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\APContact;
  16 use Friendica\Model\Item;
  17 use Friendica\Model\Profile;
  18 use Friendica\Model\Term;
  19 use Friendica\Model\User;
  20 use Friendica\Util\DateTimeFormat;
  21 use Friendica\Util\Crypto;
  22 use Friendica\Content\Text\BBCode;
  23 use Friendica\Content\Text\HTML;
  24 use Friendica\Util\JsonLD;
  25 use Friendica\Util\LDSignature;
  26 use Friendica\Core\Config;
  27
  28 /**
  29  * @brief ActivityPub Protocol class
  30  * The ActivityPub Protocol is a message exchange protocol defined by the W3C.
  31  * https://www.w3.org/TR/activitypub/
  32  * https://www.w3.org/TR/activitystreams-core/
  33  * https://www.w3.org/TR/activitystreams-vocabulary/
  34  *
  35  * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
  36  * https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/
  37  *
  38  * Digest: https://tools.ietf.org/html/rfc5843
  39  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
  40  *
  41  * Mastodon implementation of supported activities:
  42  * https://github.com/tootsuite/mastodon/blob/master/app/lib/activitypub/activity.rb#L26
  43  *
  44  * To-do:
  45  *
  46  * Receiver:
  47  * - Update Note
  48  * - Delete Note
  49  * - Delete Person
  50  * - Undo Announce
  51  * - Reject Follow
  52  * - Undo Accept
  53  * - Undo Follow
  54  * - Add
  55  * - Create Image
  56  * - Create Video
  57  * - Event
  58  * - Remove
  59  * - Block
  60  * - Flag
  61  *
  62  * Transmitter:
  63  * - Announce
  64  * - Undo Announce
  65  * - Update Person
  66  * - Reject Follow
  67  * - Event
  68  *
  69  * General:
  70  * - Attachments
  71  * - nsfw (sensitive)
  72  * - Queueing unsucessful deliveries
  73  * - Polling the outboxes for missing content?
  74  * - Possibly using the LD-JSON parser
  75  */
  76 class ActivityPub
  77 {
  78         const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
  79         const CONTEXT = ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
  80                 ['vcard' => 'http://www.w3.org/2006/vcard/ns#',
  81                 'diaspora' => 'https://diasporafoundation.org#',
  82                 'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
  83                 'sensitive' => 'as:sensitive', 'Hashtag' => 'as:Hashtag']];
  84
  85         /**
  86          * @brief Checks if the web request is done for the AP protocol
  87          *
  88          * @return is it AP?
  89          */
  90         public static function isRequest()
  91         {
  92                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  93                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  94         }
  95
  96         /**
  97          * @brief collects the lost of followers of the given owner
  98          *
  99          * @param array $owner Owner array
 100          * @param integer $page Page number
 101          *
 102          * @return array of owners
 103          */
 104         public static function getFollowers($owner, $page = null)
 105         {
 106                 $condition = ['rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
 107                         'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
 108                 $count = DBA::count('contact', $condition);
 109
 110                 $data = ['@context' => self::CONTEXT];
 111                 $data['id'] = System::baseUrl() . '/followers/' . $owner['nickname'];
 112                 $data['type'] = 'OrderedCollection';
 113                 $data['totalItems'] = $count;
 114
 115                 // When we hide our friends we will only show the pure number but don't allow more.
 116                 $profile = Profile::getProfileForUser($owner['uid']);
 117                 if (!empty($profile['hide-friends'])) {
 118                         return $data;
 119                 }
 120
 121                 if (empty($page)) {
 122                         $data['first'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=1';
 123                 } else {
 124                         $list = [];
 125
 126                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 127                         while ($contact = DBA::fetch($contacts)) {
 128                                 $list[] = $contact['url'];
 129                         }
 130
 131                         if (!empty($list)) {
 132                                 $data['next'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=' . ($page + 1);
 133                         }
 134
 135                         $data['partOf'] = System::baseUrl() . '/followers/' . $owner['nickname'];
 136
 137                         $data['orderedItems'] = $list;
 138                 }
 139
 140                 return $data;
 141         }
 142
 143         /**
 144          * @brief Create list of following contacts
 145          *
 146          * @param array $owner Owner array
 147          * @param integer $page Page numbe
 148          *
 149          * @return array of following contacts
 150          */
 151         public static function getFollowing($owner, $page = null)
 152         {
 153                 $condition = ['rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
 154                         'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
 155                 $count = DBA::count('contact', $condition);
 156
 157                 $data = ['@context' => self::CONTEXT];
 158                 $data['id'] = System::baseUrl() . '/following/' . $owner['nickname'];
 159                 $data['type'] = 'OrderedCollection';
 160                 $data['totalItems'] = $count;
 161
 162                 // When we hide our friends we will only show the pure number but don't allow more.
