]> git.mxchange.org Git - friendica.git/blobdiff - src/Protocol/ActivityPub.php
Merge pull request #5792 from MrPetovan/task/add-cache-console
[friendica.git] / src / Protocol / ActivityPub.php
index 3bf304adc9b988b0ee8389ae30fd71aab9ce4c94..ef4a48479ea2a4c677704763af81d10272e443a8 100644 (file)
@@ -44,27 +44,24 @@ use Friendica\Core\Config;
  * To-do:
  *
  * Receiver:
- * - Update Note
- * - Delete Note
- * - Delete Person
+ * - Update (Image, Video, Article, Note)
+ * - Event
  * - Undo Announce
- * - Reject Follow
- * - Undo Accept
- * - Undo Follow
+ *
+ * Check what this is meant to do:
  * - Add
- * - Create Image
- * - Create Video
- * - Event
- * - Remove
  * - Block
  * - Flag
+ * - Remove
+ * - Undo Block
+ * - Undo Accept (Problem: This could invert a contact accept or an event accept)
  *
  * Transmitter:
+ * - Event
+ *
+ * Complicated:
  * - Announce
  * - Undo Announce
- * - Update Person
- * - Reject Follow
- * - Event
  *
  * General:
  * - Attachments
@@ -75,14 +72,15 @@ use Friendica\Core\Config;
  */
 class ActivityPub
 {
-       const PUBLIC = 'https://www.w3.org/ns/activitystreams#Public';
+       const PUBLIC_COLLECTION = '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',
-               'vcard' => 'http://www.w3.org/2006/vcard/ns#',
-               'diaspora' => 'https://diasporafoundation.org#',
+               ['vcard' => 'http://www.w3.org/2006/vcard/ns#',
+               'diaspora' => 'https://diasporafoundation.org/ns/',
                'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
                'sensitive' => 'as:sensitive', 'Hashtag' => 'as:Hashtag']];
-
+       const ACCOUNT_TYPES = ['Person', 'Organization', 'Service', 'Group', 'Application'];
+       const CONTENT_TYPES = ['Note', 'Article', 'Video', 'Image'];
+       const ACTIVITY_TYPES = ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'];
        /**
         * @brief Checks if the web request is done for the AP protocol
         *
@@ -114,7 +112,7 @@ class ActivityPub
                $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']);
+               $profile = Profile::getByUID($owner['uid']);
                if (!empty($profile['hide-friends'])) {
                        return $data;
                }
@@ -161,7 +159,7 @@ class ActivityPub
                $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']);
+               $profile = Profile::getByUID($owner['uid']);
                if (!empty($profile['hide-friends'])) {
                        return $data;
                }
@@ -244,7 +242,6 @@ class ActivityPub
         */
        public static function profile($uid)
        {
-               $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', 'page-flags'];
@@ -268,7 +265,7 @@ class ActivityPub
                $data = ['@context' => self::CONTEXT];
                $data['id'] = $contact['url'];
                $data['diaspora:guid'] = $user['guid'];
-               $data['type'] = $accounttype[$user['account-type']];
+               $data['type'] = self::ACCOUNT_TYPES[$user['account-type']];
                $data['following'] = System::baseUrl() . '/following/' . $user['nickname'];
                $data['followers'] = System::baseUrl() . '/followers/' . $user['nickname'];
                $data['inbox'] = System::baseUrl() . '/inbox/' . $user['nickname'];
@@ -313,9 +310,9 @@ class ActivityPub
                $activity = json_decode($conversation['source'], true);
 
                $actor = JsonLD::fetchElement($activity, 'actor', 'id');
-               $profile = APContact::getProfileByURL($actor);
+               $profile = APContact::getByURL($actor);
 
-               $item_profile = APContact::getProfileByURL($item['author-link']);
+               $item_profile = APContact::getByURL($item['author-link']);
                $exclude[] = $item['author-link'];
 
                if ($item['gravity'] == GRAVITY_PARENT) {
@@ -324,8 +321,7 @@ class ActivityPub
 
                $permissions['to'][] = $actor;
 
