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/ns/',
  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' => $item['body'], 'mediaType' => "text/bbcode"];
 716
 717                 if (!empty($item['signed_text']) && ($item['uri'] != $item['thr-parent'])) {
 718                         $data['diaspora:comment'] = $item['signed_text'];
 719                 }
 720
 721                 $data['attachment'] = []; // @ToDo
 722                 $data['tag'] = self::createTagList($item);
 723                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 724
 725                 return $data;
 726         }
 727
 728         /**
 729          * @brief Transmits a given activity to a target
 730          *
 731          * @param array $activity
 732          * @param string $target Target profile
 733          * @param integer $uid User ID
 734          */
 735         public static function transmitActivity($activity, $target, $uid)
 736         {
 737                 $profile = APContact::getProfileByURL($target);
 738
 739                 $owner = User::getOwnerDataById($uid);
 740
 741                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 742                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 743                         'type' => $activity,
 744                         'actor' => $owner['url'],
 745                         'object' => $profile['url'],
 746                         'to' => $profile['url']];
 747
 748                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 749
 750                 $signed = LDSignature::sign($data, $owner);
 751                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 752         }
 753
 754         /**
 755          * @brief Transmit a message that the contact request had been accepted
 756          *
 757          * @param string $target Target profile
 758          * @param $id
 759          * @param integer $uid User ID
 760          */
 761         public static function transmitContactAccept($target, $id, $uid)
 762         {
 763                 $profile = APContact::getProfileByURL($target);
 764
 765                 $owner = User::getOwnerDataById($uid);
 766                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 767                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 768                         'type' => 'Accept',
 769                         'actor' => $owner['url'],
 770                         'object' => ['id' => $id, 'type' => 'Follow',
 771                                 'actor' => $profile['url'],
 772                                 'object' => $owner['url']],
 773                         'to' => $profile['url']];
 774
 775                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 776
 777                 $signed = LDSignature::sign($data, $owner);
 778                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 779         }
 780
 781         /**
 782          * @brief
 783          *
 784          * @param string $target Target profile
 785          * @param $id
 786          * @param integer $uid User ID
 787          */
 788         public static function transmitContactReject($target, $id, $uid)
 789         {
 790                 $profile = APContact::getProfileByURL($target);
 791
 792                 $owner = User::getOwnerDataById($uid);
 793                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 794                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 795                         'type' => 'Reject',
 796                         'actor' => $owner['url'],
 797                         'object' => ['id' => $id, 'type' => 'Follow',
 798                                 'actor' => $profile['url'],
 799                                 'object' => $owner['url']],
 800                         'to' => $profile['url']];
 801
 802                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 803
 804                 $signed = LDSignature::sign($data, $owner);
 805                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 806         }
 807
 808         /**
 809          * @brief
 810          *
 811          * @param string $target Target profile
 812          * @param integer $uid User ID
 813          */
 814         public static function transmitContactUndo($target, $uid)
 815         {
 816                 $profile = APContact::getProfileByURL($target);
 817
 818                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 819
 820                 $owner = User::getOwnerDataById($uid);
 821                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 822                         'id' => $id,
 823                         'type' => 'Undo',
 824                         'actor' => $owner['url'],
 825                         'object' => ['id' => $id, 'type' => 'Follow',
 826                                 'actor' => $owner['url'],
 827                                 'object' => $profile['url']],
 828                         'to' => $profile['url']];
 829
 830                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 831
 832                 $signed = LDSignature::sign($data, $owner);
 833                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 834         }
 835
 836         /**
 837          * Fetches ActivityPub content from the given url
 838          *
 839          * @param string $url content url
 840          * @return array
 841          */
 842         public static function fetchContent($url)
 843         {
 844                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 845                 if (!$ret['success'] || empty($ret['body'])) {
 846                         return;
 847                 }
 848                 return json_decode($ret['body'], true);
 849         }
 850
 851         /**
