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\Profile;
  17 use Friendica\Model\Term;
  18 use Friendica\Model\User;
  19 use Friendica\Util\DateTimeFormat;
  20 use Friendica\Util\Crypto;
  21 use Friendica\Content\Text\BBCode;
  22 use Friendica\Content\Text\HTML;
  23 use Friendica\Util\JsonLD;
  24 use Friendica\Util\LDSignature;
  25 use Friendica\Core\Config;
  26
  27 /**
  28  * @brief ActivityPub Protocol class
  29  * The ActivityPub Protocol is a message exchange protocol defined by the W3C.
  30  * https://www.w3.org/TR/activitypub/
  31  * https://www.w3.org/TR/activitystreams-core/
  32  * https://www.w3.org/TR/activitystreams-vocabulary/
  33  *
  34  * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
  35  * https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/
  36  *
  37  * Digest: https://tools.ietf.org/html/rfc5843
  38  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
  39  *
  40  * Mastodon implementation of supported activities:
  41  * https://github.com/tootsuite/mastodon/blob/master/app/lib/activitypub/activity.rb#L26
  42  *
  43  * To-do:
  44  *
  45  * Receiver:
  46  * - Update Note
  47  * - Delete Note
  48  * - Delete Person
  49  * - Undo Announce
  50  * - Reject Follow
  51  * - Undo Accept
  52  * - Undo Follow
  53  * - Add
  54  * - Create Image
  55  * - Create Video
  56  * - Event
  57  * - Remove
  58  * - Block
  59  * - Flag
  60  *
  61  * Transmitter:
  62  * - Announce
  63  * - Undo Announce
  64  * - Update Person
  65  * - Reject Follow
  66  * - Event
  67  *
  68  * General:
  69  * - Attachments
  70  * - nsfw (sensitive)
  71  * - Queueing unsucessful deliveries
  72  * - Polling the outboxes for missing content?
  73  * - Possibly using the LD-JSON parser
  74  */
  75 class ActivityPub
  76 {
  77         const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
  78         const CONTEXT = ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
  79                 ['ostatus' => 'http://ostatus.org#', 'uuid' => 'http://schema.org/identifier',
  80                 'sensitive' => 'as:sensitive', 'Hashtag' => 'as:Hashtag',
  81                 'atomUri' => 'ostatus:atomUri', 'conversation' => 'ostatus:conversation',
  82                 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']];
  83
  84         public static function isRequest()
  85         {
  86                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  87                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  88         }
  89
  90         public static function getFollowers($owner, $page = null)
  91         {
  92                 $condition = ['rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
  93                         'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
  94                 $count = DBA::count('contact', $condition);
  95
  96                 $data = ['@context' => self::CONTEXT];
  97                 $data['id'] = System::baseUrl() . '/followers/' . $owner['nickname'];
  98                 $data['type'] = 'OrderedCollection';
  99                 $data['totalItems'] = $count;
 100
 101                 // When we hide our friends we will only show the pure number but don't allow more.
 102                 $profile = Profile::getProfileForUser($owner['uid']);
 103                 if (!empty($profile['hide-friends'])) {
 104                         return $data;
 105                 }
 106
 107                 if (empty($page)) {
 108                         $data['first'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=1';
 109                 } else {
 110                         $list = [];
 111
 112                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 113                         while ($contact = DBA::fetch($contacts)) {
 114                                 $list[] = $contact['url'];
 115                         }
 116
 117                         if (!empty($list)) {
 118                                 $data['next'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=' . ($page + 1);
 119                         }
 120
 121                         $data['partOf'] = System::baseUrl() . '/followers/' . $owner['nickname'];
 122
 123                         $data['orderedItems'] = $list;
 124                 }
 125
 126                 return $data;
 127         }
 128
 129         public static function getFollowing($owner, $page = null)
 130         {
 131                 $condition = ['rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
 132                         'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
 133                 $count = DBA::count('contact', $condition);
 134
 135                 $data = ['@context' => self::CONTEXT];
 136                 $data['id'] = System::baseUrl() . '/following/' . $owner['nickname'];
 137                 $data['type'] = 'OrderedCollection';
 138                 $data['totalItems'] = $count;
 139
 140                 // When we hide our friends we will only show the pure number but don't allow more.
 141                 $profile = Profile::getProfileForUser($owner['uid']);
 142                 if (!empty($profile['hide-friends'])) {
 143                         return $data;
 144                 }
 145
 146                 if (empty($page)) {
 147                         $data['first'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=1';
 148                 } else {
 149                         $list = [];
 150
 151                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 152                         while ($contact = DBA::fetch($contacts)) {
 153                                 $list[] = $contact['url'];
 154                         }
 155
 156                         if (!empty($list)) {
 157                                 $data['next'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=' . ($page + 1);
 158                         }
 159
 160                         $data['partOf'] = System::baseUrl() . '/following/' . $owner['nickname'];
 161
 162                         $data['orderedItems'] = $list;
 163                 }
 164
 165                 return $data;
 166         }
 167
 168         public static function getOutbox($owner, $page = null)
 169         {
 170                 $public_contact = Contact::getIdForURL($owner['url'], 0, true);
 171
 172                 $condition = ['uid' => $owner['uid'], 'contact-id' => $owner['id'], 'author-id' => $public_contact,
 173                         'wall' => true, 'private' => false, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT],
 174                         'deleted' => false, 'visible' => true];
 175                 $count = DBA::count('item', $condition);
 176
 177                 $data = ['@context' => self::CONTEXT];
 178                 $data['id'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
 179                 $data['type'] = 'OrderedCollection';
 180                 $data['totalItems'] = $count;
 181
 182                 if (empty($page)) {
 183                         $data['first'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=1';
 184                 } else {
 185                         $list = [];
 186
 187                         $condition['parent-network'] = Protocol::NATIVE_SUPPORT;
 188
 189                         $items = Item::select(['id'], $condition, ['limit' => [($page - 1) * 20, 20], 'order' => ['created' => true]]);
 190                         while ($item = Item::fetch($items)) {
 191                                 $object = self::createObjectFromItemID($item['id']);
 192                                 unset($object['@context']);
 193                                 $list[] = $object;
 194                         }
 195
 196                         if (!empty($list)) {
 197                                 $data['next'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=' . ($page + 1);
 198                         }
 199
 200                         $data['partOf'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
 201
 202                         $data['orderedItems'] = $list;
 203                 }
 204
 205                 return $data;
 206         }
 207
 208         /**
 209          * Return the ActivityPub profile of the given user
 210          *
 211          * @param integer $uid User ID
 212          * @return array
 213          */
 214         public static function profile($uid)
 215         {
 216                 $accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application'];
 217                 $condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
 218                         'account_removed' => false, 'verified' => true];
 219                 $fields = ['guid', 'nickname', 'pubkey', 'account-type', 'page-flags'];
 220                 $user = DBA::selectFirst('user', $fields, $condition);
 221                 if (!DBA::isResult($user)) {
 222                         return [];
 223                 }
 224
 225                 $fields = ['locality', 'region', 'country-name'];
 226                 $profile = DBA::selectFirst('profile', $fields, ['uid' => $uid, 'is-default' => true]);
 227                 if (!DBA::isResult($profile)) {
 228                         return [];
 229                 }
 230
 231                 $fields = ['name', 'url', 'location', 'about', 'avatar'];
 232                 $contact = DBA::selectFirst('contact', $fields, ['uid' => $uid, 'self' => true]);
