X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;ds=sidebyside;f=src%2FProtocol%2FActivityPub%2FReceiver.php;h=11e7151e1e9f57e7bff9b0cd1d86390bce6a8d12;hb=ce38e63399aa41b87836dea85f13e3c0491ef5e3;hp=3d183aec56a6ed38d2da24c6f0fce482e402c9c0;hpb=ee3a8ccb3bbb4c214f7410976bd9f6ae95be40f1;p=friendica.git

diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index 3d183aec56..11e7151e1e 100644
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -27,6 +27,9 @@ use Friendica\Content\Text\HTML;
 use Friendica\Content\Text\Markdown;
 use Friendica\Core\Logger;
 use Friendica\Core\Protocol;
+use Friendica\Core\System;
+use Friendica\Database\Database;
+use Friendica\DI;
 use Friendica\Model\Contact;
 use Friendica\Model\APContact;
 use Friendica\Model\Item;
@@ -34,9 +37,11 @@ use Friendica\Model\Post;
 use Friendica\Model\User;
 use Friendica\Protocol\Activity;
 use Friendica\Protocol\ActivityPub;
+use Friendica\Util\DateTimeFormat;
 use Friendica\Util\HTTPSignature;
 use Friendica\Util\JsonLD;
 use Friendica\Util\LDSignature;
+use Friendica\Util\Network;
 use Friendica\Util\Strings;
 
 /**
@@ -68,15 +73,22 @@ class Receiver
 	const TARGET_ANSWER = 6;
 	const TARGET_GLOBAL = 7;
 
+	const COMPLETION_NONE    = 0;
+	const COMPLETION_ANNOUCE = 1;
+	const COMPLETION_RELAY   = 2;
+	const COMPLETION_MANUAL  = 3;
+	const COMPLETION_AUTO    = 4;
+
 	/**
 	 * Checks incoming message from the inbox
 	 *
-	 * @param         $body
-	 * @param         $header
+	 * @param string  $body Body string
+	 * @param array   $header Header lines
 	 * @param integer $uid User ID
+	 * @return void
 	 * @throws \Exception
 	 */
-	public static function processInbox($body, $header, $uid)
+	public static function processInbox(string $body, array $header, int $uid)
 	{
 		$activity = json_decode($body, true);
 		if (empty($activity)) {
@@ -86,9 +98,10 @@ class Receiver
 
 		$ldactivity = JsonLD::compact($activity);
 
-		$actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
+		$actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id') ?? '';
 
 		$apcontact = APContact::getByURL($actor);
+
 		if (empty($apcontact)) {
 			Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 			return;
@@ -142,7 +155,46 @@ class Receiver
 			$trust_source = false;
 		}
 
-		self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
+		$fetchQueue = new FetchQueue();
+		self::processActivity($fetchQueue, $ldactivity, $body, $uid, $trust_source, true, $signer, $http_signer);
+		$fetchQueue->process();
+	}
+
+	private static function enqueuePost(array $ldactivity = [], string $type, int $uid, string $http_signer): array
+	{
+		$fields = [
+ 			'activity-id' => $ldactivity['id'],
+			'object-id' => $ldactivity['object_id'],
+			'type' => $type,
+			'object-type' => $ldactivity['object_type'],
+			'activity' => json_encode($ldactivity, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT),
+			'received' => DateTimeFormat::utcNow(),
+		];
+
+		if (!empty($ldactivity['object_object_type'])) {
+			$fields['object-object-type'] = $ldactivity['object_object_type'];
+		}
+
+		if (!empty($http_signer)) {
+			$fields['signer'] = $http_signer;
+		}
+
+		DBA::insert('inbox-entry', $fields, Database::INSERT_IGNORE);
+
+		$queue = DBA::selectFirst('inbox-entry', ['id'], ['activity-id' => $ldactivity['id']]);
+		if (!empty($queue['id'])) {
+			$ldactivity['entry-id'] = $queue['id'];
+			DBA::insert('inbox-entry-receiver', ['queue-id' => $queue['id'], 'uid' => $uid], Database::INSERT_IGNORE);
+		}
+		return $ldactivity;
+	}
+
+	public static function removeFromQueue(array $activity = [])
+	{
+		if (empty($activity['entry-id'])) {
+			return;
+		}
+		DBA::delete('inbox-entry', ['id' => $activity['entry-id']]);
 	}
 