 852          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 853          *
 854          * @param string $url profile url
 855          * @return array
 856          */
 857         public static function probeProfile($url)
 858         {
 859                 $apcontact = APContact::getProfileByURL($url, true);
 860                 if (empty($apcontact)) {
 861                         return false;
 862                 }
 863
 864                 $profile = ['network' => Protocol::ACTIVITYPUB];
 865                 $profile['nick'] = $apcontact['nick'];
 866                 $profile['name'] = $apcontact['name'];
 867                 $profile['guid'] = $apcontact['uuid'];
 868                 $profile['url'] = $apcontact['url'];
 869                 $profile['addr'] = $apcontact['addr'];
 870                 $profile['alias'] = $apcontact['alias'];
 871                 $profile['photo'] = $apcontact['photo'];
 872                 // $profile['community']
 873                 // $profile['keywords']
 874                 // $profile['location']
 875                 $profile['about'] = $apcontact['about'];
 876                 $profile['batch'] = $apcontact['sharedinbox'];
 877                 $profile['notify'] = $apcontact['inbox'];
 878                 $profile['poll'] = $apcontact['outbox'];
 879                 $profile['pubkey'] = $apcontact['pubkey'];
 880                 $profile['baseurl'] = $apcontact['baseurl'];
 881
 882                 // Remove all "null" fields
 883                 foreach ($profile as $field => $content) {
 884                         if (is_null($content)) {
 885                                 unset($profile[$field]);
 886                         }
 887                 }
 888
 889                 return $profile;
 890         }
 891
 892         /**
 893          * @brief
 894          *
 895          * @param $body
 896          * @param $header
 897          * @param integer $uid User ID
 898          */
 899         public static function processInbox($body, $header, $uid)
 900         {
 901                 $http_signer = HTTPSignature::getSigner($body, $header);
 902                 if (empty($http_signer)) {
 903                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 904                         return;
 905                 } else {
 906                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 907                 }
 908
 909                 $activity = json_decode($body, true);
 910
 911                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 912                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
 913
 914                 if (empty($activity)) {
 915                         logger('Invalid body.', LOGGER_DEBUG);
 916                         return;
 917                 }
 918
 919                 if (LDSignature::isSigned($activity)) {
 920                         $ld_signer = LDSignature::getSigner($activity);
 921                         if (empty($ld_signer)) {
 922                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
 923                         }
 924                         if (!empty($ld_signer && ($actor == $http_signer))) {
 925                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
 926                                 $trust_source = true;
 927                         } elseif (!empty($ld_signer)) {
 928                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
 929                                 $trust_source = true;
 930                         } elseif ($actor == $http_signer) {
 931                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
 932                                 $trust_source = true;
 933                         } else {
 934                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
 935                                 $trust_source = false;
 936                         }
 937                 } elseif ($actor == $http_signer) {
 938                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 939                         $trust_source = true;
 940                 } else {
 941                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 942                         $trust_source = false;
 943                 }
 944
 945                 self::processActivity($activity, $body, $uid, $trust_source);
 946         }
 947
 948         /**
 949          * @brief
 950          *
 951          * @param $url
 952          * @param integer $uid User ID
 953          */
 954         public static function fetchOutbox($url, $uid)
 955         {
 956                 $data = self::fetchContent($url);
 957                 if (empty($data)) {
 958                         return;
 959                 }
 960
 961                 if (!empty($data['orderedItems'])) {
 962                         $items = $data['orderedItems'];
 963                 } elseif (!empty($data['first']['orderedItems'])) {
 964                         $items = $data['first']['orderedItems'];
 965                 } elseif (!empty($data['first'])) {
 966                         self::fetchOutbox($data['first'], $uid);
 967                         return;
 968                 } else {
 969                         $items = [];
 970                 }
 971
 972                 foreach ($items as $activity) {
 973                         self::processActivity($activity, '', $uid, true);
 974                 }
 975         }
 976
 977         /**
 978          * @brief
 979          *
 980          * @param array $activity
 981          * @param integer $uid User ID
 982          * @param $trust_source
 983          *
 984          * @return
 985          */
 986         private static function prepareObjectData($activity, $uid, &$trust_source)
 987         {
 988                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 989                 if (empty($actor)) {
