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_COLLECTION = '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                 $profile = Profile::getByUID($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                 $profile = Profile::getByUID($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                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 327                         if (empty($activity[$element])) {
 328                                 continue;
 329                         }
 330                         if (is_string($activity[$element])) {
 331                                 $activity[$element] = [$activity[$element]];
 332                         }
 333
 334                         foreach ($activity[$element] as $receiver) {
 335                                 if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 336                                         $receiver = $item_profile['followers'];
 337                                 }
 338                                 if (!in_array($receiver, $exclude)) {
 339                                         $permissions[$element][] = $receiver;
 340                                 }
 341                         }
 342                 }
 343                 return $permissions;
 344         }
 345
 346         /**
 347          * @brief Creates an array of permissions from an item thread
 348          *
 349          * @param array $item
 350          *
 351          * @return permission array
 352          */
 353         public static function createPermissionBlockForItem($item)
 354         {
 355                 $data = ['to' => [], 'cc' => []];
 356
 357                 $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 358
 359                 $actor_profile = APContact::getProfileByURL($item['author-link']);
 360
 361                 $terms = Term::tagArrayFromItemId($item['id'], TERM_MENTION);
 362
 363                 $contacts[$item['author-link']] = $item['author-link'];
 364
 365                 if (!$item['private']) {
 366                         $data['to'][] = self::PUBLIC_COLLECTION;
 367                         if (!empty($actor_profile['followers'])) {
 368                                 $data['cc'][] = $actor_profile['followers'];
 369                         }
 370
 371                         foreach ($terms as $term) {
 372                                 if ($term['type'] != TERM_MENTION) {
 373                                         continue;
 374                                 }
 375                                 $profile = APContact::getProfileByURL($term['url'], false);
 376                                 if (!empty($profile) && empty($contacts[$profile['url']])) {
 377                                         $data['cc'][] = $profile['url'];
 378                                         $contacts[$profile['url']] = $profile['url'];
 379                                 }
 380                         }
 381                 } else {
 382                         $receiver_list = Item::enumeratePermissions($item);
 383
 384                         $mentioned = [];
 385
 386                         foreach ($terms as $term) {
 387                                 if ($term['type'] != TERM_MENTION) {
 388                                         continue;
 389                                 }
 390                                 $cid = Contact::getIdForURL($term['url'], $item['uid']);
 391                                 if (!empty($cid) && in_array($cid, $receiver_list)) {
 392                                         $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
 393                                         $data['to'][] = $contact['url'];
 394                                         $contacts[$contact['url']] = $contact['url'];
 395                                 }
 396                         }
 397
 398                         foreach ($receiver_list as $receiver) {
 399                                 $contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
 400                                 if (empty($contacts[$contact['url']])) {
 401                                         $data['cc'][] = $contact['url'];
 402                                         $contacts[$contact['url']] = $contact['url'];
 403                                 }
 404                         }
 405                 }
 406
 407                 $parents = Item::select(['id', 'author-link', 'owner-link', 'gravity'], ['parent' => $item['parent']]);
 408                 while ($parent = Item::fetch($parents)) {
 409                         // Don't include data from future posts
 410                         if ($parent['id'] >= $item['id']) {
 411                                 continue;
 412                         }
 413
 414                         $profile = APContact::getProfileByURL($parent['author-link'], false);
 415                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 416                                 $data['cc'][] = $profile['url'];
 417                                 $contacts[$profile['url']] = $profile['url'];
 418                         }
 419
 420                         if ($item['gravity'] != GRAVITY_PARENT) {
 421                                 continue;
 422                         }
 423
 424                         $profile = APContact::getProfileByURL($parent['owner-link'], false);
 425                         if (!empty($profile) && empty($contacts[$profile['url']])) {
 426                                 $data['cc'][] = $profile['url'];
 427                                 $contacts[$profile['url']] = $profile['url'];
 428                         }
 429                 }
 430                 DBA::close($parents);
 431
 432                 if (empty($data['to'])) {
 433                         $data['to'] = $data['cc'];
 434                         $data['cc'] = [];
 435                 }
 436
 437                 return $data;
 438         }
 439
 440         /**
 441          * @brief Fetches an array of inboxes for the given item and user
 442          *
 443          * @param array $item
 444          * @param integer $uid User ID
 445          *
 446          * @return array with inboxes
 447          */
 448         public static function fetchTargetInboxes($item, $uid)
 449         {
 450                 $permissions = self::createPermissionBlockForItem($item);
 451                 if (empty($permissions)) {
 452                         return [];
 453                 }
 454
 455                 $inboxes = [];
 456
 457                 if ($item['gravity'] == GRAVITY_ACTIVITY) {
 458                         $item_profile = APContact::getProfileByURL($item['author-link']);
 459                 } else {
 460                         $item_profile = APContact::getProfileByURL($item['owner-link']);
 461                 }
 462
 463                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 464                         if (empty($permissions[$element])) {
 465                                 continue;
 466                         }
 467
 468                         foreach ($permissions[$element] as $receiver) {
 469                                 if ($receiver == $item_profile['followers']) {
 470                                         $contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
 471                                                 'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB,
 472                                                 'archive' => false, 'pending' => false]);
 473                                         while ($contact = DBA::fetch($contacts)) {
 474                                                 $contact = defaults($contact, 'batch', $contact['notify']);
 475                                                 $inboxes[$contact] = $contact;
 476                                         }
 477                                         DBA::close($contacts);
 478                                 } else {
 479                                         $profile = APContact::getProfileByURL($receiver);
 480                                         if (!empty($profile)) {
 481                                                 $target = defaults($profile, 'sharedinbox', $profile['inbox']);
 482                                                 $inboxes[$target] = $target;
 483                                         }
 484                                 }
 485                         }
 486                 }
 487
 488                 return $inboxes;
 489         }
 490
 491         /**
 492          * @brief Returns the activity type of a given item
 493          *
 494          * @param array $item
 495          *
 496          * @return activity type
 497          */
 498         public static function getTypeOfItem($item)
 499         {
 500                 if ($item['verb'] == ACTIVITY_POST) {
 501                         if ($item['created'] == $item['edited']) {
 502                                 $type = 'Create';
 503                         } else {
 504                                 $type = 'Update';
 505                         }
 506                 } elseif ($item['verb'] == ACTIVITY_LIKE) {
 507                         $type = 'Like';
 508                 } elseif ($item['verb'] == ACTIVITY_DISLIKE) {
 509                         $type = 'Dislike';
 510                 } elseif ($item['verb'] == ACTIVITY_ATTEND) {
 511                         $type = 'Accept';
 512                 } elseif ($item['verb'] == ACTIVITY_ATTENDNO) {
 513                         $type = 'Reject';
 514                 } elseif ($item['verb'] == ACTIVITY_ATTENDMAYBE) {
 515                         $type = 'TentativeAccept';
 516                 } else {
 517                         $type = '';
 518                 }
 519
 520                 return $type;
 521         }
 522
 523         /**
 524          * @brief Creates an activity array for a given item id
 525          *
 526          * @param integer $item_id
 527          * @param boolean $object_mode Is the activity item is used inside another object?