-               $elements = ['to', 'cc', 'bto', 'bcc'];
-               foreach ($elements as $element) {
+               foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
                        if (empty($activity[$element])) {
                                continue;
                        }
@@ -346,11 +342,11 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Creates an array of permissions from an item thread
         *
         * @param array $item
         *
-        * @return 
+        * @return permission array
         */
        public static function createPermissionBlockForItem($item)
        {
@@ -358,23 +354,20 @@ class ActivityPub
 
                $data = array_merge($data, self::fetchPermissionBlockFromConversation($item));
 
-               $actor_profile = APContact::getProfileByURL($item['author-link']);
+               $actor_profile = APContact::getByURL($item['author-link']);
 
-               $terms = Term::tagArrayFromItemId($item['id']);
+               $terms = Term::tagArrayFromItemId($item['id'], TERM_MENTION);
 
                $contacts[$item['author-link']] = $item['author-link'];
 
                if (!$item['private']) {
-                       $data['to'][] = self::PUBLIC;
+                       $data['to'][] = self::PUBLIC_COLLECTION;
                        if (!empty($actor_profile['followers'])) {
                                $data['cc'][] = $actor_profile['followers'];
                        }
 
                        foreach ($terms as $term) {
-                               if ($term['type'] != TERM_MENTION) {
-                                       continue;
-                               }
-                               $profile = APContact::getProfileByURL($term['url'], false);
+                               $profile = APContact::getByURL($term['url'], false);
                                if (!empty($profile) && empty($contacts[$profile['url']])) {
                                        $data['cc'][] = $profile['url'];
                                        $contacts[$profile['url']] = $profile['url'];
@@ -386,9 +379,6 @@ class ActivityPub
                        $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]);
@@ -413,7 +403,7 @@ class ActivityPub
                                continue;
                        }
 
-                       $profile = APContact::getProfileByURL($parent['author-link'], false);
+                       $profile = APContact::getByURL($parent['author-link'], false);
                        if (!empty($profile) && empty($contacts[$profile['url']])) {
                                $data['cc'][] = $profile['url'];
                                $contacts[$profile['url']] = $profile['url'];
@@ -423,7 +413,7 @@ class ActivityPub
                                continue;
                        }
 
-                       $profile = APContact::getProfileByURL($parent['owner-link'], false);
+                       $profile = APContact::getByURL($parent['owner-link'], false);
                        if (!empty($profile) && empty($contacts[$profile['url']])) {
                                $data['cc'][] = $profile['url'];
                                $contacts[$profile['url']] = $profile['url'];
@@ -440,12 +430,39 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Fetches a list of inboxes of followers of a given user
+        *
+        * @param integer $uid User ID
+        *
+        * @return array of follower inboxes
+        */
+       public static function fetchTargetInboxesforUser($uid)
+       {
+               $inboxes = [];
+
+               $condition = ['uid' => $uid, 'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
+
+               if (!empty($uid)) {
+                       $condition['rel'] = [Contact::FOLLOWER, Contact::FRIEND];
+               }
+
+               $contacts = DBA::select('contact', ['notify', 'batch'], $condition);
+               while ($contact = DBA::fetch($contacts)) {
+                       $contact = defaults($contact, 'batch', $contact['notify']);
+                       $inboxes[$contact] = $contact;
+               }
+               DBA::close($contacts);
+
+               return $inboxes;
+       }
+
+       /**
+        * @brief Fetches an array of inboxes for the given item and user
         *
         * @param array $item
-        * @param $uid
+        * @param integer $uid User ID
         *
-        * @return 
+        * @return array with inboxes
         */
        public static function fetchTargetInboxes($item, $uid)
        {
@@ -457,28 +474,21 @@ class ActivityPub
                $inboxes = [];
 
                if ($item['gravity'] == GRAVITY_ACTIVITY) {
-                       $item_profile = APContact::getProfileByURL($item['author-link']);
+                       $item_profile = APContact::getByURL($item['author-link']);
                } else {
-                       $item_profile = APContact::getProfileByURL($item['owner-link']);
+                       $item_profile = APContact::getByURL($item['owner-link']);
                }
 