 990                         logger('Empty actor', LOGGER_DEBUG);
 991                         return [];
 992                 }
 993
 994                 // Fetch all receivers from to, cc, bto and bcc
 995                 $receivers = self::getReceivers($activity, $actor);
 996
 997                 // When it is a delivery to a personal inbox we add that user to the receivers
 998                 if (!empty($uid)) {
 999                         $owner = User::getOwnerDataById($uid);
1000                         $additional = ['uid:' . $uid => $uid];
1001                         $receivers = array_merge($receivers, $additional);
1002                 }
1003
1004                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
1005
1006                 $object_id = JsonLD::fetchElement($activity, 'object', 'id');
1007                 if (empty($object_id)) {
1008                         logger('No object found', LOGGER_DEBUG);
1009                         return [];
1010                 }
1011
1012                 // Fetch the content only on activities where this matters
1013                 if (in_array($activity['type'], ['Create', 'Announce'])) {
1014                         $object_data = self::fetchObject($object_id, $activity['object'], $trust_source);
1015                         if (empty($object_data)) {
1016                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
1017                                 return [];
1018                         }
1019                         // We had been able to retrieve the object data - so we can trust the source
1020                         $trust_source = true;
1021                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
1022                         // Create a mostly empty array out of the activity data (instead of the object).
1023                         // This way we later don't have to check for the existence of ech individual array element.
1024                         $object_data = self::processObject($activity);
1025                         $object_data['name'] = $activity['type'];
1026                         $object_data['author'] = $activity['actor'];
1027                         $object_data['object'] = $object_id;
1028                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
1029                 } else {
1030                         $object_data = [];
1031                         $object_data['id'] = $activity['id'];
1032                         $object_data['object'] = $activity['object'];
1033                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
1034                 }
1035
1036                 $object_data = self::addActivityFields($object_data, $activity);
1037
1038                 $object_data['type'] = $activity['type'];
1039                 $object_data['owner'] = $actor;
1040                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
1041
1042                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
1043
1044                 return $object_data;
1045         }
1046
1047         /**
1048          * @brief
1049          *
1050          * @param array $activity
1051          * @param $body
1052          * @param integer $uid User ID
1053          * @param $trust_source
1054          */
1055         private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
1056         {
1057                 if (empty($activity['type'])) {
1058                         logger('Empty type', LOGGER_DEBUG);
1059                         return;
1060                 }
1061
1062                 if (empty($activity['object'])) {
1063                         logger('Empty object', LOGGER_DEBUG);
1064                         return;
1065                 }
1066
1067                 if (empty($activity['actor'])) {
1068                         logger('Empty actor', LOGGER_DEBUG);
1069                         return;
1070
1071                 }
1072
1073                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
1074                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
1075                 if (empty($object_data)) {
1076                         logger('No object data found', LOGGER_DEBUG);
1077                         return;
1078                 }
1079
1080                 if (!$trust_source) {
1081                         logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
1082                 }
1083
1084                 switch ($activity['type']) {
1085                         case 'Create':
1086                         case 'Announce':
1087                                 self::createItem($object_data, $body);
1088                                 break;
1089
1090                         case 'Like':
1091                                 self::likeItem($object_data, $body);
1092                                 break;
1093
1094                         case 'Dislike':
1095                                 self::dislikeItem($object_data, $body);
1096                                 break;
1097
1098                         case 'Update':
1099                                 if (in_array($object_data['object_type'], ['Person', 'Organization', 'Service', 'Group', 'Application'])) {
1100                                         self::updatePerson($object_data, $body);
1101                                 }
1102                                 break;
1103
1104                         case 'Delete':
1105                                 break;
1106
1107                         case 'Follow':
1108                                 self::followUser($object_data);
1109                                 break;
1110
1111                         case 'Accept':
1112                                 if ($object_data['object_type'] == 'Follow') {
1113                                         self::acceptFollowUser($object_data);
1114                                 }
