X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FProtocol%2FActivityPub.php;h=95542ba966200b9fb14aa261f11013814e0468cc;hb=c083ae047c4259dcfa1c61a3795679bbf1b08d8c;hp=5b5d16e85a9c3813ab33e8a3047a2364253508c4;hpb=699a4140f9a4bf31d406b684e58ea3b8ef3417c2;p=friendica.git

diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index 5b5d16e85a..95542ba966 100644
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -13,12 +13,14 @@ use Friendica\Core\Protocol;
 use Friendica\Model\Conversation;
 use Friendica\Model\Contact;
 use Friendica\Model\Item;
+use Friendica\Model\Term;
 use Friendica\Model\User;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Crypto;
 use Friendica\Content\Text\BBCode;
 use Friendica\Content\Text\HTML;
-use Friendica\Network\Probe;
+use Friendica\Util\JsonLD;
+use Friendica\Util\LDSignature;
 
 /**
  * @brief ActivityPub Protocol class
@@ -32,6 +34,7 @@ use Friendica\Network\Probe;
  *
  * Digest: https://tools.ietf.org/html/rfc5843
  * https://tools.ietf.org/html/draft-cavage-http-signatures-10#ref-15
+ * https://github.com/digitalbazaar/php-json-ld
  *
  * Part of the code for HTTP signing is taken from the Osada project.
  * https://framagit.org/macgirvin/osada
@@ -43,13 +46,13 @@ use Friendica\Network\Probe;
  * - Object Types: Person, Tombstome
  *
  * Transmitter:
- * - Activities: Like, Dislike, Update, Delete
- * - Object Tyoes: Article, Announce, Person, Tombstone
+ * - Activities: Like, Dislike, Update, Delete, Announce
+ * - Object Tyoes: Article, Person, Tombstone
  *
  * General:
- * - Message distribution
- * - Endpoints: Outbox, Object, Follower, Following
+ * - Endpoints: Outbox, Follower, Following
  * - General cleanup
+ * - Queueing unsucessful deliveries
  */
 class ActivityPub
 {
@@ -61,38 +64,6 @@ class ActivityPub
 			stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
 	}
 
-	public static function transmit($data, $target, $uid)
-	{
-		$owner = User::getOwnerDataById($uid);
-
-		if (!$owner) {
-			return;
-		}
-
-		$content = json_encode($data);
-
-		// Header data that is about to be signed.
-		$host = parse_url($target, PHP_URL_HOST);
-		$path = parse_url($target, PHP_URL_PATH);
-		$digest = 'SHA-256=' . base64_encode(hash('sha256', $content, true));
-		$content_length = strlen($content);
-
-		$headers = ['Content-Length: ' . $content_length, 'Digest: ' . $digest, 'Host: ' . $host];
-
-		$signed_data = "(request-target): post " . $path . "\ncontent-length: " . $content_length . "\ndigest: " . $digest . "\nhost: " . $host;
-
-		$signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
-
-		$headers[] = 'Signature: keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) content-length digest host",signature="' . $signature . '"';
-
-		$headers[] = 'Content-Type: application/activity+json';
-
-		Network::post($target, $content, $headers);
-		$return_code = BaseObject::getApp()->get_curl_code();
-
-		logger('Transmit to ' . $target . ' returned ' . $return_code);
-	}
-
 	/**
 	 * Return the ActivityPub profile of the given user
 	 *
@@ -101,10 +72,10 @@ class ActivityPub
 	 */
 	public static function profile($uid)
 	{
-		$accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application', 'page-flags'];
+		$accounttype = ['Person', 'Organization', 'Service', 'Group', 'Application'];
 		$condition = ['uid' => $uid, 'blocked' => false, 'account_expired' => false,
 			'account_removed' => false, 'verified' => true];
-		$fields = ['guid', 'nickname', 'pubkey', 'account-type'];
+		$fields = ['guid', 'nickname', 'pubkey', 'account-type', 'page-flags'];
 		$user = DBA::selectFirst('user', $fields, $condition);
 		if (!DBA::isResult($user)) {
 			return [];
@@ -123,9 +94,8 @@ class ActivityPub
 		}
 
 		$data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
-			['uuid' => 'http://schema.org/identifier', 'sensitive' => 'as:sensitive',
-			'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
-			'vcard' => 'http://www.w3.org/2006/vcard/ns#']]];
+			['vcard' => 'http://www.w3.org/2006/vcard/ns#', 'uuid' => 'http://schema.org/identifier',
+			'sensitive' => 'as:sensitive', 'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers']]];
 