 163                 $profile = Profile::getProfileForUser($owner['uid']);
 164                 if (!empty($profile['hide-friends'])) {
 165                         return $data;
 166                 }
 167
 168                 if (empty($page)) {
 169                         $data['first'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=1';
 170                 } else {
 171                         $list = [];
 172
 173                         $contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
 174                         while ($contact = DBA::fetch($contacts)) {
 175                                 $list[] = $contact['url'];
 176                         }
 177
 178                         if (!empty($list)) {
 179                                 $data['next'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=' . ($page + 1);
 180                         }
 181
 182                         $data['partOf'] = System::baseUrl() . '/following/' . $owner['nickname'];
 183
 184                         $data['orderedItems'] = $list;
 185                 }
 186
 187                 return $data;
 188         }
 189
 190         /**
 191          * @brief Public posts for the given owner
 192          *
 193          * @param array $owner Owner array
 194          * @param integer $page Page numbe
 195          *
 196          * @return array of posts
 197          */
 198         public static function getOutbox($owner, $page = null)
 199         {
 200                 $public_contact = Contact::getIdForURL($owner['url'], 0, true);
 201
 202                 $condition = ['uid' => $owner['uid'], 'contact-id' => $owner['id'], 'author-id' => $public_contact,
 203                         'wall' => true, 'private' => false, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT],
 204                         'deleted' => false, 'visible' => true];
 205                 $count = DBA::count('item', $condition);
 206
 207                 $data = ['@context' => self::CONTEXT];
 208                 $data['id'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
 209                 $data['type'] = 'OrderedCollection';
 210                 $data['totalItems'] = $count;
 211
 212                 if (empty($page)) {
 213                         $data['first'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=1';
 214                 } else {
 215                         $list = [];
 216
 217                         $condition['parent-network'] = Protocol::NATIVE_SUPPORT;
 218
 219                         $items = Item::select(['id'], $condition, ['limit' => [($page - 1) * 20, 20], 'order' => ['created' => true]]);
 220                         while ($item = Item::fetch($items)) {
 221                                 $object = self::createObjectFromItemID($item['id']);
 222                                 unset($object['@context']);
 223                                 $list[] = $object;
 224                         }
 225
 226                         if (!empty($list)) {
 227                                 $data['next'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=' . ($page + 1);
 228                         }
 229
 230                         $data['partOf'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
 231
 232                         $data['orderedItems'] = $list;
 233                 }
 234
 235                 return $data;
 236         }
 237
 238         /**
 239          * Return the ActivityPub profile of the given user
 240          *
 241          * @param integer $uid User ID
 242          * @return profile array
 243          */
 244         public static function profile($uid)
 245         {
 246                 $accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application'];
 247                 $condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
 248                         'account_removed' => false, 'verified' => true];
 249                 $fields = ['guid', 'nickname', 'pubkey', 'account-type', 'page-flags'];
 250                 $user = DBA::selectFirst('user', $fields, $condition);
 251                 if (!DBA::isResult($user)) {
 252                         return [];
 253                 }
 254
 255                 $fields = ['locality', 'region', 'country-name'];
 256                 $profile = DBA::selectFirst('profile', $fields, ['uid' => $uid, 'is-default' => true]);
 257                 if (!DBA::isResult($profile)) {
 258                         return [];
 259                 }
 260
 261                 $fields = ['name', 'url', 'location', 'about', 'avatar'];
 262                 $contact = DBA::selectFirst('contact', $fields, ['uid' => $uid, 'self' => true]);
 263                 if (!DBA::isResult($contact)) {
 264                         return [];
 265                 }
 266
 267                 $data = ['@context' => self::CONTEXT];
 268                 $data['id'] = $contact['url'];
 269                 $data['diaspora:guid'] = $user['guid'];
 270                 $data['type'] = $accounttype[$user['account-type']];
 271                 $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
 272                 $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
 273                 $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
 274                 $data['outbox'] = System::baseUrl() . '/outbox/' . $user['nickname'];
 275                 $data['preferredUsername'] = $user['nickname'];
 276                 $data['name'] = $contact['name'];
 277                 $data['vcard:hasAddress'] = ['@type' => 'vcard:Home', 'vcard:country-name' => $profile['country-name'],
 278                         'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 279                 $data['summary'] = $contact['about'];
 280                 $data['url'] = $contact['url'];
 281                 $data['manuallyApprovesFollowers'] = in_array($user['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 282                 $data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 283                         'owner' => $contact['url'],
 284                         'publicKeyPem' => $user['pubkey']];
 285                 $data['endpoints'] = ['sharedInbox' => System::baseUrl() . '/inbox'];
 286                 $data['icon'] = ['type' => 'Image',
 287                         'url' => $contact['avatar']];
 288
 289                 // tags: https://kitty.town/@inmysocks/100656097926961126.json
 290                 return $data;
 291         }
 292
 293         /**
 294          * @brief Returns an array with permissions of a given item array
 295          *
 296          * @param array $item
 297          *
 298          * @return array with permissions
 299          */
 300         private static function fetchPermissionBlockFromConversation($item)
 301         {
 302                 if (empty($item['thr-parent'])) {
 303                         return [];
 304                 }
 305
 306                 $condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 307                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 308                 if (!DBA::isResult($conversation)) {
 309                         return [];
 310                 }
 311
 312                 $activity = json_decode($conversation['source'], true);
 313
 314                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 315                 $profile = APContact::getProfileByURL($actor);
 316
 317                 $item_profile = APContact::getProfileByURL($item['author-link']);
 318                 $exclude[] = $item['author-link'];
 319
 320                 if ($item['gravity'] == GRAVITY_PARENT) {
 321                         $exclude[] = $item['owner-link'];
 322                 }
 323
 324                 $permissions['to'][] = $actor;
 325
 326                 $elements = ['to', 'cc', 'bto', 'bcc'];
 327                 foreach ($elements as $element) {
 328                         if (empty($activity[$element])) {
 329                                 continue;
 330                         }
 331                         if (is_string($activity[$element])) {
 332                                 $activity[$element] = [$activity[$element]];
 333                         }
 334
 335                         foreach ($activity[$element] as $receiver) {
 336                                 if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 337                                         $receiver = $item_profile['followers'];
 338                                 }
 339                                 if (!in_array($receiver, $exclude)) {
 340                                         $permissions[$element][] = $receiver;
 341                                 }
 342                         }
 343                 }
 344                 return $permissions;
 345         }
 346
 347         /**
 348          * @brief Creates an array of permissions from an item thread
 349          *
 350          * @param array $item
 351          *
 352          * @return permission array
 353          */
 354         public static function createPermissionBlockForItem($item)
 355         {
 356                 $data = ['to' => [], 'cc' => []];
 357
 358                 $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 359
 360                 $actor_profile = APContact::getProfileByURL($item['author-link']);
 361
 362                 $terms = Term::tagArrayFromItemId($item['id']);
 363
 364                 $contacts[$item['author-link']] = $item['author-link'];
 365
 366                 if (!$item['private']) {