 	/**
@@ -190,12 +242,16 @@ class Receiver
 			return;
 		}
 
-		$id = Processor::fetchMissingActivity($object_id, [], $actor);
+		$fetchQueue = new FetchQueue();
+
+		$id = Processor::fetchMissingActivity($fetchQueue, $object_id, [], $actor, self::COMPLETION_RELAY);
 		if (empty($id)) {
 			Logger::notice('Relayed message had not been fetched', ['id' => $object_id]);
 			return;
 		}
 
+		$fetchQueue->process();
+
 		$item_id = Item::searchByLink($object_id);
 		if ($item_id) {
 			Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
@@ -211,11 +267,11 @@ class Receiver
 	 * @param string  $object_id Object ID of the the provided object
 	 * @param integer $uid       User ID
 	 *
-	 * @return string with object type
+	 * @return string with object type or NULL
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 * @throws \ImagickException
 	 */
-	private static function fetchObjectType($activity, $object_id, $uid = 0)
+	private static function fetchObjectType(array $activity, string $object_id, int $uid = 0)
 	{
 		if (!empty($activity['as:object'])) {
 			$object_type = JsonLD::fetchElement($activity['as:object'], '@type');
@@ -259,21 +315,11 @@ class Receiver
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 * @throws \ImagickException
 	 */
-	public static function prepareObjectData($activity, $uid, $push, &$trust_source)
+	public static function prepareObjectData(array $activity, int $uid, bool $push, bool &$trust_source): array
 	{
 		$id = JsonLD::fetchElement($activity, '@id');
 		if (!empty($id) && !$trust_source) {
-			if (empty($uid)) {
-				$actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
-				if (empty($actor)) {
-					$actor = '';
-				}
-	
-				// Fetch a user out of the receivers of the message.
-				$fetch_uid = Receiver::getBestUserForActivity($activity, $actor);
-			} else {
-				$fetch_uid = $uid;
-			}
+			$fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 
 			$fetched_activity = ActivityPub::fetchContent($id, $fetch_uid);
 			if (!empty($fetched_activity)) {
@@ -307,19 +353,25 @@ class Receiver
 			$reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 		}
 
+		$urls = self::getReceiverURL($activity);
+
 		// When it is a delivery to a personal inbox we add that user to the receivers
 		if (!empty($uid)) {
 			$additional = [$uid => $uid];
 			$receivers = array_replace($receivers, $additional);
 			if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 				$reception_types[$uid] = self::TARGET_BCC;
+				$owner = User::getOwnerDataById($uid);
+				if (!empty($owner['url'])) {
+					$urls['as:bcc'][] = $owner['url'];
+				}
 			}
-		} else {
-			// We possibly need some user to fetch private content,
-			// so we fetch the first out ot the list.
-			$uid = self::getFirstUserFromReceivers($receivers);
 		}
 
+		// We possibly need some user to fetch private content,
+		// so we fetch one out of the receivers if no uid is provided.
+		$fetch_uid = $uid ?: self::getBestUserForActivity($activity);
+
 		$object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 		if (empty($object_id)) {
 			Logger::info('No object found');
@@ -331,11 +383,11 @@ class Receiver
 			return [];
 		}
 