 		$data['id'] = $contact['url'];
 		$data['uuid'] = $user['guid'];
@@ -140,7 +110,7 @@ class ActivityPub
 			'vcard:region' => $profile['region'], 'vcard:locality' => $profile['locality']];
 		$data['summary'] = $contact['about'];
 		$data['url'] = $contact['url'];
-		$data['manuallyApprovesFollowers'] = in_array($profile['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
+		$data['manuallyApprovesFollowers'] = in_array($user['page-flags'], [Contact::PAGE_NORMAL, Contact::PAGE_PRVGROUP]);
 		$data['publicKey'] = ['id' => $contact['url'] . '#main-key',
 			'owner' => $contact['url'],
 			'publicKeyPem' => $user['pubkey']];
@@ -152,63 +122,316 @@ class ActivityPub
 		return $data;
 	}
 
+	private static function fetchPermissionBlockFromConversation($item)
+	{
+		if (empty($item['thr-parent'])) {
+			return [];
+		}
+
+		$condition = ['item-uri' => $item['thr-parent'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
+		$conversation = DBA::selectFirst('conversation', ['source'], $condition);
+		if (!DBA::isResult($conversation)) {
+			return [];
+		}
+
+		$activity = json_decode($conversation['source'], true);
+
+		$actor = JsonLD::fetchElement($activity, 'actor', 'id');
+		$profile = ActivityPub::fetchprofile($actor);
+
+		$item_profile = ActivityPub::fetchprofile($item['owner-link']);
+
+		$permissions = [];
+
+		$elements = ['to', 'cc', 'bto', 'bcc'];
+		foreach ($elements as $element) {
+			if (empty($activity[$element])) {
+				continue;
+			}
+			if (is_string($activity[$element])) {
+				$activity[$element] = [$activity[$element]];
+			}
+			foreach ($activity[$element] as $receiver) {
+				if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
+					$receiver = $item_profile['followers'];
+				}
+				if ($receiver != $item['owner-link']) {
+					$permissions[$element][] = $receiver;
+				}
+			}
+		}
+		return $permissions;
+	}
+
+	public static function createPermissionBlockForItem($item)
+	{
+		$data = ['to' => [], 'cc' => []];
+
+		$data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
+
+		$actor_profile = ActivityPub::fetchprofile($item['author-link']);
+
+		$terms = Term::tagArrayFromItemId($item['id']);
+
+		$contacts[$item['author-link']] = $item['author-link'];
+
+		if (!$item['private']) {
+			$data['to'][] = self::PUBLIC;
+			if (!empty($actor_profile['followers'])) {
+				$data['cc'][] = $actor_profile['followers'];
+			}
+
+			foreach ($terms as $term) {
+				if ($term['type'] != TERM_MENTION) {
+					continue;
+				}
+				$profile = self::fetchprofile($term['url']);
+				if (!empty($profile) && empty($contacts[$profile['url']])) {
+					$data['cc'][] = $profile['url'];
+					$contacts[$profile['url']] = $profile['url'];
+				}
+			}
+		} else {
+			$receiver_list = Item::enumeratePermissions($item);
+
+			$mentioned = [];
+
+			foreach ($terms as $term) {
+				if ($term['type'] != TERM_MENTION) {
+					continue;
+				}
+				$cid = Contact::getIdForURL($term['url'], $item['uid']);
+				if (!empty($cid) && in_array($cid, $receiver_list)) {
+					$contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
+					$data['to'][] = $contact['url'];
+					$contacts[$contact['url']] = $contact['url'];
+				}
+			}
+
+			foreach ($receiver_list as $receiver) {
+				$contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
+				if (empty($contacts[$contact['url']])) {
+					$data['cc'][] = $contact['url'];
+					$contacts[$contact['url']] = $contact['url'];
+				}
+			}
+		}
+
+		$parents = Item::select(['author-link', 'owner-link'], ['parent' => $item['parent']]);
+		while ($parent = Item::fetch($parents)) {
+			$profile = self::fetchprofile($parent['author-link']);
+			if (!empty($profile) && empty($contacts[$profile['url']])) {
+				$data['cc'][] = $profile['url'];
+				$contacts[$profile['url']] = $profile['url'];
+			}
+
+			$profile = self::fetchprofile($parent['owner-link']);
+			if (!empty($profile) && empty($contacts[$profile['url']])) {
+				$data['cc'][] = $profile['url'];
+				$contacts[$profile['url']] = $profile['url'];
+			}
+		}
+		DBA::close($parents);
+
+		if (empty($data['to'])) {
+			$data['to'] = $data['cc'];
+			$data['cc'] = [];
+		}
+
+		return $data;
+	}
+
+	public static function fetchTargetInboxes($item, $uid)
+	{
+		$permissions = self::createPermissionBlockForItem($item);
+		if (empty($permissions)) {
+			return [];
+		}
+
+		$inboxes = [];
+
+		$item_profile = ActivityPub::fetchprofile($item['owner-link']);
+
+		$elements = ['to', 'cc', 'bto', 'bcc'];
+		foreach ($elements as $element) {
+			if (empty($permissions[$element])) {
+				continue;
+			}
+			foreach ($permissions[$element] as $receiver) {
+				if ($receiver == $item_profile['followers']) {
+					$contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $uid,
+						'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
+					while ($contact = DBA::fetch($contacts)) {
+						$contact = defaults($contact, 'batch', $contact['notify']);
+						$inboxes[$contact] = $contact;
+					}
+					DBA::close($contacts);
+				} else {
+					$profile = self::fetchprofile($receiver);
+					if (!empty($profile)) {
+						$target = defaults($profile, 'sharedinbox', $profile['inbox']);
+						$inboxes[$target] = $target;
+					}
+				}
+			}
+		}
+
+		if (!empty($item_profile['sharedinbox'])) {
+			unset($inboxes[$item_profile['sharedinbox']]);
+		}
+
+		if (!empty($item_profile['inbox'])) {
+			unset($inboxes[$item_profile['inbox']]);
+		}
+
+		return $inboxes;
+	}
+
 	public static function createActivityFromItem($item_id)
 	{
 		$item = Item::selectFirst([], ['id' => $item_id]);
 