-               $elements = ['to', 'cc', 'bto', 'bcc'];
-               foreach ($elements as $element) {
+               foreach (['to', 'cc', 'bto', 'bcc'] 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);
+                                       $inboxes = self::fetchTargetInboxesforUser($uid);
                                } else {
-                                       $profile = APContact::getProfileByURL($receiver);
+                                       $profile = APContact::getByURL($receiver);
                                        if (!empty($profile)) {
                                                $target = defaults($profile, 'sharedinbox', $profile['inbox']);
                                                $inboxes[$target] = $target;
@@ -491,11 +501,11 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Returns the activity type of a given item
         *
         * @param array $item
         *
-        * @return 
+        * @return activity type
         */
        public static function getTypeOfItem($item)
        {
@@ -523,12 +533,12 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Creates an activity array for a given item id
         *
-        * @param $item_id
-        * @param $object_mode
+        * @param integer $item_id
+        * @param boolean $object_mode Is the activity item is used inside another object?
         *
-        * @return 
+        * @return array of activity
         */
        public static function createActivityFromItem($item_id, $object_mode = false)
        {
@@ -576,7 +586,7 @@ class ActivityPub
                $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
 
                if (in_array($data['type'], ['Create', 'Update', 'Announce', 'Delete'])) {
-                       $data['object'] = self::CreateNote($item);
+                       $data['object'] = self::createNote($item);
                } elseif ($data['type'] == 'Undo') {
                        $data['object'] = self::createActivityFromItem($item_id, true);
                } else {
@@ -593,11 +603,11 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Creates an object array for a given item id
         *
-        * @param $item_id
+        * @param integer $item_id
         *
-        * @return 
+        * @return object array
         */
        public static function createObjectFromItemID($item_id)
        {
@@ -608,44 +618,42 @@ class ActivityPub
                }
 
                $data = ['@context' => self::CONTEXT];
-               $data = array_merge($data, self::CreateNote($item));
+               $data = array_merge($data, self::createNote($item));
 
                return $data;
        }
 
        /**
-        * @brief 
+        * @brief Returns a tag array for a given item array
         *
         * @param array $item
         *
-        * @return 
+        * @return array of tags
         */
        private static function createTagList($item)
        {
                $tags = [];
 
-               $terms = Term::tagArrayFromItemId($item['id']);
+               $terms = Term::tagArrayFromItemId($item['id'], TERM_MENTION);
                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'];
-                               }
-
-                               $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
+                       $contact = Contact::getDetailsByURL($term['url']);
+                       if (!empty($contact['addr'])) {
+                               $mention = '@' . $contact['addr'];
+                       } else {
+                               $mention = '@' . $term['url'];
                        }
+
+                       $tags[] = ['type' => 'Mention', 'href' => $term['url'], 'name' => $mention];
                }
                return $tags;
        }
 
        /**
-        * @brief 
+        * @brief Fetches the "context" value for a givem item array from the "conversation" table
         *
         * @param array $item
         *
-        * @return 
+        * @return string with context url
         */
        private static function fetchContextURLForItem($item)
        {
@@ -655,19 +663,19 @@ class ActivityPub
                } elseif (DBA::isResult($conversation) && !empty($conversation['conversation-uri'])) {
                        $context_uri = $conversation['conversation-uri'];
                } else {
-                       $context_uri = str_replace('/object/', '/context/', $item['parent-uri']);
+                       $context_uri = str_replace('/objects/', '/context/', $item['parent-uri']);
                }
                return $context_uri;
        }
 
        /**
-        * @brief 
+        * @brief Creates a note/article object array
         *
         * @param array $item
         *
-        * @return 
+        * @return object array
         */
-       private static function CreateNote($item)
+       private static function createNote($item)
        {
                if (!empty($item['title'])) {
                        $type = 'Article';
@@ -714,6 +722,11 @@ class ActivityPub
 
                $data['content'] = BBCode::convert($item['body'], false, 7);
                $data['source'] = ['content' => $item['body'], 'mediaType' => "text/bbcode"];
+
+               if (!empty($item['signed_text']) && ($item['uri'] != $item['thr-parent'])) {
+                       $data['diaspora:comment'] = $item['signed_text'];
+               }
+
                $data['attachment'] = []; // @ToDo
                $data['tag'] = self::createTagList($item);
                $data = array_merge($data, ActivityPub::createPermissionBlockForItem($item));
@@ -722,17 +735,67 @@ class ActivityPub
        }
 
