Add cookbook entry about generating urls in console commands

cookbook/console/generating_urls.rst

@@ -0,0 +1,73 @@
+.. index::
+   single: Console; Generating URLs
+
+How to generate URLs with a custom host in Console Commands
+===========================================================
+
+The command line context does not know about your VirtualHost or domain name,
+therefore if you generate absolute URLs within a Console Command you generally
+end up with something like ``http://localhost/foo/bar`` which is not very
+useful.
+
+There are two ways of configuring the request context, at the application level
+and per Command.
+
+Configuring the Request Context globally
+----------------------------------------
+
+To configure the Request Context - which is used by the URL Generator - you can
+redefine the parameters it uses as default values to change the default host
+(localhost) and scheme (http). Note that this does not impact URLs generated
+via normal web requests, since those will override the defaults.
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # app/config/parameters.yml
+        parameters:
+            router.request_context.host: example.org
+            router.request_context.scheme: https
+
+    .. code-block:: xml
+
+        <!-- app/config/parameters.xml -->
+
+        <?xml version="1.0" encoding="UTF-8"?>
+
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+            <parameters>
+                <parameter key="router.request_context.host">example.org</parameter>
+                <parameter key="router.request_context.scheme">https</parameter>
+            </parameters>
+        </container>
+
+    .. code-block:: php
+
+        // app/config/config_test.php
+        $container->setParameter('router.request_context.host', 'example.org');
+        $container->setParameter('router.request_context.scheme', 'https');
+
+Configuring the Request Context per Command
+-------------------------------------------
+
+To change it only in one command you can simply fetch the Request Context
+service and override its settings:
+
+.. code-block:: php
+
+    // src/Acme/DemoBundle/Command/DemoCommand.php
+    class DemoCommand extends ContainerAwareCommand
+    {
+        protected function execute(InputInterface $input, OutputInterface $output)
+        {
+            $context = $this->getContainer()->get('router')->getContext();
+            $context->setHost('example.com');
+            $context->setScheme('https');
+
+            // your code here
+        }
+    }
+