src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Database\DBA;
  25 use Friendica\Content\Text\HTML;
  26 use Friendica\Content\Text\Markdown;
  27 use Friendica\Core\Logger;
  28 use Friendica\Core\Protocol;
  29 use Friendica\Model\Contact;
  30 use Friendica\Model\APContact;
  31 use Friendica\Model\Conversation;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\DateTimeFormat;
  37 use Friendica\Util\HTTPSignature;
  38 use Friendica\Util\JsonLD;
  39 use Friendica\Util\LDSignature;
  40 use Friendica\Util\Strings;
  41
  42 /**
  43  * ActivityPub Receiver Protocol class
  44  *
  45  * To-Do:
  46  * @todo Undo Announce
  47  *
  48  * Check what this is meant to do:
  49  * - Add
  50  * - Block
  51  * - Flag
  52  * - Remove
  53  * - Undo Block
  54  */
  55 class Receiver
  56 {
  57         const PUBLIC_COLLECTION = 'as:Public';
  58         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  59         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event'];
  60         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  61
  62         /**
  63          * Checks if the web request is done for the AP protocol
  64          *
  65          * @return bool is it AP?
  66          */
  67         public static function isRequest()
  68         {
  69                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  70                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  71         }
  72
  73         /**
  74          * Checks incoming message from the inbox
  75          *
  76          * @param         $body
  77          * @param         $header
  78          * @param integer $uid User ID
  79          * @throws \Exception
  80          */
  81         public static function processInbox($body, $header, $uid)
  82         {
  83                 $http_signer = HTTPSignature::getSigner($body, $header);
  84                 if (empty($http_signer)) {
  85                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  86                         return;
  87                 } else {
  88                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  89                 }
  90
  91                 $activity = json_decode($body, true);
  92
  93                 if (empty($activity)) {
  94                         Logger::warning('Invalid body.');
  95                         return;
  96                 }
  97
  98                 $ldactivity = JsonLD::compact($activity);
  99
 100                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 101
 102                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 103
 104                 if (LDSignature::isSigned($activity)) {
 105                         $ld_signer = LDSignature::getSigner($activity);
 106                         if (empty($ld_signer)) {
 107                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 108                         }
 109                         if (!empty($ld_signer && ($actor == $http_signer))) {
 110                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 111                                 $trust_source = true;
 112                         } elseif (!empty($ld_signer)) {
 113                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 114                                 $trust_source = true;
 115                         } elseif ($actor == $http_signer) {
 116                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 117                                 $trust_source = true;
 118                         } else {
 119                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 120                                 $trust_source = false;
 121                         }
 122                 } elseif ($actor == $http_signer) {
 123                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 124                         $trust_source = true;
 125                 } else {
 126                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 127                         $trust_source = false;
 128                 }
 129
 130                 self::processActivity($ldactivity, $body, $uid, $trust_source, true);
 131         }
 132
 133         /**
 134          * Fetches the object type for a given object id
 135          *
 136          * @param array   $activity
 137          * @param string  $object_id Object ID of the the provided object
 138          * @param integer $uid       User ID
 139          *
 140          * @return string with object type
 141          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 142          * @throws \ImagickException
 143          */
 144         private static function fetchObjectType($activity, $object_id, $uid = 0)
 145         {
 146                 if (!empty($activity['as:object'])) {
 147                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 148                         if (!empty($object_type)) {
 149                                 return $object_type;
 150                         }
 151                 }
 152
 153                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 154                         // We just assume "note" since it doesn't make a difference for the further processing
 155                         return 'as:Note';
 156                 }
 157
 158                 $profile = APContact::getByURL($object_id);
 159                 if (!empty($profile['type'])) {
 160                         return 'as:' . $profile['type'];
 161                 }
 162
 163                 $data = ActivityPub::fetchContent($object_id, $uid);
 164                 if (!empty($data)) {
 165                         $object = JsonLD::compact($data);
 166                         $type = JsonLD::fetchElement($object, '@type');
 167                         if (!empty($type)) {
 168                                 return $type;
 169                         }
 170                 }
 171
 172                 return null;
 173         }
 174
 175         /**
 176          * Prepare the object array
 177          *
 178          * @param array   $activity
 179          * @param integer $uid User ID
 180          * @param         $trust_source
 181          *
 182          * @return array with object data
 183          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 184          * @throws \ImagickException
 185          */