 528          *
 529          * @return array of activity
 530          */
 531         public static function createActivityFromItem($item_id, $object_mode = false)
 532         {
 533                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 534
 535                 if (!DBA::isResult($item)) {
 536                         return false;
 537                 }
 538
 539                 $condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
 540                 $conversation = DBA::selectFirst('conversation', ['source'], $condition);
 541                 if (DBA::isResult($conversation)) {
 542                         $data = json_decode($conversation['source']);
 543                         if (!empty($data)) {
 544                                 return $data;
 545                         }
 546                 }
 547
 548                 $type = self::getTypeOfItem($item);
 549
 550                 if (!$object_mode) {
 551                         $data = ['@context' => self::CONTEXT];
 552
 553                         if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
 554                                 $type = 'Undo';
 555                         } elseif ($item['deleted']) {
 556                                 $type = 'Delete';
 557                         }
 558                 } else {
 559                         $data = [];
 560                 }
 561
 562                 $data['id'] = $item['uri'] . '#' . $type;
 563                 $data['type'] = $type;
 564                 $data['actor'] = $item['author-link'];
 565
 566                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 567
 568                 if ($item["created"] != $item["edited"]) {
 569                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 570                 }
 571
 572                 $data['context'] = self::fetchContextURLForItem($item);
 573
 574                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 575
 576                 if (in_array($data['type'], ['Create', 'Update', 'Announce', 'Delete'])) {
 577                         $data['object'] = self::createNote($item);
 578                 } elseif ($data['type'] == 'Undo') {
 579                         $data['object'] = self::createActivityFromItem($item_id, true);
 580                 } else {
 581                         $data['object'] = $item['thr-parent'];
 582                 }
 583
 584                 $owner = User::getOwnerDataById($item['uid']);
 585
 586                 if (!$object_mode) {
 587                         return LDSignature::sign($data, $owner);
 588                 } else {
 589                         return $data;
 590                 }
 591         }
 592
 593         /**
 594          * @brief Creates an object array for a given item id
 595          *
 596          * @param integer $item_id
 597          *
 598          * @return object array
 599          */
 600         public static function createObjectFromItemID($item_id)
 601         {
 602                 $item = Item::selectFirst([], ['id' => $item_id, 'parent-network' => Protocol::NATIVE_SUPPORT]);
 603
 604                 if (!DBA::isResult($item)) {
 605                         return false;
 606                 }
 607
 608                 $data = ['@context' => self::CONTEXT];
 609                 $data = array_merge($data, self::createNote($item));
 610
 611                 return $data;
 612         }
 613
 614         /**
 615          * @brief Returns a tag array for a given item array
 616          *
 617          * @param array $item
 618          *
 619          * @return array of tags
 620          */
 621         private static function createTagList($item)
 622         {
 623                 $tags = [];
 624
 625                 $terms = Term::tagArrayFromItemId($item['id'], TERM_MENTION);
 626                 foreach ($terms as $term) {
 627                         if ($term['type'] == TERM_MENTION) {
 628                                 $contact = Contact::getDetailsByURL($term['url']);
 629                                 if (!empty($contact['addr'])) {
 630                                         $mention = '@' . $contact['addr'];
 631                                 } else {
 632                                         $mention = '@' . $term['url'];
 633                                 }
 634
 635                                 $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 636                         }
 637                 }
 638                 return $tags;
 639         }
 640
 641         /**
 642          * @brief Fetches the "context" value for a givem item array from the "conversation" table
 643          *
 644          * @param array $item
 645          *
 646          * @return string with context url
 647          */
 648         private static function fetchContextURLForItem($item)
 649         {
 650                 $conversation = DBA::selectFirst('conversation', ['conversation-href', 'conversation-uri'], ['item-uri' => $item['parent-uri']]);
 651                 if (DBA::isResult($conversation) && !empty($conversation['conversation-href'])) {
 652                         $context_uri = $conversation['conversation-href'];
 653                 } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 654                         $context_uri = $conversation['conversation-uri'];
 655                 } else {
 656                         $context_uri = str_replace('/object/', '/context/', $item['parent-uri']);
 657                 }
 658                 return $context_uri;
 659         }
 660
 661         /**
 662          * @brief Creates a note/article object array
 663          *
 664          * @param array $item
 665          *
 666          * @return object array
 667          */
 668         private static function createNote($item)
 669         {
 670                 if (!empty($item['title'])) {
 671                         $type = 'Article';
 672                 } else {
 673                         $type = 'Note';
 674                 }
 675
 676                 if ($item['deleted']) {
 677                         $type = 'Tombstone';
 678                 }
 679
 680                 $data = [];
 681                 $data['id'] = $item['uri'];
 682                 $data['type'] = $type;
 683
 684                 if ($item['deleted']) {
 685                         return $data;
 686                 }
 687
 688                 $data['summary'] = null; // Ignore by now
 689
 690                 if ($item['uri'] != $item['thr-parent']) {
 691                         $data['inReplyTo'] = $item['thr-parent'];
 692                 } else {
 693                         $data['inReplyTo'] = null;
 694                 }
 695
 696                 $data['diaspora:guid'] = $item['guid'];
 697                 $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 698
 699                 if ($item["created"] != $item["edited"]) {
 700                         $data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 701                 }
 702
