Corrention of wrong code example. The request service is not available in Commandline (CLI) - You cannot create a service ("request") of an inactive scope

Author: cdfre

book/routing.rst

@@ -1116,11 +1116,11 @@ method:
     the current ``Request`` object. This is detected automatically based
     on server information supplied by PHP. When generating absolute URLs for
     scripts run from the command line, you'll need to manually set the desired
-    host on the ``Request`` object:
+    host on the ``RequestContext`` object:
 
     .. code-block:: php
     
-        $request->headers->set('HOST', 'www.example.com');
+        $router->getContext()->setHost('www.example.com');
 
 .. index::
    single: Routing; Generating URLs in a template