Best way to combine fragment and object caching for memcached and Rails

Question

Lets say you have a fragment of the page which displays the most recent posts, and you expire it in 30 minutes. I\'m using Rails here.

<% cache(\"recent_posts         


        

Answer 1

just as a piece of thought:

in application controller define

def when_fragment_expired( name, time_options = nil )
        # idea of avoiding race conditions
        # downside: needs 2 cache lookups
        # in view we actually cache indefinetely 
        # but we expire with a 2nd fragment in the controller which is expired time based
        return if ActionController::Base.cache_store.exist?( 'fragments/' + name ) && ActionController::Base.cache_store.exist?( fragment_cache_key( name ) )

        # the time_fraqgment_cache uses different time options
        time_options = time_options - Time.now if time_options.is_a?( Time )

        # set an artificial fragment which expires after given time
        ActionController::Base.cache_store.write("fragments/" + name, 1, :expires_in => time_options )

        ActionController::Base.cache_store.delete( "views/"+name )        
        yield    
  end

then in any action use

    def index
when_fragment_expired "cache_key", 5.minutes
@object = YourObject.expensive_operations
end
end

in view

cache "cache_key" do
view_code
end