 703                 $data['url'] = $item['plink'];
 704                 $data['attributedTo'] = $item['author-link'];
 705                 $data['actor'] = $item['author-link'];
 706                 $data['sensitive'] = false; // - Query NSFW
 707                 $data['context'] = self::fetchContextURLForItem($item);
 708
 709                 if (!empty($item['title'])) {
 710                         $data['name'] = BBCode::convert($item['title'], false, 7);
 711                 }
 712
 713                 $data['content'] = BBCode::convert($item['body'], false, 7);
 714                 $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
 715
 716                 if (!empty($item['signed_text']) && ($item['uri'] != $item['thr-parent'])) {
 717                         $data['diaspora:comment'] = $item['signed_text'];
 718                 }
 719
 720                 $data['attachment'] = []; // @ToDo
 721                 $data['tag'] = self::createTagList($item);
 722                 $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 723
 724                 return $data;
 725         }
 726
 727         /**
 728          * @brief Transmits a given activity to a target
 729          *
 730          * @param array $activity
 731          * @param string $target Target profile
 732          * @param integer $uid User ID
 733          */
 734         public static function transmitActivity($activity, $target, $uid)
 735         {
 736                 $profile = APContact::getProfileByURL($target);
 737
 738                 $owner = User::getOwnerDataById($uid);
 739
 740                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 741                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 742                         'type' => $activity,
 743                         'actor' => $owner['url'],
 744                         'object' => $profile['url'],
 745                         'to' => $profile['url']];
 746
 747                 logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 748
 749                 $signed = LDSignature::sign($data, $owner);
 750                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 751         }
 752
 753         /**
 754          * @brief Transmit a message that the contact request had been accepted
 755          *
 756          * @param string $target Target profile
 757          * @param $id
 758          * @param integer $uid User ID
 759          */
 760         public static function transmitContactAccept($target, $id, $uid)
 761         {
 762                 $profile = APContact::getProfileByURL($target);
 763
 764                 $owner = User::getOwnerDataById($uid);
 765                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 766                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 767                         'type' => 'Accept',
 768                         'actor' => $owner['url'],
 769                         'object' => ['id' => $id, 'type' => 'Follow',
 770                                 'actor' => $profile['url'],
 771                                 'object' => $owner['url']],
 772                         'to' => $profile['url']];
 773
 774                 logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 775
 776                 $signed = LDSignature::sign($data, $owner);
 777                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 778         }
 779
 780         /**
 781          * @brief
 782          *
 783          * @param string $target Target profile
 784          * @param $id
 785          * @param integer $uid User ID
 786          */
 787         public static function transmitContactReject($target, $id, $uid)
 788         {
 789                 $profile = APContact::getProfileByURL($target);
 790
 791                 $owner = User::getOwnerDataById($uid);
 792                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 793                         'id' => System::baseUrl() . '/activity/' . System::createGUID(),
 794                         'type' => 'Reject',
 795                         'actor' => $owner['url'],
 796                         'object' => ['id' => $id, 'type' => 'Follow',
 797                                 'actor' => $profile['url'],
 798                                 'object' => $owner['url']],
 799                         'to' => $profile['url']];
 800
 801                 logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 802
 803                 $signed = LDSignature::sign($data, $owner);
 804                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 805         }
 806
 807         /**
 808          * @brief
 809          *
 810          * @param string $target Target profile
 811          * @param integer $uid User ID
 812          */
 813         public static function transmitContactUndo($target, $uid)
 814         {
 815                 $profile = APContact::getProfileByURL($target);
 816
 817                 $id = System::baseUrl() . '/activity/' . System::createGUID();
 818
 819                 $owner = User::getOwnerDataById($uid);
 820                 $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
 821                         'id' => $id,
 822                         'type' => 'Undo',
 823                         'actor' => $owner['url'],
 824                         'object' => ['id' => $id, 'type' => 'Follow',
 825                                 'actor' => $owner['url'],
 826                                 'object' => $profile['url']],
 827                         'to' => $profile['url']];
 828
 829                 logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 830
 831                 $signed = LDSignature::sign($data, $owner);
 832                 HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 833         }
 834
 835         /**
 836          * Fetches ActivityPub content from the given url
 837          *
 838          * @param string $url content url
 839          * @return array
 840          */
 841         public static function fetchContent($url)
 842         {
 843                 $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
 844                 if (!$ret['success'] || empty($ret['body'])) {
 845                         return;
 846                 }
 847                 return json_decode($ret['body'], true);
 848         }
 849
 850         /**
 851          * Fetches a profile from the given url into an array that is compatible to Probe::uri
 852          *
 853          * @param string $url profile url
 854          * @return array
 855          */
 856         public static function probeProfile($url)
 857         {
 858                 $apcontact = APContact::getProfileByURL($url, true);
 859                 if (empty($apcontact)) {
 860                         return false;
 861                 }
 862
 863                 $profile = ['network' => Protocol::ACTIVITYPUB];
 864                 $profile['nick'] = $apcontact['nick'];
 865                 $profile['name'] = $apcontact['name'];
 866                 $profile['guid'] = $apcontact['uuid'];
