X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FProtocol%2FActivityPub%2FReceiver.php;h=1bc6f9041545dcdfb594e28fd92190e3b6c332ed;hb=07cea24430420cb0ac2b1d8f870d7292002c7faf;hp=7fe1f128f496b746efbed1bd24ccf854964913d6;hpb=fabc90e9dd5f1c4280a9bfa6c6930a3fc985f87a;p=friendica.git

diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index 7fe1f128f4..1bc6f90415 100644
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -12,6 +12,7 @@ use Friendica\Model\APContact;
 use Friendica\Model\Conversation;
 use Friendica\Model\Item;
 use Friendica\Model\User;
+use Friendica\Protocol\Activity;
 use Friendica\Protocol\ActivityPub;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\HTTPSignature;
@@ -42,43 +43,44 @@ class Receiver
 	/**
 	 * Checks if the web request is done for the AP protocol
 	 *
-	 * @return is it AP?
+	 * @return bool is it AP?
 	 */
 	public static function isRequest()
 	{
-		return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
-			stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
+		return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
+			stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
 	}
 
 	/**
 	 * Checks incoming message from the inbox
 	 *
-	 * @param $body
-	 * @param $header
+	 * @param         $body
+	 * @param         $header
 	 * @param integer $uid User ID
+	 * @throws \Exception
 	 */
 	public static function processInbox($body, $header, $uid)
 	{
 		$http_signer = HTTPSignature::getSigner($body, $header);
 		if (empty($http_signer)) {
-			Logger::log('Invalid HTTP signature, message will be discarded.', Logger::DEBUG);
+			Logger::warning('Invalid HTTP signature, message will be discarded.');
 			return;
 		} else {
-			Logger::log('HTTP signature is signed by ' . $http_signer, Logger::DEBUG);
+			Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 		}
 
 		$activity = json_decode($body, true);
 
 		if (empty($activity)) {
-			Logger::log('Invalid body.', Logger::DEBUG);
+			Logger::warning('Invalid body.');
 			return;
 		}
 
 		$ldactivity = JsonLD::compact($activity);
 
-		$actor = JsonLD::fetchElement($ldactivity, 'as:actor');
+		$actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 
-		Logger::log('Message for user ' . $uid . ' is from actor ' . $actor, Logger::DEBUG);
+		Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 
 		if (LDSignature::isSigned($activity)) {
 			$ld_signer = LDSignature::getSigner($activity);
@@ -114,9 +116,11 @@ class Receiver
 	 *
 	 * @param array   $activity
 	 * @param string  $object_id Object ID of the the provided object
-	 * @param integer $uid User ID
+	 * @param integer $uid       User ID
 	 *
 	 * @return string with object type
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
 	private static function fetchObjectType($activity, $object_id, $uid = 0)
 	{
@@ -152,15 +156,17 @@ class Receiver
 	/**
 	 * Prepare the object array
 	 *
-	 * @param array $activity
+	 * @param array   $activity
 	 * @param integer $uid User ID
-	 * @param $trust_source
+	 * @param         $trust_source
 	 *
 	 * @return array with object data
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
 	private static function prepareObjectData($activity, $uid, &$trust_source)
 	{
-		$actor = JsonLD::fetchElement($activity, 'as:actor');
+		$actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 		if (empty($actor)) {
 			Logger::log('Empty actor', Logger::DEBUG);
 			return [];
@@ -183,12 +189,17 @@ class Receiver
 
 		Logger::log('Receivers: ' . $uid . ' - ' . json_encode($receivers), Logger::DEBUG);
 
-		$object_id = JsonLD::fetchElement($activity, 'as:object');
+		$object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 		if (empty($object_id)) {
 			Logger::log('No object found', Logger::DEBUG);
 			return [];
 		}
 
+		if (!is_string($object_id)) {
+			Logger::info('Invalid object id', ['object' => $object_id]);
+			return [];
+		}
+
 		$object_type = self::fetchObjectType($activity, $object_id, $uid);
 