 233                 if (!DBA::isResult($contact)) {
 234                         return [];
 235                 }
 236
 237                 $data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
 238                         ['vcard' => 'http://www.w3.org/2006/vcard/ns#', 'uuid' => 'http://schema.org/identifier',
 239                         'sensitive' => 'as:sensitive', 'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers']]];
 240
 241                 $data['id'] = $contact['url'];
 242                 $data['uuid'] = $user['guid'];
 243                 $data['type'] = $accounttype[$user['account-type']];
 244                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 245                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 246                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 247                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 248                 $data['preferredUsername'] = $user['nickname'];
 249                 $data['name'] = $contact['name'];
 250                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 251                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 252                 $data['summary'] = $contact['about'];
 253                 $data['url'] = $contact['url'];
 254                 $data['manuallyApprovesFollowers'] = in_array($user['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 255                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 256                         'owner' => $contact['url'],
 257                         'publicKeyPem' => $user['pubkey']];
 258                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 259                 $data['icon'] = ['type' => 'Image',
 260                         'url' => $contact['avatar']];
 261
 262                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 263                 return $data;
 264         }
 265
 266         private static function fetchPermissionBlockFromConversation($item)
 267         {
 268                 if (empty($item['thr-parent'])) {
 269                         return [];
 270                 }
 271
 272                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 273                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 274                 if (!DBA::isResult($conversation)) {
 275                         return [];
 276                 }
 277
 278                 $activity = json_decode($conversation['source'], true);
 279
 280                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 281                 $profile = ActivityPub::fetchprofile($actor);
 282
 283                 $item_profile = ActivityPub::fetchprofile($item['author-link']);
 284                 $exclude[] = $item['author-link'];
 285
 286                 if ($item['gravity'] == GRAVITY_PARENT) {
 287                         $exclude[] = $item['owner-link'];
 288                 }
 289
 290                 $permissions['to'][] = $actor;
 291
 292                 $elements = ['to', 'cc', 'bto', 'bcc'];
 293                 foreach ($elements as $element) {
 294                         if (empty($activity[$element])) {
 295                                 continue;
 296                         }
 297                         if (is_string($activity[$element])) {
 298                                 $activity[$element] = [$activity[$element]];
 299                         }
 300
 301                         foreach ($activity[$element] as $receiver) {
 302                                 if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 303                                         $receiver = $item_profile['followers'];
 304                                 }
 305                                 if (!in_array($receiver, $exclude)) {
 306                                         $permissions[$element][] = $receiver;
 307                                 }
 308                         }
 309                 }
 310                 return $permissions;
 311         }
 312
 313         public static function createPermissionBlockForItem($item)
 314         {
 315                 $data = ['to' => [], 'cc' => []];
 316
 317                 $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 318
 319                 $actor_profile = ActivityPub::fetchprofile($item['author-link']);
 320
 321                 $terms = Term::tagArrayFromItemId($item['id']);
 322
 323                 $contacts[$item['author-link']] = $item['author-link'];
 324
 325                 if (!$item['private']) {
 326                         $data['to'][] = self::PUBLIC;
 327                         if (!empty($actor_profile['followers'])) {
 328                                 $data['cc'][] = $actor_profile['followers'];
 329                         }
 330
 331                         foreach ($terms as $term) {
 332                                 if ($term['type'] != TERM_MENTION) {
 333                                         continue;
 334                                 }
 335                                 $profile = self::fetchprofile($term['url'], false);
 336                                 if (!empty($profile) && empty($contacts[$profile['url']])) {
 337                                         $data['cc'][] = $profile['url'];
 338                                         $contacts[$profile['url']] = $profile['url'];
 339                                 }
 340                         }
 341                 } else {
 342                         $receiver_list = Item::enumeratePermissions($item);
 343
 344                         $mentioned = [];
 345
 346                         foreach ($terms as $term) {
 347                                 if ($term['type'] != TERM_MENTION) {
 348                                         continue;
 349                                 }
 350                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 351                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 352                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 353                                         $data['to'][] = $contact['url'];
 354                                         $contacts[$contact['url']] = $contact['url'];
 355                                 }
 356                         }
 357
 358                         foreach ($receiver_list as $receiver) {
 359                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 360                                 if (empty($contacts[$contact['url']])) {
 361                                         $data['cc'][] = $contact['url'];
 362                                         $contacts[$contact['url']] = $contact['url'];
 363                                 }
 364                         }
 365                 }
 366
 367                 $parents = Item::select(['id', 'author-link', 'owner-link', 'gravity'], ['parent' => $item['parent']]);
 368                 while ($parent = Item::fetch($parents)) {
 369                         // Don't include data from future posts
 370                         if ($parent['id'] >= $item['id']) {
 371                                 continue;
 372                         }
 373
 374                         $profile = self::fetchprofile($parent['author-link'], false);
 375                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 376                                 $data['cc'][] = $profile['url'];
 377                                 $contacts[$profile['url']] = $profile['url'];
 378                         }
 379
 380                         if ($item['gravity'] != GRAVITY_PARENT) {
 381                                 continue;
 382                         }
 383
 384                         $profile = self::fetchprofile($parent['owner-link'], false);
 385                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 386                                 $data['cc'][] = $profile['url'];
 387                                 $contacts[$profile['url']] = $profile['url'];
 388                         }
 389                 }
 390                 DBA::close($parents);
 391
 392                 if (empty($data['to'])) {
 393                         $data['to'] = $data['cc'];
 394                         $data['cc'] = [];
 395                 }
 396
 397                 return $data;
 398         }
 399
 400         public static function fetchTargetInboxes($item, $uid)
 401         {
 402                 $permissions = self::createPermissionBlockForItem($item);
 403                 if (empty($permissions)) {
 404                         return [];
 405                 }
 406
 407                 $inboxes = [];
 408
 409                 if ($item['gravity'] == GRAVITY_ACTIVITY) {
 410                         $item_profile = ActivityPub::fetchprofile($item['author-link']);
 411                 } else {
 412                         $item_profile = ActivityPub::fetchprofile($item['owner-link']);
 413                 }
 414
 415                 $elements = ['to', 'cc', 'bto', 'bcc'];
 416                 foreach ($elements as $element) {
 417                         if (empty($permissions[$element])) {
 418                                 continue;
 419                         }
 420
 421                         foreach ($permissions[$element] as $receiver) {
 422                                 if ($receiver == $item_profile['followers']) {
 423                                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
