X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FProtocol%2FActivityPub.php;h=fa88847f37892e50e203a7d78d375c7dcd952d56;hb=8c7e5bb776583ac97b31bc023fbc335b1a2b1251;hp=bd125aaaef1d3a03dce762c29e060e3a0645b496;hpb=0d51474e73dc50ac0b7159cb92fcadeafb976fc1;p=friendica.git

diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index bd125aaaef..fa88847f37 100644
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -13,6 +13,7 @@ use Friendica\Core\Protocol;
 use Friendica\Model\Conversation;
 use Friendica\Model\Contact;
 use Friendica\Model\Item;
+use Friendica\Model\Profile;
 use Friendica\Model\Term;
 use Friendica\Model\User;
 use Friendica\Util\DateTimeFormat;
@@ -20,6 +21,8 @@ use Friendica\Util\Crypto;
 use Friendica\Content\Text\BBCode;
 use Friendica\Content\Text\HTML;
 use Friendica\Util\JsonLD;
+use Friendica\Util\LDSignature;
+use Friendica\Core\Config;
 
 /**
  * @brief ActivityPub Protocol class
@@ -33,29 +36,33 @@ use Friendica\Util\JsonLD;
  *
  * 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
+ * Mastodon implementation of supported activities:
+ * https://github.com/tootsuite/mastodon/blob/master/app/lib/activitypub/activity.rb#L26
  *
  * To-do:
  *
  * Receiver:
- * - Activities: Dislike, Update, Delete
+ * - Activities: Update (Notes, Person), Delete (Person, Activities, Notes)
  * - Object Types: Person, Tombstome
  *
  * Transmitter:
- * - Activities: Like, Dislike, Update, Delete
- * - Object Tyoes: Article, Announce, Person, Tombstone
+ * - Activities: Announce, Update (Person)
+ * - Object Tyoes: Person
  *
  * General:
- * - Message distribution
- * - Endpoints: Outbox, Object, Follower, Following
- * - General cleanup
+ * - Queueing unsucessful deliveries
+ * - Event support
+ * - Polling the outboxes for missing content?
  */
 class ActivityPub
 {
 	const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
+	const CONTEXT = ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1',
+		['ostatus' => 'http://ostatus.org#', 'uuid' => 'http://schema.org/identifier',
+		'sensitive' => 'as:sensitive', 'Hashtag' => 'as:Hashtag',
+		'atomUri' => 'ostatus:atomUri', 'conversation' => 'ostatus:conversation',
+		'inReplyToAtomUri' => 'ostatus:inReplyToAtomUri']];
 
 	public static function isRequest()
 	{
@@ -63,36 +70,122 @@ class ActivityPub
 			stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
 	}
 
-	public static function transmit($data, $target, $uid)
+	public static function getFollowers($owner, $page = null)
 	{
-		$owner = User::getOwnerDataById($uid);
+		$condition = ['rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
+			'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
+		$count = DBA::count('contact', $condition);
 
-		if (!$owner) {
-			return;
+		$data = ['@context' => self::CONTEXT];
+		$data['id'] = System::baseUrl() . '/followers/' . $owner['nickname'];
+		$data['type'] = 'OrderedCollection';
+		$data['totalItems'] = $count;
+
+		// When we hide our friends we will only show the pure number but don't allow more.
+		$profile = Profile::getProfileForUser($owner['uid']);
+		if (!empty($profile['hide-friends'])) {
+			return $data;
 		}
 
-		$content = json_encode($data);
+		if (empty($page)) {
+			$data['first'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=1';
+		} else {
+			$list = [];
 
-		// 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);
+			$contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
+			while ($contact = DBA::fetch($contacts)) {
+				$list[] = $contact['url'];
+			}
 
-		$headers = ['Content-Length: ' . $content_length, 'Digest: ' . $digest, 'Host: ' . $host];
+			if (!empty($list)) {
+				$data['next'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=' . ($page + 1);
+			}
 
