/**
  * Rad\Authentication\Provider\BasicHttpAuthentication constructor
  *
  * @param ServerRequest $request
  */
 public function __construct(ServerRequest $request)
 {
     if (isset($request->getServerParams()['PHP_AUTH_USER'])) {
         $this->identity = $request->getServerParams()['PHP_AUTH_USER'];
     }
     if (isset($request->getServerParams()['PHP_AUTH_PW'])) {
         $this->credential = $request->getServerParams()['PHP_AUTH_PW'];
     }
     parent::__construct($this->identity, $this->credential);
 }