 424                                                 'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
 425                                         while ($contact = DBA::fetch($contacts)) {
 426                                                 $contact = defaults($contact, 'batch', $contact['notify']);
 427                                                 $inboxes[$contact] = $contact;
 428                                         }
 429                                         DBA::close($contacts);
 430                                 } else {
 431                                         $profile = self::fetchprofile($receiver);
 432                                         if (!empty($profile)) {
 433                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 434                                                 $inboxes[$target] = $target;
 435                                         }
 436                                 }
 437                         }
 438                 }
 439
 440                 return $inboxes;
 441         }
 442
 443         public static function getTypeOfItem($item)
 444         {
 445                 if ($item['verb'] == ACTIVITY_POST) {
 446                         if ($item['created'] == $item['edited']) {
 447                                 $type = 'Create';
 448                         } else {
 449                                 $type = 'Update';
 450                         }
 451                 } elseif ($item['verb'] == ACTIVITY_LIKE) {
 452                         $type = 'Like';
 453                 } elseif ($item['verb'] == ACTIVITY_DISLIKE) {
 454                         $type = 'Dislike';
 455                 } elseif ($item['verb'] == ACTIVITY_ATTEND) {
 456                         $type = 'Accept';
 457                 } elseif ($item['verb'] == ACTIVITY_ATTENDNO) {
 458                         $type = 'Reject';
 459                 } elseif ($item['verb'] == ACTIVITY_ATTENDMAYBE) {
 460                         $type = 'TentativeAccept';
 461                 } else {
 462                         $type = '';
 463                 }
 464
 465                 return $type;
 466         }
 467
 468         public static function createActivityFromItem($item_id, $object_mode = false)
 469         {
 470                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 471
 472                 if (!DBA::isResult($item)) {
 473                         return false;
 474                 }
 475
 476                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 477                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 478                 if (DBA::isResult($conversation)) {
 479                         $data = json_decode($conversation['source']);
 480                         if (!empty($data)) {
 481                                 return $data;
 482                         }
 483                 }
 484
 485                 $type = self::getTypeOfItem($item);
 486
 487                 if (!$object_mode) {
 488                         $data = ['@context' => self::CONTEXT];
 489
 490                         if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
 491                                 $type = 'Undo';
 492                         } elseif ($item['deleted']) {
 493                                 $type = 'Delete';
 494                         }
 495                 } else {
 496                         $data = [];
 497                 }
 498
 499                 $data['id'] = $item['uri'] . '#' . $type;
 500                 $data['type'] = $type;
 501                 $data['actor'] = $item['author-link'];
 502
 503                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 504
 505                 if ($item["created"] != $item["edited"]) {
 506                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 507                 }
 508
 509                 $data['context'] = self::fetchContextURLForItem($item);
 510
 511                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 512
 513                 if (in_array($data['type'], ['Create', 'Update', 'Announce', 'Delete'])) {
 514                         $data['object'] = self::CreateNote($item);
 515                 } elseif ($data['type'] == 'Undo') {
 516                         $data['object'] = self::createActivityFromItem($item_id, true);
 517                 } else {
 518                         $data['object'] = $item['thr-parent'];
 519                 }
 520
 521                 $owner = User::getOwnerDataById($item['uid']);
 522
 523                 if (!$object_mode) {
 524                         return LDSignature::sign($data, $owner);
 525                 } else {
 526                         return $data;
 527                 }
 528         }
 529
 530         public static function createObjectFromItemID($item_id)
 531         {
 532                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 533
 534                 if (!DBA::isResult($item)) {
 535                         return false;
 536                 }
 537
 538                 $data = ['@context' => self::CONTEXT];
 539                 $data = array_merge($data, self::CreateNote($item));
 540
 541                 return $data;
 542         }
 543
 544         private static function createTagList($item)
 545         {
 546                 $tags = [];
 547
 548                 $terms = Term::tagArrayFromItemId($item['id']);
 549                 foreach ($terms as $term) {
 550                         if ($term['type'] == TERM_MENTION) {
 551                                 $contact = Contact::getDetailsByURL($term['url']);
 552                                 if (!empty($contact['addr'])) {
 553                                         $mention = '@' . $contact['addr'];
 554                                 } else {
 555                                         $mention = '@' . $term['url'];
 556                                 }
 557
 558                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 559                         }
 560                 }
 561                 return $tags;
 562         }
 563
 564         private static function fetchConversationURLForItem($item)
 565         {
 566                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
 567                 if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 568                         $conversation_uri = $conversation['conversation-uri'];
 569                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
 570                         $conversation_uri = $conversation['conversation-href'];
 571                 } else {
 572                         $conversation_uri = str_replace('/object/', '/context/', $item['parent-uri']);
 573                 }
 574                 return $conversation_uri;
 575         }
 576
 577         private static function fetchContextURLForItem($item)
 578         {
 579                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
 580                 if (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
 581                         $context_uri = $conversation['conversation-href'];
 582                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 583                         $context_uri = $conversation['conversation-uri'];
 584                 } else {
 585                         $context_uri = str_replace('/object/', '/context/', $item['parent-uri']);
 586                 }
 587                 return $context_uri;
 588         }
 589
 590         private static function CreateNote($item)
 591         {
 592                 if (!empty($item['title'])) {
 593                         $type = 'Article';
 594                 } else {
 595                         $type = 'Note';
 596                 }
 597
 598                 if ($item['deleted']) {
 599                         $type = 'Tombstone';
 600                 }
 601
 602                 $data = [];
 603                 $data['id'] = $item['uri'];
 604                 $data['type'] = $type;
 605
 606                 if ($item['deleted']) {
 607                         return $data;
 608                 }
 609
 610                 $data['summary'] = null; // Ignore by now
 611
 612                 if ($item['uri'] != $item['thr-parent']) {
 613                         $data['inReplyTo'] = $item['thr-parent'];
 614                 } else {
 615                         $data['inReplyTo'] = null;
 616                 }
 617
 618                 $data['uuid'] = $item['guid'];
 619                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 620
 621                 if ($item["created"] != $item["edited"]) {
 622                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 623                 }
 624
 625                 $data['url'] = $item['plink'];
 626                 $data['attributedTo'] = $item['author-link'];
 627                 $data['actor'] = $item['author-link'];
 628                 $data['sensitive'] = false; // - Query NSFW
 629                 $data['conversation'] = self::fetchConversationURLForItem($item);
 630                 $data['context'] = self::fetchContextURLForItem($item);
 631
 632                 if (!empty($item['title'])) {
 633                         $data['name'] = BBCode::convert($item['title'], false, 7);
 634                 }
 635
 636                 $data['content'] = BBCode::convert($item['body'], false, 7);
