symfony routing, use value from Request as default - symfony

Question

I've got the following route definition
my_route:
path: /actual-path/
defaults:
_controller: MyBundle:MyController:detail
id: application_id
requirements:
methods: GET
id: \d+
The controller requires a parameter called $id.
But I don't want to use the $id in the url, I want to use a value that is available in $request->attributes->get('application_id')
There is a listener that will inject two parameters (application_id and application) into the request object as attributes prior to the routing process, so this value is in there. (It would be easy to also inject it into the RequestContext).
Is there a way I can use attributes values from the Request or RequestContext object in my routing as defaults?
Now I could simply do $request->attributes->get('application_id') in my controller. But this controller will be used in several cases. In other cases the $id is to be passed through the url. I find it cleaner to set the id in the routing than build a if-else clause in the controller somewhere.

Answer 1

It appears not to be possible to do "mapping" between variables in the request object and the parameters you need to be required in your route/controller-action. I think this would be a good thing, as it would become quite complex otherwise.
I went with the solution to extend the controller and build in a small switch there.
Basically, if the route specifies id === null, it will do a fallback to application_id that is in the Request object. Otherwise it will use the value provided. I just need to set a requirement on id on the routes that must not use the fallback.
All without running an additional Listener which might be a bit "expensive" in processing time (for each request).
Example of routes:
my_route:
path: /actual-path/
defaults:
_controller: MyBundle:MyController:detail
id: null
requirements:
methods: GET
my_other_route:
path: /other-path/{id}
defaults:
_controller: MyBundle:MyController:detail
requirements:
methods: GET
id: \d+
And how to handle this in your controller:
// fallback to system id
if ($id === null) {
$id = $request->attributes->get('administration_id', null);
}
Because you extend the controller/action, you could also change the name of the parameter in the action (as long as the type does not change).
I did not do this, as I could quite easily put the switch between the provided id and the fallback from the listener in another method.