 367                         $data['to'][] = self::PUBLIC;
 368                         if (!empty($actor_profile['followers'])) {
 369                                 $data['cc'][] = $actor_profile['followers'];
 370                         }
 371
 372                         foreach ($terms as $term) {
 373                                 if ($term['type'] != TERM_MENTION) {
 374                                         continue;
 375                                 }
 376                                 $profile = APContact::getProfileByURL($term['url'], false);
 377                                 if (!empty($profile) && empty($contacts[$profile['url']])) {
 378                                         $data['cc'][] = $profile['url'];
 379                                         $contacts[$profile['url']] = $profile['url'];
 380                                 }
 381                         }
 382                 } else {
 383                         $receiver_list = Item::enumeratePermissions($item);
 384
 385                         $mentioned = [];
 386
 387                         foreach ($terms as $term) {
 388                                 if ($term['type'] != TERM_MENTION) {
 389                                         continue;
 390                                 }
 391                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 392                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 393                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 394                                         $data['to'][] = $contact['url'];
 395                                         $contacts[$contact['url']] = $contact['url'];
 396                                 }
 397                         }
 398
 399                         foreach ($receiver_list as $receiver) {
 400                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 401                                 if (empty($contacts[$contact['url']])) {
 402                                         $data['cc'][] = $contact['url'];
 403                                         $contacts[$contact['url']] = $contact['url'];
 404                                 }
 405                         }
 406                 }
 407
 408                 $parents = Item::select(['id', 'author-link', 'owner-link', 'gravity'], ['parent' => $item['parent']]);
 409                 while ($parent = Item::fetch($parents)) {
 410                         // Don't include data from future posts
 411                         if ($parent['id'] >= $item['id']) {
 412                                 continue;
 413                         }
 414
 415                         $profile = APContact::getProfileByURL($parent['author-link'], false);
 416                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 417                                 $data['cc'][] = $profile['url'];
 418                                 $contacts[$profile['url']] = $profile['url'];
 419                         }
 420
 421                         if ($item['gravity'] != GRAVITY_PARENT) {
 422                                 continue;
 423                         }
 424
 425                         $profile = APContact::getProfileByURL($parent['owner-link'], false);
 426                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 427                                 $data['cc'][] = $profile['url'];
 428                                 $contacts[$profile['url']] = $profile['url'];
 429                         }
 430                 }
 431                 DBA::close($parents);
 432
 433                 if (empty($data['to'])) {
 434                         $data['to'] = $data['cc'];
 435                         $data['cc'] = [];
 436                 }
 437
 438                 return $data;
 439         }
 440
 441         /**
 442          * @brief Fetches an array of inboxes for the given item and user
 443          *
 444          * @param array $item
 445          * @param integer $uid User ID
 446          *
 447          * @return array with inboxes
 448          */
 449         public static function fetchTargetInboxes($item, $uid)
 450         {
 451                 $permissions = self::createPermissionBlockForItem($item);
 452                 if (empty($permissions)) {
 453                         return [];
 454                 }
 455
 456                 $inboxes = [];
 457
 458                 if ($item['gravity'] == GRAVITY_ACTIVITY) {
 459                         $item_profile = APContact::getProfileByURL($item['author-link']);
 460                 } else {
 461                         $item_profile = APContact::getProfileByURL($item['owner-link']);
 462                 }
 463
 464                 $elements = ['to', 'cc', 'bto', 'bcc'];
 465                 foreach ($elements as $element) {
 466                         if (empty($permissions[$element])) {
 467                                 continue;
 468                         }
 469
 470                         foreach ($permissions[$element] as $receiver) {
 471                                 if ($receiver == $item_profile['followers']) {
 472                                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
 473                                                 'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
 474                                         while ($contact = DBA::fetch($contacts)) {
 475                                                 $contact = defaults($contact, 'batch', $contact['notify']);
 476                                                 $inboxes[$contact] = $contact;
 477                                         }
 478                                         DBA::close($contacts);
 479                                 } else {
 480                                         $profile = APContact::getProfileByURL($receiver);
 481                                         if (!empty($profile)) {
 482                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 483                                                 $inboxes[$target] = $target;
 484                                         }
 485                                 }
 486                         }
 487                 }
 488
 489                 return $inboxes;
 490         }
 491
 492         /**
 493          * @brief Returns the activity type of a given item
 494          *
 495          * @param array $item
 496          *
 497          * @return activity type
 498          */
 499         public static function getTypeOfItem($item)
 500         {
 501                 if ($item['verb'] == ACTIVITY_POST) {
 502                         if ($item['created'] == $item['edited']) {
 503                                 $type = 'Create';
 504                         } else {
 505                                 $type = 'Update';
 506                         }
 507                 } elseif ($item['verb'] == ACTIVITY_LIKE) {
 508                         $type = 'Like';
 509                 } elseif ($item['verb'] == ACTIVITY_DISLIKE) {
 510                         $type = 'Dislike';
 511                 } elseif ($item['verb'] == ACTIVITY_ATTEND) {
 512                         $type = 'Accept';
 513                 } elseif ($item['verb'] == ACTIVITY_ATTENDNO) {
 514                         $type = 'Reject';
 515                 } elseif ($item['verb'] == ACTIVITY_ATTENDMAYBE) {
 516                         $type = 'TentativeAccept';
 517                 } else {
 518                         $type = '';
 519                 }
 520
 521                 return $type;
 522         }
 523
 524         /**
 525          * @brief Creates an activity array for a given item id
 526          *
 527          * @param integer $item_id
 528          * @param boolean $object_mode Is the activity item is used inside another object?
 529          *
 530          * @return array of activity
 531          */
 532         public static function createActivityFromItem($item_id, $object_mode = false)
 533         {
 534                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 535
 536                 if (!DBA::isResult($item)) {
 537                         return false;
 538                 }
 539
 540                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 541                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 542                 if (DBA::isResult($conversation)) {
 543                         $data = json_decode($conversation['source']);
 544                         if (!empty($data)) {
 545                                 return $data;
 546                         }
 547                 }
 548
 549                 $type = self::getTypeOfItem($item);
 550
 551                 if (!$object_mode) {
 552                         $data = ['@context' => self::CONTEXT];
 553
 554                         if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
 555                                 $type = 'Undo';
 556                         } elseif ($item['deleted']) {
 557                                 $type = 'Delete';
 558                         }
 559                 } else {
 560                         $data = [];
 561                 }
 562
 563                 $data['id'] = $item['uri'] . '#' . $type;
 564                 $data['type'] = $type;
 565                 $data['actor'] = $item['author-link'];
 566
 567                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 568
 569                 if ($item["created"] != $item["edited"]) {