 186         private static function prepareObjectData($activity, $uid, $push, &$trust_source)
 187         {
 188                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 189                 if (empty($actor)) {
 190                         Logger::log('Empty actor', Logger::DEBUG);
 191                         return [];
 192                 }
 193
 194                 $type = JsonLD::fetchElement($activity, '@type');
 195
 196                 // Fetch all receivers from to, cc, bto and bcc
 197                 $receivers = self::getReceivers($activity, $actor);
 198
 199                 // When it is a delivery to a personal inbox we add that user to the receivers
 200                 if (!empty($uid)) {
 201                         $additional = ['uid:' . $uid => $uid];
 202                         $receivers = array_merge($receivers, $additional);
 203                 } else {
 204                         // We possibly need some user to fetch private content,
 205                         // so we fetch the first out ot the list.
 206                         $uid = self::getFirstUserFromReceivers($receivers);
 207                 }
 208
 209                 Logger::log('Receivers: ' . $uid . ' - ' . json_encode($receivers), Logger::DEBUG);
 210
 211                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 212                 if (empty($object_id)) {
 213                         Logger::log('No object found', Logger::DEBUG);
 214                         return [];
 215                 }
 216
 217                 if (!is_string($object_id)) {
 218                         Logger::info('Invalid object id', ['object' => $object_id]);
 219                         return [];
 220                 }
 221
 222                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 223
 224                 // Fetch the content only on activities where this matters
 225                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 226                         if ($type == 'as:Announce') {
 227                                 $trust_source = false;
 228                                 $push = false;
 229                         }
 230                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $uid);
 231                         if (empty($object_data)) {
 232                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 233                                 return [];
 234                         }
 235
 236                         $object_data['object_id'] = $object_id;
 237                         $object_data['push'] = $push;
 238
 239                         // Test if it is an answer to a mail
 240                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 241                                 $object_data['directmessage'] = true;
 242                         } else {
 243                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 244                         }
 245
 246                         // We had been able to retrieve the object data - so we can trust the source
 247                         $trust_source = true;
 248                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 249                         // Create a mostly empty array out of the activity data (instead of the object).
 250                         // This way we later don't have to check for the existence of ech individual array element.
 251                         $object_data = self::processObject($activity);
 252                         $object_data['name'] = $type;
 253                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 254                         $object_data['object_id'] = $object_id;
 255                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 256                 } elseif (in_array($type, ['as:Add'])) {
 257                         $object_data = [];
 258                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 259                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 260                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 261                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 262                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 263                 } else {
 264                         $object_data = [];
 265                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 266                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 267                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 268                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 269                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 270
 271                         // An Undo is done on the object of an object, so we need that type as well
 272                         if ($type == 'as:Undo') {
 273                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 274                         }
 275                 }
 276
 277                 $object_data = self::addActivityFields($object_data, $activity);
 278
 279                 if (empty($object_data['object_type'])) {
 280                         $object_data['object_type'] = $object_type;
 281                 }
 282
 283                 $object_data['type'] = $type;
 284                 $object_data['actor'] = $actor;
 285                 $object_data['item_receiver'] = $receivers;
 286                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 287
 288                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 289
 290                 return $object_data;
 291         }
 292
 293         /**
 294          * Fetches the first user id from the receiver array
 295          *
 296          * @param array $receivers Array with receivers
 297          * @return integer user id;
 298          */
 299         public static function getFirstUserFromReceivers($receivers)
 300         {
 301                 foreach ($receivers as $receiver) {
 302                         if (!empty($receiver)) {
 303                                 return $receiver;
 304                         }
 305                 }
 306                 return 0;
 307         }
 308
 309         /**
 310          * Store the unprocessed data into the conversation table
 311          * This has to be done outside the regular function,
 312          * since we store everything - not only item posts.