1115                                 break;
1116
1117                         case 'Undo':
1118                                 if ($object_data['object_type'] == 'Follow') {
1119                                         self::undoFollowUser($object_data);
1120                                 } elseif (in_array($object_data['object_type'], ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'])) {
1121                                         self::undoActivity($object_data);
1122                                 }
1123                                 break;
1124
1125                         default:
1126                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
1127                                 break;
1128                 }
1129         }
1130
1131         /**
1132          * @brief
1133          *
1134          * @param array $activity
1135          * @param $actor
1136          *
1137          * @return
1138          */
1139         private static function getReceivers($activity, $actor)
1140         {
1141                 $receivers = [];
1142
1143                 // When it is an answer, we inherite the receivers from the parent
1144                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1145                 if (!empty($replyto)) {
1146                         $parents = Item::select(['uid'], ['uri' => $replyto]);
1147                         while ($parent = Item::fetch($parents)) {
1148                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
1149                         }
1150                 }
1151
1152                 if (!empty($actor)) {
1153                         $profile = APContact::getProfileByURL($actor);
1154                         $followers = defaults($profile, 'followers', '');
1155
1156                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
1157                 } else {
1158                         logger('Empty actor', LOGGER_DEBUG);
1159                         $followers = '';
1160                 }
1161
1162                 $elements = ['to', 'cc', 'bto', 'bcc'];
1163                 foreach ($elements as $element) {
1164                         if (empty($activity[$element])) {
1165                                 continue;
1166                         }
1167
1168                         // The receiver can be an arror or a string
1169                         if (is_string($activity[$element])) {
1170                                 $activity[$element] = [$activity[$element]];
1171                         }
1172
1173                         foreach ($activity[$element] as $receiver) {
1174                                 if ($receiver == self::PUBLIC) {
1175                                         $receivers['uid:0'] = 0;
1176                                 }
1177
1178                                 if (($receiver == self::PUBLIC) && !empty($actor)) {
1179                                         // This will most likely catch all OStatus connections to Mastodon
1180                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
1181                                         $contacts = DBA::select('contact', ['uid'], $condition);
1182                                         while ($contact = DBA::fetch($contacts)) {
1183                                                 if ($contact['uid'] != 0) {
1184                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1185                                                 }
1186                                         }
1187                                         DBA::close($contacts);
1188                                 }
1189
1190                                 if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
1191                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1192                                                 'network' => Protocol::ACTIVITYPUB];
1193                                         $contacts = DBA::select('contact', ['uid'], $condition);
1194                                         while ($contact = DBA::fetch($contacts)) {
1195                                                 if ($contact['uid'] != 0) {
1196                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1197                                                 }
1198                                         }
1199                                         DBA::close($contacts);
1200                                         continue;
1201                                 }
1202
1203                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1204                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1205                                 if (!DBA::isResult($contact)) {
1206                                         continue;
1207                                 }
1208                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1209                         }
1210                 }
1211
1212                 self::switchContacts($receivers, $actor);
1213
1214                 return $receivers;
1215         }
1216
1217         /**
1218          * @brief
1219          *
1220          * @param $cid
1221          * @param integer $uid User ID
1222          * @param $url
1223          */
1224         private static function switchContact($cid, $uid, $url)
1225         {
1226                 $profile = ActivityPub::probeProfile($url);
1227                 if (empty($profile)) {
1228                         return;
1229                 }
1230
1231                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' from OStatus to ActivityPub');
1232
1233                 $photo = $profile['photo'];
1234                 unset($profile['photo']);
1235                 unset($profile['baseurl']);
1236
1237                 $profile['nurl'] = normalise_link($profile['url']);
1238                 DBA::update('contact', $profile, ['id' => $cid]);
1239
