]> git.mxchange.org Git - friendica.git/blobdiff - src/Protocol/ActivityPub.php
all endpoints are now working
[friendica.git] / src / Protocol / ActivityPub.php
index b27101aac8fb2f30a07f8b11ab93cce2310068d9..fa88847f37892e50e203a7d78d375c7dcd952d56 100644 (file)
@@ -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;
@@ -21,6 +22,7 @@ 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
@@ -34,29 +36,33 @@ use Friendica\Util\LDSignature;
  *
  * 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, Announce
- * - Object Tyoes: Article, Person, Tombstone
+ * - Activities: Announce, Update (Person)
+ * - Object Tyoes: Person
  *
  * General:
- * - Endpoints: Outbox, 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()
        {
@@ -64,6 +70,124 @@ class ActivityPub
                        stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
        }
 
+       public static function getFollowers($owner, $page = null)
+       {
+               $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);
+
+               $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 $data;
+               }
+
+               if (empty($page)) {
+                       $data['first'] = System::baseUrl() . '/followers/' . $owner['nickname'] . '?page=1';
+               } else {
+                       $list = [];
+
+                       $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() . '/followers/' . $owner['nickname'] . '?page=' . ($page + 1);
+                       }
+
+                       $data['partOf'] = System::baseUrl() . '/followers/' . $owner['nickname'];
+
+                       $data['orderedItems'] = $list;
+               }
+
+               return $data;
+       }
+
+       public static function getFollowing($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;
+
+               // 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 = [];
+
+                       $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;
+       }
+
        /**
         * Return the ActivityPub profile of the given user
         *
@@ -122,7 +246,7 @@ class ActivityPub
                return $data;
        }
 
-       public static function fetchPermissionBlockFromConversation($item)
+       private static function fetchPermissionBlockFromConversation($item)
        {
                if (empty($item['thr-parent'])) {
                        return [];
@@ -139,6 +263,13 @@ class ActivityPub
                $actor = JsonLD::fetchElement($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'];
@@ -150,10 +281,12 @@ class ActivityPub
                                $activity[$element] = [$activity[$element]];
                        }
                        foreach ($activity[$element] as $receiver) {
-                               if ($receiver == $profile['followers']) {
-                                       $receiver = System::baseUrl() . '/followers/' . $item['author-nick'];
+                               if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
+                                       $receiver = $item_profile['followers'];
+                               }
+                               if (!in_array($receiver, $exclude)) {
+                                       $permissions[$element][] = $receiver;
                                }
-                               $permissions[$element][] = $receiver;
                        }
                }
                return $permissions;
@@ -165,27 +298,32 @@ class ActivityPub
 
                $data = array_merge($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 = [];
-                       $contacts = [];
 
                        foreach ($terms as $term) {
                                if ($term['type'] != TERM_MENTION) {
@@ -206,97 +344,107 @@ class ActivityPub
                                        $contacts[$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']] = $profile['url'];
+                       }
+
+                       if ($item['gravity'] != GRAVITY_PARENT) {
+                               continue;
+                       }
 
-                       if (empty($data['to'])) {
-                               $data['to'] = $data['cc'];
-                               $data['cc'] = [];
+                       $profile = self::fetchprofile($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, $uid)
        {
+               $permissions = self::createPermissionBlockForItem($item);
+               if (empty($permissions)) {
+                       return [];
+               }
+
                $inboxes = [];
 
-               $parents = Item::select(['author-link', 'owner-link'], ['parent' => $item['parent']]);
-               while ($parent = Item::fetch($parents)) {
-                       $profile = self::fetchprofile($parent['author-link']);
-                       if (!empty($profile)) {
-                               $target = defaults($profile, 'sharedinbox', $profile['inbox']);
-                               $inboxes[$target] = $target;
-                       }
-                       $profile = self::fetchprofile($parent['owner-link']);
-                       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 {
+                       $item_profile = ActivityPub::fetchprofile($item['owner-link']);
                }
-               DBA::close($parents);
-
-               $terms = Term::tagArrayFromItemId($item['id']);
-               if (!$item['private']) {
-                       $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);
 
-                       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;
-                               }
+               $elements = ['to', 'cc', 'bto', 'bcc'];
+               foreach ($elements as $element) {
+                       if (empty($permissions[$element])) {
+                               continue;
                        }
-               } else {
-                       $receiver_list = Item::enumeratePermissions($item);
-                       $mentioned = [];
 