 867                 $profile['url'] = $apcontact['url'];
 868                 $profile['addr'] = $apcontact['addr'];
 869                 $profile['alias'] = $apcontact['alias'];
 870                 $profile['photo'] = $apcontact['photo'];
 871                 // $profile['community']
 872                 // $profile['keywords']
 873                 // $profile['location']
 874                 $profile['about'] = $apcontact['about'];
 875                 $profile['batch'] = $apcontact['sharedinbox'];
 876                 $profile['notify'] = $apcontact['inbox'];
 877                 $profile['poll'] = $apcontact['outbox'];
 878                 $profile['pubkey'] = $apcontact['pubkey'];
 879                 $profile['baseurl'] = $apcontact['baseurl'];
 880
 881                 // Remove all "null" fields
 882                 foreach ($profile as $field => $content) {
 883                         if (is_null($content)) {
 884                                 unset($profile[$field]);
 885                         }
 886                 }
 887
 888                 return $profile;
 889         }
 890
 891         /**
 892          * @brief
 893          *
 894          * @param $body
 895          * @param $header
 896          * @param integer $uid User ID
 897          */
 898         public static function processInbox($body, $header, $uid)
 899         {
 900                 $http_signer = HTTPSignature::getSigner($body, $header);
 901                 if (empty($http_signer)) {
 902                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 903                         return;
 904                 } else {
 905                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 906                 }
 907
 908                 $activity = json_decode($body, true);
 909
 910                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 911                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
 912
 913                 if (empty($activity)) {
 914                         logger('Invalid body.', LOGGER_DEBUG);
 915                         return;
 916                 }
 917
 918                 if (LDSignature::isSigned($activity)) {
 919                         $ld_signer = LDSignature::getSigner($activity);
 920                         if (empty($ld_signer)) {
 921                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
 922                         }
 923                         if (!empty($ld_signer && ($actor == $http_signer))) {
 924                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
 925                                 $trust_source = true;
 926                         } elseif (!empty($ld_signer)) {
 927                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
 928                                 $trust_source = true;
 929                         } elseif ($actor == $http_signer) {
 930                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
 931                                 $trust_source = true;
 932                         } else {
 933                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
 934                                 $trust_source = false;
 935                         }
 936                 } elseif ($actor == $http_signer) {
 937                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 938                         $trust_source = true;
 939                 } else {
 940                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 941                         $trust_source = false;
 942                 }
 943
 944                 self::processActivity($activity, $body, $uid, $trust_source);
 945         }
 946
 947         /**
 948          * @brief
 949          *
 950          * @param $url
 951          * @param integer $uid User ID
 952          */
 953         public static function fetchOutbox($url, $uid)
 954         {
 955                 $data = self::fetchContent($url);
 956                 if (empty($data)) {
 957                         return;
 958                 }
 959
 960                 if (!empty($data['orderedItems'])) {
 961                         $items = $data['orderedItems'];
 962                 } elseif (!empty($data['first']['orderedItems'])) {
 963                         $items = $data['first']['orderedItems'];
 964                 } elseif (!empty($data['first'])) {
 965                         self::fetchOutbox($data['first'], $uid);
 966                         return;
 967                 } else {
 968                         $items = [];
 969                 }
 970
 971                 foreach ($items as $activity) {
 972                         self::processActivity($activity, '', $uid, true);
 973                 }
 974         }
 975
 976         /**
 977          * @brief
 978          *
 979          * @param array $activity
 980          * @param integer $uid User ID
 981          * @param $trust_source
 982          *
 983          * @return
 984          */
 985         private static function prepareObjectData($activity, $uid, &$trust_source)
 986         {
 987                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 988                 if (empty($actor)) {
 989                         logger('Empty actor', LOGGER_DEBUG);
 990                         return [];
 991                 }
 992
 993                 // Fetch all receivers from to, cc, bto and bcc
 994                 $receivers = self::getReceivers($activity, $actor);
 995
 996                 // When it is a delivery to a personal inbox we add that user to the receivers
 997                 if (!empty($uid)) {
 998                         $owner = User::getOwnerDataById($uid);
 999                         $additional = ['uid:' . $uid => $uid];
1000                         $receivers = array_merge($receivers, $additional);
1001                 }
1002
1003                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
1004
1005                 $object_id = JsonLD::fetchElement($activity, 'object', 'id');
1006                 if (empty($object_id)) {
1007                         logger('No object found', LOGGER_DEBUG);
1008                         return [];
1009                 }
1010
1011                 // Fetch the content only on activities where this matters
1012                 if (in_array($activity['type'], ['Create', 'Announce'])) {
1013                         $object_data = self::fetchObject($object_id, $activity['object'], $trust_source);
1014                         if (empty($object_data)) {
1015                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
1016                                 return [];
1017                         }
1018                         // We had been able to retrieve the object data - so we can trust the source
1019                         $trust_source = true;
1020                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
1021                         // Create a mostly empty array out of the activity data (instead of the object).