+		if (!DBA::isResult($item)) {
+			return false;
+		}
+
+		$condition = ['item-uri' => $item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB];
+		$conversation = DBA::selectFirst('conversation', ['source'], $condition);
+		if (DBA::isResult($conversation)) {
+			$data = json_decode($conversation['source']);
+			if (!empty($data)) {
+				return $data;
+			}
+		}
+
 		$data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
-			['Emoji' => 'toot:Emoji', 'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
-			'conversation' => 'ostatus:conversation', 'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri',
-			'ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
-			'toot' => 'http://joinmastodon.org/ns#']]];
+			['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
+			'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
+			'conversation' => 'ostatus:conversation',
+			'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
 
+		$data['id'] = $item['uri'] . '#activity';
 		$data['type'] = 'Create';
-		$data['id'] = $item['uri'] . '/activity';
 		$data['actor'] = $item['author-link'];
-		$data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
-		$data['object'] = self::createNote($item);
+
+		$data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
+
+		if ($item["created"] != $item["edited"]) {
+			$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
+		}
+
+		$data['context_id'] = $item['parent'];
+		$data['context'] = self::createConversationURLFromItem($item);
+
+		$data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
+
+		$data['object'] = self::createObjectTypeFromItem($item);
+
+		$owner = User::getOwnerDataById($item['uid']);
+
+		return LDSignature::sign($data, $owner);
+	}
+
+	public static function createObjectFromItemID($item_id)
+	{
+		$item = Item::selectFirst([], ['id' => $item_id]);
+
+		if (!DBA::isResult($item)) {
+			return false;
+		}
+
+		$data = ['@context' => ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
+			['ostatus' => 'http://ostatus.org#', 'sensitive' => 'as:sensitive',
+			'Hashtag' => 'as:Hashtag', 'atomUri' => 'ostatus:atomUri',
+			'conversation' => 'ostatus:conversation',
+			'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']]];
+
+		$data = array_merge($data, self::createObjectTypeFromItem($item));
+
+
 		return $data;
 	}
 
-	public static function createNote($item)
+	private static function createTagList($item)
 	{
-		$data = [];
-		$data['type'] = 'Note';
-		$data['id'] = $item['uri'];
+		$tags = [];
+
+		$terms = Term::tagArrayFromItemId($item['id']);
+		foreach ($terms as $term) {
+			if ($term['type'] == TERM_MENTION) {
+				$contact = Contact::getDetailsByURL($term['url']);
+				if (!empty($contact['addr'])) {
+					$mention = '@' . $contact['addr'];
+				} else {
+					$mention = '@' . $term['url'];
+				}
 
-		if ($item['uri'] != $item['thr-parent']) {
-			$data['inReplyTo'] = $item['thr-parent'];
+				$tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
+			}
 		}
+		return $tags;
+	}
 
+	private static function createConversationURLFromItem($item)
+	{
 		$conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
 		if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
 			$conversation_uri = $conversation['conversation-uri'];
 		} else {
 			$conversation_uri = $item['parent-uri'];
 		}
+		return $conversation_uri;
+	}
 