1240                 Contact::updateAvatar($photo, $uid, $cid);
1241         }
1242
1243         /**
1244          * @brief
1245          *
1246          * @param $receivers
1247          * @param $actor
1248          */
1249         private static function switchContacts($receivers, $actor)
1250         {
1251                 if (empty($actor)) {
1252                         return;
1253                 }
1254
1255                 foreach ($receivers as $receiver) {
1256                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
1257                         if (DBA::isResult($contact)) {
1258                                 self::switchContact($contact['id'], $receiver, $actor);
1259                         }
1260
1261                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
1262                         if (DBA::isResult($contact)) {
1263                                 self::switchContact($contact['id'], $receiver, $actor);
1264                         }
1265                 }
1266         }
1267
1268         /**
1269          * @brief
1270          *
1271          * @param $object_data
1272          * @param array $activity
1273          *
1274          * @return
1275          */
1276         private static function addActivityFields($object_data, $activity)
1277         {
1278                 if (!empty($activity['published']) && empty($object_data['published'])) {
1279                         $object_data['published'] = $activity['published'];
1280                 }
1281
1282                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1283                         $object_data['updated'] = $activity['updated'];
1284                 }
1285
1286                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1287                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1288                 }
1289
1290                 if (!empty($activity['instrument'])) {
1291                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1292                 }
1293                 return $object_data;
1294         }
1295
1296         /**
1297          * @brief
1298          *
1299          * @param $object_id
1300          * @param $object
1301          * @param $trust_source
1302          *
1303          * @return
1304          */
1305         private static function fetchObject($object_id, $object = [], $trust_source = false)
1306         {
1307                 if (!$trust_source || is_string($object)) {
1308                         $data = self::fetchContent($object_id);
1309                         if (empty($data)) {
1310                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
1311                                 $data = $object_id;
1312                         } else {
1313                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
1314                         }
1315                 } else {
1316                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
1317                         $data = $object;
1318                 }
1319
1320                 if (is_string($data)) {
1321                         $item = Item::selectFirst([], ['uri' => $data]);
1322                         if (!DBA::isResult($item)) {
1323                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1324                                 return false;
1325                         }
1326                         logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
1327                         $data = self::createNote($item);
1328                 }
1329
1330                 if (empty($data['type'])) {
1331                         logger('Empty type', LOGGER_DEBUG);
1332                         return false;
1333                 }
1334
1335                 switch ($data['type']) {
1336                         case 'Note':
1337                         case 'Article':
1338                         case 'Video':
1339                                 return self::processObject($data);
1340
1341                         case 'Announce':
1342                                 if (empty($data['object'])) {
1343                                         return false;
1344                                 }
1345                                 return self::fetchObject($data['object']);
1346
1347                         case 'Person':
1348                         case 'Tombstone':
1349                                 break;
1350
1351                         default:
1352                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1353                                 break;
1354                 }
1355         }
1356
1357         /**
1358          * @brief
1359          *
1360          * @param $object
1361          *
1362          * @return
1363          */
1364         private static function processObject(&$object)
1365         {
1366                 if (empty($object['id'])) {
1367                         return false;
1368                 }
1369
1370                 $object_data = [];
1371                 $object_data['object_type'] = $object['type'];
1372                 $object_data['id'] = $object['id'];
1373
1374                 if (!empty($object['inReplyTo'])) {
1375                         $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1376                 } else {
1377                         $object_data['reply-to-id'] = $object_data['id'];
1378                 }
1379
1380                 $object_data['published'] = defaults($object, 'published', null);
1381                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1382
1383                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1384                         $object_data['published'] = $object_data['updated'];
1385                 }
1386
1387                 $actor = JsonLD::fetchElement($object, 'attributedTo', 'id');
1388                 if (empty($actor)) {