 637                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 638                 $data['attachment'] = []; // @ToDo
 639                 $data['tag'] = self::createTagList($item);
 640                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 641
 642                 return $data;
 643         }
 644
 645         public static function transmitActivity($activity, $target, $uid)
 646         {
 647                 $profile = self::fetchprofile($target);
 648
 649                 $owner = User::getOwnerDataById($uid);
 650
 651                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 652                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 653                         'type' => $activity,
 654                         'actor' => $owner['url'],
 655                         'object' => $profile['url'],
 656                         'to' => $profile['url']];
 657
 658                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 659
 660                 $signed = LDSignature::sign($data, $owner);
 661                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 662         }
 663
 664         public static function transmitContactAccept($target, $id, $uid)
 665         {
 666                 $profile = self::fetchprofile($target);
 667
 668                 $owner = User::getOwnerDataById($uid);
 669                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 670                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 671                         'type' => 'Accept',
 672                         'actor' => $owner['url'],
 673                         'object' => ['id' => $id, 'type' => 'Follow',
 674                                 'actor' => $profile['url'],
 675                                 'object' => $owner['url']],
 676                         'to' => $profile['url']];
 677
 678                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 679
 680                 $signed = LDSignature::sign($data, $owner);
 681                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 682         }
 683
 684         public static function transmitContactReject($target, $id, $uid)
 685         {
 686                 $profile = self::fetchprofile($target);
 687
 688                 $owner = User::getOwnerDataById($uid);
 689                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 690                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 691                         'type' => 'Reject',
 692                         'actor' => $owner['url'],
 693                         'object' => ['id' => $id, 'type' => 'Follow',
 694                                 'actor' => $profile['url'],
 695                                 'object' => $owner['url']],
 696                         'to' => $profile['url']];
 697
 698                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 699
 700                 $signed = LDSignature::sign($data, $owner);
 701                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 702         }
 703
 704         public static function transmitContactUndo($target, $uid)
 705         {
 706                 $profile = self::fetchprofile($target);
 707
 708                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 709
 710                 $owner = User::getOwnerDataById($uid);
 711                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 712                         'id' => $id,
 713                         'type' => 'Undo',
 714                         'actor' => $owner['url'],
 715                         'object' => ['id' => $id, 'type' => 'Follow',
 716                                 'actor' => $owner['url'],
 717                                 'object' => $profile['url']],
 718                         'to' => $profile['url']];
 719
 720                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 721
 722                 $signed = LDSignature::sign($data, $owner);
 723                 return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 724         }
 725
 726         /**
 727          * Fetches ActivityPub content from the given url
 728          *
 729          * @param string $url content url
 730          * @return array
 731          */
 732         public static function fetchContent($url)
 733         {
 734                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 735                 if (!$ret['success'] || empty($ret['body'])) {
 736                         return;
 737                 }
 738                 return json_decode($ret['body'], true);
 739         }
 740
 741         /**
 742          * Resolves the profile url from the address by using webfinger
 743          *
 744          * @param string $addr profile address (user@domain.tld)
 745          * @return string url
 746          */
 747         private static function addrToUrl($addr)
 748         {
 749                 $addr_parts = explode('@', $addr);
 750                 if (count($addr_parts) != 2) {
 751                         return false;
 752                 }
 753
 754                 $webfinger = 'https://' . $addr_parts[1] . '/.well-known/webfinger?resource=acct:' . urlencode($addr);
 755
 756                 $ret = Network::curl($webfinger, false, $redirects, ['accept_content' => 'application/jrd+json,application/json']);
 757                 if (!$ret['success'] || empty($ret['body'])) {
 758                         return false;
 759                 }
 760
 761                 $data = json_decode($ret['body'], true);
 762
 763                 if (empty($data['links'])) {
 764                         return false;
 765                 }
 766
 767                 foreach ($data['links'] as $link) {
 768                         if (empty($link['href']) || empty($link['rel']) || empty($link['type'])) {
 769                                 continue;
 770                         }
 771
 772                         if (($link['rel'] == 'self') && ($link['type'] == 'application/activity+json')) {
 773                                 return $link['href'];
 774                         }
 775                 }
 776
 777                 return false;
 778         }
 779
 780         /**
 781          * Fetches a profile form a given url
 782          *
 783          * @param string  $url    profile url
 784          * @param boolean $update true = always update, false = never update, null = update when not found
 785          * @return array profile array
 786          */
 787         public static function fetchprofile($url, $update = null)
 788         {
 789                 if (empty($url)) {
 790                         return false;
 791                 }
 792
 793                 if (empty($update)) {
 794                         $apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
 795                         if (DBA::isResult($apcontact)) {
 796                                 return $apcontact;
 797                         }
 798
 799                         $apcontact = DBA::selectFirst('apcontact', [], ['alias' => $url]);
 800                         if (DBA::isResult($apcontact)) {
 801                                 return $apcontact;
 802                         }
 803
 804                         $apcontact = DBA::selectFirst('apcontact', [], ['addr' => $url]);
 805                         if (DBA::isResult($apcontact)) {
 806                                 return $apcontact;
 807                         }
 808
 809                         if (!is_null($update)) {
 810                                 return false;
 811                         }
 812                 }
 813
 814                 if (empty(parse_url($url, PHP_URL_SCHEME))) {
 815                         $url = self::addrToUrl($url);
 816                         if (empty($url)) {
 817                                 return false;
 818                         }
 819                 }
 820
 821                 $data = self::fetchContent($url);
 822
 823                 if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 824                         return false;
 825                 }
 826
 827                 $apcontact = [];
 828                 $apcontact['url'] = $data['id'];
 829                 $apcontact['uuid'] = defaults($data, 'uuid', null);
 830                 $apcontact['type'] = defaults($data, 'type', null);
 831                 $apcontact['following'] = defaults($data, 'following', null);
 832                 $apcontact['followers'] = defaults($data, 'followers', null);
 833                 $apcontact['inbox'] = defaults($data, 'inbox', null);
 834                 $apcontact['outbox'] = defaults($data, 'outbox', null);
 835                 $apcontact['sharedinbox'] = JsonLD::fetchElement($data, 'endpoints', 'sharedInbox');
 836                 $apcontact['nick'] = defaults($data, 'preferredUsername', null);
 837                 $apcontact['name'] = defaults($data, 'name', $apcontact['nick']);
 838                 $apcontact['about'] = defaults($data, 'summary', '');
 839                 $apcontact['photo'] = JsonLD::fetchElement($data, 'icon', 'url');
 840                 $apcontact['alias'] = JsonLD::fetchElement($data, 'url', 'href');
 841
 842                 $parts = parse_url($apcontact['url']);
 843                 unset($parts['scheme']);
 844                 unset($parts['path']);
 845                 $apcontact['addr'] = $apcontact['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 846