 		// Fetch the content only on activities where this matters
@@ -201,21 +212,37 @@ class Receiver
 				Logger::log("Object data couldn't be processed", Logger::DEBUG);
 				return [];
 			}
+			$object_data['object_id'] = $object_id;
+
+			// Test if it is an answer to a mail
+			if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
+				$object_data['directmessage'] = true;
+			} else {
+				$object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
+			}
+
 			// We had been able to retrieve the object data - so we can trust the source
 			$trust_source = true;
-		} elseif (in_array($type, ['as:Like', 'as:Dislike'])) {
+		} elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 			// Create a mostly empty array out of the activity data (instead of the object).
 			// This way we later don't have to check for the existence of ech individual array element.
 			$object_data = self::processObject($activity);
 			$object_data['name'] = $type;
-			$object_data['author'] = JsonLD::fetchElement($activity, 'as:actor');
+			$object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 			$object_data['object_id'] = $object_id;
 			$object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
+		} elseif (in_array($type, ['as:Add'])) {
+			$object_data = [];
+			$object_data['id'] = JsonLD::fetchElement($activity, '@id');
+			$object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
+			$object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
+			$object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
+			$object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 		} else {
 			$object_data = [];
 			$object_data['id'] = JsonLD::fetchElement($activity, '@id');
-			$object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object');
-			$object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor');
+			$object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
+			$object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 			$object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 			$object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 
@@ -233,7 +260,8 @@ class Receiver
 
 		$object_data['type'] = $type;
 		$object_data['actor'] = $actor;
-		$object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
+		$object_data['item_receiver'] = $receivers;
+		$object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 
 		Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 
@@ -263,6 +291,7 @@ class Receiver
 	 *
 	 * @param array  $activity Array with activity data
 	 * @param string $body     The raw message
+	 * @throws \Exception
 	 */
 	private static function storeConversation($activity, $body)
 	{
@@ -273,9 +302,9 @@ class Receiver
 		$conversation = [
 			'protocol' => Conversation::PARCEL_ACTIVITYPUB,
 			'item-uri' => $activity['id'],
-			'reply-to-uri' => defaults($activity, 'reply-to-id', ''),
-			'conversation-href' => defaults($activity, 'context', ''),
-			'conversation-uri' => defaults($activity, 'conversation', ''),
+			'reply-to-uri' => $activity['reply-to-id'] ?? '',
+			'conversation-href' => $activity['context'] ?? '',
+			'conversation-uri' => $activity['conversation'] ?? '',
 			'source' => $body,
 			'received' => DateTimeFormat::utcNow()];
 
@@ -289,6 +318,7 @@ class Receiver
 	 * @param string  $body
 	 * @param integer $uid          User ID
 	 * @param boolean $trust_source Do we trust the source?
+	 * @throws \Exception
 	 */
 	public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 	{
@@ -298,12 +328,12 @@ class Receiver
 			return;
 		}
 
-		if (!JsonLD::fetchElement($activity, 'as:object')) {
+		if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 			Logger::log('Empty object', Logger::DEBUG);
 			return;
 		}
 
-		if (!JsonLD::fetchElement($activity, 'as:actor')) {
+		if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
 			Logger::log('Empty actor', Logger::DEBUG);
 			return;
 
@@ -311,8 +341,8 @@ class Receiver
 
 		// Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
 		if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
-			$actor = JsonLD::fetchElement($activity, 'as:actor');
-			$attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo');
+			$actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
+			$attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 			$trust_source = ($actor == $attributed_to);
 			if (!$trust_source) {
 				Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
@@ -331,7 +361,10 @@ class Receiver
 			return;
 		}
 
-		self::storeConversation($object_data, $body);
+		// Only store content related stuff - and no announces, since they possibly overwrite the original content
+		if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
+			self::storeConversation($object_data, $body);
+		}
 
