fkooman\OAuth\Client\ClientConfig::validateEndpointUri PHP Method

    private function validateEndpointUri($endpointUri)
    {
        if (!is_string($endpointUri) || 0 >= strlen($endpointUri)) {
            throw new ClientConfigException('uri must be a non-empty string');
        }
        if (false === filter_var($endpointUri, FILTER_VALIDATE_URL)) {
            throw new ClientConfigException('uri must be valid URL');
        }
        // not allowed to have a fragment (#) in it
        if (null !== parse_url($endpointUri, PHP_URL_FRAGMENT)) {
            throw new ClientConfigException('uri must not contain a fragment');
        }
    }