                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1382                 if (empty($cid)) {
1383                         return;
1384                 }
1385
1386                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1387                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1388                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1389                 }
1390
1391                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1392                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1393         }
1394
1395         private static function acceptFollowUser($activity)
1396         {
1397                 $uid = self::getUserOfObject($activity['object']);
1398                 if (empty($uid)) {
1399                         return;
1400                 }
1401
1402                 $owner = User::getOwnerDataById($uid);
1403
1404                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1405                 if (empty($cid)) {
1406                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1407                         return;
1408                 }
1409
1410                 $fields = ['pending' => false];
1411
1412                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1413                 if ($contact['rel'] == Contact::FOLLOWER) {
1414                         $fields['rel'] = Contact::FRIEND;
1415                 }
1416
1417                 $condition = ['id' => $cid];
1418                 DBA::update('contact', $fields, $condition);
1419                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1420         }
1421
1422         private static function undoFollowUser($activity)
1423         {
1424                 $uid = self::getUserOfObject($activity['object']);
1425                 if (empty($uid)) {
1426                         return;
1427                 }
1428
1429                 $owner = User::getOwnerDataById($uid);
1430
1431                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1432                 if (empty($cid)) {
1433                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1434                         return;
1435                 }
1436
1437                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1438                 if (!DBA::isResult($contact)) {
1439                         return;
1440                 }
1441
1442                 Contact::removeFollower($owner, $contact);
1443                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1444         }
1445 }