 		// Internal flag for thread completion. See Processor.php
 		if (!empty($activity['thread-completion'])) {
@@ -340,27 +373,54 @@ class Receiver
 
 		switch ($type) {
 			case 'as:Create':
+				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::createItem($object_data);
+				}
+				break;
+
+			case 'as:Add':
+				if ($object_data['object_type'] == 'as:tag') {
+					ActivityPub\Processor::addTag($object_data);
+				}
+				break;
+
 			case 'as:Announce':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					$profile = APContact::getByURL($object_data['actor']);
+					// Reshared posts from persons appear as summary at the bottom
+					// If this isn't set, then a single reshare appears on top. This is used for groups.
+					$object_data['thread-completion'] = ($profile['type'] != 'Group');
+
 					ActivityPub\Processor::createItem($object_data);
+
+					// Add the bottom reshare information only for persons
+					if ($profile['type'] != 'Group') {
+						$announce_object_data = self::processObject($activity);
+						$announce_object_data['name'] = $type;
+						$announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
+						$announce_object_data['object_id'] = $object_data['object_id'];
+						$announce_object_data['object_type'] = $object_data['object_type'];
+
+						ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
+					}
 				}
 				break;
 
 			case 'as:Like':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, ACTIVITY_LIKE);
+					ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 				}
 				break;
 
 			case 'as:Dislike':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, ACTIVITY_DISLIKE);
+					ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 				}
 				break;
 
 			case 'as:TentativeAccept':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDMAYBE);
+					ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 				}
 				break;
 
@@ -368,21 +428,24 @@ class Receiver
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 					ActivityPub\Processor::updateItem($object_data);
 				} elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
-					ActivityPub\Processor::updatePerson($object_data, $body);
+					ActivityPub\Processor::updatePerson($object_data);
 				}
 				break;
 
 			case 'as:Delete':
 				if ($object_data['object_type'] == 'as:Tombstone') {
-					ActivityPub\Processor::deleteItem($object_data, $body);
+					ActivityPub\Processor::deleteItem($object_data);
 				} elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
-					ActivityPub\Processor::deletePerson($object_data, $body);
+					ActivityPub\Processor::deletePerson($object_data);
 				}
 				break;
 
 			case 'as:Follow':
 				if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 					ActivityPub\Processor::followUser($object_data);
+				} elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					$object_data['reply-to-id'] = $object_data['object_id'];
+					ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 				}
 				break;
 
@@ -390,7 +453,7 @@ class Receiver
 				if ($object_data['object_type'] == 'as:Follow') {
 					ActivityPub\Processor::acceptFollowUser($object_data);
 				} elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTEND);
+					ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 				}
 				break;
 
@@ -398,7 +461,7 @@ class Receiver
 				if ($object_data['object_type'] == 'as:Follow') {
 					ActivityPub\Processor::rejectFollowUser($object_data);
 				} elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDNO);
+					ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 				}
 				break;
 
@@ -424,18 +487,19 @@ class Receiver
 	/**
 	 * Fetch the receiver list from an activity array
 	 *
-	 * @param array $activity
+	 * @param array  $activity
 	 * @param string $actor
-	 * @param array $tags
+	 * @param array  $tags
 	 *
 	 * @return array with receivers (user id)
+	 * @throws \Exception
 	 */
 	private static function getReceivers($activity, $actor, $tags = [])
 	{
 		$receivers = [];
 
 		// When it is an answer, we inherite the receivers from the parent
-		$replyto = JsonLD::fetchElement($activity, 'as:inReplyTo');
+		$replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 		if (!empty($replyto)) {
 			$parents = Item::select(['uid'], ['uri' => $replyto]);
 			while ($parent = Item::fetch($parents)) {
@@ -445,7 +509,7 @@ class Receiver
 
 		if (!empty($actor)) {
 			$profile = APContact::getByURL($actor);
-			$followers = defaults($profile, 'followers', '');
+			$followers = $profile['followers'] ?? '';
 
 			Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 		} else {
@@ -454,7 +518,7 @@ class Receiver
 		}
 
 		foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
-			$receiver_list = JsonLD::fetchElementArray($activity, $element);
+			$receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 			if (empty($receiver_list)) {
 				continue;
 			}
@@ -491,13 +555,13 @@ class Receiver
 
 				// Check if the potential receiver is following the actor
 				// Exception: The receiver is targetted via "to" or this is a comment
-				if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::ACCOUNT_TYPE_COMMUNITY)) {
-					$networks = [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::DIASPORA, Protocol::OSTATUS];
+				if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
+					$networks = Protocol::FEDERATED;
 					$condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 						'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 
 					// Forum posts are only accepted from forum contacts
-					if ($contact['contact-type'] == Contact::ACCOUNT_TYPE_COMMUNITY) {
+					if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 						$condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 					}
 