1022                         // This way we later don't have to check for the existence of ech individual array element.
1023                         $object_data = self::processObject($activity);
1024                         $object_data['name'] = $activity['type'];
1025                         $object_data['author'] = $activity['actor'];
1026                         $object_data['object'] = $object_id;
1027                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
1028                 } else {
1029                         $object_data = [];
1030                         $object_data['id'] = $activity['id'];
1031                         $object_data['object'] = $activity['object'];
1032                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
1033                 }
1034
1035                 $object_data = self::addActivityFields($object_data, $activity);
1036
1037                 $object_data['type'] = $activity['type'];
1038                 $object_data['owner'] = $actor;
1039                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
1040
1041                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
1042
1043                 return $object_data;
1044         }
1045
1046         /**
1047          * @brief
1048          *
1049          * @param array $activity
1050          * @param $body
1051          * @param integer $uid User ID
1052          * @param $trust_source
1053          */
1054         private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
1055         {
1056                 if (empty($activity['type'])) {
1057                         logger('Empty type', LOGGER_DEBUG);
1058                         return;
1059                 }
1060
1061                 if (empty($activity['object'])) {
1062                         logger('Empty object', LOGGER_DEBUG);
1063                         return;
1064                 }
1065
1066                 if (empty($activity['actor'])) {
1067                         logger('Empty actor', LOGGER_DEBUG);
1068                         return;
1069
1070                 }
1071
1072                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
1073                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
1074                 if (empty($object_data)) {
1075                         logger('No object data found', LOGGER_DEBUG);
1076                         return;
1077                 }
1078
1079                 if (!$trust_source) {
1080                         logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
1081                 }
1082
1083                 switch ($activity['type']) {
1084                         case 'Create':
1085                         case 'Announce':
1086                                 self::createItem($object_data, $body);
1087                                 break;
1088
1089                         case 'Like':
1090                                 self::likeItem($object_data, $body);
1091                                 break;
1092
1093                         case 'Dislike':
1094                                 self::dislikeItem($object_data, $body);
1095                                 break;
1096
1097                         case 'Update':
1098                                 if (in_array($object_data['object_type'], ['Person', 'Organization', 'Service', 'Group', 'Application'])) {
1099                                         self::updatePerson($object_data, $body);
1100                                 }
1101                                 break;
1102
1103                         case 'Delete':
1104                                 break;
1105
1106                         case 'Follow':
1107                                 self::followUser($object_data);
1108                                 break;
1109
1110                         case 'Accept':
1111                                 if ($object_data['object_type'] == 'Follow') {
1112                                         self::acceptFollowUser($object_data);
1113                                 }
1114                                 break;
1115
1116                         case 'Undo':
1117                                 if ($object_data['object_type'] == 'Follow') {
1118                                         self::undoFollowUser($object_data);
1119                                 } elseif (in_array($object_data['object_type'], ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'])) {
1120                                         self::undoActivity($object_data);
1121                                 }
1122                                 break;
1123
1124                         default:
1125                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
1126                                 break;
1127                 }
1128         }
1129
1130         /**
1131          * @brief
1132          *
1133          * @param array $activity
1134          * @param $actor
1135          *
1136          * @return
1137          */
1138         private static function getReceivers($activity, $actor)
1139         {
1140                 $receivers = [];
1141
1142                 // When it is an answer, we inherite the receivers from the parent
1143                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1144                 if (!empty($replyto)) {
1145                         $parents = Item::select(['uid'], ['uri' => $replyto]);
1146                         while ($parent = Item::fetch($parents)) {
1147                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
1148                         }
1149                 }
1150
1151                 if (!empty($actor)) {
1152                         $profile = APContact::getProfileByURL($actor);
1153                         $followers = defaults($profile, 'followers', '');
1154
1155                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
1156                 } else {
1157                         logger('Empty actor', LOGGER_DEBUG);
1158                         $followers = '';
1159                 }
1160
1161                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
1162                         if (empty($activity[$element])) {
1163                                 continue;
1164                         }
1165
1166                         // The receiver can be an array or a string
1167                         if (is_string($activity[$element])) {
1168                                 $activity[$element] = [$activity[$element]];
1169                         }
1170
1171                         foreach ($activity[$element] as $receiver) {
1172                                 if ($receiver == self::PUBLIC_COLLECTION) {
1173                                         $receivers['uid:0'] = 0;
1174                                 }
1175
1176                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
1177                                         // This will most likely catch all OStatus connections to Mastodon
1178                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
1179                                                 , 'archive' => false, 'pending' => false];
1180                                         $contacts = DBA::select('contact', ['uid'], $condition);
1181                                         while ($contact = DBA::fetch($contacts)) {
1182                                                 if ($contact['uid'] != 0) {
1183                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1184                                                 }
1185                                         }
1186                                         DBA::close($contacts);
1187                                 }
1188
1189                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
1190                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1191                                                 'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
1192                                         $contacts = DBA::select('contact', ['uid'], $condition);
1193                                         while ($contact = DBA::fetch($contacts)) {
1194                                                 if ($contact['uid'] != 0) {
1195                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
1196                                                 }
1197                                         }
1198                                         DBA::close($contacts);
1199                                         continue;
1200                                 }
1201
1202                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
1203                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
1204                                 if (!DBA::isResult($contact)) {
1205                                         continue;
1206                                 }
1207                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