-		$object_type = self::fetchObjectType($activity, $object_id, $uid);
+		$object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 
 		// Fetch the activity on Lemmy "Announce" messages (announces of activities)
 		if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
-			$data = ActivityPub::fetchContent($object_id, $uid);
+			$data = ActivityPub::fetchContent($object_id, $fetch_uid);
 			if (!empty($data)) {
 				$type = $object_type;
 				$activity = JsonLD::compact($data);
@@ -343,7 +395,7 @@ class Receiver
 				// Some variables need to be refetched since the activity changed
 				$actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 				$object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
-				$object_type = self::fetchObjectType($activity, $object_id, $uid);
+				$object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 			}
 		}
 
@@ -356,11 +408,11 @@ class Receiver
 			$object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 			$object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 			$object_data['push'] = $push;
-		} elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce']) || strpos($type, '#emojiReaction')) {
-		// Fetch the content only on activities where this matters
-		// We can receive "#emojiReaction" when fetching content from Hubzilla systems
+		} elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce', 'as:Invite']) || strpos($type, '#emojiReaction')) {
+			// Fetch the content only on activities where this matters
+			// We can receive "#emojiReaction" when fetching content from Hubzilla systems
 			// Always fetch on "Announce"
-			$object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
+			$object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $fetch_uid);
 			if (empty($object_data)) {
 				Logger::info("Object data couldn't be processed");
 				return [];
@@ -380,7 +432,7 @@ class Receiver
 			} else {
 				$object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 			}
-		} elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
+		} elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow', 'litepub:EmojiReact', 'as:View'])) && in_array($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 each individual array element.
 			$object_data = self::processObject($activity);
@@ -389,7 +441,7 @@ class Receiver
 			$object_data['object_id'] = $object_id;
 			$object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 			$object_data['push'] = $push;
-		} elseif (in_array($type, ['as:Add'])) {
+		} elseif (in_array($type, ['as:Add', 'as:Remove'])) {
 			$object_data = [];
 			$object_data['id'] = JsonLD::fetchElement($activity, '@id');
 			$object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
@@ -408,7 +460,7 @@ class Receiver
 
 			// An Undo is done on the object of an object, so we need that type as well
 			if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
-				$object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
+				$object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 			}
 		}
 
@@ -418,6 +470,12 @@ class Receiver
 			$object_data['object_type'] = $object_type;
 		}
 
+		foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
+			if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
+				$object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
+			}
+		}
+
 		$object_data['type'] = $type;
 		$object_data['actor'] = $actor;
 		$object_data['item_receiver'] = $receivers;
@@ -447,7 +505,7 @@ class Receiver
 	 * @param array $receivers Array with receivers
 	 * @return integer user id;
 	 */
-	public static function getFirstUserFromReceivers($receivers)
+	public static function getFirstUserFromReceivers(array $receivers): int
 	{
 		foreach ($receivers as $receiver) {
 			if (!empty($receiver)) {
@@ -460,14 +518,17 @@ class Receiver
 	/**
 	 * Processes the activity object
 	 *
-	 * @param array   $activity     Array with activity data
-	 * @param string  $body
-	 * @param integer $uid          User ID
-	 * @param boolean $trust_source Do we trust the source?
-	 * @param boolean $push         Message had been pushed to our system
-	 * @throws \Exception
+	 * @param FetchQueue $fetchQueue
+	 * @param array      $activity     Array with activity data
+	 * @param string     $body         The unprocessed body
+	 * @param int|null   $uid          User ID
+	 * @param boolean    $trust_source Do we trust the source?
+	 * @param boolean    $push         Message had been pushed to our system
+	 * @param array      $signer       The signer of the post
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 * @throws \ImagickException
 	 */
-	public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
+	public static function processActivity(FetchQueue $fetchQueue, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [], string $http_signer = '')
 	{
 		$type = JsonLD::fetchElement($activity, '@type');
 		if (!$type) {
@@ -527,6 +588,11 @@ class Receiver
 		if (!empty($activity['thread-completion'])) {
 			$object_data['thread-completion'] = $activity['thread-completion'];
 		}
+
+		if (!empty($activity['completion-mode'])) {
+			$object_data['completion-mode'] = $activity['completion-mode'];
+		}
+
 		if (!empty($activity['thread-children-type'])) {
 			$object_data['thread-children-type'] = $activity['thread-children-type'];
 		}
@@ -536,25 +602,51 @@ class Receiver
 			$object_data['from-relay'] = $activity['from-relay'];
 		}
 