 313          *
 314          * @param array  $activity Array with activity data
 315          * @param string $body     The raw message
 316          * @throws \Exception
 317          */
 318         private static function storeConversation($activity, $body)
 319         {
 320                 if (empty($body) || empty($activity['id'])) {
 321                         return;
 322                 }
 323
 324                 $conversation = [
 325                         'protocol' => Conversation::PARCEL_ACTIVITYPUB,
 326                         'item-uri' => $activity['id'],
 327                         'reply-to-uri' => $activity['reply-to-id'] ?? '',
 328                         'conversation-href' => $activity['context'] ?? '',
 329                         'conversation-uri' => $activity['conversation'] ?? '',
 330                         'source' => $body,
 331                         'received' => DateTimeFormat::utcNow()];
 332
 333                 DBA::insert('conversation', $conversation, true);
 334         }
 335
 336         /**
 337          * Processes the activity object
 338          *
 339          * @param array   $activity     Array with activity data
 340          * @param string  $body
 341          * @param integer $uid          User ID
 342          * @param boolean $trust_source Do we trust the source?
 343          * @throws \Exception
 344          */
 345         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false, $push = false)
 346         {
 347                 $type = JsonLD::fetchElement($activity, '@type');
 348                 if (!$type) {
 349                         Logger::log('Empty type', Logger::DEBUG);
 350                         return;
 351                 }
 352
 353                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 354                         Logger::log('Empty object', Logger::DEBUG);
 355                         return;
 356                 }
 357
 358                 if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
 359                         Logger::log('Empty actor', Logger::DEBUG);
 360                         return;
 361
 362                 }
 363
 364                 // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
 365                 if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
 366                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 367                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 368                         $trust_source = ($actor == $attributed_to);
 369                         if (!$trust_source) {
 370                                 Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
 371                         }
 372                 }
 373
 374                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 375                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 376                 if (empty($object_data)) {
 377                         Logger::log('No object data found', Logger::DEBUG);
 378                         return;
 379                 }
 380
 381                 if (!$trust_source) {
 382                         Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
 383                         return;
 384                 }
 385
 386                 // Only store content related stuff - and no announces, since they possibly overwrite the original content
 387                 if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
 388                         self::storeConversation($object_data, $body);
 389                 }
 390
 391                 // Internal flag for thread completion. See Processor.php
 392                 if (!empty($activity['thread-completion'])) {
 393                         $object_data['thread-completion'] = $activity['thread-completion'];
 394                 }
 395
 396                 switch ($type) {
 397                         case 'as:Create':
 398                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 399                                         ActivityPub\Processor::createItem($object_data);
 400                                 }
 401                                 break;
 402
 403                         case 'as:Add':
 404                                 if ($object_data['object_type'] == 'as:tag') {
 405                                         ActivityPub\Processor::addTag($object_data);
 406                                 }
 407                                 break;
 408
 409                         case 'as:Announce':
 410                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 411                                         $profile = APContact::getByURL($object_data['actor']);
 412                                         // Reshared posts from persons appear as summary at the bottom
 413                                         // If this isn't set, then a single reshare appears on top. This is used for groups.