1208                         }
1209                 }
1210
1211                 self::switchContacts($receivers, $actor);
1212
1213                 return $receivers;
1214         }
1215
1216         /**
1217          * @brief
1218          *
1219          * @param $cid
1220          * @param integer $uid User ID
1221          * @param $url
1222          */
1223         private static function switchContact($cid, $uid, $url)
1224         {
1225                 $profile = ActivityPub::probeProfile($url);
1226                 if (empty($profile)) {
1227                         return;
1228                 }
1229
1230                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' from OStatus to ActivityPub');
1231
1232                 $photo = $profile['photo'];
1233                 unset($profile['photo']);
1234                 unset($profile['baseurl']);
1235
1236                 $profile['nurl'] = normalise_link($profile['url']);
1237                 DBA::update('contact', $profile, ['id' => $cid]);
1238
1239                 Contact::updateAvatar($photo, $uid, $cid);
1240         }
1241
1242         /**
1243          * @brief
1244          *
1245          * @param $receivers
1246          * @param $actor
1247          */
1248         private static function switchContacts($receivers, $actor)
1249         {
1250                 if (empty($actor)) {
1251                         return;
1252                 }
1253
1254                 foreach ($receivers as $receiver) {
1255                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
1256                         if (DBA::isResult($contact)) {
1257                                 self::switchContact($contact['id'], $receiver, $actor);
1258                         }
1259
1260                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
1261                         if (DBA::isResult($contact)) {
1262                                 self::switchContact($contact['id'], $receiver, $actor);
1263                         }
1264                 }
1265         }
1266
1267         /**
1268          * @brief
1269          *
1270          * @param $object_data
1271          * @param array $activity
1272          *
1273          * @return
1274          */
1275         private static function addActivityFields($object_data, $activity)
1276         {
1277                 if (!empty($activity['published']) && empty($object_data['published'])) {
1278                         $object_data['published'] = $activity['published'];
1279                 }
1280
1281                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
1282                         $object_data['updated'] = $activity['updated'];
1283                 }
1284
1285                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
1286                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
1287                 }
1288
1289                 if (!empty($activity['instrument'])) {
1290                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
1291                 }
1292                 return $object_data;
1293         }
1294
1295         /**
1296          * @brief
1297          *
1298          * @param $object_id
1299          * @param $object
1300          * @param $trust_source
1301          *
1302          * @return
1303          */
1304         private static function fetchObject($object_id, $object = [], $trust_source = false)
1305         {
1306                 if (!$trust_source || is_string($object)) {
1307                         $data = self::fetchContent($object_id);
1308                         if (empty($data)) {
1309                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
1310                                 $data = $object_id;
1311                         } else {
1312                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
1313                         }
1314                 } else {
1315                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
1316                         $data = $object;
1317                 }
1318
1319                 if (is_string($data)) {
1320                         $item = Item::selectFirst([], ['uri' => $data]);
1321                         if (!DBA::isResult($item)) {
1322                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
1323                                 return false;
1324                         }
1325                         logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
1326                         $data = self::createNote($item);
1327                 }
1328
1329                 if (empty($data['type'])) {
1330                         logger('Empty type', LOGGER_DEBUG);
1331                         return false;
1332                 }
1333
1334                 switch ($data['type']) {
1335                         case 'Note':
1336                         case 'Article':
1337                         case 'Video':
1338                                 return self::processObject($data);
1339
1340                         case 'Announce':
1341                                 if (empty($data['object'])) {
1342                                         return false;
1343                                 }
1344                                 return self::fetchObject($data['object']);
1345
1346                         case 'Person':
1347                         case 'Tombstone':
1348                                 break;
1349
1350                         default:
1351                                 logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
1352                                 break;
1353                 }
1354         }
1355
1356         /**
1357          * @brief
1358          *
1359          * @param $object
1360          *
1361          * @return
1362          */
1363         private static function processObject(&$object)
1364         {
1365                 if (empty($object['id'])) {
1366                         return false;
1367                 }
1368
1369                 $object_data = [];
1370                 $object_data['object_type'] = $object['type'];
1371                 $object_data['id'] = $object['id'];
1372
1373                 if (!empty($object['inReplyTo'])) {
1374                         $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
1375                 } else {
1376                         $object_data['reply-to-id'] = $object_data['id'];
1377                 }
1378
1379                 $object_data['published'] = defaults($object, 'published', null);
1380                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
1381
1382                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1383                         $object_data['published'] = $object_data['updated'];
1384                 }
1385
1386                 $actor = JsonLD::fetchElement($object, 'attributedTo', 'id');
1387                 if (empty($actor)) {
1388                         $actor = defaults($object, 'actor', null);
1389                 }
1390
1391                 $object_data['diaspora:guid'] = defaults($object, 'diaspora:guid', null);
1392                 $object_data['owner'] = $object_data['author'] = $actor;
1393                 $object_data['context'] = defaults($object, 'context', null);
1394                 $object_data['conversation'] = defaults($object, 'conversation', null);
1395                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
1396                 $object_data['name'] = defaults($object, 'title', null);
1397                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
1398                 $object_data['summary'] = defaults($object, 'summary', null);
1399                 $object_data['content'] = defaults($object, 'content', null);
1400                 $object_data['source'] = defaults($object, 'source', null);
1401                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
1402                 $object_data['attachments'] = defaults($object, 'attachment', null);
1403                 $object_data['tags'] = defaults($object, 'tag', null);
1404                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
1405                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
1406                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
1407
1408                 // Common object data:
1409
1410                 // Unhandled
1411                 // @context, type, actor, signature, mediaType, duration, replies, icon
1412
1413                 // Also missing: (Defined in the standard, but currently unused)
1414                 // audience, preview, endTime, startTime, generator, image
1415
1416                 // Data in Notes:
1417
1418                 // Unhandled
1419                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1420                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1421
1422                 // Data in video:
1423
1424                 // To-Do?
