Is there a way to include an argument in the geojson url which was created by view with contextual filter.

When I set the geojson url in the layer setting page it get saved in the database table "openlayers_layers" in the column "data".
Could't be possible to get the the url from the browser address bar instead ?
Or maybe saving the url in the database just before the rendering of the layer on the map ?

I'm thiking about the following code to get the url from the browser address bar and construct the url to the geojson file created by views:

$geturl = explode('/', $_SERVER['REQUEST_URI']);
$city = $geturl[2];
$full_url = 'http://mydomain/italy/ . $city . '/geojson';

I'm not sure where I have to modify the code.
Maybe from line 139 in openlayers/modules/openlayers_views/openlayers_views.module ?

Can somebody help me and point me to the right direction.

Thanks in advance to everybody