1389                         $actor = defaults($object, 'actor', null);
1390                 }
1391
1392                 $object_data['diaspora:guid'] = defaults($object, 'diaspora:guid', null);
1393                 $object_data['owner'] = $object_data['author'] = $actor;
1394                 $object_data['context'] = defaults($object, 'context', null);
1395                 $object_data['conversation'] = defaults($object, 'conversation', null);
1396                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1397                 $object_data['name'] = defaults($object, 'title', null);
1398                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1399                 $object_data['summary'] = defaults($object, 'summary', null);
1400                 $object_data['content'] = defaults($object, 'content', null);
1401                 $object_data['source'] = defaults($object, 'source', null);
1402                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1403                 $object_data['attachments'] = defaults($object, 'attachment', null);
1404                 $object_data['tags'] = defaults($object, 'tag', null);
1405                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1406                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1407                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1408
1409                 // Common object data:
1410
1411                 // Unhandled
1412                 // @context, type, actor, signature, mediaType, duration, replies, icon
1413
1414                 // Also missing: (Defined in the standard, but currently unused)
1415                 // audience, preview, endTime, startTime, generator, image
1416
1417                 // Data in Notes:
1418
1419                 // Unhandled
1420                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1421                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1422
1423                 // Data in video:
1424
1425                 // To-Do?
1426                 // category, licence, language, commentsEnabled
1427
1428                 // Unhandled
1429                 // views, waitTranscoding, state, support, subtitleLanguage
1430                 // likes, dislikes, shares, comments
1431
1432                 return $object_data;
1433         }
1434
1435         /**
1436          * @brief Converts mentions from Pleroma into the Friendica format
1437          *
1438          * @param string $body
1439          *
1440          * @return converted body
1441          */
1442         private static function convertMentions($body)
1443         {
1444                 $URLSearchString = "^\[\]";
1445                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1446
1447                 return $body;
1448         }
1449
1450         /**
1451          * @brief Constructs a string with tags for a given tag array
1452          *
1453          * @param array $tags
1454          * @param boolean $sensitive
1455          *
1456          * @return string with tags
1457          */
1458         private static function constructTagList($tags, $sensitive)
1459         {
1460                 if (empty($tags)) {
1461                         return '';
1462                 }
1463
1464                 $tag_text = '';
1465                 foreach ($tags as $tag) {
1466                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1467                                 if (!empty($tag_text)) {
1468                                         $tag_text .= ',';
1469                                 }
1470
1471                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1472                         }
1473                 }
1474
1475                 /// @todo add nsfw for $sensitive
1476
1477                 return $tag_text;
1478         }
1479
1480         /**
1481          * @brief
1482          *
1483          * @param $attachments
1484          * @param array $item
1485          *
1486          * @return item array
1487          */
1488         private static function constructAttachList($attachments, $item)
1489         {
1490                 if (empty($attachments)) {
1491                         return $item;
1492                 }
1493
1494                 foreach ($attachments as $attach) {
1495                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1496                         if ($filetype == 'image') {
1497                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1498                         } else {
1499                                 if (!empty($item["attach"])) {
1500                                         $item["attach"] .= ',';
1501                                 } else {
1502                                         $item["attach"] = '';
1503                                 }
1504                                 if (!isset($attach['length'])) {
1505                                         $attach['length'] = "0";
1506                                 }
1507                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1508                         }
1509                 }
1510
1511                 return $item;
1512         }
1513
1514         /**
1515          * @brief
1516          *
1517          * @param array $activity
1518          * @param $body
1519          */
1520         private static function createItem($activity, $body)
1521         {
1522                 $item = [];
1523                 $item['verb'] = ACTIVITY_POST;
1524                 $item['parent-uri'] = $activity['reply-to-id'];
1525
1526                 if ($activity['reply-to-id'] == $activity['id']) {
1527                         $item['gravity'] = GRAVITY_PARENT;
1528                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1529                 } else {
1530                         $item['gravity'] = GRAVITY_COMMENT;