 847                 $apcontact['pubkey'] = trim(JsonLD::fetchElement($data, 'publicKey', 'publicKeyPem'));
 848
 849                 // To-Do
 850                 // manuallyApprovesFollowers
 851
 852                 // Unhandled
 853                 // @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 854
 855                 // Unhandled from Misskey
 856                 // sharedInbox, isCat
 857
 858                 // Unhandled from Kroeg
 859                 // kroeg:blocks, updated
 860
 861                 // Check if the address is resolvable
 862                 if (self::addrToUrl($apcontact['addr']) == $apcontact['url']) {
 863                         $parts = parse_url($apcontact['url']);
 864                         unset($parts['path']);
 865                         $apcontact['baseurl'] = Network::unparseURL($parts);
 866                 } else {
 867                         $apcontact['addr'] = null;
 868                         $apcontact['baseurl'] = null;
 869                 }
 870
 871                 if ($apcontact['url'] == $apcontact['alias']) {
 872                         $apcontact['alias'] = null;
 873                 }
 874
 875                 $apcontact['updated'] = DateTimeFormat::utcNow();
 876
 877                 DBA::update('apcontact', $apcontact, ['url' => $url], true);
 878
 879                 // Update some data in the contact table with various ways to catch them all
 880                 $contact_fields = ['name' => $apcontact['name'], 'about' => $apcontact['about']];
 881                 DBA::update('contact', $contact_fields, ['nurl' => normalise_link($url)]);
 882
 883                 $contacts = DBA::select('contact', ['uid', 'id'], ['nurl' => normalise_link($url)]);
 884                 while ($contact = DBA::fetch($contacts)) {
 885                         Contact::updateAvatar($apcontact['photo'], $contact['uid'], $contact['id']);
 886                 }
 887                 DBA::close($contacts);
 888
 889                 // Update the gcontact table
 890                 DBA::update('gcontact', $contact_fields, ['nurl' => normalise_link($url)]);
 891
 892                 logger('Updated profile for ' . $url, LOGGER_DEBUG);
 893
 894                 return $apcontact;
 895         }
 896
 897         /**
 898          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 899          *
 900          * @param string $url profile url
 901          * @return array
 902          */
 903         public static function probeProfile($url)
 904         {
 905                 $apcontact = self::fetchprofile($url, true);
 906                 if (empty($apcontact)) {
 907                         return false;
 908                 }
 909
 910                 $profile = ['network' => Protocol::ACTIVITYPUB];
 911                 $profile['nick'] = $apcontact['nick'];
 912                 $profile['name'] = $apcontact['name'];
 913                 $profile['guid'] = $apcontact['uuid'];
 914                 $profile['url'] = $apcontact['url'];
 915                 $profile['addr'] = $apcontact['addr'];
 916                 $profile['alias'] = $apcontact['alias'];
 917                 $profile['photo'] = $apcontact['photo'];
 918                 // $profile['community']
 919                 // $profile['keywords']
 920                 // $profile['location']
 921                 $profile['about'] = $apcontact['about'];
 922                 $profile['batch'] = $apcontact['sharedinbox'];
 923                 $profile['notify'] = $apcontact['inbox'];
 924                 $profile['poll'] = $apcontact['outbox'];
 925                 $profile['pubkey'] = $apcontact['pubkey'];
 926                 $profile['baseurl'] = $apcontact['baseurl'];
 927
 928                 // Remove all "null" fields
 929                 foreach ($profile as $field => $content) {
 930                         if (is_null($content)) {
 931                                 unset($profile[$field]);
 932                         }
 933                 }
 934
 935                 return $profile;
 936         }
 937
 938         public static function processInbox($body, $header, $uid)
 939         {
 940                 $http_signer = HTTPSignature::getSigner($body, $header);
 941                 if (empty($http_signer)) {
 942                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 943                         return;
 944                 } else {
 945                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 946                 }
 947
 948                 $activity = json_decode($body, true);
 949
 950                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 951                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
 952
 953                 if (empty($activity)) {
 954                         logger('Invalid body.', LOGGER_DEBUG);
 955                         return;
 956                 }
 957
 958                 if (LDSignature::isSigned($activity)) {
 959                         $ld_signer = LDSignature::getSigner($activity);
 960                         if (empty($ld_signer)) {
 961                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
 962                         }
 963                         if (!empty($ld_signer && ($actor == $http_signer))) {
 964                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
 965                                 $trust_source = true;
 966                         } elseif (!empty($ld_signer)) {
 967                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
 968                                 $trust_source = true;
 969                         } elseif ($actor == $http_signer) {
 970                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
 971                                 $trust_source = true;
 972                         } else {
 973                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
 974                                 $trust_source = false;
 975                         }
 976                 } elseif ($actor == $http_signer) {
 977                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 978                         $trust_source = true;
 979                 } else {
 980                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 981                         $trust_source = false;
 982                 }
 983
 984                 self::processActivity($activity, $body, $uid, $trust_source);
 985         }
 986
 987         public static function fetchOutbox($url, $uid)
 988         {
 989                 $data = self::fetchContent($url);
 990                 if (empty($data)) {
 991                         return;
 992                 }
 993
 994                 if (!empty($data['orderedItems'])) {
 995                         $items = $data['orderedItems'];
 996                 } elseif (!empty($data['first']['orderedItems'])) {
 997                         $items = $data['first']['orderedItems'];
 998                 } elseif (!empty($data['first'])) {
 999                         self::fetchOutbox($data['first'], $uid);
1000                         return;
1001                 } else {
1002                         $items = [];
1003                 }
1004
1005                 foreach ($items as $activity) {
1006                         self::processActivity($activity, '', $uid, true);
1007                 }
1008         }
1009
1010         private static function prepareObjectData($activity, $uid, &$trust_source)
1011         {
1012                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
1013                 if (empty($actor)) {
1014                         logger('Empty actor', LOGGER_DEBUG);
1015                         return [];
1016                 }
1017
1018                 // Fetch all receivers from to, cc, bto and bcc
1019                 $receivers = self::getReceivers($activity, $actor);
1020
1021                 // When it is a delivery to a personal inbox we add that user to the receivers
1022                 if (!empty($uid)) {
1023                         $owner = User::getOwnerDataById($uid);
1024                         $additional = ['uid:' . $uid => $uid];
1025                         $receivers = array_merge($receivers, $additional);
1026                 }
1027
1028                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
1029
1030                 $object_id = JsonLD::fetchElement($activity, 'object', 'id');
1031                 if (empty($object_id)) {
1032                         logger('No object found', LOGGER_DEBUG);
1033                         return [];
1034                 }
1035
1036                 // Fetch the content only on activities where this matters
1037                 if (in_array($activity['type'], ['Create', 'Announce'])) {
1038                         $object_data = self::fetchObject($object_id, $activity['object'], $trust_source);
1039                         if (empty($object_data)) {
1040                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
1041                                 return [];
1042                         }
1043                         // We had been able to retrieve the object data - so we can trust the source
1044                         $trust_source = true;
1045                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
1046                         // Create a mostly empty array out of the activity data (instead of the object).
