]> git.mxchange.org Git - friendica.git/blobdiff - include/diaspora.php
Merge branch 'develop' of https://github.com/friendica/friendica into issue/#3039...
[friendica.git] / include / diaspora.php
index c5d6943e59cd187d6826af8065e1f878ff83e7a3..fde086e200fab5b7ba8d75f2e39c9e6199d0f975 100644 (file)
@@ -3,40 +3,9 @@
  * @file include/diaspora.php
  * @brief The implementation of the diaspora protocol
  *
- * Checklist:
- *
- * Checked:
- * - send status
- * - send comment
- * - send like
- * - send mail
- * - send status retraction
- * - send comment retraction on own post
- * - send like retraction on own post
- * - send comment retraction on diaspora post
- * - send like retraction on diaspora post
- * - receive status
- * - receive reshare
- * - receive comment
- * - receive like
- * - receive connect request
- * - receive profile data
- * - receive mail
- * - receive comment retraction
- * - receive like retraction
- * - relay comment
- * - relay like
- * - relay comment retraction from diaspora
- * - relay comment retraction from friendica
- * - relay like retraction from diaspora
- * - relay like retraction from friendica
- * - send share
- *
- * Should work:
- * - receive account deletion
- * - send unshare
- *
- * Unchecked:
+ * The new protocol is described here: http://diaspora.github.io/diaspora_federation/index.html
+ * Currently this implementation here interprets the old and the new protocol and sends the old one.
+ * This will change in the future.
  */
 
 require_once("include/items.php");
@@ -49,12 +18,13 @@ require_once("include/group.php");
 require_once("include/xml.php");
 require_once("include/datetime.php");
 require_once("include/queue_fn.php");
+require_once("include/cache.php");
 
 /**
  * @brief This class contain functions to create and send Diaspora XML files
  *
  */
-class diaspora {
+class Diaspora {
 
        /**
         * @brief Return a list of relay servers
@@ -118,7 +88,7 @@ class diaspora {
         *
         * @return string the repaired signature
         */
-       function repair_signature($signature, $handle = "", $level = 1) {
+       private static function repair_signature($signature, $handle = "", $level = 1) {
 
                if ($signature == "")
                        return ($signature);
@@ -135,6 +105,59 @@ class diaspora {
                return($signature);
        }
 
+       /**
+        * @brief verify the envelope and return the verified data
+        *
+        * @param string $envelope The magic envelope
+        *
+        * @return string verified data
+        */
+       private static function verify_magic_envelope($envelope) {
+
+               $basedom = parse_xml_string($envelope, false);
+
+               if (!is_object($basedom)) {
+                       logger("Envelope is no XML file");
+                       return false;
+               }
+
+               $children = $basedom->children('http://salmon-protocol.org/ns/magic-env');
+
+               if (sizeof($children) == 0) {
+                       logger("XML has no children");
+                       return false;
+               }
+
+               $handle = "";
+
+               $data = base64url_decode($children->data);
+               $type = $children->data->attributes()->type[0];
+
+               $encoding = $children->encoding;
+
+               $alg = $children->alg;
+
+               $sig = base64url_decode($children->sig);
+               $key_id = $children->sig->attributes()->key_id[0];
+               if ($key_id != "")
+                       $handle = base64url_decode($key_id);
+
+               $b64url_data = base64url_encode($data);
+               $msg = str_replace(array("\n", "\r", " ", "\t"), array("", "", "", ""), $b64url_data);
+
+               $signable_data = $msg.".".base64url_encode($type).".".base64url_encode($encoding).".".base64url_encode($alg);
+
+               $key = self::key($handle);
+
+               $verify = rsa_verify($signable_data, $sig, $key);
+               if (!$verify) {
+                       logger('Message did not verify. Discarding.');
+                       return false;
+               }
+
+               return $data;
+       }
+
        /**
         * @brief: Decodes incoming Diaspora message
         *
@@ -146,7 +169,7 @@ class diaspora {
         * 'author' -> author diaspora handle
         * 'key' -> author public key (converted to pkcs#8)
         */
-       function decode($importer, $xml) {
+       public static function decode($importer, $xml) {
 
                $public = false;
                $basedom = parse_xml_string($xml);
@@ -268,7 +291,6 @@ class diaspora {
                return array('message' => (string)$inner_decrypted,
                                'author' => unxmlify($author_link),
                                'key' => (string)$key);
-
        }
 
 
@@ -277,7 +299,7 @@ class diaspora {
         *
         * @param array $msg The post that will be dispatched
         *
-        * @return bool Was the message accepted?
+        * @return int The message id of the generated message, "true" or "false" if there was an error
         */
        public static function dispatch_public($msg) {
 
@@ -289,7 +311,7 @@ class diaspora {
 
                // Use a dummy importer to import the data for the public copy
                $importer = array("uid" => 0, "page-flags" => PAGE_FREELOVE);
-               $item_id = self::dispatch($importer,$msg);
+               $message_id = self::dispatch($importer,$msg);
 
                // Now distribute it to the followers
                $r = q("SELECT `user`.* FROM `user` WHERE `user`.`uid` IN
@@ -298,15 +320,15 @@ class diaspora {
                        dbesc(NETWORK_DIASPORA),
                        dbesc($msg["author"])
                );
-               if($r) {
-                       foreach($r as $rr) {
+               if ($r) {
+                       foreach ($r as $rr) {
                                logger("delivering to: ".$rr["username"]);
                                self::dispatch($rr,$msg);
                        }
                } else
                        logger("No subscribers for ".$msg["author"]." ".print_r($msg, true));
 
-               return $item_id;
+               return $message_id;
        }
 
        /**
@@ -315,7 +337,7 @@ class diaspora {
         * @param array $importer Array of the importer user
         * @param array $msg The post that will be dispatched
         *
-        * @return bool Was the message accepted?
+        * @return int The message id of the generated message, "true" or "false" if there was an error
         */
        public static function dispatch($importer, $msg) {
 
@@ -323,7 +345,7 @@ class diaspora {
                // This will often be different with relayed messages (for example "like" and "comment")
                $sender = $msg["author"];
 
-               if (!diaspora::valid_posting($msg, $fields)) {
+               if (!self::valid_posting($msg, $fields)) {
                        logger("Invalid posting");
                        return false;
                }
@@ -339,6 +361,9 @@ class diaspora {
                        case "comment":
                                return self::receive_comment($importer, $sender, $fields, $msg["message"]);
 
+                       case "contact":
+                               return self::receive_contact_request($importer, $fields);
+
                        case "conversation":
                                return self::receive_conversation($importer, $msg, $fields);
 
@@ -360,9 +385,6 @@ class diaspora {
                        case "profile":
                                return self::receive_profile($importer, $fields);
 
-                       case "request":
-                               return self::receive_request($importer, $fields);
-
                        case "reshare":
                                return self::receive_reshare($importer, $fields, $msg["message"]);
 
@@ -391,12 +413,14 @@ class diaspora {
         *
         * @return bool Is the posting valid?
         */
-       private function valid_posting($msg, &$fields) {
+       private static function valid_posting($msg, &$fields) {
 
                $data = parse_xml_string($msg["message"], false);
 
-               if (!is_object($data))
+               if (!is_object($data)) {
+                       logger("No valid XML ".$msg["message"], LOGGER_DEBUG);
                        return false;
+               }
 
                $first_child = $data->getName();
 
@@ -413,11 +437,16 @@ class diaspora {
                $type = $element->getName();
                $orig_type = $type;
 
+               logger("Got message type ".$type.": ".$msg["message"], LOGGER_DATA);
+
                // All retractions are handled identically from now on.
                // In the new version there will only be "retraction".
                if (in_array($type, array("signed_retraction", "relayable_retraction")))
                        $type = "retraction";
 
+               if ($type == "request")
+                       $type = "contact";
+
                $fields = new SimpleXMLElement("<".$type."/>");
 
                $signed_data = "";
@@ -454,11 +483,11 @@ class diaspora {
                                }
                        }
 
-                       if ($fieldname == "author_signature")
+                       if (($fieldname == "author_signature") AND ($entry != ""))
                                $author_signature = base64_decode($entry);
-                       elseif ($fieldname == "parent_author_signature")
+                       elseif (($fieldname == "parent_author_signature") AND ($entry != ""))
                                $parent_author_signature = base64_decode($entry);
-                       elseif ($fieldname != "target_author_signature") {
+                       elseif (!in_array($fieldname, array("author_signature", "parent_author_signature", "target_author_signature"))) {
                                if ($signed_data != "") {
                                        $signed_data .= ";";
                                        $signed_data_parent .= ";";
@@ -483,19 +512,27 @@ class diaspora {
                        return true;
 
                // No author_signature? This is a must, so we quit.
-               if (!isset($author_signature))
+               if (!isset($author_signature)) {
+                       logger("No author signature for type ".$type." - Message: ".$msg["message"], LOGGER_DEBUG);
                        return false;
+               }
 
                if (isset($parent_author_signature)) {
                        $key = self::key($msg["author"]);
 
-                       if (!rsa_verify($signed_data, $parent_author_signature, $key, "sha256"))
+                       if (!rsa_verify($signed_data, $parent_author_signature, $key, "sha256")) {
+                               logger("No valid parent author signature for parent author ".$msg["author"]. " in type ".$type." - signed data: ".$signed_data." - Message: ".$msg["message"]." - Signature ".$parent_author_signature, LOGGER_DEBUG);
                                return false;
+                       }
                }
 
                $key = self::key($fields->author);
 
-               return rsa_verify($signed_data, $author_signature, $key, "sha256");
+               if (!rsa_verify($signed_data, $author_signature, $key, "sha256")) {
+                       logger("No valid author signature for author ".$fields->author. " in type ".$type." - signed data: ".$signed_data." - Message: ".$msg["message"]." - Signature ".$author_signature, LOGGER_DEBUG);
+                       return false;
+               } else
+                       return true;
        }
 
        /**
@@ -505,7 +542,7 @@ class diaspora {
         *
         * @return string The public key
         */
-       private function key($handle) {
+       private static function key($handle) {
                $handle = strval($handle);
 
                logger("Fetching diaspora key for: ".$handle);
@@ -524,7 +561,7 @@ class diaspora {
         *
         * @return array the queried data
         */
-       private function person_by_handle($handle) {
+       private static function person_by_handle($handle) {
 
