// 假设当前URL地址是http://192.168.1.100/demo/web/app_dev.php/m/index
$request = $this->getRequest();
// http or https 此处为http
$request->getScheme();
// 192.168.1.100
$request->getHttpHost();
// http://192.168.1.100
$request->getSchemeAndHttpHost();
// /demo/web/
$request->getBasePath();
// /demo/index.php
$request->getBaseUrl();
// eg: /demo/web/app_dev.php/user/login 不一定是/demo/web/app_dev.php/m/index 取决于routeName
$this->generateUrl('routeName');
// routeName
$routeName = $request->get('_route');