-		$data['context'] = $data['conversation'] = $conversation_uri;
-		$data['actor'] = $item['author-link'];
-		if (!$item['private']) {
-			$data['to'] = 'https://www.w3.org/ns/activitystreams#Public';
+	private static function createObjectTypeFromItem($item)
+	{
+		if (!empty($item['title'])) {
+			$type = 'Article';
+		} else {
+			$type = 'Note';
+		}
+
+		$data = [];
+		$data['id'] = $item['uri'];
+		$data['type'] = $type;
+		$data['summary'] = null; // Ignore by now
+
+		if ($item['uri'] != $item['thr-parent']) {
+			$data['inReplyTo'] = $item['thr-parent'];
+		} else {
+			$data['inReplyTo'] = null;
 		}
+
 		$data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
-		$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
+
+		if ($item["created"] != $item["edited"]) {
+			$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
+		}
+
+		$data['url'] = $item['plink'];
 		$data['attributedTo'] = $item['author-link'];
-		$data['name'] = BBCode::convert($item['title'], false, 7);
+		$data['actor'] = $item['author-link'];
+		$data['sensitive'] = false; // - Query NSFW
+		$data['context_id'] = $item['parent'];
+		$data['conversation'] = $data['context'] = self::createConversationURLFromItem($item);
+
+		if (!empty($item['title'])) {
+			$data['name'] = BBCode::convert($item['title'], false, 7);
+		}
+
 		$data['content'] = BBCode::convert($item['body'], false, 7);
 		$data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
-		//$data['summary'] = ''; // Ignore by now
-		//$data['sensitive'] = false; // - Query NSFW
+		$data['attachment'] = []; // @ToDo
+		$data['tag'] = self::createTagList($item);
+		$data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
+
 		//$data['emoji'] = []; // Ignore by now
-		//$data['tag'] = []; /// @ToDo
-		//$data['attachment'] = []; // @ToDo
 		return $data;
 	}
 
 	public static function transmitActivity($activity, $target, $uid)
 	{
-		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+		$profile = self::fetchprofile($target);
 
 		$owner = User::getOwnerDataById($uid);
 
@@ -220,12 +443,14 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['notify'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactAccept($target, $id, $uid)
 	{
-		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+		$profile = self::fetchprofile($target);
 
 		$owner = User::getOwnerDataById($uid);
 		$data = ['@context' => 'https://www.w3.org/ns/activitystreams',
@@ -238,12 +463,14 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['notify'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactReject($target, $id, $uid)
 	{
-		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+		$profile = self::fetchprofile($target);
 
 		$owner = User::getOwnerDataById($uid);
 		$data = ['@context' => 'https://www.w3.org/ns/activitystreams',
@@ -256,12 +483,14 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['notify'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactUndo($target, $uid)
 	{
-		$profile = Probe::uri($target, Protocol::ACTIVITYPUB);
+		$profile = self::fetchprofile($target);
 
 		$id = System::baseUrl() . '/activity/' . System::createGUID();
 
@@ -276,7 +505,9 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['notify'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	/**
@@ -334,208 +565,126 @@ class ActivityPub
 		return false;
 	}
 
-	public static function verifySignature($content, $http_headers)
+	public static function fetchprofile($url, $update = false)
 	{
-		$object = json_decode($content, true);
-
-		if (empty($object)) {
+		if (empty($url)) {
 			return false;
 		}
 
-		$actor = self::processElement($object, 'actor', 'id');
-
-		$headers = [];
-		$headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . $http_headers['REQUEST_URI'];
-
-		// First take every header
-		foreach ($http_headers as $k => $v) {
-			$field = str_replace('_', '-', strtolower($k));
-			$headers[$field] = $v;
-		}
-
-		// Now add every http header
-		foreach ($http_headers as $k => $v) {
-			if (strpos($k, 'HTTP_') === 0) {
-				$field = str_replace('_', '-', strtolower(substr($k, 5)));
-				$headers[$field] = $v;
+		if (!$update) {
+			$apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
+			if (DBA::isResult($apcontact)) {
+				return $apcontact;
 			}
-		}
-
-		$sig_block = ActivityPub::parseSigHeader($http_headers['HTTP_SIGNATURE']);
-
-		if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
-			return false;
-		}
 
-		$signed_data = '';
-		foreach ($sig_block['headers'] as $h) {
-			if (array_key_exists($h, $headers)) {
-				$signed_data .= $h . ': ' . $headers[$h] . "\n";
+			$apcontact = DBA::selectFirst('apcontact', [], ['alias' => $url]);
+			if (DBA::isResult($apcontact)) {
+				return $apcontact;
 			}
-		}
-		$signed_data = rtrim($signed_data, "\n");
 
-		if (empty($signed_data)) {
-			return false;
-		}
-
-		$algorithm = null;
-
-		if ($sig_block['algorithm'] === 'rsa-sha256') {
-			$algorithm = 'sha256';
-		}
-
-		if ($sig_block['algorithm'] === 'rsa-sha512') {
-			$algorithm = 'sha512';
+			$apcontact = DBA::selectFirst('apcontact', [], ['addr' => $url]);
+			if (DBA::isResult($apcontact)) {
+				return $apcontact;
+			}
 		}
 