1047                         // This way we later don't have to check for the existence of ech individual array element.
1048                         $object_data = self::ProcessObject($activity);
1049                         $object_data['name'] = $activity['type'];
1050                         $object_data['author'] = $activity['actor'];
1051                         $object_data['object'] = $object_id;
1052                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
1053                 } else {
1054                         $object_data = [];
1055                         $object_data['id'] = $activity['id'];
1056                         $object_data['object'] = $activity['object'];
1057                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
1058                 }
1059
1060                 $object_data = self::addActivityFields($object_data, $activity);
1061
1062                 $object_data['type'] = $activity['type'];
1063                 $object_data['owner'] = $actor;
1064                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
1065
1066                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
1067
1068                 return $object_data;
1069         }
1070
1071         private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
1072         {
1073                 if (empty($activity['type'])) {
1074                         logger('Empty type', LOGGER_DEBUG);
1075                         return;
1076                 }
1077
1078                 if (empty($activity['object'])) {
1079                         logger('Empty object', LOGGER_DEBUG);
1080                         return;
1081                 }
1082
1083                 if (empty($activity['actor'])) {
1084                         logger('Empty actor', LOGGER_DEBUG);
1085                         return;
1086
1087                 }
1088
1089                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
1090                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
1091                 if (empty($object_data)) {
1092                         logger('No object data found', LOGGER_DEBUG);
1093                         return;
1094                 }
1095
1096                 if (!$trust_source) {
1097                         logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
1098                 }
1099
1100                 switch ($activity['type']) {
1101                         case 'Create':
1102                         case 'Announce':
1103                                 self::createItem($object_data, $body);
1104                                 break;
1105
1106                         case 'Like':
1107                                 self::likeItem($object_data, $body);
1108                                 break;
1109
1110                         case 'Dislike':
1111                                 self::dislikeItem($object_data, $body);
1112                                 break;
1113
1114                         case 'Update':
1115                                 if (in_array($object_data['object_type'], ['Person', 'Organization', 'Service', 'Group', 'Application'])) {
1116                                         self::updatePerson($object_data, $body);
1117                                 }
1118                                 break;
1119
1120                         case 'Delete':
1121                                 break;
1122
1123                         case 'Follow':
1124                                 self::followUser($object_data);
1125                                 break;
1126
1127                         case 'Accept':
1128                                 if ($object_data['object_type'] == 'Follow') {
1129                                         self::acceptFollowUser($object_data);
1130                                 }
1131                                 break;
1132
1133                         case 'Undo':
1134                                 if ($object_data['object_type'] == 'Follow') {
1135                                         self::undoFollowUser($object_data);
1136                                 } elseif (in_array($object_data['object_type'], ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'])) {
1137                                         self::undoActivity($object_data);
1138                                 }
1139                                 break;
1140
1141                         default:
1142                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
1143                                 break;
1144                 }
1145         }
1146
1147         private static function getReceivers($activity, $actor)
1148         {
1149                 $receivers = [];
1150
1151                 // When it is an answer, we inherite the receivers from the parent
1152                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1153                 if (!empty($replyto)) {
1154                         $parents = Item::select(['uid'], ['uri' => $replyto]);
1155                         while ($parent = Item::fetch($parents)) {
1156                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
1157                         }
1158                 }
1159
1160                 if (!empty($actor)) {
1161                         $profile = self::fetchprofile($actor);
1162                         $followers = defaults($profile, 'followers', '');
1163
1164                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
1165                 } else {
1166                         logger('Empty actor', LOGGER_DEBUG);
1167                         $followers = '';
1168                 }
1169
1170                 $elements = ['to', 'cc', 'bto', 'bcc'];
1171                 foreach ($elements as $element) {
1172                         if (empty($activity[$element])) {
1173                                 continue;
1174                         }
1175
1176                         // The receiver can be an arror or a string
1177                         if (is_string($activity[$element])) {
1178                                 $activity[$element] = [$activity[$element]];
1179                         }
1180
1181                         foreach ($activity[$element] as $receiver) {
1182                                 if ($receiver == self::PUBLIC) {
1183                                         $receivers['uid:0'] = 0;
1184                                 }
1185
1186                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
1187                                         // This will most likely catch all OStatus connections to Mastodon
1188                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
1189                                         $contacts = DBA::select('contact', ['uid'], $condition);
1190                                         while ($contact = DBA::fetch($contacts)) {
1191                                                 if ($contact['uid'] != 0) {
1192                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1193                                                 }
1194                                         }
1195                                         DBA::close($contacts);
1196                                 }
1197
1198                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
1199                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1200                                                 'network' => Protocol::ACTIVITYPUB];
1201                                         $contacts = DBA::select('contact', ['uid'], $condition);
1202                                         while ($contact = DBA::fetch($contacts)) {
1203                                                 if ($contact['uid'] != 0) {
1204                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1205                                                 }
1206                                         }
1207                                         DBA::close($contacts);
1208                                         continue;
1209                                 }
1210
1211                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1212                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1213                                 if (!DBA::isResult($contact)) {
1214                                         continue;
1215                                 }
1216                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1217                         }
1218                 }
1219
1220                 self::switchContacts($receivers, $actor);
1221
1222                 return $receivers;
1223         }
1224
1225         private static function switchContact($cid, $uid, $url)
1226         {
1227                 $profile = ActivityPub::probeProfile($url);
1228                 if (empty($profile)) {
1229                         return;
1230                 }
1231
1232                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' from OStatus to ActivityPub');
1233
1234                 $photo = $profile['photo'];
1235                 unset($profile['photo']);
1236                 unset($profile['baseurl']);
1237
1238                 $profile['nurl'] = normalise_link($profile['url']);
1239                 DBA::update('contact', $profile, ['id' => $cid]);
1240
1241                 Contact::updateAvatar($photo, $uid, $cid);
1242         }
1243
1244         private static function switchContacts($receivers, $actor)
1245         {
1246                 if (empty($actor)) {
1247                         return;
1248                 }
1249
1250                 foreach ($receivers as $receiver) {
1251                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
1252                         if (DBA::isResult($contact)) {
1253                                 self::switchContact($contact['id'], $receiver, $actor);
1254                         }
1255
1256                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
1257                         if (DBA::isResult($contact)) {
1258                                 self::switchContact($contact['id'], $receiver, $actor);
1259                         }
1260                 }
1261         }
1262
1263         private static function addActivityFields($object_data, $activity)
1264         {
1265                 if (!empty($activity['published']) && empty($object_data['published'])) {
1266                         $object_data['published'] = $activity['published'];
1267                 }
1268