 414                                         $object_data['thread-completion'] = ($profile['type'] != 'Group');
 415
 416                                         ActivityPub\Processor::createItem($object_data);
 417
 418                                         // Add the bottom reshare information only for persons
 419                                         if ($profile['type'] != 'Group') {
 420                                                 $announce_object_data = self::processObject($activity);
 421                                                 $announce_object_data['name'] = $type;
 422                                                 $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 423                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 424                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 425
 426                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 427                                         }
 428                                 }
 429                                 break;
 430
 431                         case 'as:Like':
 432                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 433                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 434                                 }
 435                                 break;
 436
 437                         case 'as:Dislike':
 438                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 439                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 440                                 }
 441                                 break;
 442
 443                         case 'as:TentativeAccept':
 444                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 445                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 446                                 }
 447                                 break;
 448
 449                         case 'as:Update':
 450                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 451                                         ActivityPub\Processor::updateItem($object_data);
 452                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 453                                         ActivityPub\Processor::updatePerson($object_data);
 454                                 }
 455                                 break;
 456
 457                         case 'as:Delete':
 458                                 if ($object_data['object_type'] == 'as:Tombstone') {
 459                                         ActivityPub\Processor::deleteItem($object_data);
 460                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 461                                         ActivityPub\Processor::deletePerson($object_data);
 462                                 }
 463                                 break;
 464
 465                         case 'as:Follow':
 466                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 467                                         ActivityPub\Processor::followUser($object_data);
 468                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 469                                         $object_data['reply-to-id'] = $object_data['object_id'];
 470                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 471                                 }
 472                                 break;
 473
 474                         case 'as:Accept':
 475                                 if ($object_data['object_type'] == 'as:Follow') {
 476                                         ActivityPub\Processor::acceptFollowUser($object_data);
 477                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 478                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 479                                 }
 480                                 break;
 481
 482                         case 'as:Reject':
 483                                 if ($object_data['object_type'] == 'as:Follow') {
 484                                         ActivityPub\Processor::rejectFollowUser($object_data);
 485                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 486                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 487                                 }
 488                                 break;
 489
 490                         case 'as:Undo':
 491                                 if (($object_data['object_type'] == 'as:Follow') &&
 492                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 493                                         ActivityPub\Processor::undoFollowUser($object_data);
 494                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 495                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 496                                         ActivityPub\Processor::rejectFollowUser($object_data);
 497                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 498                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 499                                         ActivityPub\Processor::undoActivity($object_data);
 500                                 }
 501                                 break;
 502
 503                         default:
 504                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 505                                 break;
 506                 }
 507         }
 508
 509         /**
 510          * Fetch the receiver list from an activity array
 511          *
 512          * @param array  $activity
 513          * @param string $actor
 514          * @param array  $tags
 515          *
 516          * @return array with receivers (user id)
 517          * @throws \Exception
 518          */
 519         private static function getReceivers($activity, $actor, $tags = [])
 520         {
 521                 $receivers = [];
 522
 523                 // When it is an answer, we inherite the receivers from the parent
 524                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 525                 if (!empty($replyto)) {
 526                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 527                         $fixedReplyTo = Item::getURIByLink($replyto);
 528                         $replyto = $fixedReplyTo ?: $replyto;
 529
 530                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 531                         while ($parent = Item::fetch($parents)) {
 532                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 533                         }
 534                 }
 535
 536                 if (!empty($actor)) {
 537                         $profile = APContact::getByURL($actor);
 538                         $followers = $profile['followers'] ?? '';
 539
 540                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 541                 } else {
 542                         Logger::log('Empty actor', Logger::DEBUG);
 543                         $followers = '';
 544                 }
 545
 546                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 547                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 548                         if (empty($receiver_list)) {
 549                                 continue;
 550                         }
 551
 552                         foreach ($receiver_list as $receiver) {
 553                                 if ($receiver == self::PUBLIC_COLLECTION) {
 554                                         $receivers['uid:0'] = 0;
 555                                 }
 556
 557                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 558                                         // This will most likely catch all OStatus connections to Mastodon
 559                                         $condition = ['alias' => [$actor, Strings::normaliseLink($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 560                                                 , 'archive' => false, 'pending' => false];
 561                                         $contacts = DBA::select('contact', ['uid'], $condition);
 562                                         while ($contact = DBA::fetch($contacts)) {
 563                                                 if ($contact['uid'] != 0) {
 564                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 565                                                 }
 566                                         }
 567                                         DBA::close($contacts);
 568                                 }
 569