                $r = q("SELECT * FROM `fcontact` WHERE `network` = '%s' AND `addr` = '%s' LIMIT 1",
                        dbesc(NETWORK_DIASPORA),
@@ -538,6 +575,9 @@ class diaspora {
                        $d = strtotime($person["updated"]." +00:00");
                        if ($d < strtotime("now - 14 days"))
                                $update = true;
+
+                       if ($person["guid"] == "")
+                               $update = true;
                }
 
                if (!$person OR $update) {
@@ -562,7 +602,7 @@ class diaspora {
         *
         * @return string The id of the fcontact entry
         */
-       private function add_fcontact($arr, $update = false) {
+       private static function add_fcontact($arr, $update = false) {
 
                if($update) {
                        $r = q("UPDATE `fcontact` SET
@@ -571,6 +611,7 @@ class diaspora {
                                        `request` = '%s',
                                        `nick` = '%s',
                                        `addr` = '%s',
+                                       `guid` = '%s',
                                        `batch` = '%s',
                                        `notify` = '%s',
                                        `poll` = '%s',
@@ -583,7 +624,8 @@ class diaspora {
                                        dbesc($arr["photo"]),
                                        dbesc($arr["request"]),
                                        dbesc($arr["nick"]),
-                                       dbesc($arr["addr"]),
+                                       dbesc(strtolower($arr["addr"])),
+                                       dbesc($arr["guid"]),
                                        dbesc($arr["batch"]),
                                        dbesc($arr["notify"]),
                                        dbesc($arr["poll"]),
@@ -595,15 +637,16 @@ class diaspora {
                                        dbesc($arr["network"])
                                );
                } else {
-                       $r = q("INSERT INTO `fcontact` (`url`,`name`,`photo`,`request`,`nick`,`addr`,
+                       $r = q("INSERT INTO `fcontact` (`url`,`name`,`photo`,`request`,`nick`,`addr`, `guid`,
                                        `batch`, `notify`,`poll`,`confirm`,`network`,`alias`,`pubkey`,`updated`)
-                               VALUES ('%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s')",
+                               VALUES ('%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s','%s')",
                                        dbesc($arr["url"]),
                                        dbesc($arr["name"]),
                                        dbesc($arr["photo"]),
                                        dbesc($arr["request"]),
                                        dbesc($arr["nick"]),
                                        dbesc($arr["addr"]),
+                                       dbesc($arr["guid"]),
                                        dbesc($arr["batch"]),
                                        dbesc($arr["notify"]),
                                        dbesc($arr["poll"]),
@@ -627,27 +670,30 @@ class diaspora {
         * @return string the handle
         */
        public static function handle_from_contact($contact_id, $gcontact_id = 0) {
-               $handle = False;
+               $handle = false;
 
                logger("contact id is ".$contact_id." - gcontact id is ".$gcontact_id, LOGGER_DEBUG);
 
                if ($gcontact_id != 0) {
                        $r = q("SELECT `addr` FROM `gcontact` WHERE `id` = %d AND `addr` != ''",
                                intval($gcontact_id));
-                       if ($r)
-                               return $r[0]["addr"];
+
+                       if (dbm::is_result($r)) {
+                               return strtolower($r[0]["addr"]);
+                       }
                }
 
                $r = q("SELECT `network`, `addr`, `self`, `url`, `nick` FROM `contact` WHERE `id` = %d",
                        intval($contact_id));
-               if ($r) {
+
+               if (dbm::is_result($r)) {
                        $contact = $r[0];
 
                        logger("contact 'self' = ".$contact['self']." 'url' = ".$contact['url'], LOGGER_DEBUG);
 
-                       if($contact['addr'] != "")
+                       if ($contact['addr'] != "") {
                                $handle = $contact['addr'];
-                       else {
+                       else {
                                $baseurl_start = strpos($contact['url'],'://') + 3;
                                $baseurl_length = strpos($contact['url'],'/profile') - $baseurl_start; // allows installations in a subdirectory--not sure how Diaspora will handle
                                $baseurl = substr($contact['url'], $baseurl_start, $baseurl_length);
@@ -655,7 +701,30 @@ class diaspora {
                        }
                }
 
-               return $handle;
+               return strtolower($handle);
+       }
+
+       /**
+        * @brief get a url (scheme://domain.tld/u/user) from a given Diaspora*
+        * fcontact guid
+        *
+        * @param mixed $fcontact_guid Hexadecimal string guid
+        *
+        * @return string the contact url or null
+        */
+       public static function url_from_contact_guid($fcontact_guid) {
+               logger("fcontact guid is ".$fcontact_guid, LOGGER_DEBUG);
+
+               $r = q("SELECT `url` FROM `fcontact` WHERE `url` != '' AND `network` = '%s' AND `guid` = '%s'",
+                       dbesc(NETWORK_DIASPORA),
+                       dbesc($fcontact_guid)
+               );
+
+               if (dbm::is_result($r)) {
+                       return $r[0]['url'];
+               }
+
+               return null;
        }
 
        /**
@@ -666,14 +735,29 @@ class diaspora {
         *
         * @return The contact id
         */
-       private function contact_by_handle($uid, $handle) {
+       private static function contact_by_handle($uid, $handle) {
+
+               // First do a direct search on the contact table
                $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `addr` = '%s' LIMIT 1",
                        intval($uid),
                        dbesc($handle)
                );
 
-               if ($r)
+               if (dbm::is_result($r)) {
                        return $r[0];
+               } else {
+                       // We haven't found it?
+                       // We use another function for it that will possibly create a contact entry
+                       $cid = get_contact($handle, $uid);
+
+                       if ($cid > 0) {
+                               $r = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1", intval($cid));
+
+                               if (dbm::is_result($r)) {
+                                       return $r[0];
+                               }
+                       }
+               }
 
                $handle_parts = explode("@", $handle);
                $nurl_sql = "%%://".$handle_parts[1]."%%/profile/".$handle_parts[0];
@@ -682,9 +766,11 @@ class diaspora {
                        intval($uid),
                        dbesc($nurl_sql)
                );
-               if($r)
+               if (dbm::is_result($r)) {
                        return $r[0];
+               }
 
+               logger("Haven't found contact for user ".$uid." and handle ".$handle, LOGGER_DEBUG);
                return false;
        }
 
@@ -697,7 +783,7 @@ class diaspora {
         *
         * @return bool is the contact allowed to post?
         */
-       private function post_allow($importer, $contact, $is_comment = false) {
+       private static function post_allow($importer, $contact, $is_comment = false) {
 
                // perhaps we were already sharing with this person. Now they're sharing with us.
                // That makes us friends.
@@ -734,9 +820,9 @@ class diaspora {
         * @param string $handle The checked handle in the format user@domain.tld
         * @param bool $is_comment Is the check for a comment?
         *
-        * @return bool is posting allowed?
+        * @return array The contact data
         */
-       private function allowed_contact_by_handle($importer, $handle, $is_comment = false) {
+       private static function allowed_contact_by_handle($importer, $handle, $is_comment = false) {
                $contact = self::contact_by_handle($importer["uid"], $handle);
                if (!$contact) {
                        logger("A Contact for handle ".$handle." and user ".$importer["uid"]." was not found");
@@ -758,13 +844,13 @@ class diaspora {
         *
         * @return int|bool message id if the message already was stored into the system - or false.
         */
-       private function message_exists($uid, $guid) {
+       private static function message_exists($uid, $guid) {
                $r = q("SELECT `id` FROM `item` WHERE `uid` = %d AND `guid` = '%s' LIMIT 1",
                        intval($uid),
                        dbesc($guid)
                );
 
-               if($r) {
+               if (dbm::is_result($r)) {
                        logger("message ".$guid." already exists for user ".$uid);
                        return $r[0]["id"];
                }
@@ -777,20 +863,52 @@ class diaspora {
         *
         * @param array $item The item array
         */
-       private function fetch_guid($item) {
+       private static function fetch_guid($item) {
                preg_replace_callback("&\[url=/posts/([^\[\]]*)\](.*)\[\/url\]&Usi",
                        function ($match) use ($item){
                                return(self::fetch_guid_sub($match, $item));
                        },$item["body"]);
        }
 
+       /**
+        * @brief Checks for relative /people/* links in an item body to match local
+        * contacts or prepends the remote host taken from the author link.
+        *
+        * @param string $body The item body to replace links from
+        * @param string $author_link The author link for missing local contact fallback
+        *
+        * @return the replaced string
+        */
+       public function replace_people_guid($body, $author_link) {
+               $return = preg_replace_callback("&\[url=/people/([^\[\]]*)\](.*)\[\/url\]&Usi",
+                       function ($match) use ($author_link) {
+                               // $match
+                               // 0 => '[url=/people/0123456789abcdef]Foo Bar[/url]'
+                               // 1 => '0123456789abcdef'
+                               // 2 => 'Foo Bar'
+                               $handle = self::url_from_contact_guid($match[1]);
+
+                               if ($handle) {
+                                       $return = '@[url='.$handle.']'.$match[2].'[/url]';
+                               } else {
+                                       // No local match, restoring absolute remote URL from author scheme and host
+                                       $author_url = parse_url($author_link);
+                                       $return = '[url='.$author_url['scheme'].'://'.$author_url['host'].'/people/'.$match[1].']'.$match[2].'[/url]';
+                               }
+
+                               return $return;
+                       }, $body);
+
+               return $return;
+       }
+
        /**
         * @brief sub function of "fetch_guid" which checks for links in messages
         *
         * @param array $match array containing a link that has to be checked for a message link
         * @param array $item The item array
         */
-       private function fetch_guid_sub($match, $item) {
+       private static function fetch_guid_sub($match, $item) {
                if (!self::store_by_guid($match[1], $item["author-link"]))
                        self::store_by_guid($match[1], $item["owner-link"]);
        }
@@ -804,7 +922,7 @@ class diaspora {
         *
         * @return int the message id of the stored message or false
         */
-       private function store_by_guid($guid, $server, $uid = 0) {
+       private static function store_by_guid($guid, $server, $uid = 0) {
                $serverparts = parse_url($server);
                $server = $serverparts["scheme"]."://".$serverparts["host"];
 
@@ -833,16 +951,35 @@ class diaspora {
         *      'author' => The author handle
         *      'key' => The public key of the author
         */
-       private function message($guid, $server, $level = 0) {
+       private static function message($guid, $server, $level = 0) {
 
                if ($level > 5)
                        return false;
 
-               // This will work for Diaspora and newer Friendica servers
-               $source_url = $server."/p/".$guid.".xml";
-               $x = fetch_url($source_url);
-               if(!$x)
-                       return false;
+               // This will work for new Diaspora servers and Friendica servers from 3.5
+               $source_url = $server."/fetch/post/".$guid;
+               logger("Fetch post from ".$source_url, LOGGER_DEBUG);
+
+               $envelope = fetch_url($source_url);
+               if($envelope) {
+                       logger("Envelope was fetched.", LOGGER_DEBUG);
+                       $x = self::verify_magic_envelope($envelope);
+                       if (!$x)
+                               logger("Envelope could not be verified.", LOGGER_DEBUG);
+                       else
+                               logger("Envelope was verified.", LOGGER_DEBUG);
+               } else
+                       $x = false;
+
+               // This will work for older Diaspora and Friendica servers
+               if (!$x) {
+                       $source_url = $server."/p/".$guid.".xml";
+                       logger("Fetch post from ".$source_url, LOGGER_DEBUG);
+
+                       $x = fetch_url($source_url);
+                       if(!$x)
+                               return false;
+               }
 