+		$object_data = self::enqueuePost($object_data, $type, $uid, $http_signer);
+
+		if (in_array('as:Question', [$object_data['object_type'] ?? '', $object_data['object_object_type'] ?? ''])) {
+			self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+		}
+
 		switch ($type) {
 			case 'as:Create':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					$item = ActivityPub\Processor::createItem($object_data);
+					$item = ActivityPub\Processor::createItem($fetchQueue, $object_data);
 					ActivityPub\Processor::postItem($object_data, $item);
+				} elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
+					// Unhandled Peertube activity
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+				}
+				break;
+
+			case 'as:Invite':
+				if (in_array($object_data['object_type'], ['as:Event'])) {
+					$item = ActivityPub\Processor::createItem($fetchQueue, $object_data);
+					ActivityPub\Processor::postItem($object_data, $item);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Add':
 				if ($object_data['object_type'] == 'as:tag') {
 					ActivityPub\Processor::addTag($object_data);
+				} elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::addToFeaturedCollection($object_data);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Announce':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 					$object_data['thread-completion'] = Contact::getIdForURL($actor);
+					$object_data['completion-mode']   = self::COMPLETION_ANNOUCE;
 
-					$item = ActivityPub\Processor::createItem($object_data);
+					$item = ActivityPub\Processor::createItem($fetchQueue, $object_data);
 					if (empty($item)) {
 						return;
 					}
@@ -573,41 +665,79 @@ class Receiver
 						$announce_object_data['raw'] = $body;
 					}
 
-					ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
+					ActivityPub\Processor::createActivity($fetchQueue, $announce_object_data, Activity::ANNOUNCE);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Like':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::LIKE);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Dislike':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::DISLIKE);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:TentativeAccept':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::ATTENDMAYBE);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Update':
 				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
-					ActivityPub\Processor::updateItem($object_data);
+					ActivityPub\Processor::updateItem($fetchQueue, $object_data);
 				} elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 					ActivityPub\Processor::updatePerson($object_data);
+				} elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
+					// Unhandled Peertube activity
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
 			case 'as:Delete':
-				if ($object_data['object_type'] == 'as:Tombstone') {
+				if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 					ActivityPub\Processor::deleteItem($object_data);
 				} elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 					ActivityPub\Processor::deletePerson($object_data);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+				}
+				break;
+
+			case 'as:Block':
+				if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
+					ActivityPub\Processor::blockAccount($object_data);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+				}
+				break;
+
+			case 'as:Remove':
+				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::removeFromFeaturedCollection($object_data);					
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
@@ -616,7 +746,9 @@ class Receiver
 					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);
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::FOLLOW);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
@@ -624,7 +756,9 @@ 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($fetchQueue, $object_data, Activity::ATTEND);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
@@ -632,7 +766,9 @@ 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($fetchQueue, $object_data, Activity::ATTENDNO);
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
@@ -640,21 +776,91 @@ class Receiver
 				if (($object_data['object_type'] == 'as:Follow') &&
 					in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 					ActivityPub\Processor::undoFollowUser($object_data);
+				} elseif (($object_data['object_type'] == 'as:Follow') &&
+					in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::undoActivity($object_data);
 				} elseif (($object_data['object_type'] == 'as:Accept') &&
 					in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 					ActivityPub\Processor::rejectFollowUser($object_data);
-				} elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
-					in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
+				} elseif (($object_data['object_type'] == 'as:Block') &&
+					in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
+					ActivityPub\Processor::unblockAccount($object_data);
+				} elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
+					in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 					ActivityPub\Processor::undoActivity($object_data);
+				} elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
+					empty($object_data['object_object_type'])) {
+					// We cannot detect the target object. So we can ignore it.
+				} elseif (in_array($object_data['object_type'], ['as:Create']) &&
+					in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
+					// Unhandled Peertube activity
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				}
 				break;
 