 570                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 571                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
 572                                         continue;
 573                                 }
 574
 575                                 // Fetching all directly addressed receivers
 576                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 577                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 578                                 if (!DBA::isResult($contact)) {
 579                                         continue;
 580                                 }
 581
 582                                 // Check if the potential receiver is following the actor
 583                                 // Exception: The receiver is targetted via "to" or this is a comment
 584                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 585                                         $networks = Protocol::FEDERATED;
 586                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 587                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 588
 589                                         // Forum posts are only accepted from forum contacts
 590                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 591                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 592                                         }
 593
 594                                         if (!DBA::exists('contact', $condition)) {
 595                                                 continue;
 596                                         }
 597                                 }
 598
 599                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 600                         }
 601                 }
 602
 603                 self::switchContacts($receivers, $actor);
 604
 605                 return $receivers;
 606         }
 607
 608         /**
 609          * Fetch the receiver list of a given actor
 610          *
 611          * @param string $actor
 612          * @param array  $tags
 613          *
 614          * @return array with receivers (user id)
 615          * @throws \Exception
 616          */
 617         public static function getReceiverForActor($actor, $tags)
 618         {
 619                 $receivers = [];
 620                 $networks = Protocol::FEDERATED;
 621                 $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 622                         'network' => $networks, 'archive' => false, 'pending' => false];
 623                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 624                 while ($contact = DBA::fetch($contacts)) {
 625                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 626                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 627                         }
 628                 }
 629                 DBA::close($contacts);
 630                 return $receivers;
 631         }
 632
 633         /**
 634          * Tests if the contact is a valid receiver for this actor
 635          *
 636          * @param array  $contact
 637          * @param string $actor
 638          * @param array  $tags
 639          *
 640          * @return bool with receivers (user id)
 641          * @throws \Exception
 642          */
 643         private static function isValidReceiverForActor($contact, $actor, $tags)
 644         {
 645                 // Public contacts are no valid receiver
 646                 if ($contact['uid'] == 0) {
 647                         return false;
 648                 }
 649
 650                 // Are we following the contact? Then this is a valid receiver
 651                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 652                         return true;
 653                 }
 654
 655                 // When the possible receiver isn't a community, then it is no valid receiver
 656                 $owner = User::getOwnerDataById($contact['uid']);
 657                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 658                         return false;
 659                 }
 660
 661                 // Is the community account tagged?
 662                 foreach ($tags as $tag) {
 663                         if ($tag['type'] != 'Mention') {
 664                                 continue;
 665                         }
 666
 667                         if ($tag['href'] == $owner['url']) {
 668                                 return true;
 669                         }
 670                 }
 671
 672                 return false;
 673         }
 674
 675         /**
 676          * Switches existing contacts to ActivityPub
 677          *
 678          * @param integer $cid Contact ID
 679          * @param integer $uid User ID
 680          * @param string  $url Profile URL
 681          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 682          * @throws \ImagickException
 683          */
 684         public static function switchContact($cid, $uid, $url)
 685         {
 686                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 687                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 688                         return;
 689                 }
 690
 691                 if (Contact::updateFromProbe($cid, '', true)) {
 692                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 693                 }
 694
 695                 // Send a new follow request to be sure that the connection still exists
 696                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 697                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 698                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 699                 }
 700         }
 701
 702         /**
 703          *
 704          *
 705          * @param $receivers
 706          * @param $actor
 707          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 708          * @throws \ImagickException
 709          */
 710         private static function switchContacts($receivers, $actor)
 711         {
 712                 if (empty($actor)) {
 713                         return;
 714                 }
 715
 716                 foreach ($receivers as $receiver) {
 717                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 718                         if (DBA::isResult($contact)) {
 719                                 self::switchContact($contact['id'], $receiver, $actor);
 720                         }
 721
 722                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 723                         if (DBA::isResult($contact)) {
 724                                 self::switchContact($contact['id'], $receiver, $actor);
 725                         }
 726                 }
 727         }
 728
 729         /**
 730          *
 731          *
 732          * @param       $object_data
 733          * @param array $activity
 734          *
 735          * @return mixed
 736          */
 737         private static function addActivityFields($object_data, $activity)
 738         {
 739                 if (!empty($activity['published']) && empty($object_data['published'])) {
 740                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 741                 }
 742
 743                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 744                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 745                 }
 746
 747                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 748                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 749
 750                 if (!empty($object_data['object_id'])) {
 751                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 752                         $objectId = Item::getURIByLink($object_data['object_id']);
 753                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 754                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 755                                 $object_data['object_id'] = $objectId;
 756                         }
 757                 }
 758
 759                 return $object_data;
 760         }
 761
 762         /**
 763          * Fetches the object data from external ressources if needed
 764          *
 765          * @param string  $object_id    Object ID of the the provided object
 766          * @param array   $object       The provided object array
 767          * @param boolean $trust_source Do we trust the provided object?