-                       foreach ($terms as $term) {
-                               if ($term['type'] != TERM_MENTION) {
-                                       continue;
-                               }
-                               $cid = Contact::getIdForURL($term['url'], $uid);
-                               if (!empty($cid) && in_array($cid, $receiver_list)) {
-                                       $contact = DBA::selectFirst('contact', ['url'], ['id' => $cid, 'network' => Protocol::ACTIVITYPUB]);
-                                       $profile = self::fetchprofile($contact['url']);
+                       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)) {
-                                       $target = defaults($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]);
 
@@ -313,14 +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) {
+                       $data = ['@context' => self::CONTEXT];
+
+                       if ($item['deleted'] && ($item['gravity'] == GRAVITY_ACTIVITY)) {
+                               $type = 'Undo';
+                       } elseif ($item['deleted']) {
+                               $type = 'Delete';
+                       }
+               } else {
+                       $data = [];
+               }
 
-               $data['id'] = $item['uri'] . '#activity';
-               $data['type'] = 'Create';
+               $data['id'] = $item['uri'] . '#' . $type;
+               $data['type'] = $type;
                $data['actor'] = $item['author-link'];
 
                $data['published'] = DateTimeFormat::utc($item["created"]."+00:00", DateTimeFormat::ATOM);
@@ -329,13 +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);
+               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']);
 
-               return LDSignature::sign($data, $owner);
+               if (!$object_mode) {
+                       return LDSignature::sign($data, $owner);
+               } else {
+                       return $data;
+               }
        }
 
        public static function createObjectFromItemID($item_id)
@@ -346,14 +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;
        }
@@ -375,15 +537,40 @@ 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['id'] = $item['uri'];
-               $data['type'] = 'Note';
+               $data['type'] = $type;
+
+               if ($item['deleted']) {
+                       return $data;
+               }
+
                $data['summary'] = null; // Ignore by now
 
                if ($item['uri'] != $item['thr-parent']) {
@@ -392,25 +579,18 @@ class ActivityPub
                        $data['inReplyTo'] = null;
                }
 
+               $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['uri'];
+               $data['url'] = $item['plink'];
                $data['attributedTo'] = $item['author-link'];
                $data['actor'] = $item['author-link'];
                $data['sensitive'] = false; // - Query NSFW
-
-               $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'];
-               }
-
-               $data['conversation'] = $conversation_uri;
+               $data['conversation'] = $data['context'] = self::createConversationURLFromItem($item);
 
                if (!empty($item['title'])) {
                        $data['name'] = BBCode::convert($item['title'], false, 7);
@@ -519,7 +699,6 @@ class ActivityPub
                if (!$ret['success'] || empty($ret['body'])) {
                        return;
                }
-
                return json_decode($ret['body'], true);
        }
 
@@ -562,13 +741,20 @@ class ActivityPub
                return false;
        }
 
-       public static function fetchprofile($url, $update = false)
+       /**
+        * Fetches a profile form a given url
+        *
+        * @param string  $url    profile url
+        * @param boolean $update true = always update, false = never update, null = update when not found
+        * @return array profile array
+        */
+       public static function fetchprofile($url, $update = null)
        {
                if (empty($url)) {
                        return false;
                }
 
-               if (!$update) {
+               if (empty($update)) {
                        $apcontact = DBA::selectFirst('apcontact', [], ['url' => $url]);
                        if (DBA::isResult($apcontact)) {
                                return $apcontact;
@@ -583,6 +769,10 @@ class ActivityPub
                        if (DBA::isResult($apcontact)) {
                                return $apcontact;
                        }
+
+                       if (!is_null($update)) {
+                               return false;
+                       }
                }
 
                if (empty(parse_url($url, PHP_URL_SCHEME))) {
@@ -715,14 +905,17 @@ class ActivityPub
 
                if (LDSignature::isSigned($activity)) {
                        $ld_signer = LDSignature::getSigner($activity);
-                       if (!empty($ld_signer)) {
+                       if (!empty($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.', LOGGER_DEBUG);
+                               logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
                                $trust_source = false;
                        }
                } elseif ($actor == $http_signer) {
@@ -869,6 +1062,7 @@ class ActivityPub
                                break;
 
                        case 'Dislike':
+                               self::dislikeItem($object_data, $body);
                                break;
 
                        case 'Update':
@@ -1016,7 +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($data['type'])) {
@@ -1233,6 +1427,17 @@ class ActivityPub
                self::postItem($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']?
@@ -1279,6 +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.');