"Common action" for a controller

Tom Potter wrote:

Sorry if this has been asked before; it seems like a simple problem.

I have a controller called ItemController which displays information about specific items to a user on various pages. The routing looks like "items/:item/:action". Is there any way to automatically look up the :item in the items table (it's just an ID).

I tried:

before_filter { @current_item = Item.find(:first, @params[:item], :include => [:set, :card]) }

but apperently filters don't have access to params. Is there any other simple way? Or is this somehow bad practice?

From the API docs:

   class WeblogController < ActionController::Base      before_filter { |controller| false if controller.params["stop_action"] }    end