hook module idiom

Ruckus::Structure was getting extremely unwieldy.

The idiom I’m now using to add more features to it is as follows. First, assume the following:

class Structure
    def method
         # do a bunch of stuff

         # do a bunch more stuff
         return ret
    end
end

We want to add functionality in between the two comment lines:

class Structure
    def method
         # do a bunch of stuff

         # 80 more lines of inserted code

         # do a bunch more stuff
         return ret
    end
end

Instead, we do this:

class Structure
    include EightyLinesOfCode

    def method_hook(*args); super; end

    def method
         # do a bunch of stuff

         method_hook

         # do a bunch more stuff
         return ret
    end
end

module EightyLinesOfCode
    def included(klass); klass.extend(ClassMethods); end
    module ClassMethods
        # no classmethods needed this time, but keep the boilerplate
    end

    def method_hook(*args)
        # 80 lines of code now goes here

        # do we want to chain this hook? are we NOT the last hook called? then:
        super
    end
end

Easy enough. We’ll use hooks to create extension points wherever we need them in Structure, reusing as many as possible.

What’s the win? Structure now just does the core structure stuff. Random new features can be added to the ruckus/structure directory, and new features don’t cloud up the already-complicated core structure stuff.