@@ -519,14 +583,15 @@ class Receiver
 	 * Fetch the receiver list of a given actor
 	 *
 	 * @param string $actor
-	 * @param array $tags
+	 * @param array  $tags
 	 *
 	 * @return array with receivers (user id)
+	 * @throws \Exception
 	 */
 	public static function getReceiverForActor($actor, $tags)
 	{
 		$receivers = [];
-		$networks = [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::DIASPORA, Protocol::OSTATUS];
+		$networks = Protocol::FEDERATED;
 		$condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 			'network' => $networks, 'archive' => false, 'pending' => false];
 		$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
@@ -542,11 +607,12 @@ class Receiver
 	/**
 	 * Tests if the contact is a valid receiver for this actor
 	 *
-	 * @param array $contact
+	 * @param array  $contact
 	 * @param string $actor
-	 * @param array $tags
+	 * @param array  $tags
 	 *
-	 * @return array with receivers (user id)
+	 * @return bool with receivers (user id)
+	 * @throws \Exception
 	 */
 	private static function isValidReceiverForActor($contact, $actor, $tags)
 	{
@@ -562,7 +628,7 @@ class Receiver
 
 		// When the possible receiver isn't a community, then it is no valid receiver
 		$owner = User::getOwnerDataById($contact['uid']);
-		if (empty($owner) || ($owner['contact-type'] != Contact::ACCOUNT_TYPE_COMMUNITY)) {
+		if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 			return false;
 		}
 
@@ -585,31 +651,25 @@ class Receiver
 	 *
 	 * @param integer $cid Contact ID
 	 * @param integer $uid User ID
-	 * @param string $url Profile URL
+	 * @param string  $url Profile URL
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
 	public static function switchContact($cid, $uid, $url)
 	{
-		$profile = ActivityPub::probeProfile($url);
-		if (empty($profile)) {
+		if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
+			Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 			return;
 		}
 
-		Logger::log('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' to ActivityPub');
-
-		$photo = defaults($profile, 'photo', null);
-		unset($profile['photo']);
-		unset($profile['baseurl']);
-		unset($profile['guid']);
-
-		$profile['nurl'] = Strings::normaliseLink($profile['url']);
-		DBA::update('contact', $profile, ['id' => $cid]);
-
-		Contact::updateAvatar($photo, $uid, $cid);
+		if (Contact::updateFromProbe($cid, '', true)) {
+			Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
+		}
 
 		// Send a new follow request to be sure that the connection still exists
-		if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
-			ActivityPub\Transmitter::sendActivity('Follow', $profile['url'], $uid);
-			Logger::log('Send a new follow request to ' . $profile['url'] . ' for user ' . $uid, Logger::DEBUG);
+		if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
+			Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
+			ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 		}
 	}
 
@@ -618,6 +678,8 @@ class Receiver
 	 *
 	 * @param $receivers
 	 * @param $actor
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
 	private static function switchContacts($receivers, $actor)
 	{
@@ -641,10 +703,10 @@ class Receiver
 	/**
 	 *
 	 *
-	 * @param $object_data
+	 * @param       $object_data
 	 * @param array $activity
 	 *
-	 * @return
+	 * @return mixed
 	 */
 	private static function addActivityFields($object_data, $activity)
 	{
@@ -653,10 +715,11 @@ class Receiver
 		}
 
 		if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
-			$object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid');
+			$object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 		}
 
