design advice: Gemify ActiveResource subclass

Question

I've been asked to build a gem out of a number of ActiveResource subclasses in a Rails app of ours.

The difficulty is that the self.site call uses a constant set in the Rails environment file (so that dev, test, and production point to different websites). After adding my new gem to the Gemfile, I find that the app loads the gem before the environment file, so my ActiveResource models break the app.

What should I do?

Specs: Rails 3.2.3, Ruby 1.9.3

Answer 1

What I ended up doing was overriding self.site and self.format and self.connection, letting them look for the environment constant only the first time the methods are called:

module MyActiveResource

    # A flag to indicate whether the environment variable has already been sought
    attr_accessor :active_record_fields_set

    # Set site & format if not set
    def connection(refresh=false)
        set_my_active_record_fields unless active_record_fields_set
        super(refresh)
    end

    # Set site & format if not set
    def site
        set_my_active_record_fields unless active_record_fields_set
        super
    end

    # Set site & format if not set
    def format
        set_my_active_record_fields unless active_record_fields_set
        super
    end

    # Set site & format
    def set_my_active_record_fields
        self.active_record_fields_set = true
        self.site = MY_CONSTANT
        self.format = ActiveResource::Formats::XmlFormat
    end

end

Then extend MyActiveResource in my classes that descend from ActiveResource::Base.