                $source_xml = parse_xml_string($x, false);
 
@@ -851,9 +988,11 @@ class diaspora {
 
                if ($source_xml->post->reshare) {
                        // Reshare of a reshare - old Diaspora version
+                       logger("Message is a reshare", LOGGER_DEBUG);
                        return self::message($source_xml->post->reshare->root_guid, $server, ++$level);
                } elseif ($source_xml->getName() == "reshare") {
                        // Reshare of a reshare - new Diaspora version
+                       logger("Message is a new reshare", LOGGER_DEBUG);
                        return self::message($source_xml->root_guid, $server, ++$level);
                }
 
@@ -866,8 +1005,10 @@ class diaspora {
                        $author = (string)$source_xml->author;
 
                // If this isn't a "status_message" then quit
-               if (!$author)
+               if (!$author) {
+                       logger("Message doesn't seem to be a status message", LOGGER_DEBUG);
                        return false;
+               }
 
                $msg = array("message" => $x, "author" => $author);
 
@@ -886,7 +1027,7 @@ class diaspora {
         *
         * @return array the item record
         */
-       private function parent_item($uid, $guid, $author, $contact) {
+       private static function parent_item($uid, $guid, $author, $contact) {
                $r = q("SELECT `id`, `body`, `wall`, `uri`, `private`, `origin`,
                                `author-name`, `author-link`, `author-avatar`,
                                `owner-name`, `owner-link`, `owner-avatar`
@@ -928,21 +1069,27 @@ class diaspora {
         * @param array $person The record of the person
         * @param int $uid The user id
         *
-        * @return array of contact id and network type
+        * @return array
+        *      'cid' => contact id
+        *      'network' => network type
         */
-       private function author_contact_by_url($contact, $person, $uid) {
+       private static function author_contact_by_url($contact, $person, $uid) {
 
-               $r = q("SELECT `id`, `network` FROM `contact` WHERE `nurl` = '%s' AND `uid` = %d LIMIT 1",
+               $r = q("SELECT `id`, `network`, `url` FROM `contact` WHERE `nurl` = '%s' AND `uid` = %d LIMIT 1",
                        dbesc(normalise_link($person["url"])), intval($uid));
                if ($r) {
                        $cid = $r[0]["id"];
                        $network = $r[0]["network"];
+
+                       // We are receiving content from a user that is about to be terminated
+                       // This means the user is vital, so we remove a possible termination date.
+                       unmark_for_death($contact);
                } else {
                        $cid = $contact["id"];
                        $network = NETWORK_DIASPORA;
                }
 
-               return (array("cid" => $cid, "network" => $network));
+               return array("cid" => $cid, "network" => $network);
        }
 
        /**
@@ -964,7 +1111,7 @@ class diaspora {
         *
         * @return string the post link
         */
-       private function plink($addr, $guid) {
+       private static function plink($addr, $guid) {
                $r = q("SELECT `url`, `nick`, `network` FROM `fcontact` WHERE `addr`='%s' LIMIT 1", dbesc($addr));
 
                // Fallback
@@ -994,7 +1141,10 @@ class diaspora {
         *
         * @return bool Success
         */
-       private function receive_account_deletion($importer, $data) {
+       private static function receive_account_deletion($importer, $data) {
+
+               /// @todo Account deletion should remove the contact from the global contacts as well
+
                $author = notags(unxmlify($data->author));
 
                $contact = self::contact_by_handle($importer["uid"], $author);
@@ -1008,6 +1158,45 @@ class diaspora {
                return true;
        }
 
+       /**
+        * @brief Fetch the uri from our database if we already have this item (maybe from ourselves)
+        *
+        * @param string $author Author handle
+        * @param string $guid Message guid
+        * @param boolean $onlyfound Only return uri when found in the database
+        *
+        * @return string The constructed uri or the one from our database
+        */
+       private static function get_uri_from_guid($author, $guid, $onlyfound = false) {
+
+               $r = q("SELECT `uri` FROM `item` WHERE `guid` = '%s' LIMIT 1", dbesc($guid));
+               if (dbm::is_result($r)) {
+                       return $r[0]["uri"];
+               } elseif (!$onlyfound) {
+                       return $author.":".$guid;
+               }
+
+               return "";
+       }
+
+       /**
+        * @brief Fetch the guid from our database with a given uri
+        *
+        * @param string $author Author handle
+        * @param string $uri Message uri
+        *
+        * @return string The post guid
+        */
+       private static function get_guid_from_uri($uri, $uid) {
+
+               $r = q("SELECT `guid` FROM `item` WHERE `uri` = '%s' AND `uid` = %d LIMIT 1", dbesc($uri), intval($uid));
+               if (dbm::is_result($r)) {
+                       return $r[0]["guid"];
+               } else {
+                       return false;
+               }
+       }
+
        /**
         * @brief Processes an incoming comment
         *
@@ -1018,23 +1207,39 @@ class diaspora {
         *
         * @return int The message id of the generated comment or "false" if there was an error
         */
-       private function receive_comment($importer, $sender, $data, $xml) {
+       private static function receive_comment($importer, $sender, $data, $xml) {
                $guid = notags(unxmlify($data->guid));
                $parent_guid = notags(unxmlify($data->parent_guid));
                $text = unxmlify($data->text);
                $author = notags(unxmlify($data->author));
 
+               if (isset($data->created_at)) {
+                       $created_at = datetime_convert("UTC", "UTC", notags(unxmlify($data->created_at)));
+               } else {
+                       $created_at = datetime_convert();
+               }
+
+               if (isset($data->thread_parent_guid)) {
+                       $thread_parent_guid = notags(unxmlify($data->thread_parent_guid));
+                       $thr_uri = self::get_uri_from_guid("", $thread_parent_guid, true);
+               } else {
+                       $thr_uri = "";
+               }
+
                $contact = self::allowed_contact_by_handle($importer, $sender, true);
-               if (!$contact)
+               if (!$contact) {
                        return false;
+               }
 
                $message_id = self::message_exists($importer["uid"], $guid);
-               if ($message_id)
+               if ($message_id) {
                        return $message_id;
+               }
 
                $parent_item = self::parent_item($importer["uid"], $parent_guid, $author, $contact);
-               if (!$parent_item)
+               if (!$parent_item) {
                        return false;
+               }
 
                $person = self::person_by_handle($author);
                if (!is_array($person)) {
@@ -1060,24 +1265,34 @@ class diaspora {
                $datarray["owner-avatar"] = ((x($contact,"thumb")) ? $contact["thumb"] : $contact["photo"]);
 
                $datarray["guid"] = $guid;
-               $datarray["uri"] = $author.":".$guid;
+               $datarray["uri"] = self::get_uri_from_guid($author, $guid);
 
                $datarray["type"] = "remote-comment";
                $datarray["verb"] = ACTIVITY_POST;
                $datarray["gravity"] = GRAVITY_COMMENT;
-               $datarray["parent-uri"] = $parent_item["uri"];
+
+               if ($thr_uri != "") {
+                       $datarray["parent-uri"] = $thr_uri;
+               } else {
+                       $datarray["parent-uri"] = $parent_item["uri"];
+               }
 
                $datarray["object-type"] = ACTIVITY_OBJ_COMMENT;
                $datarray["object"] = $xml;
 
-               $datarray["body"] = diaspora2bb($text);
+               $datarray["changed"] = $datarray["created"] = $datarray["edited"] = $created_at;
+
+               $body = diaspora2bb($text);
+
+               $datarray["body"] = self::replace_people_guid($body, $person["url"]);
 
                self::fetch_guid($datarray);
 
                $message_id = item_store($datarray);
 
-               if ($message_id)
+               if ($message_id) {
                        logger("Stored comment ".$datarray["guid"]." with message id ".$message_id, LOGGER_DEBUG);
+               }
 
                // If we are the origin of the parent we store the original data and notify our followers
                if($message_id AND $parent_item["origin"]) {
@@ -1090,7 +1305,7 @@ class diaspora {
                        );
 
                        // notify others
-                       proc_run("php", "include/notifier.php", "comment-import", $message_id);
+                       proc_run(PRIORITY_HIGH, "include/notifier.php", "comment-import", $message_id);
                }
 
                return $message_id;
@@ -1108,13 +1323,11 @@ class diaspora {
         *
         * @return bool "true" if it was successful
         */
-       private function receive_conversation_message($importer, $contact, $data, $msg, $mesg, $conversation) {
+       private static function receive_conversation_message($importer, $contact, $data, $msg, $mesg, $conversation) {
                $guid = notags(unxmlify($data->guid));
                $subject = notags(unxmlify($data->subject));
                $author = notags(unxmlify($data->author));
 
-               $reply = 0;
-
                $msg_guid = notags(unxmlify($mesg->guid));
                $msg_parent_guid = notags(unxmlify($mesg->parent_guid));
                $msg_parent_author_signature = notags(unxmlify($mesg->parent_author_signature));
@@ -1124,16 +1337,17 @@ class diaspora {
 
                // "diaspora_handle" is the element name from the old version
                // "author" is the element name from the new version
-               if ($mesg->author)
+               if ($mesg->author) {
                        $msg_author = notags(unxmlify($mesg->author));
-               elseif ($mesg->diaspora_handle)
+               } elseif ($mesg->diaspora_handle) {
                        $msg_author = notags(unxmlify($mesg->diaspora_handle));
-               else
+               } else {
                        return false;
+               }
 
                $msg_conversation_guid = notags(unxmlify($mesg->conversation_guid));
 
-               if($msg_conversation_guid != $guid) {
+               if ($msg_conversation_guid != $guid) {
                        logger("message conversation guid does not belong to the current conversation.");
                        return false;
                }
@@ -1145,15 +1359,15 @@ class diaspora {
 
                $author_signature = base64_decode($msg_author_signature);
 
-               if(strcasecmp($msg_author,$msg["author"]) == 0) {
+               if (strcasecmp($msg_author,$msg["author"]) == 0) {
                        $person = $contact;
                        $key = $msg["key"];
                } else {
                        $person = self::person_by_handle($msg_author);
 
-                       if (is_array($person) && x($person, "pubkey"))
+                       if (is_array($person) && x($person, "pubkey")) {
                                $key = $person["pubkey"];
-                       else {
+                       else {
                                logger("unable to find author details");
                                        return false;
                        }
@@ -1164,7 +1378,7 @@ class diaspora {
                        return false;
                }
 
-               if($msg_parent_author_signature) {
+               if ($msg_parent_author_signature) {
                        $owner_signed_data = $msg_guid.";".$msg_parent_guid.";".$msg_text.";".unxmlify($mesg->created_at).";".$msg_author.";".$msg_conversation_guid;
 