-		if (empty($algorithm)) {
-			return false;
+		if (empty(parse_url($url, PHP_URL_SCHEME))) {
+			$url = self::addrToUrl($url);
+			if (empty($url)) {
+				return false;
+			}
 		}
 
-		$key = self::fetchKey($sig_block['keyId'], $actor);
-
-		if (empty($key)) {
-			return false;
-		}
+		$data = self::fetchContent($url);
 
-		if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
+		if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
 			return false;
 		}
 
-		// Check the digest when it is part of the signed data
-		if (in_array('digest', $sig_block['headers'])) {
-			$digest = explode('=', $headers['digest'], 2);
-			if ($digest[0] === 'SHA-256') {
-				$hashalg = 'sha256';
-			}
-			if ($digest[0] === 'SHA-512') {
-				$hashalg = 'sha512';
-			}
-
-			/// @todo add all hashes from the rfc
-
-			if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
-				return false;
-			}
-		}
-
-		// Check the content-length when it is part of the signed data
-		if (in_array('content-length', $sig_block['headers'])) {
-			if (strlen($content) != $headers['content-length']) {
-				return false;
-			}
-		}
+		$apcontact = [];
+		$apcontact['url'] = $data['id'];
+		$apcontact['uuid'] = defaults($data, 'uuid', null);
+		$apcontact['type'] = defaults($data, 'type', null);
+		$apcontact['following'] = defaults($data, 'following', null);
+		$apcontact['followers'] = defaults($data, 'followers', null);
+		$apcontact['inbox'] = defaults($data, 'inbox', null);
+		$apcontact['outbox'] = defaults($data, 'outbox', null);
+		$apcontact['sharedinbox'] = JsonLD::fetchElement($data, 'endpoints', 'sharedInbox');
+		$apcontact['nick'] = defaults($data, 'preferredUsername', null);
+		$apcontact['name'] = defaults($data, 'name', $apcontact['nick']);
+		$apcontact['about'] = defaults($data, 'summary', '');
+		$apcontact['photo'] = JsonLD::fetchElement($data, 'icon', 'url');
+		$apcontact['alias'] = JsonLD::fetchElement($data, 'url', 'href');
+
+		$parts = parse_url($apcontact['url']);
+		unset($parts['scheme']);
+		unset($parts['path']);
+		$apcontact['addr'] = $apcontact['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
 
-		return true;
+		$apcontact['pubkey'] = trim(JsonLD::fetchElement($data, 'publicKey', 'publicKeyPem'));
 
-	}
+		// To-Do
+		// manuallyApprovesFollowers
 
-	private static function fetchKey($id, $actor)
-	{
-		$url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
-
-		$profile = Probe::uri($url, Protocol::ACTIVITYPUB);
-		if (!empty($profile)) {
-			return $profile['pubkey'];
-		} elseif ($url != $actor) {
-			$profile = Probe::uri($actor, Protocol::ACTIVITYPUB);
-			if (!empty($profile)) {
-				return $profile['pubkey'];
-			}
-		}
+		// Unhandled
+		// @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
 
-		return false;
-	}
+		// Unhandled from Misskey
+		// sharedInbox, isCat
 
-	/**
-	 * @brief
-	 *
-	 * @param string $header
-	 * @return array associate array with
-	 *   - \e string \b keyID
-	 *   - \e string \b algorithm
-	 *   - \e array  \b headers
-	 *   - \e string \b signature
-	 */
-	private static function parseSigHeader($header)
-	{
-		$ret = [];
-		$matches = [];
+		// Unhandled from Kroeg
+		// kroeg:blocks, updated
 
-		if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
-			$ret['keyId'] = $matches[1];
+		// Check if the address is resolvable
+		if (self::addrToUrl($apcontact['addr']) == $apcontact['url']) {
+			$parts = parse_url($apcontact['url']);
+			unset($parts['path']);
+			$apcontact['baseurl'] = Network::unparseURL($parts);
+		} else {
+			$apcontact['addr'] = null;
 		}
 
-		if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
-			$ret['algorithm'] = $matches[1];
+		if ($apcontact['url'] == $apcontact['alias']) {
+			$apcontact['alias'] = null;
 		}
 
-		if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
-			$ret['headers'] = explode(' ', $matches[1]);
-		}
+		$apcontact['updated'] = DateTimeFormat::utcNow();
 
-		if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
-			$ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
-		}
+		DBA::update('apcontact', $apcontact, ['url' => $url], true);
 