        /**
-        * @brief 
+        * @brief Transmits a profile deletion to a given inbox
         *
-        * @param array $activity
-        * @param $target
-        * @param $uid
+        * @param integer $uid User ID
+        * @param string $inbox Target inbox
+        */
+       public static function transmitProfileDeletion($uid, $inbox)
+       {
+               $owner = User::getOwnerDataById($uid);
+               $profile = APContact::getByURL($owner['url']);
+
+               $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
+                       'id' => System::baseUrl() . '/activity/' . System::createGUID(),
+                       'type' => 'Delete',
+                       'actor' => $owner['url'],
+                       'object' => self::profile($uid),
+                       'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
+                       'to' => [self::PUBLIC_COLLECTION],
+                       'cc' => []];
+
+               $signed = LDSignature::sign($data, $owner);
+
+               logger('Deliver profile deletion for user ' . $uid . ' to ' . $inbox .' via ActivityPub', LOGGER_DEBUG);
+               HTTPSignature::transmit($signed, $inbox, $uid);
+       }
+
+       /**
+        * @brief Transmits a profile change to a given inbox
         *
-        * @return 
+        * @param integer $uid User ID
+        * @param string $inbox Target inbox
+        */
+       public static function transmitProfileUpdate($uid, $inbox)
+       {
+               $owner = User::getOwnerDataById($uid);
+               $profile = APContact::getByURL($owner['url']);
+
+               $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
+                       'id' => System::baseUrl() . '/activity/' . System::createGUID(),
+                       'type' => 'Update',
+                       'actor' => $owner['url'],
+                       'object' => self::profile($uid),
+                       'published' => DateTimeFormat::utcNow(DateTimeFormat::ATOM),
+                       'to' => [$profile['followers']],
+                       'cc' => []];
+
+               $signed = LDSignature::sign($data, $owner);
+
+               logger('Deliver profile update for user ' . $uid . ' to ' . $inbox .' via ActivityPub', LOGGER_DEBUG);
+               HTTPSignature::transmit($signed, $inbox, $uid);
+       }
+
+       /**
+        * @brief Transmits a given activity to a target
+        *
+        * @param array $activity
+        * @param string $target Target profile
+        * @param integer $uid User ID
         */
        public static function transmitActivity($activity, $target, $uid)
        {
-               $profile = APContact::getProfileByURL($target);
+               $profile = APContact::getByURL($target);
 
                $owner = User::getOwnerDataById($uid);
 
@@ -746,21 +809,19 @@ class ActivityPub
                logger('Sending activity ' . $activity . ' to ' . $target . ' for user ' . $uid, LOGGER_DEBUG);
 
                $signed = LDSignature::sign($data, $owner);
-               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
+               HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        /**
-        * @brief 
+        * @brief Transmit a message that the contact request had been accepted
         *
-        * @param $target
+        * @param string $target Target profile
         * @param $id
-        * @param $uid
-        *
-        * @return 
+        * @param integer $uid User ID
         */
        public static function transmitContactAccept($target, $id, $uid)
        {
-               $profile = APContact::getProfileByURL($target);
+               $profile = APContact::getByURL($target);
 
                $owner = User::getOwnerDataById($uid);
                $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
@@ -775,21 +836,19 @@ class ActivityPub
                logger('Sending accept to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 
                $signed = LDSignature::sign($data, $owner);
-               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
+               HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        /**
         * @brief 
         *
-        * @param $target
+        * @param string $target Target profile
         * @param $id
-        * @param $uid
-        *
-        * @return 
+        * @param integer $uid User ID
         */
        public static function transmitContactReject($target, $id, $uid)
        {
-               $profile = APContact::getProfileByURL($target);
+               $profile = APContact::getByURL($target);
 
                $owner = User::getOwnerDataById($uid);
                $data = ['@context' => 'https://www.w3.org/ns/activitystreams',
@@ -804,20 +863,18 @@ class ActivityPub
                logger('Sending reject to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 
                $signed = LDSignature::sign($data, $owner);
-               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
+               HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        /**
         * @brief 
         *
-        * @param $target
-        * @param $uid
-        *
-        * @return 
+        * @param string $target Target profile
+        * @param integer $uid User ID
         */
        public static function transmitContactUndo($target, $uid)
        {
-               $profile = APContact::getProfileByURL($target);
+               $profile = APContact::getByURL($target);
 