 570                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 571                 }
 572
 573                 $data['context'] = self::fetchContextURLForItem($item);
 574
 575                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 576
 577                 if (in_array($data['type'], ['Create', 'Update', 'Announce', 'Delete'])) {
 578                         $data['object'] = self::CreateNote($item);
 579                 } elseif ($data['type'] == 'Undo') {
 580                         $data['object'] = self::createActivityFromItem($item_id, true);
 581                 } else {
 582                         $data['object'] = $item['thr-parent'];
 583                 }
 584
 585                 $owner = User::getOwnerDataById($item['uid']);
 586
 587                 if (!$object_mode) {
 588                         return LDSignature::sign($data, $owner);
 589                 } else {
 590                         return $data;
 591                 }
 592         }
 593
 594         /**
 595          * @brief Creates an object array for a given item id
 596          *
 597          * @param integer $item_id
 598          *
 599          * @return object array
 600          */
 601         public static function createObjectFromItemID($item_id)
 602         {
 603                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 604
 605                 if (!DBA::isResult($item)) {
 606                         return false;
 607                 }
 608
 609                 $data = ['@context' => self::CONTEXT];
 610                 $data = array_merge($data, self::CreateNote($item));
 611
 612                 return $data;
 613         }
 614
 615         /**
 616          * @brief Returns a tag array for a given item array
 617          *
 618          * @param array $item
 619          *
 620          * @return array of tags
 621          */
 622         private static function createTagList($item)
 623         {
 624                 $tags = [];
 625
 626                 $terms = Term::tagArrayFromItemId($item['id']);
 627                 foreach ($terms as $term) {
 628                         if ($term['type'] == TERM_MENTION) {
 629                                 $contact = Contact::getDetailsByURL($term['url']);
 630                                 if (!empty($contact['addr'])) {
 631                                         $mention = '@' . $contact['addr'];
 632                                 } else {
 633                                         $mention = '@' . $term['url'];
 634                                 }
 635
 636                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 637                         }
 638                 }
 639                 return $tags;
 640         }
 641
 642         /**
 643          * @brief Fetches the "context" value for a givem item array from the "conversation" table
 644          *
 645          * @param array $item
 646          *
 647          * @return string with context url
 648          */
 649         private static function fetchContextURLForItem($item)
 650         {
 651                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
 652                 if (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
 653                         $context_uri = $conversation['conversation-href'];
 654                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 655                         $context_uri = $conversation['conversation-uri'];
 656                 } else {
 657                         $context_uri = str_replace('/object/', '/context/', $item['parent-uri']);
 658                 }
 659                 return $context_uri;
 660         }
 661
 662         /**
 663          * @brief Creates a note/article object array
 664          *
 665          * @param array $item
 666          *
 667          * @return object array
 668          */
 669         private static function CreateNote($item)
 670         {
 671                 if (!empty($item['title'])) {
 672                         $type = 'Article';
 673                 } else {
 674                         $type = 'Note';
 675                 }
 676
 677                 if ($item['deleted']) {
 678                         $type = 'Tombstone';
 679                 }
 680
 681                 $data = [];
 682                 $data['id'] = $item['uri'];
 683                 $data['type'] = $type;
 684
 685                 if ($item['deleted']) {
 686                         return $data;
 687                 }
 688
 689                 $data['summary'] = null; // Ignore by now
 690
 691                 if ($item['uri'] != $item['thr-parent']) {
 692                         $data['inReplyTo'] = $item['thr-parent'];
 693                 } else {
 694                         $data['inReplyTo'] = null;
 695                 }
 696
 697                 $data['diaspora:guid'] = $item['guid'];
 698                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 699
 700                 if ($item["created"] != $item["edited"]) {
 701                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 702                 }
 703
 704                 $data['url'] = $item['plink'];
 705                 $data['attributedTo'] = $item['author-link'];
 706                 $data['actor'] = $item['author-link'];
 707                 $data['sensitive'] = false; // - Query NSFW
 708                 $data['context'] = self::fetchContextURLForItem($item);
 709
 710                 if (!empty($item['title'])) {
 711                         $data['name'] = BBCode::convert($item['title'], false, 7);
 712                 }
 713
 714                 $data['content'] = BBCode::convert($item['body'], false, 7);
 715                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 716                 $data['attachment'] = []; // @ToDo
 717                 $data['tag'] = self::createTagList($item);
 718                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 719
 720                 return $data;
 721         }
 722
 723         /**
 724          * @brief Transmits a given activity to a target
 725          *
 726          * @param array $activity
 727          * @param string $target Target profile
 728          * @param integer $uid User ID
 729          */
 730         public static function transmitActivity($activity, $target, $uid)
 731         {
 732                 $profile = APContact::getProfileByURL($target);
 733
 734                 $owner = User::getOwnerDataById($uid);
 735
 736                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 737                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 738                         'type' => $activity,
 739                         'actor' => $owner['url'],
 740                         'object' => $profile['url'],
 741                         'to' => $profile['url']];
 742
 743                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 744
 745                 $signed = LDSignature::sign($data, $owner);
 746                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 747         }
 748
 749         /**
 750          * @brief Transmit a message that the contact request had been accepted
 751          *
 752          * @param string $target Target profile
 753          * @param $id
 754          * @param integer $uid User ID
 755          */
 756         public static function transmitContactAccept($target, $id, $uid)
 757         {
 758                 $profile = APContact::getProfileByURL($target);
 759
 760                 $owner = User::getOwnerDataById($uid);
 761                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 762                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 763                         'type' => 'Accept',
 764                         'actor' => $owner['url'],
 765                         'object' => ['id' => $id, 'type' => 'Follow',
 766                                 'actor' => $profile['url'],
 767                                 'object' => $owner['url']],
 768                         'to' => $profile['url']];
 769
 770                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 771
 772                 $signed = LDSignature::sign($data, $owner);
 773                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 774         }
 775
 776         /**
 777          * @brief
 778          *
 779          * @param string $target Target profile
 780          * @param $id
 781          * @param integer $uid User ID
 782          */
 783         public static function transmitContactReject($target, $id, $uid)
 784         {
 785                 $profile = APContact::getProfileByURL($target);
 786
 787                 $owner = User::getOwnerDataById($uid);
 788                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 789                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 790                         'type' => 'Reject',
 791                         'actor' => $owner['url'],
 792                         'object' => ['id' => $id, 'type' => 'Follow',
 793                                 'actor' => $profile['url'],
 794                                 'object' => $owner['url']],
 795                         'to' => $profile['url']];
 796
 797                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 798
 799                 $signed = LDSignature::sign($data, $owner);
 800                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 801         }
 802
 803         /**
 804          * @brief
