module AbstractController::Caching::Fragments::ClassMethods

end
end
@account.id.odd? ? "v1" : "v2"
fragment_cache_key do
class ApplicationController

Or, progressively roll out the cache invalidation using a computed value:
When it's time to invalidate all fragments, simply change the string constant.

end
fragment_cache_key "v1"
class ApplicationController

version identifier, so you can easily invalidate all caches.
For example, you may want to prefix all fragment cache keys with a global

key is generated.
either a constant `value`, or a block which computes a value each time a cache
Allows you to specify controller-wide key prefixes for cache fragments. Pass

def fragment_cache_key(value = nil, &key)
  self.fragment_cache_keys += [key || -> { value }]
end