/**
  * Returns the list of addressbooks for a specific user.
  *
  * @param string $principaluri
  * @return array
  */
 public function getAddressBooksForUser($principaluri)
 {
     $data = OC_Contacts_Addressbook::allWherePrincipalURIIs($principaluri);
     $addressbooks = array();
     foreach ($data as $i) {
         $addressbooks[] = array('id' => $i['id'], 'uri' => $i['uri'], 'principaluri' => 'principals/' . $i['userid'], '{DAV:}displayname' => $i['displayname'], '{' . Sabre_CardDAV_Plugin::NS_CARDDAV . '}addressbook-description' => $i['description'], '{http://calendarserver.org/ns/}getctag' => $i['ctag']);
     }
     return $addressbooks;
 }