-		$signed_data = "(request-target): post " . $path . "\ncontent-length: " . $content_length . "\ndigest: " . $digest . "\nhost: " . $host;
+			$data['partOf'] = System::baseUrl() . '/followers/' . $owner['nickname'];
 
-		$signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
+			$data['orderedItems'] = $list;
+		}
 
-		$headers[] = 'Signature: keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) content-length digest host",signature="' . $signature . '"';
+		return $data;
+	}
 
-		$headers[] = 'Content-Type: application/activity+json';
+	public static function getFollowing($owner, $page = null)
+	{
+		$condition = ['rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::NATIVE_SUPPORT, 'uid' => $owner['uid'],
+			'self' => false, 'hidden' => false, 'archive' => false, 'pending' => false];
+		$count = DBA::count('contact', $condition);
+
+		$data = ['@context' => self::CONTEXT];
+		$data['id'] = System::baseUrl() . '/following/' . $owner['nickname'];
+		$data['type'] = 'OrderedCollection';
+		$data['totalItems'] = $count;
 
-		Network::post($target, $content, $headers);
-		$return_code = BaseObject::getApp()->get_curl_code();
+		// When we hide our friends we will only show the pure number but don't allow more.
+		$profile = Profile::getProfileForUser($owner['uid']);
+		if (!empty($profile['hide-friends'])) {
+			return $data;
+		}
+
+		if (empty($page)) {
+			$data['first'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=1';
+		} else {
+			$list = [];
 
-		logger('Transmit to ' . $target . ' returned ' . $return_code);
+			$contacts = DBA::select('contact', ['url'], $condition, ['limit' => [($page - 1) * 100, 100]]);
+			while ($contact = DBA::fetch($contacts)) {
+				$list[] = $contact['url'];
+			}
+
+			if (!empty($list)) {
+				$data['next'] = System::baseUrl() . '/following/' . $owner['nickname'] . '?page=' . ($page + 1);
+			}
+
+			$data['partOf'] = System::baseUrl() . '/following/' . $owner['nickname'];
+
+			$data['orderedItems'] = $list;
+		}
+
+		return $data;
+	}
+
+	public static function getOutbox($owner, $page = null)
+	{
+		$public_contact = Contact::getIdForURL($owner['url'], 0, true);
+
+		$condition = ['uid' => $owner['uid'], 'contact-id' => $owner['id'], 'author-id' => $public_contact,
+			'wall' => true, 'private' => false, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT],
+			'deleted' => false, 'visible' => true];
+		$count = DBA::count('item', $condition);
+
+		$data = ['@context' => self::CONTEXT];
+		$data['id'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
+		$data['type'] = 'OrderedCollection';
+		$data['totalItems'] = $count;
+
+		if (empty($page)) {
+			$data['first'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=1';
+		} else {
+			$list = [];
+
+			$condition['parent-network'] = Protocol::NATIVE_SUPPORT;
+
+			$items = Item::select(['id'], $condition, ['limit' => [($page - 1) * 20, 20], 'order' => ['created' => true]]);
+			while ($item = Item::fetch($items)) {
+				$object = self::createObjectFromItemID($item['id']);
+				unset($object['@context']);
+				$list[] = $object;
+			}
+
+			if (!empty($list)) {
+				$data['next'] = System::baseUrl() . '/outbox/' . $owner['nickname'] . '?page=' . ($page + 1);
+			}
+
+			$data['partOf'] = System::baseUrl() . '/outbox/' . $owner['nickname'];
+
+			$data['orderedItems'] = $list;
+		}
+
+		return $data;
 	}
 