 768          * @param integer $uid          User ID for the signature that we use to fetch data
 769          *
 770          * @return array|false with trusted and valid object data
 771          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 772          * @throws \ImagickException
 773          */
 774         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 775         {
 776                 // By fetching the type we check if the object is complete.
 777                 $type = JsonLD::fetchElement($object, '@type');
 778
 779                 if (!$trust_source || empty($type)) {
 780                         $data = ActivityPub::fetchContent($object_id, $uid);
 781                         if (!empty($data)) {
 782                                 $object = JsonLD::compact($data);
 783                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 784                         } else {
 785                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 786
 787                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 788                                 if (!DBA::isResult($item)) {
 789                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 790                                         return false;
 791                                 }
 792                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 793                                 $data = ActivityPub\Transmitter::createNote($item);
 794                                 $object = JsonLD::compact($data);
 795                         }
 796                 } else {
 797                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 798                 }
 799
 800                 $type = JsonLD::fetchElement($object, '@type');
 801
 802                 if (empty($type)) {
 803                         Logger::log('Empty type', Logger::DEBUG);
 804                         return false;
 805                 }
 806
 807                 if (in_array($type, self::CONTENT_TYPES)) {
 808                         return self::processObject($object);
 809                 }
 810
 811                 if ($type == 'as:Announce') {
 812                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 813                         if (empty($object_id) || !is_string($object_id)) {
 814                                 return false;
 815                         }
 816                         return self::fetchObject($object_id, [], false, $uid);
 817                 }
 818
 819                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 820                 return false;
 821         }
 822
 823         /**
 824          * Convert tags from JSON-LD format into a simplified format
 825          *
 826          * @param array $tags Tags in JSON-LD format
 827          *
 828          * @return array with tags in a simplified format
 829          */
 830         private static function processTags($tags)
 831         {
 832                 $taglist = [];
 833
 834                 if (empty($tags)) {
 835                         return [];
 836                 }
 837
 838                 foreach ($tags as $tag) {
 839                         if (empty($tag)) {
 840                                 continue;
 841                         }
 842
 843                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 844                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 845                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 846
 847                         if (empty($element['type'])) {
 848                                 continue;
 849                         }
 850
 851                         $taglist[] = $element;
 852                 }
 853                 return $taglist;
 854         }
 855
 856         /**
 857          * Convert emojis from JSON-LD format into a simplified format
 858          *
 859          * @param $emojis
 860          * @return array with emojis in a simplified format
 861          */
 862         private static function processEmojis($emojis)
 863         {
 864                 $emojilist = [];
 865
 866                 if (empty($emojis)) {
 867                         return [];
 868                 }
 869
 870                 foreach ($emojis as $emoji) {
 871                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 872                                 continue;
 873                         }
 874
 875                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 876                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 877                                 'href' => $url];
 878
 879                         $emojilist[] = $element;
 880                 }
 881                 return $emojilist;
 882         }
 883
 884         /**
 885          * Convert attachments from JSON-LD format into a simplified format
 886          *
 887          * @param array $attachments Attachments in JSON-LD format
 888          *
 889          * @return array with attachmants in a simplified format
 890          */
 891         private static function processAttachments($attachments)
 892         {
 893                 $attachlist = [];
 894
 895                 if (empty($attachments)) {
 896                         return [];
 897                 }
 898
 899                 foreach ($attachments as $attachment) {
 900                         if (empty($attachment)) {
 901                                 continue;
 902                         }
 903
 904                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 905                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 906                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 907                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
 908                 }
 909                 return $attachlist;
 910         }
 911
 912         /**
 913          * Fetch the original source or content with the "language" Markdown or HTML
 914          *
 915          * @param array $object
 916          * @param array $object_data
 917          *
 918          * @return array
 919          * @throws \Exception
 920          */
 921         private static function getSource($object, $object_data)
 922         {
 923                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 924                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 925                 if (!empty($object_data['source'])) {