 805          *
 806          * @param string $target Target profile
 807          * @param integer $uid User ID
 808          */
 809         public static function transmitContactUndo($target, $uid)
 810         {
 811                 $profile = APContact::getProfileByURL($target);
 812
 813                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 814
 815                 $owner = User::getOwnerDataById($uid);
 816                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 817                         'id' => $id,
 818                         'type' => 'Undo',
 819                         'actor' => $owner['url'],
 820                         'object' => ['id' => $id, 'type' => 'Follow',
 821                                 'actor' => $owner['url'],
 822                                 'object' => $profile['url']],
 823                         'to' => $profile['url']];
 824
 825                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 826
 827                 $signed = LDSignature::sign($data, $owner);
 828                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 829         }
 830
 831         /**
 832          * Fetches ActivityPub content from the given url
 833          *
 834          * @param string $url content url
 835          * @return array
 836          */
 837         public static function fetchContent($url)
 838         {
 839                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 840                 if (!$ret['success'] || empty($ret['body'])) {
 841                         return;
 842                 }
 843                 return json_decode($ret['body'], true);
 844         }
 845
 846         /**
 847          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 848          *
 849          * @param string $url profile url
 850          * @return array
 851          */
 852         public static function probeProfile($url)
 853         {
 854                 $apcontact = APContact::getProfileByURL($url, true);
 855                 if (empty($apcontact)) {
 856                         return false;
 857                 }
 858
 859                 $profile = ['network' => Protocol::ACTIVITYPUB];
 860                 $profile['nick'] = $apcontact['nick'];
 861                 $profile['name'] = $apcontact['name'];
 862                 $profile['guid'] = $apcontact['uuid'];
 863                 $profile['url'] = $apcontact['url'];
 864                 $profile['addr'] = $apcontact['addr'];
 865                 $profile['alias'] = $apcontact['alias'];
 866                 $profile['photo'] = $apcontact['photo'];
 867                 // $profile['community']
 868                 // $profile['keywords']
 869                 // $profile['location']
 870                 $profile['about'] = $apcontact['about'];
 871                 $profile['batch'] = $apcontact['sharedinbox'];
 872                 $profile['notify'] = $apcontact['inbox'];
 873                 $profile['poll'] = $apcontact['outbox'];
 874                 $profile['pubkey'] = $apcontact['pubkey'];
 875                 $profile['baseurl'] = $apcontact['baseurl'];
 876
 877                 // Remove all "null" fields
 878                 foreach ($profile as $field => $content) {
 879                         if (is_null($content)) {
 880                                 unset($profile[$field]);
 881                         }
 882                 }
 883
 884                 return $profile;
 885         }
 886
 887         /**
 888          * @brief
 889          *
 890          * @param $body
 891          * @param $header
 892          * @param integer $uid User ID
 893          */
 894         public static function processInbox($body, $header, $uid)
 895         {
 896                 $http_signer = HTTPSignature::getSigner($body, $header);
 897                 if (empty($http_signer)) {
 898                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 899                         return;
 900                 } else {
 901                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 902                 }
 903
 904                 $activity = json_decode($body, true);
 905
 906                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 907                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
 908
 909                 if (empty($activity)) {
 910                         logger('Invalid body.', LOGGER_DEBUG);
 911                         return;
 912                 }
 913
 914                 if (LDSignature::isSigned($activity)) {
 915                         $ld_signer = LDSignature::getSigner($activity);
 916                         if (empty($ld_signer)) {
 917                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
 918                         }
 919                         if (!empty($ld_signer && ($actor == $http_signer))) {
 920                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
 921                                 $trust_source = true;
 922                         } elseif (!empty($ld_signer)) {
 923                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
 924                                 $trust_source = true;
 925                         } elseif ($actor == $http_signer) {
 926                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
 927                                 $trust_source = true;
 928                         } else {
 929                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
 930                                 $trust_source = false;
 931                         }
 932                 } elseif ($actor == $http_signer) {
 933                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 934                         $trust_source = true;
 935                 } else {
 936                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 937                         $trust_source = false;
 938                 }
 939
 940                 self::processActivity($activity, $body, $uid, $trust_source);
 941         }
 942
 943         /**
 944          * @brief
 945          *
 946          * @param $url
 947          * @param integer $uid User ID
 948          */
 949         public static function fetchOutbox($url, $uid)
 950         {
 951                 $data = self::fetchContent($url);
 952                 if (empty($data)) {
 953                         return;
 954                 }
 955
 956                 if (!empty($data['orderedItems'])) {
 957                         $items = $data['orderedItems'];
 958                 } elseif (!empty($data['first']['orderedItems'])) {
 959                         $items = $data['first']['orderedItems'];
 960                 } elseif (!empty($data['first'])) {
 961                         self::fetchOutbox($data['first'], $uid);
 962                         return;
 963                 } else {
 964                         $items = [];
 965                 }
 966
 967                 foreach ($items as $activity) {
 968                         self::processActivity($activity, '', $uid, true);
 969                 }
 970         }
 971
 972         /**
 973          * @brief
 974          *
 975          * @param array $activity
 976          * @param integer $uid User ID
 977          * @param $trust_source
 978          *
 979          * @return
 980          */
 981         private static function prepareObjectData($activity, $uid, &$trust_source)
 982         {
 983                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 984                 if (empty($actor)) {
 985                         logger('Empty actor', LOGGER_DEBUG);
 986                         return [];
 987                 }
 988
 989                 // Fetch all receivers from to, cc, bto and bcc
 990                 $receivers = self::getReceivers($activity, $actor);
 991
 992                 // When it is a delivery to a personal inbox we add that user to the receivers
 993                 if (!empty($uid)) {
 994                         $owner = User::getOwnerDataById($uid);
 995                         $additional = ['uid:' . $uid => $uid];
 996                         $receivers = array_merge($receivers, $additional);
 997                 }
 998
 999                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
1000
1001                 $object_id = JsonLD::fetchElement($activity, 'object', 'id');
1002                 if (empty($object_id)) {
1003                         logger('No object found', LOGGER_DEBUG);
1004                         return [];
1005                 }
1006
1007                 // Fetch the content only on activities where this matters
1008                 if (in_array($activity['type'], ['Create', 'Announce'])) {
1009                         $object_data = self::fetchObject($object_id, $activity['object'], $trust_source);
1010                         if (empty($object_data)) {
1011                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
1012                                 return [];
1013                         }
1014                         // We had been able to retrieve the object data - so we can trust the source
1015                         $trust_source = true;
1016                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
1017                         // Create a mostly empty array out of the activity data (instead of the object).
1018                         // This way we later don't have to check for the existence of ech individual array element.