 		$object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
+		$object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 
 		return $object_data;
 	}
@@ -669,9 +732,11 @@ class Receiver
 	 * @param boolean $trust_source Do we trust the provided object?
 	 * @param integer $uid          User ID for the signature that we use to fetch data
 	 *
-	 * @return array with trusted and valid object data
+	 * @return array|false with trusted and valid object data
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
-	private static function fetchObject($object_id, $object = [], $trust_source = false, $uid = 0)
+	private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 	{
 		// By fetching the type we check if the object is complete.
 		$type = JsonLD::fetchElement($object, '@type');
@@ -709,14 +774,15 @@ class Receiver
 		}
 
 		if ($type == 'as:Announce') {
-			$object_id = JsonLD::fetchElement($object, 'object');
-			if (empty($object_id)) {
+			$object_id = JsonLD::fetchElement($object, 'object', '@id');
+			if (empty($object_id) || !is_string($object_id)) {
 				return false;
 			}
 			return self::fetchObject($object_id, [], false, $uid);
 		}
 
 		Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
+		return false;
 	}
 
 	/**
@@ -740,8 +806,8 @@ class Receiver
 			}
 
 			$element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
-				'href' => JsonLD::fetchElement($tag, 'as:href'),
-				'name' => JsonLD::fetchElement($tag, 'as:name')];
+				'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
+				'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 
 			if (empty($element['type'])) {
 				continue;
@@ -755,8 +821,7 @@ class Receiver
 	/**
 	 * Convert emojis from JSON-LD format into a simplified format
 	 *
-	 * @param array $tags Tags in JSON-LD format
-	 *
+	 * @param $emojis
 	 * @return array with emojis in a simplified format
 	 */
 	private static function processEmojis($emojis)
@@ -772,8 +837,8 @@ class Receiver
 				continue;
 			}
 
-			$url = JsonLD::fetchElement($emoji['as:icon'], 'as:url');
-			$element = ['name' => JsonLD::fetchElement($emoji, 'as:name'),
+			$url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
+			$element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 				'href' => $url];
 
 			$emojilist[] = $element;
@@ -802,9 +867,9 @@ class Receiver
 			}
 
 			$attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
-				'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType'),
-				'name' => JsonLD::fetchElement($attachment, 'as:name'),
-				'url' => JsonLD::fetchElement($attachment, 'as:url')];
+				'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
+				'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
+				'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
 		}
 		return $attachlist;
 	}
@@ -815,6 +880,7 @@ class Receiver
 	 * @param array $object
 	 *
 	 * @return array
+	 * @throws \Exception
 	 */
 	private static function processObject($object)
 	{
@@ -825,10 +891,10 @@ class Receiver
 		$object_data = [];
 		$object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 		$object_data['id'] = JsonLD::fetchElement($object, '@id');
+		$object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
 
-		$object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo');
-
-		if (empty($object_data['reply-to-id'])) {
+		// An empty "id" field is translated to "./" by the compactor, so we have to check for this content
+		if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
 			$object_data['reply-to-id'] = $object_data['id'];
 		}
 
@@ -843,25 +909,27 @@ class Receiver
 			$object_data['published'] = $object_data['updated'];
 		}
 
-		$actor = JsonLD::fetchElement($object, 'as:attributedTo');
+		$actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
 		if (empty($actor)) {
-			$actor = JsonLD::fetchElement($object, 'as:actor');
+			$actor = JsonLD::fetchElement($object, 'as:actor', '@id');
 		}
 
-		$object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid');
-		$object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment');
-		$object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like');
+		$object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
+		$object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
+		$object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
 		$object_data['actor'] = $object_data['author'] = $actor;
-		$object_data['context'] = JsonLD::fetchElement($object, 'as:context');
-		$object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation');
+		$object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
+		$object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
 		$object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
-		$object_data['name'] = JsonLD::fetchElement($object, 'as:name');
-		$object_data['summary'] = JsonLD::fetchElement($object, 'as:summary');
-		$object_data['content'] = JsonLD::fetchElement($object, 'as:content');
+		$object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
+		$object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
+		$object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
 		$object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
+		$object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 		$object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
 		$object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
 		$object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
+		$object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
 		$object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
 		$object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
 		$object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
@@ -870,14 +938,15 @@ class Receiver
 		$object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 		$object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
 		$object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
-		$object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url');
+		$object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
+		$object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
 
 		// Special treatment for Hubzilla links
 		if (is_array($object_data['alternate-url'])) {
-			$object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href');
+			$object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
 
 			if (!is_string($object_data['alternate-url'])) {
-				$object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href');
+				$object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
 			}
 		}