code: public function fileExists($name)
  	{
  		$http = new \Guzzle\Http\Client();
  		try {
  			$response = $http->get($this->getUrl($name))->send();
  		} catch(ClientErrorResponseException $e) {
  			return false;
  		}
  		return $response->isSuccessful();
  	}
docs: Checks whether a file exists or not. This method only works for public resources, private resources will throw
  a 403 error exception.
  @param string $name the name of the file
  @return boolean