                        $parent_author_signature = base64_decode($msg_parent_author_signature);
@@ -1180,7 +1394,7 @@ class diaspora {
                $r = q("SELECT `id` FROM `mail` WHERE `uri` = '%s' LIMIT 1",
                        dbesc($message_uri)
                );
-               if($r) {
+               if (dbm::is_result($r)) {
                        logger("duplicate message already delivered.", LOGGER_DEBUG);
                        return false;
                }
@@ -1234,7 +1448,7 @@ class diaspora {
         *
         * @return bool Success
         */
-       private function receive_conversation($importer, $msg, $data) {
+       private static function receive_conversation($importer, $msg, $data) {
                $guid = notags(unxmlify($data->guid));
                $subject = notags(unxmlify($data->subject));
                $created_at = datetime_convert("UTC", "UTC", notags(unxmlify($data->created_at)));
@@ -1266,7 +1480,7 @@ class diaspora {
                                intval($importer["uid"]),
                                dbesc($guid),
                                dbesc($author),
-                               dbesc(datetime_convert("UTC", "UTC", $created_at)),
+                               dbesc($created_at),
                                dbesc(datetime_convert()),
                                dbesc($subject),
                                dbesc($participants)
@@ -1300,7 +1514,7 @@ class diaspora {
         *
         * @return string the body
         */
-       private function construct_like_body($contact, $parent_item, $guid) {
+       private static function construct_like_body($contact, $parent_item, $guid) {
                $bodyverb = t('%1$s likes %2$s\'s %3$s');
 
                $ulink = "[url=".$contact["url"]."]".$contact["name"]."[/url]";
@@ -1318,7 +1532,7 @@ class diaspora {
         *
         * @return string The XML
         */
-       private function construct_like_object($importer, $parent_item) {
+       private static function construct_like_object($importer, $parent_item) {
                $objtype = ACTIVITY_OBJ_NOTE;
                $link = '<link rel="alternate" type="text/html" href="'.App::get_baseurl()."/display/".$importer["nickname"]."/".$parent_item["id"].'" />';
                $parent_body = $parent_item["body"];
@@ -1342,7 +1556,7 @@ class diaspora {
         *
         * @return int The message id of the generated like or "false" if there was an error
         */
-       private function receive_like($importer, $sender, $data) {
+       private static function receive_like($importer, $sender, $data) {
                $positive = notags(unxmlify($data->positive));
                $guid = notags(unxmlify($data->guid));
                $parent_type = notags(unxmlify($data->parent_type));
@@ -1377,7 +1591,7 @@ class diaspora {
 
                // "positive" = "false" would be a Dislike - wich isn't currently supported by Diaspora
                // We would accept this anyhow.
-               if ($positive === "true")
+               if ($positive == "true")
                        $verb = ACTIVITY_LIKE;
                else
                        $verb = ACTIVITY_DISLIKE;
@@ -1397,7 +1611,7 @@ class diaspora {
                $datarray["owner-avatar"] = ((x($contact,"thumb")) ? $contact["thumb"] : $contact["photo"]);
 
                $datarray["guid"] = $guid;
-               $datarray["uri"] = $author.":".$guid;
+               $datarray["uri"] = self::get_uri_from_guid($author, $guid);
 
                $datarray["type"] = "activity";
                $datarray["verb"] = $verb;
@@ -1425,7 +1639,7 @@ class diaspora {
                        );
 
                        // notify others
-                       proc_run("php", "include/notifier.php", "comment-import", $message_id);
+                       proc_run(PRIORITY_HIGH, "include/notifier.php", "comment-import", $message_id);
                }
 
                return $message_id;
@@ -1439,7 +1653,7 @@ class diaspora {
         *
         * @return bool Success?
         */
-       private function receive_message($importer, $data) {
+       private static function receive_message($importer, $data) {
                $guid = notags(unxmlify($data->guid));
                $parent_guid = notags(unxmlify($data->parent_guid));
                $text = unxmlify($data->text);
@@ -1448,8 +1662,9 @@ class diaspora {
                $conversation_guid = notags(unxmlify($data->conversation_guid));
 
                $contact = self::allowed_contact_by_handle($importer, $author, true);
-               if (!$contact)
+               if (!$contact) {
                        return false;
+               }
 
                $conversation = null;
 
@@ -1457,16 +1672,13 @@ class diaspora {
                        intval($importer["uid"]),
                        dbesc($conversation_guid)
                );
-               if($c)
+               if ($c) {
                        $conversation = $c[0];
-               else {
+               else {
                        logger("conversation not available.");
                        return false;
                }
 
-               $reply = 0;
-
-               $body = diaspora2bb($text);
                $message_uri = $author.":".$guid;
 
                $person = self::person_by_handle($author);
@@ -1479,11 +1691,15 @@ class diaspora {
                        dbesc($message_uri),
                        intval($importer["uid"])
                );
-               if($r) {
+               if (dbm::is_result($r)) {
                        logger("duplicate message already delivered.", LOGGER_DEBUG);
                        return false;
                }
 
+               $body = diaspora2bb($text);
+
+               $body = self::replace_people_guid($body, $person["url"]);
+
                q("INSERT INTO `mail` (`uid`, `guid`, `convid`, `from-name`,`from-photo`,`from-url`,`contact-id`,`title`,`body`,`seen`,`reply`,`uri`,`parent-uri`,`created`)
                                VALUES ( %d, '%s', %d, '%s', '%s', '%s', %d, '%s', '%s', %d, %d, '%s','%s','%s')",
                        intval($importer["uid"]),
@@ -1518,7 +1734,7 @@ class diaspora {
         *
         * @return bool always true
         */
-       private function receive_participation($importer, $data) {
+       private static function receive_participation($importer, $data) {
                // I'm not sure if we can fully support this message type
                return true;
        }
@@ -1531,7 +1747,7 @@ class diaspora {
         *
         * @return bool always true
         */
-       private function receive_photo($importer, $data) {
+       private static function receive_photo($importer, $data) {
                // There doesn't seem to be a reason for this function, since the photo data is transmitted in the status message as well
                return true;
        }
@@ -1544,7 +1760,7 @@ class diaspora {
         *
         * @return bool always true
         */
-       private function receive_poll_participation($importer, $data) {
+       private static function receive_poll_participation($importer, $data) {
                // We don't support polls by now
                return true;
        }
@@ -1557,8 +1773,8 @@ class diaspora {
         *
         * @return bool Success
         */
-       private function receive_profile($importer, $data) {
-               $author = notags(unxmlify($data->author));
+       private static function receive_profile($importer, $data) {
+               $author = strtolower(notags(unxmlify($data->author)));
 
                $contact = self::contact_by_handle($importer["uid"], $author);
                if (!$contact)
@@ -1648,7 +1864,7 @@ class diaspora {
         * @param array $importer Array of the importer user
         * @param array $contact The contact that send the request
         */
-       private function receive_request_make_friend($importer, $contact) {
+       private static function receive_request_make_friend($importer, $contact) {
 
                $a = get_app();
 
@@ -1705,7 +1921,7 @@ class diaspora {
 
                                $i = item_store($arr);
                                if($i)
-                                       proc_run("php", "include/notifier.php", "activity", $i);
+                                       proc_run(PRIORITY_HIGH, "include/notifier.php", "activity", $i);
                        }
                }
        }
@@ -1717,18 +1933,18 @@ class diaspora {
         *
         * @return string The XML
         */
-        private function construct_new_friend_object($contact) {
-                $objtype = ACTIVITY_OBJ_PERSON;
-                $link = '<link rel="alternate" type="text/html" href="'.$contact["url"].'" />'."\n".
-                        '<link rel="photo" type="image/jpeg" href="'.$contact["thumb"].'" />'."\n";
+       private static function construct_new_friend_object($contact) {
+               $objtype = ACTIVITY_OBJ_PERSON;
+               $link = '<link rel="alternate" type="text/html" href="'.$contact["url"].'" />'."\n".
+                       '<link rel="photo" type="image/jpeg" href="'.$contact["thumb"].'" />'."\n";
 
-                $xmldata = array("object" => array("type" => $objtype,
-                                                "title" => $contact["name"],
-                                                "id" => $contact["url"]."/".$contact["name"],
-                                                "link" => $link));
+               $xmldata = array("object" => array("type" => $objtype,
+                                               "title" => $contact["name"],
+                                               "id" => $contact["url"]."/".$contact["name"],
+                                               "link" => $link));
 
-                return xml::from_array($xmldata, $xml, true);
-        }
+               return xml::from_array($xmldata, $xml, true);
+       }
 
        /**
         * @brief Processes incoming sharing notification
@@ -1738,22 +1954,68 @@ class diaspora {
         *
         * @return bool Success
         */
-       private function receive_request($importer, $data) {
+       private static function receive_contact_request($importer, $data) {
                $author = unxmlify($data->author);
                $recipient = unxmlify($data->recipient);
 
-               if (!$author || !$recipient)
+               if (!$author || !$recipient) {
                        return false;
+               }
 
-               $contact = self::contact_by_handle($importer["uid"],$author);
+               // the current protocol version doesn't know these fields
+               // That means that we will assume their existance
+               if (isset($data->following)) {
+                       $following = (unxmlify($data->following) == "true");
+               } else {
+                       $following = true;
+               }
 
-               if($contact) {
+               if (isset($data->sharing)) {
+                       $sharing = (unxmlify($data->sharing) == "true");
+               } else {
+                       $sharing = true;
+               }
 
-                       // perhaps we were already sharing with this person. Now they're sharing with us.
-                       // That makes us friends.
+               $contact = self::contact_by_handle($importer["uid"],$author);
 