 	/**
@@ -103,10 +196,10 @@ 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 [];
@@ -141,7 +234,7 @@ 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']];
@@ -153,27 +246,81 @@ 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['author-link']);
+		$exclude[] = $item['author-link'];
+
+		if ($item['gravity'] == GRAVITY_PARENT) {
+			$exclude[] = $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 = $item_profile['followers'];
+				}
+				if (!in_array($receiver, $exclude)) {
+					$permissions[$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;
-			$data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
+			if (!empty($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)) {
+				$profile = self::fetchprofile($term['url'], false);
+				if (!empty($profile) && empty($contacts[$profile['url']])) {
 					$data['cc'][] = $profile['url'];
+					$contacts[$profile['url']] = $profile['url'];
 				}
 			}
 		} else {
-			//$data['cc'][] = System::baseUrl() . '/followers/' . $item['author-nick'];
 			$receiver_list = Item::enumeratePermissions($item);
 
 			$mentioned = [];
@@ -186,90 +333,118 @@ class ActivityPub
 				if (!empty($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]);
-				$data['cc'][] = $contact['url'];
+				if (empty($contacts[$contact['url']])) {
+					$data['cc'][] = $contact['url'];
+					$contacts[$contact['url']] = $contact['url'];
+				}
+			}
+		}
+
+// It is to decide whether we should include all profiles in a thread to the list of receivers
+/*
+		$parents = Item::select(['author-link', 'owner-link', 'gravity'], ['parent' => $item['parent']]);
+		while ($parent = Item::fetch($parents)) {
+			$profile = self::fetchprofile($parent['author-link'], false);
+			if (!empty($profile) && empty($contacts[$profile['url']])) {
+				$data['cc'][] = $profile['url'];
+				$contacts[$profile['url']] = $profile['url'];
 			}
 
-			if (empty($data['to'])) {
-				$data['to'] = $data['cc'];
-				$data['cc'] = [];
+			if ($item['gravity'] != GRAVITY_PARENT) {
+				continue;
 			}
+
+			$profile = self::fetchprofile($parent['owner-link'], false);
+			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($item)
+	public static function fetchTargetInboxes($item, $uid)
 	{
-		$inboxes = [];
+		$permissions = self::createPermissionBlockForItem($item);
+		if (empty($permissions)) {
+			return [];
+		}
 
-		$terms = Term::tagArrayFromItemId($item['id']);
-		if (!$item['private']) {
-			$contacts = DBA::select('contact', ['notify', 'batch'], ['uid' => $item['uid'],
-					'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB]);
-			while ($contact = DBA::fetch($contacts)) {
-				$contact = defaults($contact, 'batch', $contact['notify']);
-				$inboxes[$contact] = $contact;
-			}
-			DBA::close($contacts);
+		$inboxes = [];
 
-			foreach ($terms as $term) {
-				if ($term['type'] != TERM_MENTION) {
-					continue;
-				}
-				$profile = self::fetchprofile($term['url']);
-				if (!empty($profile)) {
-					$target = defaults($profile, 'sharedinbox', $profile['inbox']);
-					$inboxes[$target] = $target;
-				}
-			}
+		if ($item['gravity'] == GRAVITY_ACTIVITY) {
+			$item_profile = ActivityPub::fetchprofile($item['author-link']);
 		} else {
-			$receiver_list = Item::enumeratePermissions($item);
+			$item_profile = ActivityPub::fetchprofile($item['owner-link']);
+		}
 
-			$mentioned = [];
+		$elements = ['to', 'cc', 'bto', 'bcc'];
+		foreach ($elements as $element) {
+			if (empty($permissions[$element])) {
+				continue;
+			}
 
-			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]);
-					$profile = self::fetchprofile($contact['url']);
-					if (!empty($profile['network'])) {
+			foreach ($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] = $target;
 					}
 				}
 			}
-
-			foreach ($receiver_list as $receiver) {
-				$contact = DBA::selectFirst('contact', ['url'], ['id' => $receiver, 'network' => Protocol::ACTIVITYPUB]);
-				$profile = self::fetchprofile($contact['url']);
-				if (!empty($profile['network'])) {
-					$target = defaults($profile, 'sharedinbox', $profile['inbox']);
-					$inboxes[$target] = $target;
-				}
-			}
 		}
 