-		return $ret;
+		return $apcontact;
 	}
 
 	/**
-	 * Fetches a profile from the given url
+	 * Fetches a profile from the given url into an array that is compatible to Probe::uri
 	 *
 	 * @param string $url profile url
 	 * @return array
 	 */
-	public static function fetchProfile($url)
+	public static function probeProfile($url)
 	{
-		if (empty(parse_url($url, PHP_URL_SCHEME))) {
-			$url = self::addrToUrl($url);
-			if (empty($url)) {
-				return false;
-			}
-		}
-
-		$data = self::fetchContent($url);
-
-		if (empty($data) || empty($data['id']) || empty($data['inbox'])) {
+		$apcontact = self::fetchprofile($url, true);
+		if (empty($apcontact)) {
 			return false;
 		}
 
 		$profile = ['network' => Protocol::ACTIVITYPUB];
-		$profile['nick'] = $data['preferredUsername'];
-		$profile['name'] = defaults($data, 'name', $profile['nick']);
-		$profile['guid'] = defaults($data, 'uuid', null);
-		$profile['url'] = $data['id'];
-
-		$parts = parse_url($profile['url']);
-		unset($parts['scheme']);
-		unset($parts['path']);
-		$profile['addr'] = $profile['nick'] . '@' . str_replace('//', '', Network::unparseURL($parts));
-		$profile['alias'] = self::processElement($data, 'url', 'href');
-		$profile['photo'] = self::processElement($data, 'icon', 'url');
+		$profile['nick'] = $apcontact['nick'];
+		$profile['name'] = $apcontact['name'];
+		$profile['guid'] = $apcontact['uuid'];
+		$profile['url'] = $apcontact['url'];
+		$profile['addr'] = $apcontact['addr'];
+		$profile['alias'] = $apcontact['alias'];
+		$profile['photo'] = $apcontact['photo'];
 		// $profile['community']
 		// $profile['keywords']
 		// $profile['location']
-		$profile['about'] = defaults($data, 'summary', '');
-		$profile['batch'] = self::processElement($data, 'endpoints', 'sharedInbox');
-		$profile['notify'] = $data['inbox'];
-		$profile['poll'] = $data['outbox'];
-		$profile['pubkey'] = self::processElement($data, 'publicKey', 'publicKeyPem');
-
-		// Check if the address is resolvable
-		if (self::addrToUrl($profile['addr']) == $profile['url']) {
-			$parts = parse_url($profile['url']);
-			unset($parts['path']);
-			$profile['baseurl'] = Network::unparseURL($parts);
-		} else {
-			unset($profile['addr']);
-		}
-
-		if ($profile['url'] == $profile['alias']) {
-			unset($profile['alias']);
-		}
+		$profile['about'] = $apcontact['about'];
+		$profile['batch'] = $apcontact['sharedinbox'];
+		$profile['notify'] = $apcontact['inbox'];
+		$profile['poll'] = $apcontact['outbox'];
+		$profile['pubkey'] = $apcontact['pubkey'];
+		$profile['baseurl'] = $apcontact['baseurl'];
 
 		// Remove all "null" fields
 		foreach ($profile as $field => $content) {
@@ -544,41 +693,56 @@ class ActivityPub
 			}
 		}
 
-		// To-Do
-		// type, manuallyApprovesFollowers
-
-		// Unhandled
-		// @context, tag, attachment, image, nomadicLocations, signature, following, followers, featured, movedTo, liked
-
-		// Unhandled from Misskey
-		// sharedInbox, isCat
-
-		// Unhandled from Kroeg
-		// kroeg:blocks, updated
-
 		return $profile;
 	}
 
 	public static function processInbox($body, $header, $uid)
 	{
-		logger('Incoming message for user ' . $uid, LOGGER_DEBUG);
-
-		if (!self::verifySignature($body, $header)) {
-			logger('Invalid signature, message will be discarded.', LOGGER_DEBUG);
+		$http_signer = HTTPSignature::getSigner($body, $header);
+		if (empty($http_signer)) {
+			logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
 			return;
+		} else {
+			logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
 		}
 
 		$activity = json_decode($body, true);
 
-		if (!is_array($activity)) {
+		$actor = JsonLD::fetchElement($activity, 'actor', 'id');
+		logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
+
+		if (empty($activity)) {
 			logger('Invalid body.', LOGGER_DEBUG);
 			return;
 		}
 
-		self::processActivity($activity, $body, $uid);
+		if (LDSignature::isSigned($activity)) {
+			$ld_signer = LDSignature::getSigner($activity);
+			if (!empty($ld_signer && ($actor == $http_signer))) {
+				logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
+				$trust_source = true;
+			} elseif (!empty($ld_signer)) {
+				logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
+				$trust_source = true;
+			} elseif ($actor == $http_signer) {
+				logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
+				$trust_source = true;
+			} else {
+				logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
+				$trust_source = false;
+			}
+		} elseif ($actor == $http_signer) {
+			logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
+			$trust_source = true;
+		} else {
+			logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
+			$trust_source = false;
+		}
+
+		self::processActivity($activity, $body, $uid, $trust_source);
 	}
 