1269                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1270                         $object_data['updated'] = $activity['updated'];
1271                 }
1272
1273                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1274                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1275                 }
1276
1277                 if (!empty($activity['instrument'])) {
1278                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1279                 }
1280                 return $object_data;
1281         }
1282
1283         private static function fetchObject($object_id, $object = [], $trust_source = false)
1284         {
1285                 if (!$trust_source || is_string($object)) {
1286                         $data = self::fetchContent($object_id);
1287                         if (empty($data)) {
1288                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
1289                                 $data = $object_id;
1290                         } else {
1291                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
1292                         }
1293                 } else {
1294                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
1295                         $data = $object;
1296                 }
1297
1298                 if (is_string($data)) {
1299                         $item = Item::selectFirst([], ['uri' => $data]);
1300                         if (!DBA::isResult($item)) {
1301                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1302                                 return false;
1303                         }
1304                         logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
1305                         $data = self::CreateNote($item);
1306                 }
1307
1308                 if (empty($data['type'])) {
1309                         logger('Empty type', LOGGER_DEBUG);
1310                         return false;
1311                 }
1312
1313                 switch ($data['type']) {
1314                         case 'Note':
1315                         case 'Article':
1316                         case 'Video':
1317                                 return self::ProcessObject($data);
1318
1319                         case 'Announce':
1320                                 if (empty($data['object'])) {
1321                                         return false;
1322                                 }
1323                                 return self::fetchObject($data['object']);
1324
1325                         case 'Person':
1326                         case 'Tombstone':
1327                                 break;
1328
1329                         default:
1330                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1331                                 break;
1332                 }
1333         }
1334
1335         private static function ProcessObject(&$object)
1336         {
1337                 if (empty($object['id'])) {
1338                         return false;
1339                 }
1340
1341                 $object_data = [];
1342                 $object_data['object_type'] = $object['type'];
1343                 $object_data['id'] = $object['id'];
1344
1345                 if (!empty($object['inReplyTo'])) {
1346                         $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1347                 } else {
1348                         $object_data['reply-to-id'] = $object_data['id'];
1349                 }
1350
1351                 $object_data['published'] = defaults($object, 'published', null);
1352                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1353
1354                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1355                         $object_data['published'] = $object_data['updated'];
1356                 }
1357
1358                 $actor = JsonLD::fetchElement($object, 'attributedTo', 'id');
1359                 if (empty($actor)) {
1360                         $actor = defaults($object, 'actor', null);
1361                 }
1362
1363                 $object_data['uuid'] = defaults($object, 'uuid', null);
1364                 $object_data['owner'] = $object_data['author'] = $actor;
1365                 $object_data['context'] = defaults($object, 'context', null);
1366                 $object_data['conversation'] = defaults($object, 'conversation', null);
1367                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1368                 $object_data['name'] = defaults($object, 'title', null);
1369                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1370                 $object_data['summary'] = defaults($object, 'summary', null);
1371                 $object_data['content'] = defaults($object, 'content', null);
1372                 $object_data['source'] = defaults($object, 'source', null);
1373                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1374                 $object_data['attachments'] = defaults($object, 'attachment', null);
1375                 $object_data['tags'] = defaults($object, 'tag', null);
1376                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1377                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1378                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1379
1380                 // Common object data:
1381
1382                 // Unhandled
1383                 // @context, type, actor, signature, mediaType, duration, replies, icon
1384
1385                 // Also missing: (Defined in the standard, but currently unused)
1386                 // audience, preview, endTime, startTime, generator, image
1387
1388                 // Data in Notes:
1389
1390                 // To-Do?
1391                 // emoji, atomUri, inReplyToAtomUri
1392
1393                 // Unhandled
1394                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1395                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1396
1397                 // Data in video:
1398
1399                 // To-Do?
1400                 // category, licence, language, commentsEnabled
1401
1402                 // Unhandled
1403                 // views, waitTranscoding, state, support, subtitleLanguage
1404                 // likes, dislikes, shares, comments
1405
1406
1407                 return $object_data;
1408         }
1409
1410         private static function convertMentions($body)
1411         {
1412                 $URLSearchString = "^\[\]";
1413                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1414
1415                 return $body;
1416         }
1417
1418         private static function constructTagList($tags, $sensitive)
1419         {
1420                 if (empty($tags)) {
1421                         return '';
1422                 }
1423
1424                 $tag_text = '';
1425                 foreach ($tags as $tag) {
1426                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1427                                 if (!empty($tag_text)) {
1428                                         $tag_text .= ',';
1429                                 }
1430
1431                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1432                         }
1433                 }
1434
1435                 /// @todo add nsfw for $sensitive
1436
1437                 return $tag_text;
1438         }
1439
1440         private static function constructAttachList($attachments, $item)
1441         {
1442                 if (empty($attachments)) {
1443                         return $item;
1444                 }
1445
1446                 foreach ($attachments as $attach) {
1447                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1448                         if ($filetype == 'image') {
1449                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1450                         } else {
1451                                 if (!empty($item["attach"])) {
1452                                         $item["attach"] .= ',';
1453                                 } else {
1454                                         $item["attach"] = '';
1455                                 }
1456                                 if (!isset($attach['length'])) {
1457                                         $attach['length'] = "0";
1458                                 }
1459                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1460                         }
1461                 }
1462
1463                 return $item;
1464         }
1465
1466         private static function createItem($activity, $body)
1467         {
1468                 $item = [];
1469                 $item['verb'] = ACTIVITY_POST;
1470                 $item['parent-uri'] = $activity['reply-to-id'];
1471
1472                 if ($activity['reply-to-id'] == $activity['id']) {
1473                         $item['gravity'] = GRAVITY_PARENT;
1474                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1475                 } else {
1476                         $item['gravity'] = GRAVITY_COMMENT;
1477                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1478                 }
1479
1480                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
1481                         logger('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
1482                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
1483                 }
1484
1485                 self::postItem($activity, $item, $body);
1486         }
1487
1488         private static function likeItem($activity, $body)
1489         {
1490                 $item = [];
1491                 $item['verb'] = ACTIVITY_LIKE;
1492                 $item['parent-uri'] = $activity['object'];
1493                 $item['gravity'] = GRAVITY_ACTIVITY;
1494                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1495
1496                 self::postItem($activity, $item, $body);
1497         }
1498
1499         private static function dislikeItem($activity, $body)
1500         {
1501                 $item = [];
1502                 $item['verb'] = ACTIVITY_DISLIKE;
1503                 $item['parent-uri'] = $activity['object'];
1504                 $item['gravity'] = GRAVITY_ACTIVITY;
1505                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1506
1507                 self::postItem($activity, $item, $body);
1508         }
1509
1510         private static function postItem($activity, $item, $body)
1511         {
1512                 /// @todo What to do with $activity['context']?