                $id = System::baseUrl() . '/activity/' . System::createGUID();
 
@@ -834,7 +891,7 @@ class ActivityPub
                logger('Sending undo to ' . $target . ' for user ' . $uid . ' with id ' . $id, LOGGER_DEBUG);
 
                $signed = LDSignature::sign($data, $owner);
-               return HTTPSignature::transmit($signed, $profile['inbox'], $uid);
+               HTTPSignature::transmit($signed, $profile['inbox'], $uid);
        }
 
        /**
@@ -847,8 +904,9 @@ class ActivityPub
        {
                $ret = Network::curl($url, false, $redirects, ['accept_content' => 'application/activity+json, application/ld+json']);
                if (!$ret['success'] || empty($ret['body'])) {
-                       return;
+                       return false;
                }
+
                return json_decode($ret['body'], true);
        }
 
@@ -860,7 +918,7 @@ class ActivityPub
         */
        public static function probeProfile($url)
        {
-               $apcontact = APContact::getProfileByURL($url, true);
+               $apcontact = APContact::getByURL($url, true);
                if (empty($apcontact)) {
                        return false;
                }
@@ -898,7 +956,7 @@ class ActivityPub
         *
         * @param $body
         * @param $header
-        * @param $uid
+        * @param integer $uid User ID
         */
        public static function processInbox($body, $header, $uid)
        {
@@ -953,7 +1011,7 @@ class ActivityPub
         * @brief 
         *
         * @param $url
-        * @param $uid
+        * @param integer $uid User ID
         */
        public static function fetchOutbox($url, $uid)
        {
@@ -982,7 +1040,7 @@ class ActivityPub
         * @brief 
         *
         * @param array $activity
-        * @param $uid
+        * @param integer $uid User ID
         * @param $trust_source
         *
         * @return 
@@ -1025,7 +1083,7 @@ class ActivityPub
                } elseif (in_array($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.
-                       $object_data = self::ProcessObject($activity);
+                       $object_data = self::processObject($activity);
                        $object_data['name'] = $activity['type'];
                        $object_data['author'] = $activity['actor'];
                        $object_data['object'] = $object_id;
@@ -1053,7 +1111,7 @@ class ActivityPub
         *
         * @param array $activity
         * @param $body
-        * @param $uid
+        * @param integer $uid User ID
         * @param $trust_source
         */
        private static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
@@ -1100,12 +1158,19 @@ class ActivityPub
                                break;
 
                        case 'Update':
-                               if (in_array($object_data['object_type'], ['Person', 'Organization', 'Service', 'Group', 'Application'])) {
+                               if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
+                                       /// @todo
+                               } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
                                        self::updatePerson($object_data, $body);
                                }
                                break;
 
                        case 'Delete':
+                               if ($object_data['object_type'] == 'Tombstone') {
+                                       self::deleteItem($object_data, $body);
+                               } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
+                                       self::deletePerson($object_data, $body);
+                               }
                                break;
 
                        case 'Follow':
@@ -1118,10 +1183,16 @@ class ActivityPub
                                }
                                break;
 
+                       case 'Reject':
+                               if ($object_data['object_type'] == 'Follow') {
+                                       self::rejectFollowUser($object_data);
+                               }
+                               break;
+
                        case 'Undo':
                                if ($object_data['object_type'] == 'Follow') {
                                        self::undoFollowUser($object_data);
-                               } elseif (in_array($object_data['object_type'], ['Like', 'Dislike', 'Accept', 'Reject', 'TentativeAccept'])) {
+                               } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
                                        self::undoActivity($object_data);
                                }
                                break;
@@ -1154,7 +1225,7 @@ class ActivityPub
                }
 
                if (!empty($actor)) {
-                       $profile = APContact::getProfileByURL($actor);
+                       $profile = APContact::getByURL($actor);
                        $followers = defaults($profile, 'followers', '');
 