1425                 // category, licence, language, commentsEnabled
1426
1427                 // Unhandled
1428                 // views, waitTranscoding, state, support, subtitleLanguage
1429                 // likes, dislikes, shares, comments
1430
1431                 return $object_data;
1432         }
1433
1434         /**
1435          * @brief Converts mentions from Pleroma into the Friendica format
1436          *
1437          * @param string $body
1438          *
1439          * @return converted body
1440          */
1441         private static function convertMentions($body)
1442         {
1443                 $URLSearchString = "^\[\]";
1444                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
1445
1446                 return $body;
1447         }
1448
1449         /**
1450          * @brief Constructs a string with tags for a given tag array
1451          *
1452          * @param array $tags
1453          * @param boolean $sensitive
1454          *
1455          * @return string with tags
1456          */
1457         private static function constructTagList($tags, $sensitive)
1458         {
1459                 if (empty($tags)) {
1460                         return '';
1461                 }
1462
1463                 $tag_text = '';
1464                 foreach ($tags as $tag) {
1465                         if (in_array($tag['type'], ['Mention', 'Hashtag'])) {
1466                                 if (!empty($tag_text)) {
1467                                         $tag_text .= ',';
1468                                 }
1469
1470                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
1471                         }
1472                 }
1473
1474                 /// @todo add nsfw for $sensitive
1475
1476                 return $tag_text;
1477         }
1478
1479         /**
1480          * @brief
1481          *
1482          * @param $attachments
1483          * @param array $item
1484          *
1485          * @return item array
1486          */
1487         private static function constructAttachList($attachments, $item)
1488         {
1489                 if (empty($attachments)) {
1490                         return $item;
1491                 }
1492
1493                 foreach ($attachments as $attach) {
1494                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
1495                         if ($filetype == 'image') {
1496                                 $item['body'] .= "\n[img]".$attach['url'].'[/img]';
1497                         } else {
1498                                 if (!empty($item["attach"])) {
1499                                         $item["attach"] .= ',';
1500                                 } else {
1501                                         $item["attach"] = '';
1502                                 }
1503                                 if (!isset($attach['length'])) {
1504                                         $attach['length'] = "0";
1505                                 }
1506                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
1507                         }
1508                 }
1509
1510                 return $item;
1511         }
1512
1513         /**
1514          * @brief
1515          *
1516          * @param array $activity
1517          * @param $body
1518          */
1519         private static function createItem($activity, $body)
1520         {
1521                 $item = [];
1522                 $item['verb'] = ACTIVITY_POST;
1523                 $item['parent-uri'] = $activity['reply-to-id'];
1524
1525                 if ($activity['reply-to-id'] == $activity['id']) {
1526                         $item['gravity'] = GRAVITY_PARENT;
1527                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
1528                 } else {
1529                         $item['gravity'] = GRAVITY_COMMENT;
1530                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
1531                 }
1532
1533                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
1534                         logger('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
1535                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
1536                 }
1537
1538                 self::postItem($activity, $item, $body);
1539         }
1540
1541         /**
1542          * @brief
1543          *
1544          * @param array $activity
1545          * @param $body
1546          */
1547         private static function likeItem($activity, $body)
1548         {
1549                 $item = [];
1550                 $item['verb'] = ACTIVITY_LIKE;
1551                 $item['parent-uri'] = $activity['object'];
1552                 $item['gravity'] = GRAVITY_ACTIVITY;
1553                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1554
1555                 self::postItem($activity, $item, $body);
1556         }
1557
1558         /**
1559          * @brief
1560          *
1561          * @param array $activity
1562          * @param $body
1563          */
1564         private static function dislikeItem($activity, $body)
1565         {
1566                 $item = [];
1567                 $item['verb'] = ACTIVITY_DISLIKE;
1568                 $item['parent-uri'] = $activity['object'];
1569                 $item['gravity'] = GRAVITY_ACTIVITY;
1570                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
1571
1572                 self::postItem($activity, $item, $body);
1573         }
1574
1575         /**
1576          * @brief
1577          *
1578          * @param array $activity
1579          * @param array $item
1580          * @param $body
1581          */
1582         private static function postItem($activity, $item, $body)
1583         {
1584                 /// @todo What to do with $activity['context']?