+			case 'as:View':
+				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::VIEW);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+				}
+				break;
+
+			case 'litepub:EmojiReact':
+				if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+					ActivityPub\Processor::createActivity($fetchQueue, $object_data, Activity::EMOJIREACT);
+				} elseif ($object_data['object_type'] == '') {
+					// The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
+				} else {
+					self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
+				}
+				break;
+	
 			default:
 				Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
+				self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 				break;
 		}
 	}
 
+	/**
+	 * Stores unhandled or unknown Activities as a file
+	 *
+	 * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
+	 * @param string  $type         Activity type
+	 * @param array   $object_data  Preprocessed array that is generated out of the received activity
+ 	 * @param array   $activity     Array with activity data
+	 * @param string  $body         The unprocessed body
+	 * @param integer $uid          User ID
+	 * @param boolean $trust_source Do we trust the source?
+	 * @param boolean $push         Message had been pushed to our system
+	 * @param array   $signer       The signer of the post
+	 * @return void
+	 */
+	private static function storeUnhandledActivity(bool $unknown, string $type, array $object_data, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
+	{
+		if (!DI::config()->get('debug', 'ap_log_unknown')) {
+			return;
+		}
+
+		$file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
+	
+		if (!empty($object_data['object_type'])) {
+			$file .= str_replace(':', '-', $object_data['object_type']) . '-';
+		}
+
+		if (!empty($object_data['object_object_type'])) {
+			$file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
+		}
+
+		$tempfile = tempnam(System::getTempPath(), $file);
+		file_put_contents($tempfile, json_encode(['activity' => $activity, 'body' => $body, 'uid' => $uid, 'trust_source' => $trust_source, 'push' => $push, 'signer' => $signer, 'object_data' => $object_data], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
+		Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
+	}
+
 	/**
 	 * Fetch a user id from an activity array
 	 *
@@ -663,9 +869,11 @@ class Receiver
 	 *
 	 * @return int   user id
 	 */
-	private static function getBestUserForActivity(array $activity, string $actor)
+	public static function getBestUserForActivity(array $activity): int
 	{
 		$uid = 0;
+		$actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
+
 		$receivers = self::getReceivers($activity, $actor);
 		foreach ($receivers as $receiver) {
 			if ($receiver['type'] == self::TARGET_GLOBAL) {
@@ -675,9 +883,40 @@ class Receiver
 				$uid = $receiver['uid'];
 			}
 		}
+
+		// When we haven't found any user yet, we just chose a user who most likely could have access to the content
+		if (empty($uid)) {
+			$contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
+			if (!empty($contact['uid'])) {
+				$uid = $contact['uid'];
+			}
+		}
+
 		return $uid;
 	}
 
+	// @TODO Missing documentation
+	public static function getReceiverURL(array $activity): array
+	{
+		$urls = [];
+
+		foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
+			$receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
+			if (empty($receiver_list)) {
+				continue;
+			}
+
+			foreach ($receiver_list as $receiver) {
+				if ($receiver == self::PUBLIC_COLLECTION) {
+					$receiver = ActivityPub::PUBLIC_COLLECTION;
+				}
+				$urls[$element][] = $receiver;
+			}
+		}
+
+		return $urls;
+	}
+
 	/**
 	 * Fetch the receiver list from an activity array
 	 *
@@ -689,9 +928,9 @@ class Receiver
 	 * @return array with receivers (user id)
 	 * @throws \Exception
 	 */
-	private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
+	private static function getReceivers(array $activity, string $actor, array $tags = [], bool $fetch_unlisted = false): array
 	{
-		$reply = $receivers = [];
+		$reply = $receivers = $profile = [];
 
