The Framework bundle only implements two asset version strategies: empty and static (defaults provided by the Asset component).

If I want to use a custom strategy for my package (eg. to add the locale its path) without overriding the defaults, the recommended solution is to:

• create a new service (my strategy)
• use a compiler pass to extract the version and version format parameters from the default static strategy my package is compiled with
• update the definition of my service with previously extracted parameters

If I have two packages with the same custom strategy but different versions, I need to duplicate my service declaration and update my compiler. And I cannot create services on-demand during the compiler pass. I could also create my own package configuration for my bundle that would override or extend the default assets.packages service.

It's neither convenient nor elegant.

I propose to add an optional parameter to set custom strategies:

#app/config/config.yml

framework:
    #...
    assets:
        base_urls: //my.cdn.com
        packages:
            pdf:
                version: %version%
                version_format: /name/space/%%2$s/pdf%%1$s
            localized_doc:
                version: %version%
                version_strategy: my.abstract.service.id # default is assets.static_version_strategy falling back on assets.empty_version_strategy if version is null (current behavior)
                version_format: /name/space/%%2$s/doc/%%3$s%/abc%1$s #%3$s would be my locale

A convenient abstract BaseVersionStrategy class could be provided that would declare setVersion and setVersionFormat to inject said parameters.

This solves a particular problem I have where I want to inject known parameters in an asset base_urls or base_path. Please provide your thoughts.