1585
1586                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['parent-uri']])) {
1587                         logger('Parent ' . $item['parent-uri'] . ' not found, message will be discarded.', LOGGER_DEBUG);
1588                         return;
1589                 }
1590
1591                 $item['network'] = Protocol::ACTIVITYPUB;
1592                 $item['private'] = !in_array(0, $activity['receiver']);
1593                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
1594                 $item['owner-id'] = Contact::getIdForURL($activity['owner'], 0, true);
1595                 $item['uri'] = $activity['id'];
1596                 $item['created'] = $activity['published'];
1597                 $item['edited'] = $activity['updated'];
1598                 $item['guid'] = $activity['diaspora:guid'];
1599                 $item['title'] = HTML::toBBCode($activity['name']);
1600                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
1601                 $item['body'] = self::convertMentions(HTML::toBBCode($activity['content']));
1602                 $item['location'] = $activity['location'];
1603                 $item['tag'] = self::constructTagList($activity['tags'], $activity['sensitive']);
1604                 $item['app'] = $activity['service'];
1605                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
1606
1607                 $item = self::constructAttachList($activity['attachments'], $item);
1608
1609                 $source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
1610                 if (!empty($source)) {
1611                         $item['body'] = $source;
1612                 }
1613
1614                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
1615                 $item['source'] = $body;
1616                 $item['conversation-href'] = $activity['context'];
1617                 $item['conversation-uri'] = $activity['conversation'];
1618
1619                 foreach ($activity['receiver'] as $receiver) {
1620                         $item['uid'] = $receiver;
1621                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
1622
1623                         if (($receiver != 0) && empty($item['contact-id'])) {
1624                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
1625                         }
1626
1627                         $item_id = Item::insert($item);
1628                         logger('Storing for user ' . $item['uid'] . ': ' . $item_id);
1629                 }
1630         }
1631
1632         /**
1633          * @brief
1634          *
1635          * @param $url
1636          * @param $child
1637          */
1638         private static function fetchMissingActivity($url, $child)
1639         {
1640                 if (Config::get('system', 'ostatus_full_threads')) {
1641                         return;
1642                 }
1643
1644                 $object = ActivityPub::fetchContent($url);
1645                 if (empty($object)) {
1646                         logger('Activity ' . $url . ' was not fetchable, aborting.');
1647                         return;
1648                 }
1649
1650                 $activity = [];
1651                 $activity['@context'] = $object['@context'];
1652                 unset($object['@context']);
1653                 $activity['id'] = $object['id'];
1654                 $activity['to'] = defaults($object, 'to', []);
1655                 $activity['cc'] = defaults($object, 'cc', []);
1656                 $activity['actor'] = $child['author'];
1657                 $activity['object'] = $object;
1658                 $activity['published'] = $object['published'];
1659                 $activity['type'] = 'Create';
1660
1661                 self::processActivity($activity);
1662                 logger('Activity ' . $url . ' had been fetched and processed.');
1663         }
1664
1665         /**
1666          * @brief perform a "follow" request
1667          *
1668          * @param array $activity
1669          */
1670         private static function followUser($activity)
1671         {
1672                 $actor = JsonLD::fetchElement($activity, 'object', 'id');
1673                 $uid = User::getIdForURL($actor);
1674                 if (empty($uid)) {
1675                         return;
1676                 }
1677
1678                 $owner = User::getOwnerDataById($uid);
1679
1680                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1681                 if (!empty($cid)) {
1682                         $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1683                 } else {
1684                         $contact = false;
1685                 }
1686
1687                 $item = ['author-id' => Contact::getIdForURL($activity['owner']),
1688                         'author-link' => $activity['owner']];
1689
1690                 Contact::addRelationship($owner, $contact, $item);
1691                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1692                 if (empty($cid)) {
1693                         return;
1694                 }
1695
1696                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid]);
1697                 if ($contact['network'] != Protocol::ACTIVITYPUB) {
1698                         Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
1699                 }
1700
1701                 DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
1702                 logger('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1703         }
1704
1705         /**
1706          * @brief Update the given profile
1707          *
1708          * @param array $activity
1709          */
1710         private static function updatePerson($activity)
1711         {
1712                 if (empty($activity['object']['id'])) {
1713                         return;
1714                 }
1715
1716                 logger('Updating profile for ' . $activity['object']['id'], LOGGER_DEBUG);
1717                 APContact::getProfileByURL($activity['object']['id'], true);
1718         }
1719
1720         /**
1721          * @brief Accept a follow request
1722          *
1723          * @param array $activity
1724          */
1725         private static function acceptFollowUser($activity)
1726         {
1727                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1728                 $uid = User::getIdForURL($actor);
1729                 if (empty($uid)) {
1730                         return;
1731                 }
1732
1733                 $owner = User::getOwnerDataById($uid);
1734
1735                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1736                 if (empty($cid)) {
1737                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1738                         return;
1739                 }
1740
1741                 $fields = ['pending' => false];
1742
1743                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1744                 if ($contact['rel'] == Contact::FOLLOWER) {
1745                         $fields['rel'] = Contact::FRIEND;
1746                 }
1747
1748                 $condition = ['id' => $cid];
1749                 DBA::update('contact', $fields, $condition);
1750                 logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1751         }
1752
1753         /**
1754          * @brief Undo activity like "like" or "dislike"
1755          *
1756          * @param array $activity
1757          */
1758         private static function undoActivity($activity)
1759         {
1760                 $activity_url = JsonLD::fetchElement($activity, 'object', 'id');
1761                 if (empty($activity_url)) {
1762                         return;
1763                 }
1764
1765                 $actor = JsonLD::fetchElement($activity, 'object', 'actor');
1766                 if (empty($actor)) {
1767                         return;
1768                 }
1769
1770                 $author_id = Contact::getIdForURL($actor);
1771                 if (empty($author_id)) {
1772                         return;
1773                 }
1774
1775                 Item::delete(['uri' => $activity_url, 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1776         }
1777
1778         /**
1779          * @brief Activity to remove a follower
1780          *
1781          * @param array $activity
1782          */
1783         private static function undoFollowUser($activity)
1784         {
1785                 $object = JsonLD::fetchElement($activity, 'object', 'object');
1786                 $uid = User::getIdForURL($object);
1787                 if (empty($uid)) {
1788                         return;
1789                 }
1790
1791                 $owner = User::getOwnerDataById($uid);
1792
1793                 $cid = Contact::getIdForURL($activity['owner'], $uid);
1794                 if (empty($cid)) {
1795                         logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
1796                         return;
1797                 }
1798
1799                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1800                 if (!DBA::isResult($contact)) {
1801                         return;
1802                 }
1803
1804                 Contact::removeFollower($owner, $contact);
1805                 logger('Undo following request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
1806         }
1807 }