1531                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1532                 }
1533
1534                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
1535                         logger('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
1536                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
1537                 }
1538
1539                 self::postItem($activity, $item, $body);
1540         }
1541
1542         /**
1543          * @brief
1544          *
1545          * @param array $activity
1546          * @param $body
1547          */
1548         private static function likeItem($activity, $body)
1549         {
1550                 $item = [];
1551                 $item['verb'] = ACTIVITY_LIKE;
1552                 $item['parent-uri'] = $activity['object'];
1553                 $item['gravity'] = GRAVITY_ACTIVITY;
1554                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1555
1556                 self::postItem($activity, $item, $body);
1557         }
1558
1559         /**
1560          * @brief
1561          *
1562          * @param array $activity
1563          * @param $body
1564          */
1565         private static function dislikeItem($activity, $body)
1566         {
1567                 $item = [];
1568                 $item['verb'] = ACTIVITY_DISLIKE;
1569                 $item['parent-uri'] = $activity['object'];
1570                 $item['gravity'] = GRAVITY_ACTIVITY;
1571                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1572
1573                 self::postItem($activity, $item, $body);
1574         }
1575
1576         /**
1577          * @brief
1578          *
1579          * @param array $activity
1580          * @param array $item
1581          * @param $body
1582          */
1583         private static function postItem($activity, $item, $body)
1584         {
1585                 /// @todo What to do with $activity['context']?
1586
1587                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['parent-uri']])) {
1588                         logger('Parent ' . $item['parent-uri'] . ' not found, message will be discarded.', LOGGER_DEBUG);
1589                         return;
1590                 }
1591
1592                 $item['network'] = Protocol::ACTIVITYPUB;
1593                 $item['private'] = !in_array(0, $activity['receiver']);
1594                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1595                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1596                 $item['uri'] = $activity['id'];
1597                 $item['created'] = $activity['published'];
1598                 $item['edited'] = $activity['updated'];
1599                 $item['guid'] = $activity['diaspora:guid'];
1600                 $item['title'] = HTML::toBBCode($activity['name']);
1601                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1602                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1603                 $item['location'] = $activity['location'];
1604                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1605                 $item['app'] = $activity['service'];
1606                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1607
1608                 $item = self::constructAttachList($activity['attachments'], $item);
1609
1610                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1611                 if (!empty($source)) {
1612                         $item['body'] = $source;
1613                 }
1614
1615                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1616                 $item['source'] = $body;
1617                 $item['conversation-href'] = $activity['context'];
1618                 $item['conversation-uri'] = $activity['conversation'];
1619
1620                 foreach ($activity['receiver'] as $receiver) {
1621                         $item['uid'] = $receiver;
1622                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1623
1624                         if (($receiver != 0) && empty($item['contact-id'])) {
1625                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1626                         }
1627
1628                         $item_id = Item::insert($item);
1629                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1630                 }
1631         }
1632
1633         /**
1634          * @brief
1635          *
1636          * @param $url
1637          * @param $child
1638          */
1639         private static function fetchMissingActivity($url, $child)
1640         {
1641                 if (Config::get('system', 'ostatus_full_threads')) {
1642                         return;
1643                 }
1644
1645                 $object = ActivityPub::fetchContent($url);
1646                 if (empty($object)) {
1647                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1648                         return;
1649                 }
1650
1651                 $activity = [];
1652                 $activity['@context'] = $object['@context'];
1653                 unset($object['@context']);
1654                 $activity['id'] = $object['id'];
1655                 $activity['to'] = defaults($object, 'to', []);
1656                 $activity['cc'] = defaults($object, 'cc', []);
1657                 $activity['actor'] = $child['author'];
1658                 $activity['object'] = $object;
1659                 $activity['published'] = $object['published'];
1660                 $activity['type'] = 'Create';
1661
1662                 self::processActivity($activity);
1663                 logger('Activity ' . $url . ' had been fetched and processed.');
1664         }
1665
1666         /**
1667          * @brief Returns the user id of a given profile url
1668          *
1669          * @param string $profile
1670          *
1671          * @return integer user id