 926                         return $object_data;
 927                 }
 928
 929                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
 930                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 931                 if (!empty($object_data['source'])) {
 932                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
 933                         return $object_data;
 934                 }
 935
 936                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
 937                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 938                 if (!empty($object_data['source'])) {
 939                         $object_data['source'] = HTML::toBBCode($object_data['source']);
 940                         return $object_data;
 941                 }
 942
 943                 return $object_data;
 944         }
 945
 946         /**
 947          * Fetches data from the object part of an activity
 948          *
 949          * @param array $object
 950          *
 951          * @return array
 952          * @throws \Exception
 953          */
 954         private static function processObject($object)
 955         {
 956                 if (!JsonLD::fetchElement($object, '@id')) {
 957                         return false;
 958                 }
 959
 960                 $object_data = [];
 961                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 962                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 963                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
 964
 965                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
 966                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
 967                         $object_data['reply-to-id'] = $object_data['id'];
 968                 } else {
 969                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 970                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
 971                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
 972                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
 973                                 $object_data['reply-to-id'] = $replyToId;
 974                         }
 975                 }
 976
 977                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 978                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 979
 980                 if (empty($object_data['updated'])) {
 981                         $object_data['updated'] = $object_data['published'];
 982                 }
 983
 984                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 985                         $object_data['published'] = $object_data['updated'];
 986                 }
 987
 988                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
 989                 if (empty($actor)) {
 990                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
 991                 }
 992
 993                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
 994                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
 995                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
 996                 $object_data['actor'] = $object_data['author'] = $actor;
 997                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
 998                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
 999                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1000                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1001                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1002                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1003                 $object_data = self::getSource($object, $object_data);
1004                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1005                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1006                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1007                 $object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
1008                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1009                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1010                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1011                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1012                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
1013                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
1014                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
1015                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1016                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1017                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1018
1019                 // Special treatment for Hubzilla links
1020                 if (is_array($object_data['alternate-url'])) {
1021                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1022
1023                         if (!is_string($object_data['alternate-url'])) {
1024                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1025                         }
1026                 }
1027
1028                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags']);
1029
1030                 // Common object data:
1031
1032                 // Unhandled
1033                 // @context, type, actor, signature, mediaType, duration, replies, icon
1034
1035                 // Also missing: (Defined in the standard, but currently unused)
1036                 // audience, preview, endTime, startTime, image
1037
1038                 // Data in Notes:
1039
1040                 // Unhandled
1041                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1042                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1043
1044                 // Data in video:
1045
1046                 // To-Do?
1047                 // category, licence, language, commentsEnabled
1048
1049                 // Unhandled
1050                 // views, waitTranscoding, state, support, subtitleLanguage
1051                 // likes, dislikes, shares, comments
1052
1053                 return $object_data;
1054         }
1055 }