Horde_Push::addReference PHP Method

    public function addReference($reference)
    {
        $this->_references[] = $reference;
        return $this;
    }

 /**
  * Push content to the recipient.
  *
  * @param Horde_Push $content The content element.
  * @param array      $options Additional options.
  *
  * @return NULL
  */
 public function push(Horde_Push $content, $options = array())
 {
     $entry = new Horde_Feed_Entry_Atom(null, $this->_client);
     $types = $content->getMimeTypes();
     if (isset($types['text/html'])) {
         $body = $content->getStringContent($types['text/html'][0]);
     } else {
         if (isset($types['text/plain'])) {
             $body = $content->getStringContent($types['text/plain'][0]);
         } else {
             $body = '';
         }
     }
     /* Give the entry its initial values. */
     $entry->{'atom:title'} = $content->getSummary();
     $entry->{'atom:title'}['type'] = 'text';
     $entry->{'atom:content'} = $body;
     $entry->{'atom:content'}['type'] = 'text';
     if (!empty($options['pretend'])) {
         return sprintf("Would push \n\n%s\n\n to %s.", (string) $entry, $this->_params['url']);
     }
     /* Authenticate. */
     $response = $this->_client->post('https://www.google.com/accounts/ClientLogin', 'accountType=GOOGLE&service=blogger&source=horde-push&Email=' . $this->_params['username'] . '&Passwd=' . $this->_params['password'], array('Content-type', 'application/x-www-form-urlencoded'));
     if ($response->code !== 200) {
         throw new Horde_Push_Exception('Expected response code 200, got ' . $response->code);
     }
     $auth = null;
     foreach (explode("\n", $response->getBody()) as $line) {
         $param = explode('=', $line);
         if ($param[0] == 'Auth') {
             $auth = $param[1];
         }
     }
     if (empty($auth)) {
         throw new Horde_Push_Exception('Missing authentication token in the response!');
     }
     /* Do the initial post. */
     try {
         $entry->save($this->_params['url'], array('Authorization' => 'GoogleLogin auth=' . $auth));
         $reference = $entry->link('alternate');
         if (!empty($reference)) {
             $content->addReference($reference);
         }
     } catch (Horde_Exception $e) {
         throw new Horde_Push_Exception($e);
     }
     return sprintf('Pushed blog entry to %s.', $this->_params['url']);
 }