-	public static function fetchOutbox($url)
+	public static function fetchOutbox($url, $uid)
 	{
 		$data = self::fetchContent($url);
 		if (empty($data)) {
@@ -590,20 +754,20 @@ class ActivityPub
 		} elseif (!empty($data['first']['orderedItems'])) {
 			$items = $data['first']['orderedItems'];
 		} elseif (!empty($data['first'])) {
-			self::fetchOutbox($data['first']);
+			self::fetchOutbox($data['first'], $uid);
 			return;
 		} else {
 			$items = [];
 		}
 
 		foreach ($items as $activity) {
-			self::processActivity($activity);
+			self::processActivity($activity, '', $uid, true);
 		}
 	}
 
-	private static function prepareObjectData($activity, $uid)
+	private static function prepareObjectData($activity, $uid, $trust_source)
 	{
-		$actor = self::processElement($activity, 'actor', 'id');
+		$actor = JsonLD::fetchElement($activity, 'actor', 'id');
 		if (empty($actor)) {
 			logger('Empty actor', LOGGER_DEBUG);
 			return [];
@@ -621,8 +785,6 @@ class ActivityPub
 
 		logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 
-		$public = in_array(0, $receivers);
-
 		if (is_string($activity['object'])) {
 			$object_url = $activity['object'];
 		} elseif (!empty($activity['object']['id'])) {
@@ -634,19 +796,19 @@ class ActivityPub
 
 		// Fetch the content only on activities where this matters
 		if (in_array($activity['type'], ['Create', 'Update', 'Announce'])) {
-			$object_data = self::fetchObject($object_url, $activity['object']);
+			$object_data = self::fetchObject($object_url, $activity['object'], $trust_source);
 			if (empty($object_data)) {
 				logger("Object data couldn't be processed", LOGGER_DEBUG);
 				return [];
 			}
 		} elseif ($activity['type'] == 'Accept') {
 			$object_data = [];
-			$object_data['object_type'] = self::processElement($activity, 'object', 'type');
-			$object_data['object'] = self::processElement($activity, 'object', 'actor');
+			$object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
+			$object_data['object'] = JsonLD::fetchElement($activity, 'object', 'actor');
 		} elseif ($activity['type'] == 'Undo') {
 			$object_data = [];
-			$object_data['object_type'] = self::processElement($activity, 'object', 'type');
-			$object_data['object'] = self::processElement($activity, 'object', 'object');
+			$object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
+			$object_data['object'] = JsonLD::fetchElement($activity, 'object', 'object');
 		} elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 			// 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.
@@ -670,7 +832,7 @@ class ActivityPub
 		return $object_data;
 	}
 
-	private static function processActivity($activity, $body = '', $uid = null)
+	private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 	{
 		if (empty($activity['type'])) {
 			logger('Empty type', LOGGER_DEBUG);
@@ -696,7 +858,7 @@ class ActivityPub
 
 		logger('Processing activity: ' . $activity['type'], LOGGER_DEBUG);
 
-		$object_data = self::prepareObjectData($activity, $uid);
+		$object_data = self::prepareObjectData($activity, $uid, $trust_source);
 		if (empty($object_data)) {
 			logger('No object data found', LOGGER_DEBUG);
 			return;
@@ -747,9 +909,18 @@ class ActivityPub
 	{
 		$receivers = [];
 
+		// When it is an answer, we inherite the receivers from the parent
+		$replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
+		if (!empty($replyto)) {
+			$parents = Item::select(['uid'], ['uri' => $replyto]);
+			while ($parent = Item::fetch($parents)) {
+				$receivers['uid:' . $parent['uid']] = $parent['uid'];
+			}
+		}
+
 		if (!empty($actor)) {
-			$data = self::fetchContent($actor);
-			$followers = defaults($data, 'followers', '');
+			$profile = self::fetchprofile($actor);
+			$followers = defaults($profile, 'followers', '');
 
 			logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 		} else {
@@ -820,23 +991,24 @@ class ActivityPub
 		}
 
 		if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
-			$object_data['parent-uri'] = self::processElement($activity, 'inReplyTo', 'id');
+			$object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
 		}
 
 		if (!empty($activity['instrument'])) {
-			$object_data['service'] = self::processElement($activity, 'instrument', 'name', 'type', 'Service');
+			$object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
 		}
 		return $object_data;
 	}
 