1672          */
1673         private static function getUserOfProfile($profile)
1674         {
1675                 $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($profile), 'self' => true]);
1676                 if (!DBA::isResult($self)) {
1677                         return false;
1678                 } else {
1679                         return $self['uid'];
1680                 }
1681         }
1682
1683         /**
1684          * @brief perform a "follow" request
1685          *
1686          * @param array $activity
1687          */
1688         private static function followUser($activity)
1689         {
1690                 $actor = JsonLD::fetchElement($activity, 'object', 'id');
1691                 $uid = self::getUserOfProfile($actor);
1692                 if (empty($uid)) {
1693                         return;
1694                 }
1695
1696                 $owner = User::getOwnerDataById($uid);
1697
1698                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1699                 if (!empty($cid)) {
1700                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1701                 } else {
1702                         $contact = false;
1703                 }
1704
1705                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1706                         'author-link' => $activity['owner']];
1707
1708                 Contact::addRelationship($owner, $contact, $item);
1709                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1710                 if (empty($cid)) {
1711                         return;
1712                 }
1713
1714                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1715                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1716                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1717                 }
1718
1719                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1720                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1721         }
1722
1723         /**
1724          * @brief Update the given profile
1725          *
1726          * @param array $activity
1727          */
1728         private static function updatePerson($activity)
1729         {
1730                 if (empty($activity['object']['id'])) {
1731                         return;
1732                 }
1733
1734                 logger('Updating profile for ' . $activity['object']['id'], LOGGER_DEBUG);
1735                 APContact::getProfileByURL($activity['object']['id'], true);
1736         }
1737
1738         /**
1739          * @brief Accept a follow request
1740          *
1741          * @param array $activity
1742          */
1743         private static function acceptFollowUser($activity)
1744         {
1745                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1746                 $uid = self::getUserOfProfile($actor);
1747                 if (empty($uid)) {
1748                         return;
1749                 }
1750
1751                 $owner = User::getOwnerDataById($uid);
1752
1753                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1754                 if (empty($cid)) {
1755                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1756                         return;
1757                 }
1758
1759                 $fields = ['pending' => false];
1760
1761                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1762                 if ($contact['rel'] == Contact::FOLLOWER) {
1763                         $fields['rel'] = Contact::FRIEND;
1764                 }
1765
1766                 $condition = ['id' => $cid];
1767                 DBA::update('contact', $fields, $condition);
1768                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1769         }
1770
1771         /**
1772          * @brief Undo activity like "like" or "dislike"
1773          *
1774          * @param array $activity
1775          */
1776         private static function undoActivity($activity)
1777         {
1778                 $activity_url = JsonLD::fetchElement($activity, 'object', 'id');
1779                 if (empty($activity_url)) {
1780                         return;
1781                 }
1782
1783                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1784                 if (empty($actor)) {
1785                         return;
1786                 }
1787
1788                 $author_id = Contact::getIdForURL($actor);
1789                 if (empty($author_id)) {
1790                         return;
1791                 }
1792
1793                 Item::delete(['uri' => $activity_url, 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1794         }
1795
1796         /**
1797          * @brief Activity to remove a follower
1798          *
1799          * @param array $activity
1800          */
1801         private static function undoFollowUser($activity)
1802         {
1803                 $object = JsonLD::fetchElement($activity, 'object', 'object');
1804                 $uid = self::getUserOfProfile($object);
1805                 if (empty($uid)) {
1806                         return;
1807                 }
1808
1809                 $owner = User::getOwnerDataById($uid);
1810
1811                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1812                 if (empty($cid)) {
1813                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1814                         return;
1815                 }
1816
1817                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1818                 if (!DBA::isResult($contact)) {
1819                         return;
1820                 }
1821
1822                 Contact::removeFollower($owner, $contact);
1823                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1824         }
1825 }