Pass a variable to an Assetic asset URL in Symfony2

It is possible through this way :

<link rel="stylesheet" href="{{ asset('bundles/yourbundle/css/'~ SOMEVAR ~'/css/' ) }}" />

For now, I don't think it is possible at all. The reason behind this is that Assetic is run upfront to dump the assets, so it does not run the Twig template to compute the variable. This is probably the same if you do it in a PHP template.

This means that runtime variables will not be computed and expanded. Thus, this make it impossible to generate the assets if a variable is used. This may change in the future, but this would incur an overhead in production each time the assets are requested by the user because Assetic would need to generate the assets.

I know it is possible to programmatically defines and generates the asset by using the code found in Assetic directly (not by using the AsseticBundle). You will need to experiment, read the source code, and do trials and errors to work out off this problem.

There is little to no documentation on Assetic at the moment. The only link I can give is the README found on the github page of Assetic here. I hope this will change soon.

Hope this helps.

To elaborate a bit on Chopchop's answer:

First you need to include all files that assetic needs to dump, as it needs to know what you need dumped. What you can make in a conditional manner is the inclusion of the asset itself at runtime.

So first put in the assetic part:

{% javascripts '@ExampleComBundle/Resources/public/js/module1.js''@ExampleComBundle/Resources/public/js/module2.js'%}{% endjavascripts %} 

Now you can put in the condition that you wanted. Both those script will be dumped at deployment time but you will be able to choose at runtime which one to include:

<link rel="stylesheet" href="{{ asset('bundles/examplecombundle/js/module' ~ WHICH_MODULE_TO_INCLUDE ~ '.js ) }}" />

The ~ character is just the concatenation operator in Twig templates.

Works of course the same with CSS and JS.