-		$profile = self::fetchprofile($item['author-link']);
-		if (!empty($profile['sharedinbox'])) {
-			unset($inboxes[$profile['sharedinbox']]);
-		}
+		return $inboxes;
+	}
 
-		if (!empty($profile['inbox'])) {
-			unset($inboxes[$profile['inbox']]);
+	public static function getTypeOfItem($item)
+	{
+		if ($item['verb'] == ACTIVITY_POST) {
+			if ($item['created'] == $item['edited']) {
+				$type = 'Create';
+			} else {
+				$type = 'Update';
+			}
+		} elseif ($item['verb'] == ACTIVITY_LIKE) {
+			$type = 'Like';
+		} elseif ($item['verb'] == ACTIVITY_DISLIKE) {
+			$type = 'Dislike';
+		} elseif ($item['verb'] == ACTIVITY_ATTEND) {
+			$type = 'Accept';
+		} elseif ($item['verb'] == ACTIVITY_ATTENDNO) {
+			$type = 'Reject';
+		} elseif ($item['verb'] == ACTIVITY_ATTENDMAYBE) {
+			$type = 'TentativeAccept';
+		} else {
+			$type = '';
 		}
 
-		return $inboxes;
+		return $type;
 	}
 
-	public static function createActivityFromItem($item_id)
+	public static function createActivityFromItem($item_id, $object_mode = false)
 	{
 		$item = Item::selectFirst([], ['id' => $item_id]);
 
@@ -286,14 +461,22 @@ class ActivityPub
 			}
 		}
 
-		$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']]];
+		$type = self::getTypeOfItem($item);
+
+		if (!$object_mode) {
+			$data = ['@context' => self::CONTEXT];
 
-		$data['type'] = 'Create';
-		$data['id'] = $item['uri'] . '#activity';
+			if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
+				$type = 'Undo';
+			} elseif ($item['deleted']) {
+				$type = 'Delete';
+			}
+		} else {
+			$data = [];
+		}
+
+		$data['id'] = $item['uri'] . '#' . $type;
+		$data['type'] = $type;
 		$data['actor'] = $item['author-link'];
 
 		$data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
@@ -302,10 +485,25 @@ class ActivityPub
 			$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 		}
 
+		$data['context'] = self::createConversationURLFromItem($item);
+
 		$data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 
-		$data['object'] = self::createNote($item);
-		return $data;
+		if (in_array($data['type'], ['Create', 'Update', 'Announce', 'Delete'])) {
+			$data['object'] = self::CreateNote($item);
+		} elseif ($data['type'] == 'Undo') {
+			$data['object'] = self::createActivityFromItem($item_id, true);
+		} else {
+			$data['object'] = $item['thr-parent'];
+		}
+
+		$owner = User::getOwnerDataById($item['uid']);
+
+		if (!$object_mode) {
+			return LDSignature::sign($data, $owner);
+		} else {
+			return $data;
+		}
 	}
 
 	public static function createObjectFromItemID($item_id)
@@ -316,14 +514,8 @@ class ActivityPub
 			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::createNote($item));
-
+		$data = ['@context' => self::CONTEXT];
+		$data = array_merge($data, self::CreateNote($item));
 
 		return $data;
 	}
@@ -345,45 +537,72 @@ class ActivityPub
 				$tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
 			}
 		}
-
 		return $tags;
 	}
 
-	public static function createNote($item)
+	private static function createConversationURLFromItem($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 $conversation_uri;
+	}
+
+	private static function CreateNote($item)
+	{
+		if (!empty($item['title'])) {
+			$type = 'Article';
+		} else {
+			$type = 'Note';
+		}
+
+		if ($item['deleted']) {
+			$type = 'Tombstone';
+		}
+
 		$data = [];
-		$data['type'] = 'Note';
 		$data['id'] = $item['uri'];
+		$data['type'] = $type;
 