 		// When it is an answer, we inherite the receivers from the parent
 		$replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
@@ -751,7 +990,7 @@ class Receiver
 
 				// Fetch the receivers for the public and the followers collection
 				if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
-					$receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target);
+					$receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
 					continue;
 				}
 
@@ -813,33 +1052,46 @@ class Receiver
 	 * @param array   $tags
 	 * @param array   $receivers
 	 * @param integer $target_type
+	 * @param array   $profile
 	 *
 	 * @return array with receivers (user id)
 	 * @throws \Exception
 	 */
-	private static function getReceiverForActor($actor, $tags, $receivers, $target_type)
+	private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
 	{
 		$basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 			'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 
-		$condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
-		$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
-		while ($contact = DBA::fetch($contacts)) {
-			if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
-				$receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
+		if (!empty($profile['uri-id'])) {
+			$condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
+			$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
+			while ($contact = DBA::fetch($contacts)) {
+				if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
+					$receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
+				}
 			}
-		}
-		DBA::close($contacts);
-
-		// The queries are split because of performance issues
-		$condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
-		$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
-		while ($contact = DBA::fetch($contacts)) {
-			if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
-				$receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
+			DBA::close($contacts);
+		} else {
+			// This part will only be called while post update 1426 wasn't finished
+			$condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
+			$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
+			while ($contact = DBA::fetch($contacts)) {
+				if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
+					$receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
+				}
+			}
+			DBA::close($contacts);
+
+			// The queries are split because of performance issues
+			$condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
+			$contacts = DBA::select('contact', ['uid', 'rel'], $condition);
+			while ($contact = DBA::fetch($contacts)) {
+				if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
+					$receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
+				}
 			}
+			DBA::close($contacts);
 		}
-		DBA::close($contacts);
 		return $receivers;
 	}
 
@@ -847,13 +1099,12 @@ class Receiver
 	 * Tests if the contact is a valid receiver for this actor
 	 *
 	 * @param array  $contact
-	 * @param string $actor
 	 * @param array  $tags
 	 *
 	 * @return bool with receivers (user id)
 	 * @throws \Exception
 	 */
-	private static function isValidReceiverForActor($contact, $tags)
+	private static function isValidReceiverForActor(array $contact, array $tags): bool
 	{
 		// Are we following the contact? Then this is a valid receiver
 		if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
@@ -886,10 +1137,11 @@ class Receiver
 	 * @param integer $cid Contact ID
 	 * @param integer $uid User ID
 	 * @param string  $url Profile URL
+	 * @return void
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 * @throws \ImagickException
 	 */
-	public static function switchContact($cid, $uid, $url)
+	public static function switchContact(int $cid, int $uid, string $url)
 	{
 		if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 			Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
@@ -908,10 +1160,11 @@ class Receiver
 	}
 
 	/**
-	 *
+	 * @TODO Fix documentation and type-hints
 	 *
 	 * @param $receivers
 	 * @param $actor
+	 * @return void
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 * @throws \ImagickException
 	 */
@@ -935,14 +1188,14 @@ class Receiver
 	}
 
 	/**
-	 *
+	 * @TODO Fix documentation and type-hints
 	 *
 	 * @param       $object_data
 	 * @param array $activity
 	 *
 	 * @return mixed
 	 */
-	private static function addActivityFields($object_data, $activity)
+	private static function addActivityFields($object_data, array $activity)
 	{
 		if (!empty($activity['published']) && empty($object_data['published'])) {
 			$object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
@@ -1062,7 +1315,7 @@ class Receiver
 	 * @param array $languages
 	 * @return array Languages
 	 */
-	public static function processLanguages(array $languages)
+	public static function processLanguages(array $languages): array
 	{
 		if (empty($languages)) {
 			return [];
@@ -1085,7 +1338,7 @@ class Receiver
 	 *
 	 * @return array with tags in a simplified format
 	 */
-	public static function processTags(array $tags)
+	public static function processTags(array $tags): array
 	{
 		$taglist = [];
 