-                       self::receive_request_make_friend($importer, $contact);
-                       return true;
+               // perhaps we were already sharing with this person. Now they're sharing with us.
+               // That makes us friends.
+               if ($contact) {
+                       if ($following AND $sharing) {
+                               logger("Author ".$author." (Contact ".$contact["id"].") wants to have a bidirectional conection.", LOGGER_DEBUG);
+                               self::receive_request_make_friend($importer, $contact);
+
+                               // refetch the contact array
+                               $contact = self::contact_by_handle($importer["uid"],$author);
+
+                               // If we are now friends, we are sending a share message.
+                               // Normally we needn't to do so, but the first message could have been vanished.
+                               if (in_array($contact["rel"], array(CONTACT_IS_FRIEND, CONTACT_IS_FOLLOWER))) {
+                                       $u = q("SELECT * FROM `user` WHERE `uid` = %d LIMIT 1", intval($importer["uid"]));
+                                       if ($u) {
+                                               logger("Sending share message to author ".$author." - Contact: ".$contact["id"]." - User: ".$importer["uid"], LOGGER_DEBUG);
+                                               $ret = self::send_share($u[0], $contact);
+                                       }
+                               }
+                               return true;
+                       } else { /// @todo Handle all possible variations of adding and retracting of permissions
+                               logger("Author ".$author." (Contact ".$contact["id"].") wants to change the relationship: Following: ".$following." - sharing: ".$sharing. "(By now unsupported)", LOGGER_DEBUG);
+                               return false;
+                       }
+               }
+
+               if (!$following AND $sharing AND in_array($importer["page-flags"], array(PAGE_SOAPBOX, PAGE_NORMAL))) {
+                       logger("Author ".$author." wants to share with us - but doesn't want to listen. Request is ignored.", LOGGER_DEBUG);
+                       return false;
+               } elseif (!$following AND !$sharing) {
+                       logger("Author ".$author." doesn't want anything - and we don't know the author. Request is ignored.", LOGGER_DEBUG);
+                       return false;
+               } elseif (!$following AND $sharing) {
+                       logger("Author ".$author." wants to share with us.", LOGGER_DEBUG);
+               } elseif ($following AND $sharing) {
+                       logger("Author ".$author." wants to have a bidirectional conection.", LOGGER_DEBUG);
+               } elseif ($following AND !$sharing) {
+                       logger("Author ".$author." wants to listen to us.", LOGGER_DEBUG);
                }
 
                $ret = self::person_by_handle($author);
@@ -1793,15 +2055,19 @@ class diaspora {
                        return;
                }
 
-               $g = q("SELECT `def_gid` FROM `user` WHERE `uid` = %d LIMIT 1",
-                       intval($importer["uid"])
-               );
+               logger("Author ".$author." was added as contact number ".$contact_record["id"].".", LOGGER_DEBUG);
 
-               if($g && intval($g[0]["def_gid"]))
-                       group_add_member($importer["uid"], "", $contact_record["id"], $g[0]["def_gid"]);
+               $def_gid = get_default_group($importer['uid'], $ret["network"]);
+
+               if(intval($def_gid))
+                       group_add_member($importer["uid"], "", $contact_record["id"], $def_gid);
+
+               update_contact_avatar($ret["photo"], $importer['uid'], $contact_record["id"], true);
 
                if($importer["page-flags"] == PAGE_NORMAL) {
 
+                       logger("Sending intra message for author ".$author.".", LOGGER_DEBUG);
+
                        $hash = random_string().(string)time();   // Generate a confirm_key
 
                        $ret = q("INSERT INTO `intro` (`uid`, `contact-id`, `blocked`, `knowyou`, `note`, `hash`, `datetime`)
@@ -1818,14 +2084,18 @@ class diaspora {
 
                        // automatic friend approval
 
+                       logger("Does an automatic friend approval for author ".$author.".", LOGGER_DEBUG);
+
                        update_contact_avatar($contact_record["photo"],$importer["uid"],$contact_record["id"]);
 
                        // technically they are sharing with us (CONTACT_IS_SHARING),
                        // but if our page-type is PAGE_COMMUNITY or PAGE_SOAPBOX
                        // we are going to change the relationship and make them a follower.
 
-                       if($importer["page-flags"] == PAGE_FREELOVE)
+                       if (($importer["page-flags"] == PAGE_FREELOVE) AND $sharing AND $following)
                                $new_relation = CONTACT_IS_FRIEND;
+                       elseif (($importer["page-flags"] == PAGE_FREELOVE) AND $sharing)
+                               $new_relation = CONTACT_IS_SHARING;
                        else
                                $new_relation = CONTACT_IS_FOLLOWER;
 
@@ -1844,8 +2114,13 @@ class diaspora {
                        );
 
                        $u = q("SELECT * FROM `user` WHERE `uid` = %d LIMIT 1", intval($importer["uid"]));
-                       if($u)
+                       if($u) {
+                               logger("Sending share message (Relation: ".$new_relation.") to author ".$author." - Contact: ".$contact_record["id"]." - User: ".$importer["uid"], LOGGER_DEBUG);
                                $ret = self::send_share($u[0], $contact_record);
+
+                               // Send the profile data, maybe it weren't transmitted before
+                               self::send_profile($importer["uid"], array($contact_record));
+                       }
                }
 
                return true;
@@ -1860,7 +2135,7 @@ class diaspora {
         *
         * @return array The fetched item
         */
-       private function original_item($guid, $orig_author, $author) {
+       private static function original_item($guid, $orig_author, $author) {
 
                // Do we already have this item?
                $r = q("SELECT `body`, `tag`, `app`, `created`, `object-type`, `uri`, `guid`,
@@ -1868,56 +2143,54 @@ class diaspora {
                                FROM `item` WHERE `guid` = '%s' AND `visible` AND NOT `deleted` AND `body` != '' LIMIT 1",
                        dbesc($guid));
 
-               if($r) {
+               if (dbm::is_result($r)) {
                        logger("reshared message ".$guid." already exists on system.");
 
                        // Maybe it is already a reshared item?
                        // Then refetch the content, if it is a reshare from a reshare.
                        // If it is a reshared post from another network then reformat to avoid display problems with two share elements
-                       if (self::is_reshare($r[0]["body"], true))
+                       if (self::is_reshare($r[0]["body"], true)) {
                                $r = array();
-                       elseif (self::is_reshare($r[0]["body"], false)) {
+                       elseif (self::is_reshare($r[0]["body"], false)) {
                                $r[0]["body"] = diaspora2bb(bb2diaspora($r[0]["body"]));
 
+                               $r[0]["body"] = self::replace_people_guid($r[0]["body"], $r[0]["author-link"]);
+
                                // Add OEmbed and other information to the body
                                $r[0]["body"] = add_page_info_to_body($r[0]["body"], false, true);
 
                                return $r[0];
-                       } else
+                       } else {
                                return $r[0];
+                       }
                }
 
-               if (!$r) {
+               if (!dbm::is_result($r)) {
                        $server = "https://".substr($orig_author, strpos($orig_author, "@") + 1);
-                       logger("1st try: reshared message ".$guid." will be fetched from original server: ".$server);
+                       logger("1st try: reshared message ".$guid." will be fetched via SSL from the server ".$server);
                        $item_id = self::store_by_guid($guid, $server);
 
                        if (!$item_id) {
                                $server = "http://".substr($orig_author, strpos($orig_author, "@") + 1);
-                               logger("2nd try: reshared message ".$guid." will be fetched from original server: ".$server);
+                               logger("2nd try: reshared message ".$guid." will be fetched without SLL from the server ".$server);
                                $item_id = self::store_by_guid($guid, $server);
                        }
 
-                       // Deactivated by now since there is a risk that someone could manipulate postings through this method
-/*                     if (!$item_id) {
-                               $server = "https://".substr($author, strpos($author, "@") + 1);
-                               logger("3rd try: reshared message ".$guid." will be fetched from sharer's server: ".$server);
-                               $item_id = self::store_by_guid($guid, $server);
-                       }
-                       if (!$item_id) {
-                               $server = "http://".substr($author, strpos($author, "@") + 1);
-                               logger("4th try: reshared message ".$guid." will be fetched from sharer's server: ".$server);
-                               $item_id = self::store_by_guid($guid, $server);
-                       }
-*/
                        if ($item_id) {
                                $r = q("SELECT `body`, `tag`, `app`, `created`, `object-type`, `uri`, `guid`,
                                                `author-name`, `author-link`, `author-avatar`
                                        FROM `item` WHERE `id` = %d AND `visible` AND NOT `deleted` AND `body` != '' LIMIT 1",
                                        intval($item_id));
 
-                               if ($r)
+                               if (dbm::is_result($r)) {
+                                       // If it is a reshared post from another network then reformat to avoid display problems with two share elements
+                                       if (self::is_reshare($r[0]["body"], false)) {
+                                               $r[0]["body"] = diaspora2bb(bb2diaspora($r[0]["body"]));
+                                               $r[0]["body"] = self::replace_people_guid($r[0]["body"], $r[0]["author-link"]);
+                                       }
+
                                        return $r[0];
+                               }
 
                        }
                }
@@ -1933,25 +2206,28 @@ class diaspora {
         *
         * @return int the message id
         */
-       private function receive_reshare($importer, $data, $xml) {
+       private static function receive_reshare($importer, $data, $xml) {
                $root_author = notags(unxmlify($data->root_author));
                $root_guid = notags(unxmlify($data->root_guid));
                $guid = notags(unxmlify($data->guid));
                $author = notags(unxmlify($data->author));
                $public = notags(unxmlify($data->public));
-               $created_at = notags(unxmlify($data->created_at));
+               $created_at = datetime_convert("UTC", "UTC", notags(unxmlify($data->created_at)));
 
                $contact = self::allowed_contact_by_handle($importer, $author, false);
-               if (!$contact)
+               if (!$contact) {
                        return false;
+               }
 
                $message_id = self::message_exists($importer["uid"], $guid);
-               if ($message_id)
+               if ($message_id) {
                        return $message_id;
+               }
 
                $original_item = self::original_item($root_guid, $root_author, $author);
-               if (!$original_item)
+               if (!$original_item) {
                        return false;
+               }
 
                $orig_url = App::get_baseurl()."/display/".$original_item["guid"];
 
@@ -1970,7 +2246,7 @@ class diaspora {
                $datarray["owner-avatar"] = $datarray["author-avatar"];
 
                $datarray["guid"] = $guid;
-               $datarray["uri"] = $datarray["parent-uri"] = $author.":".$guid;
+               $datarray["uri"] = $datarray["parent-uri"] = self::get_uri_from_guid($author, $guid);
 
                $datarray["verb"] = ACTIVITY_POST;
                $datarray["gravity"] = GRAVITY_PARENT;
@@ -1986,15 +2262,16 @@ class diaspora {
 
                $datarray["plink"] = self::plink($author, $guid);
                $datarray["private"] = (($public == "false") ? 1 : 0);
-               $datarray["changed"] = $datarray["created"] = $datarray["edited"] = datetime_convert("UTC", "UTC", $created_at);
+               $datarray["changed"] = $datarray["created"] = $datarray["edited"] = $created_at;
 
                $datarray["object-type"] = $original_item["object-type"];
 
                self::fetch_guid($datarray);
                $message_id = item_store($datarray);
 
-               if ($message_id)
+               if ($message_id) {
                        logger("Stored reshare ".$datarray["guid"]." with message id ".$message_id, LOGGER_DEBUG);
+               }
 
                return $message_id;
        }
@@ -2008,7 +2285,7 @@ class diaspora {
         *
         * @return bool success
         */
-       private function item_retraction($importer, $contact, $data) {
+       private static function item_retraction($importer, $contact, $data) {
                $target_type = notags(unxmlify($data->target_type));
                $target_guid = notags(unxmlify($data->target_guid));
                $author = notags(unxmlify($data->author));
@@ -2023,12 +2300,7 @@ class diaspora {
                        dbesc($target_guid),
                        intval($importer["uid"])
                );
-               if (!$r)
-                       return false;
-
-               // Only delete it if the author really fits
-               if (!link_compare($r[0]["author-link"], $person["url"])) {
-                       logger("Item author ".$r[0]["author-link"]." doesn't fit to expected contact ".$person["url"], LOGGER_DEBUG);
+               if (!$r) {
                        return false;
                }
 
