trait LocalAwareRedirectResponseTrait

trait LocalAwareRedirectResponseTrait {
    
    /**
     * The request context.
     *
     * @var \Drupal\Core\Routing\RequestContext
     */
    protected $requestContext;
    
    /**
     * Determines whether a path is local.
     *
     * @param string $url
     *   The internal path or external URL being linked to, such as "node/34" or
     *   "http://example.com/foo".
     *
     * @return bool
     *   TRUE or FALSE, where TRUE indicates a local path.
     */
    protected function isLocal($url) {
        return !UrlHelper::isExternal($url) || UrlHelper::externalIsLocal($url, $this->getRequestContext()
            ->getCompleteBaseUrl());
    }
    
    /**
     * Returns the request context.
     *
     * @return \Drupal\Core\Routing\RequestContext
     *   The request context.
     */
    protected function getRequestContext() {
        if (!isset($this->requestContext)) {
            $this->requestContext = \Drupal::service('router.request_context');
        }
        return $this->requestContext;
    }
    
    /**
     * Sets the request context.
     *
     * @param \Drupal\Core\Routing\RequestContext $request_context
     *   The request context.
     *
     * @return $this
     */
    public function setRequestContext(RequestContext $request_context) {
        $this->requestContext = $request_context;
        return $this;
    }

}