-		if ($item['uri'] != $item['thr-parent']) {
-			$data['inReplyTo'] = $item['thr-parent'];
+		if ($item['deleted']) {
+			return $data;
 		}
 
-		$conversation = DBA::selectFirst('conversation', ['conversation-uri'], ['item-uri' => $item['parent-uri']]);
-		if (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
-			$conversation_uri = $conversation['conversation-uri'];
+		$data['summary'] = null; // Ignore by now
+
+		if ($item['uri'] != $item['thr-parent']) {
+			$data['inReplyTo'] = $item['thr-parent'];
 		} else {
-			$conversation_uri = $item['parent-uri'];
+			$data['inReplyTo'] = null;
 		}
 
-		$data['context'] = $data['conversation'] = $conversation_uri;
-		$data['actor'] = $item['author-link'];
-		$data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
+		$data['uuid'] = $item['guid'];
 		$data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
 
 		if ($item["created"] != $item["edited"]) {
 			$data['updated'] = DateTimeFormat::utc($item["edited"]."+00:00", DateTimeFormat::ATOM);
 		}
 
+		$data['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['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['emoji'] = []; // Ignore by now
-		$data['tag'] = self::createTagList($item);
 		$data['attachment'] = []; // @ToDo
+		$data['tag'] = self::createTagList($item);
+		$data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
+
+		//$data['emoji'] = []; // Ignore by now
 		return $data;
 	}
 
@@ -401,7 +620,9 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['inbox'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactAccept($target, $id, $uid)
@@ -419,7 +640,9 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['inbox'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactReject($target, $id, $uid)
@@ -437,7 +660,9 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['inbox'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	public static function transmitContactUndo($target, $uid)
@@ -457,7 +682,9 @@ class ActivityPub
 			'to' => $profile['url']];
 
 		logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
-		return self::transmit($data,  $profile['inbox'], $uid);
+
+		$signed = LDSignature::sign($data, $owner);
+		return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
 	}
 
 	/**
@@ -472,7 +699,6 @@ class ActivityPub
 		if (!$ret['success'] || empty($ret['body'])) {
 			return;
 		}
-
 		return json_decode($ret['body'], true);
 	}
 
@@ -515,161 +741,20 @@ class ActivityPub
 		return false;
 	}
 
-	public static function verifySignature($content, $http_headers)
-	{
-		$object = json_decode($content, true);
-
-		if (empty($object)) {
-			return false;
-		}
-
-		$actor = JsonLD::fetchElement($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;
-			}
-		}
-
-		$sig_block = ActivityPub::parseSigHeader($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";
-			}
-		}
-		$signed_data = rtrim($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') {
-			$algorithm = 'sha512';
-		}
-
-		if (empty($algorithm)) {
-			return false;
-		}
-
-		$key = self::fetchKey($sig_block['keyId'], $actor);
-
-		if (empty($key)) {
-			return false;
-		}
-
-		if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm)) {
-			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) != $headers['content-length']) {
-				return false;
-			}
-		}
-
-		return true;
-
-	}
-
-	private static function fetchKey($id, $actor)
-	{
-		$url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
-
-		$profile = self::fetchprofile($url);
-		if (!empty($profile)) {
-			return $profile['pubkey'];
-		} elseif ($url != $actor) {
-			$profile = self::fetchprofile($actor);
-			if (!empty($profile)) {
-				return $profile['pubkey'];
-			}
-		}
-
-		return false;
-	}
-
 	/**
-	 * @brief
+	 * Fetches a profile form a given url
 	 *
-	 * @param string $header
-	 * @return array associate array with
-	 *   - \e string \b keyID
-	 *   - \e string \b algorithm
-	 *   - \e array  \b headers
-	 *   - \e string \b signature
+	 * @param string  $url    profile url
+	 * @param boolean $update true = always update, false = never update, null = update when not found
+	 * @return array profile array
 	 */
-	private static function parseSigHeader($header)
-	{
-		$ret = [];
-		$matches = [];
-
-		if (preg_match('/keyId="(.*?)"/ism',$header,$matches)) {
-			$ret['keyId'] = $matches[1];
-		}
-
-		if (preg_match('/algorithm="(.*?)"/ism',$header,$matches)) {
-			$ret['algorithm'] = $matches[1];
-		}
-
-		if (preg_match('/headers="(.*?)"/ism',$header,$matches)) {
-			$ret['headers'] = explode(' ', $matches[1]);
-		}
-
-		if (preg_match('/signature="(.*?)"/ism',$header,$matches)) {
-			$ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1]));
-		}
-
-		return $ret;
-	}
-
-	public static function fetchprofile($url, $update = false)
+	public static function fetchprofile($url, $update = null)
 	{
 		if (empty($url)) {
 			return false;
 		}
 