@@ -2053,9 +2325,9 @@ class diaspora {
                logger("Deleted target ".$target_guid." (".$r[0]["id"].") from user ".$importer["uid"]." parent: ".$p[0]["id"], LOGGER_DEBUG);
 
                // Now check if the retraction needs to be relayed by us
-               if($p[0]["origin"]) {
+               if ($p[0]["origin"]) {
                        // notify others
-                       proc_run("php", "include/notifier.php", "drop", $r[0]["id"]);
+                       proc_run(PRIORITY_HIGH, "include/notifier.php", "drop", $r[0]["id"]);
                }
 
                return true;
@@ -2070,7 +2342,7 @@ class diaspora {
         *
         * @return bool Success
         */
-       private function receive_retraction($importer, $sender, $data) {
+       private static function receive_retraction($importer, $sender, $data) {
                $target_type = notags(unxmlify($data->target_type));
 
                $contact = self::contact_by_handle($importer["uid"], $sender);
@@ -2089,10 +2361,11 @@ class diaspora {
                        case "StatusMessage":
                                return self::item_retraction($importer, $contact, $data);;
 
+                       case "Contact":
                        case "Person":
                                /// @todo What should we do with an "unshare"?
                                // Removing the contact isn't correct since we still can read the public items
-                               //contact_remove($contact["id"]);
+                               contact_remove($contact["id"]);
                                return true;
 
                        default:
@@ -2111,13 +2384,12 @@ class diaspora {
         *
         * @return int The message id of the newly created item
         */
-       private function receive_status_message($importer, $data, $xml) {
-
+       private static function receive_status_message($importer, $data, $xml) {
                $raw_message = unxmlify($data->raw_message);
                $guid = notags(unxmlify($data->guid));
                $author = notags(unxmlify($data->author));
                $public = notags(unxmlify($data->public));
-               $created_at = notags(unxmlify($data->created_at));
+               $created_at = datetime_convert("UTC", "UTC", notags(unxmlify($data->created_at)));
                $provider_display_name = notags(unxmlify($data->provider_display_name));
 
                /// @todo enable support for polls
@@ -2127,17 +2399,21 @@ class diaspora {
                //      die("poll!\n");
                //}
                $contact = self::allowed_contact_by_handle($importer, $author, false);
-               if (!$contact)
+               if (!$contact) {
                        return false;
+               }
 
                $message_id = self::message_exists($importer["uid"], $guid);
-               if ($message_id)
+               if ($message_id) {
                        return $message_id;
+               }
 
                $address = array();
-               if ($data->location)
-                       foreach ($data->location->children() AS $fieldname => $data)
+               if ($data->location) {
+                       foreach ($data->location->children() AS $fieldname => $data) {
                                $address[$fieldname] = notags(unxmlify($data));
+                       }
+               }
 
                $body = diaspora2bb($raw_message);
 
@@ -2145,17 +2421,19 @@ class diaspora {
 
                // Attach embedded pictures to the body
                if ($data->photo) {
-                       foreach ($data->photo AS $photo)
+                       foreach ($data->photo AS $photo) {
                                $body = "[img]".unxmlify($photo->remote_photo_path).
                                        unxmlify($photo->remote_photo_name)."[/img]\n".$body;
+                       }
 
-                       $datarray["object-type"] = ACTIVITY_OBJ_PHOTO;
+                       $datarray["object-type"] = ACTIVITY_OBJ_IMAGE;
                } else {
                        $datarray["object-type"] = ACTIVITY_OBJ_NOTE;
 
                        // Add OEmbed and other information to the body
-                       if (!self::is_redmatrix($contact["url"]))
+                       if (!self::is_redmatrix($contact["url"])) {
                                $body = add_page_info_to_body($body, false, true);
+                       }
                }
 
                $datarray["uid"] = $importer["uid"];
@@ -2171,33 +2449,37 @@ class diaspora {
                $datarray["owner-avatar"] = $datarray["author-avatar"];
 
                $datarray["guid"] = $guid;
-               $datarray["uri"] = $datarray["parent-uri"] = $author.":".$guid;
+               $datarray["uri"] = $datarray["parent-uri"] = self::get_uri_from_guid($author, $guid);
 
                $datarray["verb"] = ACTIVITY_POST;
                $datarray["gravity"] = GRAVITY_PARENT;
 
                $datarray["object"] = $xml;
 
-               $datarray["body"] = $body;
+               $datarray["body"] = self::replace_people_guid($body, $contact["url"]);
 
-               if ($provider_display_name != "")
+               if ($provider_display_name != "") {
                        $datarray["app"] = $provider_display_name;
+               }
 
                $datarray["plink"] = self::plink($author, $guid);
                $datarray["private"] = (($public == "false") ? 1 : 0);
-               $datarray["changed"] = $datarray["created"] = $datarray["edited"] = datetime_convert("UTC", "UTC", $created_at);
+               $datarray["changed"] = $datarray["created"] = $datarray["edited"] = $created_at;
 
-               if (isset($address["address"]))
+               if (isset($address["address"])) {
                        $datarray["location"] = $address["address"];
+               }
 
-               if (isset($address["lat"]) AND isset($address["lng"]))
+               if (isset($address["lat"]) AND isset($address["lng"])) {
                        $datarray["coord"] = $address["lat"]." ".$address["lng"];
+               }
 
                self::fetch_guid($datarray);
                $message_id = item_store($datarray);
 
-               if ($message_id)
+               if ($message_id) {
                        logger("Stored item ".$datarray["guid"]." with message id ".$message_id, LOGGER_DEBUG);
+               }
 
                return $message_id;
        }
@@ -2213,20 +2495,56 @@ class diaspora {
         *
         * @return string the handle in the format user@domain.tld
         */
-       private function my_handle($contact) {
-               if ($contact["addr"] != "")
+       private static function my_handle($contact) {
+               if ($contact["addr"] != "") {
                        return $contact["addr"];
+               }
 
                // Normally we should have a filled "addr" field - but in the past this wasn't the case
                // So - just in case - we build the the address here.
-               if ($contact["nickname"] != "")
+               if ($contact["nickname"] != "") {
                        $nick = $contact["nickname"];
-               else
+               } else {
                        $nick = $contact["nick"];
+               }
 
                return $nick."@".substr(App::get_baseurl(), strpos(App::get_baseurl(),"://") + 3);
        }
 
+       /**
+        * @brief Creates the envelope for the "fetch" endpoint
+        *
+        * @param string $msg The message that is to be transmitted
+        * @param array $user The record of the sender
+        *
+        * @return string The envelope
+        */
+
+       public static function build_magic_envelope($msg, $user) {
+
+               $b64url_data = base64url_encode($msg);
+               $data = str_replace(array("\n", "\r", " ", "\t"), array("", "", "", ""), $b64url_data);
+
+               $key_id = base64url_encode(self::my_handle($user));
+               $type = "application/xml";
+               $encoding = "base64url";
+               $alg = "RSA-SHA256";
+               $signable_data = $data.".".base64url_encode($type).".".base64url_encode($encoding).".".base64url_encode($alg);
+               $signature = rsa_sign($signable_data, $user["prvkey"]);
+               $sig = base64url_encode($signature);
+
+               $xmldata = array("me:env" => array("me:data" => $data,
+                                                       "@attributes" => array("type" => $type),
+                                                       "me:encoding" => $encoding,
+                                                       "me:alg" => $alg,
+                                                       "me:sig" => $sig,
+                                                       "@attributes2" => array("key_id" => $key_id)));
+
+               $namespaces = array("me" => "http://salmon-protocol.org/ns/magic-env");
+
+               return xml::from_array($xmldata, $xml, false, $namespaces);
+       }
+
        /**
         * @brief Creates the envelope for a public message
         *
@@ -2238,7 +2556,7 @@ class diaspora {
         *
         * @return string The envelope
         */
-       private function build_public_message($msg, $user, $contact, $prvkey, $pubkey) {
+       private static function build_public_message($msg, $user, $contact, $prvkey, $pubkey) {
 
                logger("Message: ".$msg, LOGGER_DATA);
 
@@ -2258,11 +2576,11 @@ class diaspora {
                $sig = base64url_encode($signature);
 
                $xmldata = array("diaspora" => array("header" => array("author_id" => $handle),
-                                               "me:env" => array("me:encoding" => "base64url",
-                                                               "me:alg" => "RSA-SHA256",
-                                                               "me:data" => $data,
-                                                               "@attributes" => array("type" => "application/xml"),
-                                                               "me:sig" => $sig)));
+                                                       "me:env" => array("me:encoding" => $encoding,
+                                                       "me:alg" => $alg,
+                                                       "me:data" => $data,
+                                                       "@attributes" => array("type" => $type),
+                                                       "me:sig" => $sig)));
 
                $namespaces = array("" => "https://joindiaspora.com/protocol",
                                "me" => "http://salmon-protocol.org/ns/magic-env");
@@ -2284,7 +2602,7 @@ class diaspora {
         *
         * @return string The envelope
         */
-       private function build_private_message($msg, $user, $contact, $prvkey, $pubkey) {
+       private static function build_private_message($msg, $user, $contact, $prvkey, $pubkey) {
 
                logger("Message: ".$msg, LOGGER_DATA);
 
@@ -2348,10 +2666,10 @@ class diaspora {
                $cipher_json = base64_encode($encrypted_header_json_object);
 
                $xmldata = array("diaspora" => array("encrypted_header" => $cipher_json,
-                                               "me:env" => array("me:encoding" => "base64url",
-                                                               "me:alg" => "RSA-SHA256",
+                                               "me:env" => array("me:encoding" => $encoding,
+                                                               "me:alg" => $alg,
                                                                "me:data" => $data,
-                                                               "@attributes" => array("type" => "application/xml"),
+                                                               "@attributes" => array("type" => $type),
                                                                "me:sig" => $sig)));
 
                $namespaces = array("" => "https://joindiaspora.com/protocol",
@@ -2375,7 +2693,7 @@ class diaspora {
         *
         * @return string The message that will be transmitted to other servers
         */
-       private function build_message($msg, $user, $contact, $prvkey, $pubkey, $public = false) {
+       private static function build_message($msg, $user, $contact, $prvkey, $pubkey, $public = false) {
 
                if ($public)
                        $magic_env =  self::build_public_message($msg,$user,$contact,$prvkey,$pubkey);
@@ -2395,7 +2713,7 @@ class diaspora {
         *
         * @return string The signature
         */
-       private function signature($owner, $message) {
+       private static function signature($owner, $message) {
                $sigmsg = $message;
                unset($sigmsg["author_signature"]);
                unset($sigmsg["parent_author_signature"]);
@@ -2448,7 +2766,7 @@ class diaspora {
 
                logger("transmit: ".$logid."-".$guid." returns: ".$return_code);
 