1019                         $object_data = self::ProcessObject($activity);
1020                         $object_data['name'] = $activity['type'];
1021                         $object_data['author'] = $activity['actor'];
1022                         $object_data['object'] = $object_id;
1023                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
1024                 } else {
1025                         $object_data = [];
1026                         $object_data['id'] = $activity['id'];
1027                         $object_data['object'] = $activity['object'];
1028                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
1029                 }
1030
1031                 $object_data = self::addActivityFields($object_data, $activity);
1032
1033                 $object_data['type'] = $activity['type'];
1034                 $object_data['owner'] = $actor;
1035                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
1036
1037                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
1038
1039                 return $object_data;
1040         }
1041
1042         /**
1043          * @brief
1044          *
1045          * @param array $activity
1046          * @param $body
1047          * @param integer $uid User ID
1048          * @param $trust_source
1049          */
1050         private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
1051         {
1052                 if (empty($activity['type'])) {
1053                         logger('Empty type', LOGGER_DEBUG);
1054                         return;
1055                 }
1056
1057                 if (empty($activity['object'])) {
1058                         logger('Empty object', LOGGER_DEBUG);
1059                         return;
1060                 }
1061
1062                 if (empty($activity['actor'])) {
1063                         logger('Empty actor', LOGGER_DEBUG);
1064                         return;
1065
1066                 }
1067
1068                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
1069                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
1070                 if (empty($object_data)) {
1071                         logger('No object data found', LOGGER_DEBUG);
1072                         return;
1073                 }
1074
1075                 if (!$trust_source) {
1076                         logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
1077                 }
1078
1079                 switch ($activity['type']) {
1080                         case 'Create':
1081                         case 'Announce':
1082                                 self::createItem($object_data, $body);
1083                                 break;
1084
1085                         case 'Like':
1086                                 self::likeItem($object_data, $body);
1087                                 break;
1088
1089                         case 'Dislike':
1090                                 self::dislikeItem($object_data, $body);
1091                                 break;
1092
1093                         case 'Update':
1094                                 if (in_array($object_data['object_type'], ['Person', 'Organization', 'Service', 'Group', 'Application'])) {
1095                                         self::updatePerson($object_data, $body);
1096                                 }
1097                                 break;
1098
1099                         case 'Delete':
1100                                 break;
1101
1102                         case 'Follow':
1103                                 self::followUser($object_data);
1104                                 break;
1105
1106                         case 'Accept':
1107                                 if ($object_data['object_type'] == 'Follow') {
1108                                         self::acceptFollowUser($object_data);
1109                                 }
1110                                 break;
1111
1112                         case 'Undo':
1113                                 if ($object_data['object_type'] == 'Follow') {
1114                                         self::undoFollowUser($object_data);
1115                                 } elseif (in_array($object_data['object_type'], ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'])) {
1116                                         self::undoActivity($object_data);
1117                                 }
1118                                 break;
1119
1120                         default:
1121                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
1122                                 break;
1123                 }
1124         }
1125
1126         /**
1127          * @brief
1128          *
1129          * @param array $activity
1130          * @param $actor
1131          *
1132          * @return
1133          */
1134         private static function getReceivers($activity, $actor)
1135         {
1136                 $receivers = [];
1137
1138                 // When it is an answer, we inherite the receivers from the parent
1139                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1140                 if (!empty($replyto)) {
1141                         $parents = Item::select(['uid'], ['uri' => $replyto]);
1142                         while ($parent = Item::fetch($parents)) {
1143                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
1144                         }
1145                 }
1146
1147                 if (!empty($actor)) {
1148                         $profile = APContact::getProfileByURL($actor);
1149                         $followers = defaults($profile, 'followers', '');
1150
1151                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
1152                 } else {
1153                         logger('Empty actor', LOGGER_DEBUG);
1154                         $followers = '';
1155                 }
1156
1157                 $elements = ['to', 'cc', 'bto', 'bcc'];
1158                 foreach ($elements as $element) {
1159                         if (empty($activity[$element])) {
1160                                 continue;
1161                         }
1162
1163                         // The receiver can be an arror or a string
1164                         if (is_string($activity[$element])) {
1165                                 $activity[$element] = [$activity[$element]];
1166                         }
1167
1168                         foreach ($activity[$element] as $receiver) {
1169                                 if ($receiver == self::PUBLIC) {
1170                                         $receivers['uid:0'] = 0;
1171                                 }
1172
1173                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
1174                                         // This will most likely catch all OStatus connections to Mastodon
1175                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
1176                                         $contacts = DBA::select('contact', ['uid'], $condition);
1177                                         while ($contact = DBA::fetch($contacts)) {
1178                                                 if ($contact['uid'] != 0) {
1179                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1180                                                 }
1181                                         }
1182                                         DBA::close($contacts);
1183                                 }
1184
1185                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
1186                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1187                                                 'network' => Protocol::ACTIVITYPUB];
1188                                         $contacts = DBA::select('contact', ['uid'], $condition);
1189                                         while ($contact = DBA::fetch($contacts)) {
1190                                                 if ($contact['uid'] != 0) {
1191                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1192                                                 }
1193                                         }
1194                                         DBA::close($contacts);
1195                                         continue;
1196                                 }
1197
1198                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1199                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1200                                 if (!DBA::isResult($contact)) {
1201                                         continue;
1202                                 }
1203                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1204                         }
1205                 }
1206
1207                 self::switchContacts($receivers, $actor);
1208
1209                 return $receivers;
1210         }
1211
1212         /**
1213          * @brief
1214          *
1215          * @param $cid
1216          * @param integer $uid User ID
1217          * @param $url
1218          */
1219         private static function switchContact($cid, $uid, $url)
1220         {
1221                 $profile = ActivityPub::probeProfile($url);
1222                 if (empty($profile)) {
1223                         return;
1224                 }
1225
1226                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' from OStatus to ActivityPub');
1227
1228                 $photo = $profile['photo'];
1229                 unset($profile['photo']);
1230                 unset($profile['baseurl']);
1231
1232                 $profile['nurl'] = normalise_link($profile['url']);
1233                 DBA::update('contact', $profile, ['id' => $cid]);
1234
1235                 Contact::updateAvatar($photo, $uid, $cid);
1236         }
1237
1238         /**
1239          * @brief
1240          *
1241          * @param $receivers
1242          * @param $actor
1243          */
1244         private static function switchContacts($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         /**
1264          * @brief
1265          *
1266          * @param $object_data
1267          * @param array $activity
1268          *
1269          * @return
1270          */
1271         private static function addActivityFields($object_data, $activity)
1272         {
1273                 if (!empty($activity['published']) && empty($object_data['published'])) {
1274                         $object_data['published'] = $activity['published'];
1275                 }
1276
1277                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1278                         $object_data['updated'] = $activity['updated'];
1279                 }
1280
1281                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1282                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1283                 }
1284
1285                 if (!empty($activity['instrument'])) {
1286                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1287                 }
1288                 return $object_data;
1289         }
1290
1291         /**
1292          * @brief
1293          *
1294          * @param $object_id
1295          * @param $object
1296          * @param $trust_source
1297          *
1298          * @return
1299          */