-	private static function fetchObject($object_url, $object = [], $public = true)
+	private static function fetchObject($object_url, $object = [], $trust_source = false)
 	{
-		if ($public) {
+		if (!$trust_source || is_string($object)) {
 			$data = self::fetchContent($object_url);
 			if (empty($data)) {
 				logger('Empty content for ' . $object_url . ', check if content is available locally.', LOGGER_DEBUG);
 				$data = $object_url;
-				$data = $object;
+			} else {
+				logger('Fetched content for ' . $object_url, LOGGER_DEBUG);
 			}
 		} else {
 			logger('Using original object for url ' . $object_url, LOGGER_DEBUG);
@@ -850,7 +1022,7 @@ class ActivityPub
 				return false;
 			}
 			logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
-			$data = self::createNote($item);
+			$data = self::createObjectTypeFromItem($item);
 		}
 
 		if (empty($data['type'])) {
@@ -900,7 +1072,7 @@ class ActivityPub
 		$object_data['uri'] = $object['id'];
 
 		if (!empty($object['inReplyTo'])) {
-			$object_data['reply-to-uri'] = self::processElement($object, 'inReplyTo', 'id');
+			$object_data['reply-to-uri'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
 		} else {
 			$object_data['reply-to-uri'] = $object_data['uri'];
 		}
@@ -913,7 +1085,7 @@ class ActivityPub
 		}
 
 		$object_data['uuid'] = defaults($object, 'uuid', null);
-		$object_data['owner'] = $object_data['author'] = self::processElement($object, 'attributedTo', 'id');
+		$object_data['owner'] = $object_data['author'] = JsonLD::fetchElement($object, 'attributedTo', 'id');
 		$object_data['context'] = defaults($object, 'context', null);
 		$object_data['conversation'] = defaults($object, 'conversation', null);
 		$object_data['sensitive'] = defaults($object, 'sensitive', null);
@@ -922,11 +1094,11 @@ class ActivityPub
 		$object_data['summary'] = defaults($object, 'summary', null);
 		$object_data['content'] = defaults($object, 'content', null);
 		$object_data['source'] = defaults($object, 'source', null);
-		$object_data['location'] = self::processElement($object, 'location', 'name', 'type', 'Place');
+		$object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
 		$object_data['attachments'] = defaults($object, 'attachment', null);
 		$object_data['tags'] = defaults($object, 'tag', null);
-		$object_data['service'] = self::processElement($object, 'instrument', 'name', 'type', 'Service');
-		$object_data['alternate-url'] = self::processElement($object, 'url', 'href');
+		$object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
+		$object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
 		$object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
 
 		// Unhandled
@@ -973,41 +1145,6 @@ class ActivityPub
 		return $object_data;
 	}
 
-	private static function processElement($array, $element, $key, $type = null, $type_value = null)
-	{
-		if (empty($array)) {
-			return false;
-		}
-
-		if (empty($array[$element])) {
-			return false;
-		}
-
-		if (is_string($array[$element])) {
-			return $array[$element];
-		}
-
-		if (is_null($type_value)) {
-			if (!empty($array[$element][$key])) {
-				return $array[$element][$key];
-			}
-
-			if (!empty($array[$element][0][$key])) {
-				return $array[$element][0][$key];
-			}
-
-			return false;
-		}
-
-		if (!empty($array[$element][$key]) && !empty($array[$element][$type]) && ($array[$element][$type] == $type_value)) {
-			return $array[$element][$key];
-		}
-
-		/// @todo Add array search
-
-		return false;
-	}
-
 	private static function convertMentions($body)
 	{
 		$URLSearchString = "^\[\]";
@@ -1029,6 +1166,11 @@ class ActivityPub
 					$tag_text .= ',';
 				}
 
+				if (empty($tag['href'])) {
+					//$tag['href']
+					logger('Blubb!');
+				}
+
 				$tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
 			}
 		}
@@ -1119,7 +1261,7 @@ class ActivityPub
 
 		$item = self::constructAttachList($activity['attachments'], $item);
 
-		$source = self::processElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
+		$source = JsonLD::fetchElement($activity, 'source', 'content', 'mediaType', 'text/bbcode');
 		if (!empty($source)) {
 			$item['body'] = $source;
 		}
@@ -1155,10 +1297,11 @@ class ActivityPub
 		$activity['id'] = $object['id'];
 		$activity['to'] = defaults($object, 'to', []);
 		$activity['cc'] = defaults($object, 'cc', []);
-		$activity['actor'] = $activity['author'];
+		$activity['actor'] = $child['author'];
 		$activity['object'] = $object;
 		$activity['published'] = $object['published'];
 		$activity['type'] = 'Create';
+
 		self::processActivity($activity);
 		logger('Activity ' . $url . ' had been fetched and processed.');
 	}