                        logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
@@ -1163,25 +1234,25 @@ class ActivityPub
                        $followers = '';
                }
 
-               $elements = ['to', 'cc', 'bto', 'bcc'];
-               foreach ($elements as $element) {
+               foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
                        if (empty($activity[$element])) {
                                continue;
                        }
 
-                       // The receiver can be an arror or a string
+                       // The receiver can be an array or a string
                        if (is_string($activity[$element])) {
                                $activity[$element] = [$activity[$element]];
                        }
 
                        foreach ($activity[$element] as $receiver) {
-                               if ($receiver == self::PUBLIC) {
+                               if ($receiver == self::PUBLIC_COLLECTION) {
                                        $receivers['uid:0'] = 0;
                                }
 
-                               if (($receiver == self::PUBLIC) && !empty($actor)) {
+                               if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
                                        // This will most likely catch all OStatus connections to Mastodon
-                                       $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]];
+                                       $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
+                                               , 'archive' => false, 'pending' => false];
                                        $contacts = DBA::select('contact', ['uid'], $condition);
                                        while ($contact = DBA::fetch($contacts)) {
                                                if ($contact['uid'] != 0) {
@@ -1191,9 +1262,9 @@ class ActivityPub
                                        DBA::close($contacts);
                                }
 
-                               if (in_array($receiver, [$followers, self::PUBLIC]) && !empty($actor)) {
+                               if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
                                        $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
-                                               'network' => Protocol::ACTIVITYPUB];
+                                               'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
                                        $contacts = DBA::select('contact', ['uid'], $condition);
                                        while ($contact = DBA::fetch($contacts)) {
                                                if ($contact['uid'] != 0) {
@@ -1222,7 +1293,7 @@ class ActivityPub
         * @brief 
         *
         * @param $cid
-        * @param $uid
+        * @param integer $uid User ID
         * @param $url
         */
        private static function switchContact($cid, $uid, $url)
@@ -1328,7 +1399,7 @@ class ActivityPub
                                return false;
                        }
                        logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
-                       $data = self::CreateNote($item);
+                       $data = self::createNote($item);
                }
 
                if (empty($data['type'])) {
@@ -1336,26 +1407,18 @@ class ActivityPub
                        return false;
                }
 
-               switch ($data['type']) {
-                       case 'Note':
-                       case 'Article':
-                       case 'Video':
-                               return self::ProcessObject($data);
-
-                       case 'Announce':
-                               if (empty($data['object'])) {
-                                       return false;
-                               }
-                               return self::fetchObject($data['object']);
-
-                       case 'Person':
-                       case 'Tombstone':
-                               break;
+               if (in_array($data['type'], self::CONTENT_TYPES)) {
+                       return self::processObject($data);
+               }
 
-                       default:
-                               logger('Unknown object type: ' . $data['type'], LOGGER_DEBUG);
-                               break;
+               if ($data['type'] == 'Announce') {
+                       if (empty($data['object'])) {
+                               return false;
+                       }
+                       return self::fetchObject($data['object']);
                }
+
+               logger('Unhandled object type: ' . $data['type'], LOGGER_DEBUG);
        }
 
        /**
@@ -1365,7 +1428,7 @@ class ActivityPub
         *
         * @return 
         */
-       private static function ProcessObject(&$object)
+       private static function processObject($object)
        {
                if (empty($object['id'])) {
                        return false;
@@ -1393,7 +1456,7 @@ class ActivityPub
                        $actor = defaults($object, 'actor', null);
                }
 
-               $object_data['uuid'] = defaults($object, 'uuid', null);
+               $object_data['diaspora:guid'] = defaults($object, 'diaspora:guid', null);
                $object_data['owner'] = $object_data['author'] = $actor;
                $object_data['context'] = defaults($object, 'context', null);
                $object_data['conversation'] = defaults($object, 'conversation', null);
@@ -1560,6 +1623,20 @@ class ActivityPub
                self::postItem($activity, $item, $body);
        }
 