1300         private static function fetchObject($object_id, $object = [], $trust_source = false)
1301         {
1302                 if (!$trust_source || is_string($object)) {
1303                         $data = self::fetchContent($object_id);
1304                         if (empty($data)) {
1305                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
1306                                 $data = $object_id;
1307                         } else {
1308                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
1309                         }
1310                 } else {
1311                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
1312                         $data = $object;
1313                 }
1314
1315                 if (is_string($data)) {
1316                         $item = Item::selectFirst([], ['uri' => $data]);
1317                         if (!DBA::isResult($item)) {
1318                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1319                                 return false;
1320                         }
1321                         logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
1322                         $data = self::CreateNote($item);
1323                 }
1324
1325                 if (empty($data['type'])) {
1326                         logger('Empty type', LOGGER_DEBUG);
1327                         return false;
1328                 }
1329
1330                 switch ($data['type']) {
1331                         case 'Note':
1332                         case 'Article':
1333                         case 'Video':
1334                                 return self::ProcessObject($data);
1335
1336                         case 'Announce':
1337                                 if (empty($data['object'])) {
1338                                         return false;
1339                                 }
1340                                 return self::fetchObject($data['object']);
1341
1342                         case 'Person':
1343                         case 'Tombstone':
1344                                 break;
1345
1346                         default:
1347                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1348                                 break;
1349                 }
1350         }
1351
1352         /**
1353          * @brief
1354          *
1355          * @param $object
1356          *
1357          * @return
1358          */
1359         private static function ProcessObject(&$object)
1360         {
1361                 if (empty($object['id'])) {
1362                         return false;
1363                 }
1364
1365                 $object_data = [];
1366                 $object_data['object_type'] = $object['type'];
1367                 $object_data['id'] = $object['id'];
1368
1369                 if (!empty($object['inReplyTo'])) {
1370                         $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1371                 } else {
1372                         $object_data['reply-to-id'] = $object_data['id'];
1373                 }
1374
1375                 $object_data['published'] = defaults($object, 'published', null);
1376                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1377
1378                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1379                         $object_data['published'] = $object_data['updated'];
1380                 }
1381
1382                 $actor = JsonLD::fetchElement($object, 'attributedTo', 'id');
1383                 if (empty($actor)) {
1384                         $actor = defaults($object, 'actor', null);
1385                 }
1386
1387                 $object_data['diaspora:guid'] = defaults($object, 'diaspora:guid', null);
1388                 $object_data['owner'] = $object_data['author'] = $actor;
1389                 $object_data['context'] = defaults($object, 'context', null);
1390                 $object_data['conversation'] = defaults($object, 'conversation', null);
1391                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1392                 $object_data['name'] = defaults($object, 'title', null);
1393                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1394                 $object_data['summary'] = defaults($object, 'summary', null);
1395                 $object_data['content'] = defaults($object, 'content', null);
1396                 $object_data['source'] = defaults($object, 'source', null);
1397                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1398                 $object_data['attachments'] = defaults($object, 'attachment', null);
1399                 $object_data['tags'] = defaults($object, 'tag', null);
1400                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1401                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1402                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1403
1404                 // Common object data:
1405
1406                 // Unhandled
1407                 // @context, type, actor, signature, mediaType, duration, replies, icon
1408
1409                 // Also missing: (Defined in the standard, but currently unused)
1410                 // audience, preview, endTime, startTime, generator, image
1411
1412                 // Data in Notes:
1413
1414                 // Unhandled
1415                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1416                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1417
1418                 // Data in video:
1419
1420                 // To-Do?
1421                 // category, licence, language, commentsEnabled
1422
1423                 // Unhandled
1424                 // views, waitTranscoding, state, support, subtitleLanguage
1425                 // likes, dislikes, shares, comments
1426
1427                 return $object_data;
1428         }
1429
1430         /**
1431          * @brief Converts mentions from Pleroma into the Friendica format
1432          *
1433          * @param string $body
1434          *
1435          * @return converted body
1436          */
1437         private static function convertMentions($body)
1438         {
1439                 $URLSearchString = "^\[\]";
1440                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1441
1442                 return $body;
1443         }
1444
1445         /**
1446          * @brief Constructs a string with tags for a given tag array
1447          *
1448          * @param array $tags
1449          * @param boolean $sensitive
1450          *
1451          * @return string with tags
1452          */
1453         private static function constructTagList($tags, $sensitive)
1454         {
1455                 if (empty($tags)) {
1456                         return '';
1457                 }
1458
1459                 $tag_text = '';
1460                 foreach ($tags as $tag) {
1461                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1462                                 if (!empty($tag_text)) {
1463                                         $tag_text .= ',';
1464                                 }
1465
1466                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1467                         }
1468                 }
1469
1470                 /// @todo add nsfw for $sensitive
1471
1472                 return $tag_text;
1473         }
1474
1475         /**
1476          * @brief
1477          *
1478          * @param $attachments
1479          * @param array $item
1480          *
1481          * @return item array
1482          */
1483         private static function constructAttachList($attachments, $item)
1484         {
1485                 if (empty($attachments)) {
1486                         return $item;
1487                 }
1488
1489                 foreach ($attachments as $attach) {
1490                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1491                         if ($filetype == 'image') {
1492                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1493                         } else {
1494                                 if (!empty($item["attach"])) {
1495                                         $item["attach"] .= ',';
1496                                 } else {
1497                                         $item["attach"] = '';
1498                                 }
1499                                 if (!isset($attach['length'])) {
1500                                         $attach['length'] = "0";
1501                                 }
1502                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1503                         }
1504                 }
1505
1506                 return $item;
1507         }
1508
1509         /**
1510          * @brief
1511          *
1512          * @param array $activity
1513          * @param $body
1514          */
1515         private static function createItem($activity, $body)
1516         {
1517                 $item = [];
1518                 $item['verb'] = ACTIVITY_POST;
1519                 $item['parent-uri'] = $activity['reply-to-id'];
1520
1521                 if ($activity['reply-to-id'] == $activity['id']) {
1522                         $item['gravity'] = GRAVITY_PARENT;
1523                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1524                 } else {
1525                         $item['gravity'] = GRAVITY_COMMENT;
1526                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1527                 }
1528
1529                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
1530                         logger('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
1531                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
1532                 }
1533
1534                 self::postItem($activity, $item, $body);
1535         }
1536
1537         /**
1538          * @brief
1539          *
1540          * @param array $activity
1541          * @param $body
1542          */
1543         private static function likeItem($activity, $body)
1544         {
1545                 $item = [];
1546                 $item['verb'] = ACTIVITY_LIKE;
1547                 $item['parent-uri'] = $activity['object'];
1548                 $item['gravity'] = GRAVITY_ACTIVITY;
1549                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1550
1551                 self::postItem($activity, $item, $body);
1552         }
1553
1554         /**
1555          * @brief
1556          *
1557          * @param array $activity
1558          * @param $body
1559          */
1560         private static function dislikeItem($activity, $body)
1561         {
1562                 $item = [];
1563                 $item['verb'] = ACTIVITY_DISLIKE;
1564                 $item['parent-uri'] = $activity['object'];
1565                 $item['gravity'] = GRAVITY_ACTIVITY;
1566                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1567
1568                 self::postItem($activity, $item, $body);
1569         }
1570
1571         /**
1572          * @brief
1573          *
1574          * @param array $activity
1575          * @param array $item
1576          * @param $body
1577          */
1578         private static function postItem($activity, $item, $body)
1579         {
1580                 /// @todo What to do with $activity['context']?