-               if(!$return_code || (($return_code == 503) && (stristr($a->get_curl_headers(), "retry-after")))) {
+               if (!$return_code || (($return_code == 503) && (stristr($a->get_curl_headers(), "retry-after")))) {
                        logger("queue message");
 
                        $r = q("SELECT `id` FROM `queue` WHERE `cid` = %d AND `network` = '%s' AND `content` = '%s' AND `batch` = %d LIMIT 1",
@@ -2457,18 +2775,38 @@ class diaspora {
                                dbesc($slap),
                                intval($public_batch)
                        );
-                       if($r) {
+                       if ($r) {
                                logger("add_to_queue ignored - identical item already in queue");
                        } else {
                                // queue message for redelivery
                                add_to_queue($contact["id"], NETWORK_DIASPORA, $slap, $public_batch);
+
+                               // The message could not be delivered. We mark the contact as "dead"
+                               mark_for_death($contact);
                        }
+               } elseif (($return_code >= 200) AND ($return_code <= 299)) {
+                       // We successfully delivered a message, the contact is alive
+                       unmark_for_death($contact);
                }
 
                return(($return_code) ? $return_code : (-1));
        }
 
 
+       /**
+        * @brief Build the post xml
+        *
+        * @param string $type The message type
+        * @param array $message The message data
+        *
+        * @return string The post XML
+        */
+       public static function build_post_xml($type, $message) {
+
+               $data = array("XML" => array("post" => array($type => $message)));
+               return xml::from_array($data, $xml);
+       }
+
        /**
         * @brief Builds and transmit messages
         *
@@ -2482,15 +2820,17 @@ class diaspora {
         *
         * @return int Result of the transmission
         */
-       private function build_and_transmit($owner, $contact, $type, $message, $public_batch = false, $guid = "", $spool = false) {
-
-               $data = array("XML" => array("post" => array($type => $message)));
+       private static function build_and_transmit($owner, $contact, $type, $message, $public_batch = false, $guid = "", $spool = false) {
 
-               $msg = xml::from_array($data, $xml);
+               $msg = self::build_post_xml($type, $message);
 
                logger('message: '.$msg, LOGGER_DATA);
                logger('send guid '.$guid, LOGGER_DEBUG);
 
+               // Fallback if the private key wasn't transmitted in the expected field
+               if ($owner['uprvkey'] == "")
+                       $owner['uprvkey'] = $owner['prvkey'];
+
                $slap = self::build_message($msg, $owner, $contact, $owner['uprvkey'], $contact['pubkey'], $public_batch);
 
                if ($spool) {
@@ -2517,6 +2857,8 @@ class diaspora {
                $message = array("sender_handle" => self::my_handle($owner),
                                "recipient_handle" => $contact["addr"]);
 
+               logger("Send share ".print_r($message, true), LOGGER_DEBUG);
+
                return self::build_and_transmit($owner, $contact, "request", $message);
        }
 
@@ -2534,6 +2876,8 @@ class diaspora {
                                "diaspora_handle" => self::my_handle($owner),
                                "type" => "Person");
 
+               logger("Send unshare ".print_r($message, true), LOGGER_DEBUG);
+
                return self::build_and_transmit($owner, $contact, "retraction", $message);
        }
 
@@ -2550,7 +2894,7 @@ class diaspora {
 
                // Skip if it isn't a pure repeated messages
                // Does it start with a share?
-               if (strpos($body, "[share") > 0)
+               if ((strpos($body, "[share") > 0) AND $complete)
                        return(false);
 
                // Does it end with a share?
@@ -2611,28 +2955,110 @@ class diaspora {
                        $link = $matches[1];
 
                $ret["root_guid"] = preg_replace("=https?://(.*)/posts/(.*)=ism", "$2", $link);
-               if (($ret["root_guid"] == $link) OR ($ret["root_guid"] == ""))
+               if (($ret["root_guid"] == $link) OR (trim($ret["root_guid"]) == ""))
                        return(false);
+
                return($ret);
        }
 
        /**
-        * @brief Sends a post
+        * @brief Create an event array
+        *
+        * @param integer $event_id The id of the event
+        *
+        * @return array with event data
+        */
+       private static function build_event($event_id) {
+
+               $r = q("SELECT `guid`, `uid`, `start`, `finish`, `nofinish`, `summary`, `desc`, `location`, `adjust` FROM `event` WHERE `id` = %d", intval($event_id));
+               if (!dbm::is_result($r)) {
+                       return array();
+               }
+
+               $event = $r[0];
+
+               $eventdata = array();
+
+               $r = q("SELECT `timezone` FROM `user` WHERE `uid` = %d", intval($event['uid']));
+               if (!dbm::is_result($r)) {
+                       return array();
+               }
+
+               $user = $r[0];
+
+               $r = q("SELECT `addr`, `nick` FROM `contact` WHERE `uid` = %d AND `self`", intval($event['uid']));
+               if (!dbm::is_result($r)) {
+                       return array();
+               }
+
+               $owner = $r[0];
+
+               $eventdata['author'] = self::my_handle($owner);
+
+               if ($event['guid']) {
+                       $eventdata['guid'] = $event['guid'];
+               }
+
+               $mask = 'Y-m-d\TH:i:s\Z';
+
+               /// @todo - establish "all day" events in Friendica
+               $eventdata["all_day"] = "false";
+
+               if (!$event['adjust']) {
+                       $eventdata['timezone'] = $user['timezone'];
+
+                       if ($eventdata['timezone'] == "") {
+                               $eventdata['timezone'] = 'UTC';
+                       }
+               }
+
+               if ($event['start']) {
+                       $eventdata['start'] = datetime_convert($eventdata['timezone'], "UTC", $event['start'], $mask);
+               }
+               if ($event['finish'] AND !$event['nofinish']) {
+                       $eventdata['end'] = datetime_convert($eventdata['timezone'], "UTC", $event['finish'], $mask);
+               }
+               if ($event['summary']) {
+                       $eventdata['summary'] = html_entity_decode(bb2diaspora($event['summary']));
+               }
+               if ($event['desc']) {
+                       $eventdata['description'] = html_entity_decode(bb2diaspora($event['desc']));
+               }
+               if ($event['location']) {
+                       $location = array();
+                       $location["address"] = html_entity_decode(bb2diaspora($event['location']));
+                       $location["lat"] = 0;
+                       $location["lng"] = 0;
+                       $eventdata['location'] = $location;
+               }
+
+               return $eventdata;
+       }
+
+       /**
+        * @brief Create a post (status message or reshare)
         *
         * @param array $item The item that will be exported
         * @param array $owner the array of the item owner
-        * @param array $contact Target of the communication
-        * @param bool $public_batch Is it a public post?
         *
-        * @return int The result of the transmission
+        * @return array
+        * 'type' -> Message type ("status_message" or "reshare")
+        * 'message' -> Array of XML elements of the status
         */
-       public static function send_status($item, $owner, $contact, $public_batch = false) {
+       public static function build_status($item, $owner) {
+
+               $cachekey = "diaspora:build_status:".$item['guid'];
+
+               $result = Cache::get($cachekey);
+               if (!is_null($result)) {
+                       return $result;
+               }
 
                $myaddr = self::my_handle($owner);
 
                $public = (($item["private"]) ? "false" : "true");
 
-               $created = datetime_convert("UTC", "UTC", $item["created"], 'Y-m-d H:i:s \U\T\C');
+               $created = datetime_convert("UTC", "UTC", $item["created"], 'Y-m-d\TH:i:s\Z');
 
                // Detect a share element and do a reshare
                if (!$item['private'] AND ($ret = self::is_reshare($item["body"]))) {
@@ -2684,13 +3110,46 @@ class diaspora {
                                        "created_at" => $created,
                                        "provider_display_name" => $item["app"]);
 
-                       if (count($location) == 0)
+                       // Diaspora rejects messages when they contain a location without "lat" or "lng"
+                       if (!isset($location["lat"]) OR !isset($location["lng"])) {
                                unset($message["location"]);
+                       }
+
+                       if ($item['event-id'] > 0) {
+                               $event = self::build_event($item['event-id']);
+                               if (count($event)) {
+                                       $message['event'] = $event;
+
+                                       /// @todo Once Diaspora supports it, we will remove the body
+                                       // $message['raw_message'] = '';
+                               }
+                       }
 
                        $type = "status_message";
                }
 
-               return self::build_and_transmit($owner, $contact, $type, $message, $public_batch, $item["guid"]);
+               $msg = array("type" => $type, "message" => $message);
+
+               Cache::set($cachekey, $msg, CACHE_QUARTER_HOUR);
+
+               return $msg;
+       }
+
+       /**
+        * @brief Sends a post
+        *
+        * @param array $item The item that will be exported
+        * @param array $owner the array of the item owner
+        * @param array $contact Target of the communication
+        * @param bool $public_batch Is it a public post?
+        *
+        * @return int The result of the transmission
+        */
+       public static function send_status($item, $owner, $contact, $public_batch = false) {
+
+               $status = self::build_status($item, $owner);
+
+               return self::build_and_transmit($owner, $contact, $status["type"], $status["message"], $public_batch, $item["guid"]);
        }
 
        /**
@@ -2701,17 +3160,21 @@ class diaspora {
         *
         * @return array The data for a "like"
         */
-       private function construct_like($item, $owner) {
+       private static function construct_like($item, $owner) {
 
                $p = q("SELECT `guid`, `uri`, `parent-uri` FROM `item` WHERE `uri` = '%s' LIMIT 1",
                        dbesc($item["thr-parent"]));
-               if(!$p)
+               if (!dbm::is_result($p))
                        return false;
 
                $parent = $p[0];
 
                $target_type = ($parent["uri"] === $parent["parent-uri"] ? "Post" : "Comment");
-               $positive = "true";
+               if ($item['verb'] === ACTIVITY_LIKE) {
+                       $positive = "true";
+               } elseif ($item['verb'] === ACTIVITY_DISLIKE) {
+                       $positive = "false";
+               }
 
                return(array("positive" => $positive,
                                "guid" => $item["guid"],
@@ -2721,6 +3184,45 @@ class diaspora {
                                "diaspora_handle" => self::my_handle($owner)));
        }
 
