Completely override has_many accessor

rubyonrails-talk
1

Hi,

I have an unusual use-case where I need to override a has_many accessor to return an array of results depending on some the value of a class variable. I've tried several solutions, the closest to success using the extension option:

[code] has_many :meta_associations, :as => :meta_extendable do           # Find any meta_associations that are joined to this activerecord instance           def meta_associations(*args)             options = args.extract_options!

            if proxy_owner.class.applicable_type == proxy_owner.class.name               options[:conditions] ||= { :meta_extendable_id => proxy_owner.id,                                          :meta_extendable_type => proxy_owner.class.applicable_type }             else               options[:conditions] ||= { :meta_extendable_id => proxy_owner.send (proxy_owner.class.applicable_type_foreign_key.to_sym),                                          :meta_extendable_type => proxy_owner.class.applicable_type }             end

            MetaAssociation.find(args.first, options)           end

        end [/code]

However, this just gives me an instance.meta_associations.meta_associations method, rather than overriding the default instance.meta_associations. Is this possible, or should I forget using :has_many and manually write all the collection accessors/mutators?

Thanks, Chris

2

However, this just gives me an instance.meta_associations.meta_associations method, rather than overriding the default instance.meta_associations. Is this possible, or should I forget using :has_many and manually write all the collection accessors/mutators?

Well you cannot overwrite the instance.meta_associations method like
that (since you're adding method to the associations proxy, but
foo.meta_associations just returns that proxy).

You may get some mileage out of overwriting the methods that actually
load the association (find_target, the method that generates the scope
used for other operations etc)

Fred

3

Hi Fred,

Thanks for your reply. I tried overriding the methods directly, but they seem to be ignored by AR and the association proxy takes precedence over my implementation. However, I've looked over my code and am going to try a different approach than trying to override the original accessors for now; I'll post back how I get on.

Thanks, Chris