1581
1582                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['parent-uri']])) {
1583                         logger('Parent ' . $item['parent-uri'] . ' not found, message will be discarded.', LOGGER_DEBUG);
1584                         return;
1585                 }
1586
1587                 $item['network'] = Protocol::ACTIVITYPUB;
1588                 $item['private'] = !in_array(0, $activity['receiver']);
1589                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1590                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1591                 $item['uri'] = $activity['id'];
1592                 $item['created'] = $activity['published'];
1593                 $item['edited'] = $activity['updated'];
1594                 $item['guid'] = $activity['diaspora:guid'];
1595                 $item['title'] = HTML::toBBCode($activity['name']);
1596                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1597                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1598                 $item['location'] = $activity['location'];
1599                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1600                 $item['app'] = $activity['service'];
1601                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1602
1603                 $item = self::constructAttachList($activity['attachments'], $item);
1604
1605                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1606                 if (!empty($source)) {
1607                         $item['body'] = $source;
1608                 }
1609
1610                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1611                 $item['source'] = $body;
1612                 $item['conversation-href'] = $activity['context'];
1613                 $item['conversation-uri'] = $activity['conversation'];
1614
1615                 foreach ($activity['receiver'] as $receiver) {
1616                         $item['uid'] = $receiver;
1617                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1618
1619                         if (($receiver != 0) && empty($item['contact-id'])) {
1620                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1621                         }
1622
1623                         $item_id = Item::insert($item);
1624                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1625                 }
1626         }
1627
1628         /**
1629          * @brief
1630          *
1631          * @param $url
1632          * @param $child
1633          */
1634         private static function fetchMissingActivity($url, $child)
1635         {
1636                 if (Config::get('system', 'ostatus_full_threads')) {
1637                         return;
1638                 }
1639
1640                 $object = ActivityPub::fetchContent($url);
1641                 if (empty($object)) {
1642                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1643                         return;
1644                 }
1645
1646                 $activity = [];
1647                 $activity['@context'] = $object['@context'];
1648                 unset($object['@context']);
1649                 $activity['id'] = $object['id'];
1650                 $activity['to'] = defaults($object, 'to', []);
1651                 $activity['cc'] = defaults($object, 'cc', []);
1652                 $activity['actor'] = $child['author'];
1653                 $activity['object'] = $object;
1654                 $activity['published'] = $object['published'];
1655                 $activity['type'] = 'Create';
1656
1657                 self::processActivity($activity);
1658                 logger('Activity ' . $url . ' had been fetched and processed.');
1659         }
1660
1661         /**
1662          * @brief Returns the user id of a given profile url
1663          *
1664          * @param string $profile
1665          *
1666          * @return integer user id
1667          */
1668         private static function getUserOfProfile($profile)
1669         {
1670                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($profile), 'self' => true]);
1671                 if (!DBA::isResult($self)) {
1672                         return false;
1673                 } else {
1674                         return $self['uid'];
1675                 }
1676         }
1677
1678         /**
1679          * @brief perform a "follow" request
1680          *
1681          * @param array $activity
1682          */
1683         private static function followUser($activity)
1684         {
1685                 $actor = JsonLD::fetchElement($activity, 'object', 'id');
1686                 $uid = self::getUserOfProfile($actor);
1687                 if (empty($uid)) {
1688                         return;
1689                 }
1690
1691                 $owner = User::getOwnerDataById($uid);
1692
1693                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1694                 if (!empty($cid)) {
1695                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1696                 } else {
1697                         $contact = false;
1698                 }
1699
1700                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1701                         'author-link' => $activity['owner']];
1702
1703                 Contact::addRelationship($owner, $contact, $item);
1704                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1705                 if (empty($cid)) {
1706                         return;
1707                 }
1708
1709                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1710                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1711                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1712                 }
1713
1714                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1715                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1716         }
1717
1718         /**
1719          * @brief Update the given profile
1720          *
1721          * @param array $activity
1722          */
1723         private static function updatePerson($activity)
1724         {
1725                 if (empty($activity['object']['id'])) {
1726                         return;
1727                 }
1728
1729                 logger('Updating profile for ' . $activity['object']['id'], LOGGER_DEBUG);
1730                 APContact::getProfileByURL($activity['object']['id'], true);
1731         }
1732
1733         /**
1734          * @brief Accept a follow request
1735          *
1736          * @param array $activity
1737          */
1738         private static function acceptFollowUser($activity)
1739         {
1740                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1741                 $uid = self::getUserOfProfile($actor);
1742                 if (empty($uid)) {
1743                         return;
1744                 }
1745
1746                 $owner = User::getOwnerDataById($uid);
1747
1748                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1749                 if (empty($cid)) {
1750                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1751                         return;
1752                 }
1753
1754                 $fields = ['pending' => false];
1755
1756                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1757                 if ($contact['rel'] == Contact::FOLLOWER) {
1758                         $fields['rel'] = Contact::FRIEND;
1759                 }
1760
1761                 $condition = ['id' => $cid];
1762                 DBA::update('contact', $fields, $condition);
1763                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1764         }
1765
1766         /**
1767          * @brief Undo activity like "like" or "dislike"
1768          *
1769          * @param array $activity
1770          */
1771         private static function undoActivity($activity)
1772         {
1773                 $activity_url = JsonLD::fetchElement($activity, 'object', 'id');
1774                 if (empty($activity_url)) {
1775                         return;
1776                 }
1777
1778                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1779                 if (empty($actor)) {
1780                         return;
1781                 }
1782
1783                 $author_id = Contact::getIdForURL($actor);
1784                 if (empty($author_id)) {
1785                         return;
1786                 }
1787
1788                 Item::delete(['uri' => $activity_url, 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1789         }
1790
1791         /**
1792          * @brief Activity to remove a follower
1793          *
1794          * @param array $activity
1795          */
1796         private static function undoFollowUser($activity)
1797         {
1798                 $object = JsonLD::fetchElement($activity, 'object', 'object');
1799                 $uid = self::getUserOfProfile($object);
1800                 if (empty($uid)) {
1801                         return;
1802                 }
1803
1804                 $owner = User::getOwnerDataById($uid);
1805
1806                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1807                 if (empty($cid)) {
1808                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1809                         return;
1810                 }
1811
1812                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1813                 if (!DBA::isResult($contact)) {
1814                         return;
1815                 }
1816
1817                 Contact::removeFollower($owner, $contact);
1818                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1819         }
1820 }