+       /**
+        * @brief Creates an "EventParticipation" object
+        *
+        * @param array $item The item that will be exported
+        * @param array $owner the array of the item owner
+        *
+        * @return array The data for an "EventParticipation"
+        */
+       private static function construct_attend($item, $owner) {
+
+               $p = q("SELECT `guid`, `uri`, `parent-uri` FROM `item` WHERE `uri` = '%s' LIMIT 1",
+                       dbesc($item["thr-parent"]));
+               if (!dbm::is_result($p))
+                       return false;
+
+               $parent = $p[0];
+
+               switch ($item['verb']) {
+                       case ACTIVITY_ATTEND:
+                               $attend_answer = 'accepted';
+                               break;
+                       case ACTIVITY_ATTENDNO:
+                               $attend_answer = 'declined';
+                               break;
+                       case ACTIVITY_ATTENDMAYBE:
+                               $attend_answer = 'tentative';
+                               break;
+                       default:
+                               logger('Unknown verb '.$item['verb'].' in item '.$item['guid']);
+                               return false;
+               }
+
+               return(array("author" => self::my_handle($owner),
+                               "guid" => $item["guid"],
+                               "parent_guid" => $parent["guid"],
+                               "status" => $attend_answer,
+                               "author_signature" => ""));
+       }
+
        /**
         * @brief Creates the object for a comment
         *
@@ -2729,25 +3231,43 @@ class diaspora {
         *
         * @return array The data for a comment
         */
-       private function construct_comment($item, $owner) {
+       private static function construct_comment($item, $owner) {
+
+               $cachekey = "diaspora:construct_comment:".$item['guid'];
+
+               $result = Cache::get($cachekey);
+               if (!is_null($result)) {
+                       return $result;
+               }
 
                $p = q("SELECT `guid` FROM `item` WHERE `parent` = %d AND `id` = %d LIMIT 1",
                        intval($item["parent"]),
                        intval($item["parent"])
                );
 
-               if (!$p)
+               if (!dbm::is_result($p))
                        return false;
 
                $parent = $p[0];
 
                $text = html_entity_decode(bb2diaspora($item["body"]));
+               $created = datetime_convert("UTC", "UTC", $item["created"], 'Y-m-d\TH:i:s\Z');
 
-               return(array("guid" => $item["guid"],
+               $comment = array("guid" => $item["guid"],
                                "parent_guid" => $parent["guid"],
                                "author_signature" => "",
                                "text" => $text,
-                               "diaspora_handle" => self::my_handle($owner)));
+                               /// @todo Currently disabled until Diaspora supports it: "created_at" => $created,
+                               "diaspora_handle" => self::my_handle($owner));
+
+               // Send the thread parent guid only if it is a threaded comment
+               if ($item['thr-parent'] != $item['parent-uri']) {
+                       $comment['thread_parent_guid'] = self::get_guid_from_uri($item['thr-parent'], $item['uid']);
+               }
+
+               Cache::set($cachekey, $comment, CACHE_QUARTER_HOUR);
+
+               return($comment);
        }
 
        /**
@@ -2762,7 +3282,10 @@ class diaspora {
         */
        public static function send_followup($item,$owner,$contact,$public_batch = false) {
 
-               if($item['verb'] === ACTIVITY_LIKE) {
+               if (in_array($item['verb'], array(ACTIVITY_ATTEND, ACTIVITY_ATTENDNO, ACTIVITY_ATTENDMAYBE))) {
+                       $message = self::construct_attend($item, $owner);
+                       $type = "event_participation";
+               } elseif (in_array($item["verb"], array(ACTIVITY_LIKE, ACTIVITY_DISLIKE))) {
                        $message = self::construct_like($item, $owner);
                        $type = "like";
                } else {
@@ -2786,7 +3309,7 @@ class diaspora {
         *
         * @return string The message
         */
-       private function message_from_signature($item, $signature) {
+       private static function message_from_signature($item, $signature) {
 
                // Split the signed text
                $signed_parts = explode(";", $signature['signed_text']);
@@ -2950,7 +3473,7 @@ class diaspora {
                        intval($item["uid"])
                );
 
-               if (!$r) {
+               if (!dbm::is_result($r)) {
                        logger("conversation not found.");
                        return;
                }
@@ -2959,13 +3482,13 @@ class diaspora {
                $conv = array(
                        "guid" => $cnv["guid"],
                        "subject" => $cnv["subject"],
-                       "created_at" => datetime_convert("UTC", "UTC", $cnv['created'], 'Y-m-d H:i:s \U\T\C'),
+                       "created_at" => datetime_convert("UTC", "UTC", $cnv['created'], 'Y-m-d\TH:i:s\Z'),
                        "diaspora_handle" => $cnv["creator"],
                        "participant_handles" => $cnv["recips"]
                );
 
                $body = bb2diaspora($item["body"]);
-               $created = datetime_convert("UTC", "UTC", $item["created"], 'Y-m-d H:i:s \U\T\C');
+               $created = datetime_convert("UTC", "UTC", $item["created"], 'Y-m-d\TH:i:s\Z');
 
                $signed_text = $item["guid"].";".$cnv["guid"].";".$body.";".$created.";".$myaddr.";".$cnv['guid'];
                $sig = base64_encode(rsa_sign($signed_text, $owner["uprvkey"], "sha256"));
@@ -2987,7 +3510,7 @@ class diaspora {
                } else {
                        $message = array("guid" => $cnv["guid"],
                                        "subject" => $cnv["subject"],
-                                       "created_at" => datetime_convert("UTC", "UTC", $cnv['created'], 'Y-m-d H:i:s \U\T\C'),
+                                       "created_at" => datetime_convert("UTC", "UTC", $cnv['created'], 'Y-m-d\TH:i:s\Z'),
                                        "message" => $msg,
                                        "diaspora_handle" => $cnv["creator"],
                                        "participant_handles" => $cnv["recips"]);
@@ -3003,17 +3526,18 @@ class diaspora {
         *
         * @param int $uid The user id
         */
-       public static function send_profile($uid) {
+       public static function send_profile($uid, $recips = false) {
 
                if (!$uid)
                        return;
 
-               $recips = q("SELECT `id`,`name`,`network`,`pubkey`,`notify` FROM `contact` WHERE `network` = '%s'
-                       AND `uid` = %d AND `rel` != %d",
-                       dbesc(NETWORK_DIASPORA),
-                       intval($uid),
-                       intval(CONTACT_IS_SHARING)
-               );
+               if (!$recips)
+                       $recips = q("SELECT `id`,`name`,`network`,`pubkey`,`notify` FROM `contact` WHERE `network` = '%s'
+                               AND `uid` = %d AND `rel` != %d",
+                               dbesc(NETWORK_DIASPORA),
+                               intval($uid),
+                               intval(CONTACT_IS_SHARING)
+                       );
                if (!$recips)
                        return;
 
@@ -3077,8 +3601,10 @@ class diaspora {
                                "searchable" => $searchable,
                                "tag_string" => $tags);
 
-               foreach($recips as $recip)
+               foreach($recips as $recip) {
+                       logger("Send updated profile data for user ".$uid." to contact ".$recip["id"], LOGGER_DEBUG);
                        self::build_and_transmit($profile, $recip, "profile", $message, false, "", true);
+               }
        }
 
        /**
@@ -3091,12 +3617,6 @@ class diaspora {
         */
        public static function store_like_signature($contact, $post_id) {
 
-               $enabled = intval(get_config('system','diaspora_enabled'));
-               if (!$enabled) {
-                       logger('Diaspora support disabled, not storing like signature', LOGGER_DEBUG);
-                       return false;
-               }
-
                // Is the contact the owner? Then fetch the private key
                if (!$contact['self'] OR ($contact['uid'] == 0)) {
                        logger("No owner post, so not storing signature", LOGGER_DEBUG);
@@ -3119,26 +3639,13 @@ class diaspora {
                $message = self::construct_like($r[0], $contact);
                $message["author_signature"] = self::signature($contact, $message);
 
-               // In the future we will store the signature more flexible to support new fields.
-               // Right now we cannot change this since old Friendica versions (prior to 3.5) can only handle this format.
-               // (We are transmitting this data here via DFRN)
-
-               $signed_text = $message["positive"].";".$message["guid"].";".$message["target_type"].";".
-                               $message["parent_guid"].";".$message["diaspora_handle"];
-
-               q("INSERT INTO `sign` (`iid`,`signed_text`,`signature`,`signer`) VALUES (%d,'%s','%s','%s')",
-                       intval($post_id),
-                       dbesc($signed_text),
-                       dbesc($message["author_signature"]),
-                       dbesc($message["diaspora_handle"])
+               // We now store the signature more flexible to dynamically support new fields.
+               // This will break Diaspora compatibility with Friendica versions prior to 3.5.
+               q("INSERT INTO `sign` (`iid`,`signed_text`) VALUES (%d,'%s')",
+                       intval($message_id),
+                       dbesc(json_encode($message))
                );
 
-               // This here will replace the lines above, once Diaspora changed its protocol
-               //q("INSERT INTO `sign` (`iid`,`signed_text`) VALUES (%d,'%s')",
-               //      intval($message_id),
-               //      dbesc(json_encode($message))
-               //);
-
                logger('Stored diaspora like signature');
                return true;
        }
@@ -3160,36 +3667,18 @@ class diaspora {
                        return false;
                }
 
-               $enabled = intval(get_config('system','diaspora_enabled'));
-               if (!$enabled) {
-                       logger('Diaspora support disabled, not storing comment signature', LOGGER_DEBUG);
-                       return false;
-               }
-
                $contact["uprvkey"] = $uprvkey;
 
                $message = self::construct_comment($item, $contact);
                $message["author_signature"] = self::signature($contact, $message);
 
-               // In the future we will store the signature more flexible to support new fields.
-               // Right now we cannot change this since old Friendica versions (prior to 3.5) can only handle this format.
-               // (We are transmitting this data here via DFRN)
-               $signed_text = $message["guid"].";".$message["parent_guid"].";".
-                               $message["text"].";".$message["diaspora_handle"];
-
-               q("INSERT INTO `sign` (`iid`,`signed_text`,`signature`,`signer`) VALUES (%d,'%s','%s','%s')",
+               // We now store the signature more flexible to dynamically support new fields.
+               // This will break Diaspora compatibility with Friendica versions prior to 3.5.
+               q("INSERT INTO `sign` (`iid`,`signed_text`) VALUES (%d,'%s')",
                        intval($message_id),
-                       dbesc($signed_text),
-                       dbesc($message["author_signature"]),
-                       dbesc($message["diaspora_handle"])
+                       dbesc(json_encode($message))
                );
 
-               // This here will replace the lines above, once Diaspora changed its protocol
-               //q("INSERT INTO `sign` (`iid`,`signed_text`) VALUES (%d,'%s')",
-               //      intval($message_id),
-               //      dbesc(json_encode($message))
-               //);
-
                logger('Stored diaspora comment signature');
                return true;
        }