+       /**
+        * @brief Delete items
+        *
+        * @param array $activity
+        * @param $body
+        */
+       private static function deleteItem($activity)
+       {
+               $owner = Contact::getIdForURL($activity['owner']);
+               $object = JsonLD::fetchElement($activity, 'object', 'id');
+               logger('Deleting item ' . $object . ' from ' . $owner, LOGGER_DEBUG);
+               Item::delete(['uri' => $object, 'owner-id' => $owner]);
+       }
+
        /**
         * @brief 
         *
@@ -1667,23 +1744,6 @@ class ActivityPub
                logger('Activity ' . $url . ' had been fetched and processed.');
        }
 
-       /**
-        * @brief Returns the user id of a given profile url
-        *
-        * @param string $profile
-        *
-        * @return integer user id
-        */
-       private static function getUserOfProfile($profile)
-       {
-               $self = DBA::selectFirst('contact', ['uid'], ['nurl' => normalise_link($profile), 'self' => true]);
-               if (!DBA::isResult($self)) {
-                       return false;
-               } else {
-                       return $self['uid'];
-               }
-       }
-
        /**
         * @brief perform a "follow" request
         *
@@ -1692,7 +1752,7 @@ class ActivityPub
        private static function followUser($activity)
        {
                $actor = JsonLD::fetchElement($activity, 'object', 'id');
-               $uid = self::getUserOfProfile($actor);
+               $uid = User::getIdForURL($actor);
                if (empty($uid)) {
                        return;
                }
@@ -1736,7 +1796,33 @@ class ActivityPub
                }
 
                logger('Updating profile for ' . $activity['object']['id'], LOGGER_DEBUG);
-               APContact::getProfileByURL($activity['object']['id'], true);
+               APContact::getByURL($activity['object']['id'], true);
+       }
+
+       /**
+        * @brief Delete the given profile
+        *
+        * @param array $activity
+        */
+       private static function deletePerson($activity)
+       {
+               if (empty($activity['object']['id']) || empty($activity['object']['actor'])) {
+                       logger('Empty object id or actor.', LOGGER_DEBUG);
+                       return;
+               }
+
+               if ($activity['object']['id'] != $activity['object']['actor']) {
+                       logger('Object id does not match actor.', LOGGER_DEBUG);
+                       return;
+               }
+
+               $contacts = DBA::select('contact', ['id'], ['nurl' => normalise_link($activity['object']['id'])]);
+               while ($contact = DBA::fetch($contacts)) {
+                       Contact::remove($contact["id"]);
+               }
+               DBA::close($contacts);
+
+               logger('Deleted contact ' . $activity['object']['id'], LOGGER_DEBUG);
        }
 
        /**
@@ -1747,7 +1833,7 @@ class ActivityPub
        private static function acceptFollowUser($activity)
        {
                $actor = JsonLD::fetchElement($activity, 'object', 'actor');
-               $uid = self::getUserOfProfile($actor);
+               $uid = User::getIdForURL($actor);
                if (empty($uid)) {
                        return;
                }
@@ -1772,6 +1858,35 @@ class ActivityPub
                logger('Accept contact request from contact ' . $cid . ' for user ' . $uid, LOGGER_DEBUG);
        }
 
+       /**
+        * @brief Reject a follow request
+        *
+        * @param array $activity
+        */
+       private static function rejectFollowUser($activity)
+       {
+               $actor = JsonLD::fetchElement($activity, 'object', 'actor');
+               $uid = User::getIdForURL($actor);
+               if (empty($uid)) {
+                       return;
+               }
+
+               $owner = User::getOwnerDataById($uid);
+
+               $cid = Contact::getIdForURL($activity['owner'], $uid);
+               if (empty($cid)) {
+                       logger('No contact found for ' . $activity['owner'], LOGGER_DEBUG);
+                       return;
+               }
+
+               if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING, 'pending' => true])) {
+                       Contact::remove($cid);
+                       logger('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', LOGGER_DEBUG);
+               } else {
+                       logger('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', LOGGER_DEBUG);
+               }
+       }
+
        /**
         * @brief Undo activity like "like" or "dislike"
         *
@@ -1805,7 +1920,7 @@ class ActivityPub
        private static function undoFollowUser($activity)
        {
                $object = JsonLD::fetchElement($activity, 'object', 'object');
-               $uid = self::getUserOfProfile($object);
+               $uid = User::getIdForURL($object);
                if (empty($uid)) {
                        return;
                }