-		if (!$update) {
+		if (empty($update)) {
 			$apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
 			if (DBA::isResult($apcontact)) {
 				return $apcontact;
@@ -684,6 +769,10 @@ class ActivityPub
 			if (DBA::isResult($apcontact)) {
 				return $apcontact;
 			}
+
+			if (!is_null($update)) {
+				return false;
+			}
 		}
 
 		if (empty(parse_url($url, PHP_URL_SCHEME))) {
@@ -796,24 +885,51 @@ class ActivityPub
 
 	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($data)) {
@@ -825,18 +941,18 @@ class ActivityPub
 		} elseif (!empty($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)
 	{
 		$actor = JsonLD::fetchElement($activity, 'actor', 'id');
 		if (empty($actor)) {
@@ -856,8 +972,6 @@ 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'])) {
@@ -869,7 +983,7 @@ 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 [];
@@ -905,7 +1019,7 @@ 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);
@@ -931,7 +1045,7 @@ 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;
@@ -948,6 +1062,7 @@ class ActivityPub
 				break;
 
 			case 'Dislike':
+				self::dislikeItem($object_data, $body);
 				break;
 
 			case 'Update':
@@ -982,6 +1097,15 @@ 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)) {
 			$profile = self::fetchprofile($actor);
 			$followers = defaults($profile, 'followers', '');
@@ -1064,14 +1188,15 @@ class ActivityPub
 		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);
@@ -1085,7 +1210,7 @@ class ActivityPub
 				return false;
 			}
 			logger('Using already stored item for url ' . $object_url, LOGGER_DEBUG);
-			$data = self::createNote($item);
+			$data = self::CreateNote($item);
 		}
 
 		if (empty($data['type'])) {
@@ -1302,6 +1427,17 @@ class ActivityPub
 		self::postItem($activity, $item, $body);
 	}
 
+	private static function dislikeItem($activity, $body)
+	{
+		$item = [];
+		$item['verb'] = ACTIVITY_DISLIKE;
+		$item['parent-uri'] = $activity['object'];
+		$item['gravity'] = GRAVITY_ACTIVITY;
+		$item['object-type'] = ACTIVITY_OBJ_NOTE;
+
+		self::postItem($activity, $item, $body);
+	}
+
 	private static function postItem($activity, $item, $body)
 	{
 		/// @todo What to do with $activity['context']?
@@ -1348,6 +1484,10 @@ class ActivityPub
 
 	private static function fetchMissingActivity($url, $child)
 	{
+		if (Config::get('system', 'ostatus_full_threads')) {
+			return;
+		}
+
 		$object = ActivityPub::fetchContent($url);
 		if (empty($object)) {
 			logger('Activity ' . $url . ' was not fetchable, aborting.');
@@ -1364,6 +1504,7 @@ class ActivityPub
 		$activity['object'] = $object;
 		$activity['published'] = $object['published'];
 		$activity['type'] = 'Create';
+
 		self::processActivity($activity);
 		logger('Activity ' . $url . ' had been fetched and processed.');
 	}