There are many scenarios where you might want the same controller action / method in your Rails application to perform multiple functions. For example, a wizard with multiple steps or a single form with multiple-stage AJAX calls. What you want to do is provide a 'context' to the specific request and have the controller handle that in some different way.

Until now, one way to do this would be to use a parameter on the URL (e.g.: http://yourapp/post/show/1?stage=something_here) and then simply branch the logic based on the parameter. Bruce Williams saw an opportunity to make things a little better, and has developed in_context. It still uses a parameter on the URL or in the request, but he made the branching mechanism somewhat cleaner.

The in_context page provides the best info, but here's a quick demonstration of the branching:

render :update do |page|
	# Stuff at this point happens regardless of context
	in_context do |context|
		context.nil? do
			# This happens if no context is passed
		end
   		context.workflow_one do
			# One workflow goes through here..
   		end
   		context.workflow_two do
     		# And another through here..
   		end
 	end
end