@@ -1117,7 +1370,7 @@ class Receiver
 	 * @param array $emojis
 	 * @return array with emojis in a simplified format
 	 */
-	private static function processEmojis(array $emojis)
+	private static function processEmojis(array $emojis): array
 	{
 		$emojilist = [];
 
@@ -1143,7 +1396,7 @@ class Receiver
 	 *
 	 * @return array Attachments in a simplified format
 	 */
-	private static function processAttachments(array $attachments)
+	private static function processAttachments(array $attachments): array
 	{
 		$attachlist = [];
 
@@ -1253,16 +1506,75 @@ class Receiver
 		return $attachlist;
 	}
 
+	/**
+	 * Convert questions from JSON-LD format into a simplified format
+	 *
+	 * @param array $object
+	 *
+	 * @return array Questions in a simplified format
+	 */
+	private static function processQuestion(array $object): array
+	{
+		$question = [];
+
+		if (!empty($object['as:oneOf'])) {
+			$question['multiple'] = false;
+			$options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
+		} elseif (!empty($object['as:anyOf'])) {
+			$question['multiple'] = true;
+			$options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
+		} else {
+			return [];
+		}
+
+		$closed = JsonLD::fetchElement($object, 'as:closed', '@value');
+		if (!empty($closed)) {
+			$question['end-time'] = $closed;
+		} else {
+			$question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
+		}
+
+		$question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
+		$question['options'] = [];
+
+		$voters = 0;
+
+		foreach ($options as $option) {
+			if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
+				continue;
+			}
+
+			$name = JsonLD::fetchElement($option, 'as:name', '@value');
+
+			if (empty($option['as:replies'])) {
+				continue;
+			}
+
+			$replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
+
+			$question['options'][] = ['name' => $name, 'replies' => $replies];
+
+			$voters += (int)$replies;
+		}
+
+		// For single choice question we can count the number of voters if not provided (like with Misskey)
+		if (empty($question['voters']) && !$question['multiple']) {
+			$question['voters'] = $voters;
+		}
+
+		return $question;
+	}
+
 	/**
 	 * Fetch the original source or content with the "language" Markdown or HTML
 	 *
 	 * @param array $object
 	 * @param array $object_data
 	 *
-	 * @return array
+	 * @return array Object data (?)
 	 * @throws \Exception
 	 */
-	private static function getSource($object, $object_data)
+	private static function getSource(array $object, array $object_data): array
 	{
 		$object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 		$object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
@@ -1391,10 +1703,10 @@ class Receiver
 	 *
 	 * @param array $object
 	 *
-	 * @return array
+	 * @return array|bool Object data or FALSE if $object does not contain @id element
 	 * @throws \Exception
 	 */
-	private static function processObject($object)
+	private static function processObject(array $object)
 	{
 		if (!JsonLD::fetchElement($object, '@id')) {
 			return false;
@@ -1487,6 +1799,10 @@ class Receiver
 			}
 		}
 
+		if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
+			$object_data['alternate-url'] = null;
+		}
+
 		if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
 			$object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
 			$object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
@@ -1500,14 +1816,19 @@ class Receiver
 			$object_data['alternate-url'] = null;
 		}
 
-		$receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
+		if ($object_data['object_type'] == 'as:Question') {
+			$object_data['question'] = self::processQuestion($object);
+		}
+
+		$receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true);
 		$receivers = $reception_types = [];
 		foreach ($receiverdata as $key => $data) {
 			$receivers[$key] = $data['uid'];
 			$reception_types[$data['uid']] = $data['type'] ?? 0;
 		}
 
-		$object_data['receiver'] = $receivers;
+		$object_data['receiver_urls']  = self::getReceiverURL($object);
+		$object_data['receiver']       = $receivers;
 		$object_data['reception_type'] = $reception_types;
 
 		$object_data['unlisted'] = in_array(-1, $object_data['receiver']);