1513
1514                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['parent-uri']])) {
1515                         logger('Parent ' . $item['parent-uri'] . ' not found, message will be discarded.', LOGGER_DEBUG);
1516                         return;
1517                 }
1518
1519                 $item['network'] = Protocol::ACTIVITYPUB;
1520                 $item['private'] = !in_array(0, $activity['receiver']);
1521                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1522                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1523                 $item['uri'] = $activity['id'];
1524                 $item['created'] = $activity['published'];
1525                 $item['edited'] = $activity['updated'];
1526                 $item['guid'] = $activity['uuid'];
1527                 $item['title'] = HTML::toBBCode($activity['name']);
1528                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1529                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1530                 $item['location'] = $activity['location'];
1531                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1532                 $item['app'] = $activity['service'];
1533                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1534
1535                 $item = self::constructAttachList($activity['attachments'], $item);
1536
1537                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1538                 if (!empty($source)) {
1539                         $item['body'] = $source;
1540                 }
1541
1542                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1543                 $item['source'] = $body;
1544                 $item['conversation-href'] = $activity['context'];
1545                 $item['conversation-uri'] = $activity['conversation'];
1546
1547                 foreach ($activity['receiver'] as $receiver) {
1548                         $item['uid'] = $receiver;
1549                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1550
1551                         if (($receiver != 0) && empty($item['contact-id'])) {
1552                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1553                         }
1554
1555                         $item_id = Item::insert($item);
1556                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1557                 }
1558         }
1559
1560         private static function fetchMissingActivity($url, $child)
1561         {
1562                 if (Config::get('system', 'ostatus_full_threads')) {
1563                         return;
1564                 }
1565
1566                 $object = ActivityPub::fetchContent($url);
1567                 if (empty($object)) {
1568                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1569                         return;
1570                 }
1571
1572                 $activity = [];
1573                 $activity['@context'] = $object['@context'];
1574                 unset($object['@context']);
1575                 $activity['id'] = $object['id'];
1576                 $activity['to'] = defaults($object, 'to', []);
1577                 $activity['cc'] = defaults($object, 'cc', []);
1578                 $activity['actor'] = $child['author'];
1579                 $activity['object'] = $object;
1580                 $activity['published'] = $object['published'];
1581                 $activity['type'] = 'Create';
1582
1583                 self::processActivity($activity);
1584                 logger('Activity ' . $url . ' had been fetched and processed.');
1585         }
1586
1587         private static function getUserOfObject($object)
1588         {
1589                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($object), 'self' => true]);
1590                 if (!DBA::isResult($self)) {
1591                         return false;
1592                 } else {
1593                         return $self['uid'];
1594                 }
1595         }
1596
1597         private static function followUser($activity)
1598         {
1599                 $actor = JsonLD::fetchElement($activity, 'object', 'id');
1600                 $uid = self::getUserOfObject($actor);
1601                 if (empty($uid)) {
1602                         return;
1603                 }
1604
1605                 $owner = User::getOwnerDataById($uid);
1606
1607                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1608                 if (!empty($cid)) {
1609                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1610                 } else {
1611                         $contact = false;
1612                 }
1613
1614                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1615                         'author-link' => $activity['owner']];
1616
1617                 Contact::addRelationship($owner, $contact, $item);
1618                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1619                 if (empty($cid)) {
1620                         return;
1621                 }
1622
1623                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1624                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1625                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1626                 }
1627
1628                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1629                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1630         }
1631
1632         private static function updatePerson($activity)
1633         {
1634                 if (empty($activity['object']['id'])) {
1635                         return;
1636                 }
1637
1638                 logger('Updating profile for ' . $activity['object']['id'], LOGGER_DEBUG);
1639                 self::fetchprofile($activity['object']['id'], true);
1640         }
1641
1642         private static function acceptFollowUser($activity)
1643         {
1644                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1645                 $uid = self::getUserOfObject($actor);
1646                 if (empty($uid)) {
1647                         return;
1648                 }
1649
1650                 $owner = User::getOwnerDataById($uid);
1651
1652                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1653                 if (empty($cid)) {
1654                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1655                         return;
1656                 }
1657
1658                 $fields = ['pending' => false];
1659
1660                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1661                 if ($contact['rel'] == Contact::FOLLOWER) {
1662                         $fields['rel'] = Contact::FRIEND;
1663                 }
1664
1665                 $condition = ['id' => $cid];
1666                 DBA::update('contact', $fields, $condition);
1667                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1668         }
1669
1670         private static function undoActivity($activity)
1671         {
1672                 $activity_url = JsonLD::fetchElement($activity, 'object', 'id');
1673                 if (empty($activity_url)) {
1674                         return;
1675                 }
1676
1677                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1678                 if (empty($actor)) {
1679                         return;
1680                 }
1681
1682                 $author_id = Contact::getIdForURL($actor);
1683                 if (empty($author_id)) {
1684                         return;
1685                 }
1686
1687                 Item::delete(['uri' => $activity_url, 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1688         }
1689
1690         private static function undoFollowUser($activity)
1691         {
1692                 $object = JsonLD::fetchElement($activity, 'object', 'object');
1693                 $uid = self::getUserOfObject($object);
1694                 if (empty($uid)) {
1695                         return;
1696                 }
1697
1698                 $owner = User::getOwnerDataById($uid);
1699
1700                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1701                 if (empty($cid)) {
1702                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1703                         return;
1704                 }
1705
1706                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1707                 if (!DBA::isResult($contact)) {
1708                         return;
1709                 }
1710
1711                 Contact::removeFollower($owner, $contact);
1712                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1713         }
1714 }