AssociationProxy class decoupling suggestion

rubyonrails-core
1

Hi guys!

I'm writing a small bridge app now, and I have following class:

class Board   belongs_to :user_n, ...   belongs_to :user_e, ...   belongs_to :user_s, ...   belongs_to :user_w, ...

  def users     [user_n, user_e, user_s, user_w]   end end

What I'm trying to do is to return something similar to AssociationProxy in the method users. I see no point of creating many- to-many association here - the only thing that I want to achieve is:

board.users.owner(card) # returns user that owns given card

I've spent some time on analysing AssociationProxy class, and I think it's possible to decouple general Proxy class from it. It'd be really nice to implement the "users" method like:

def users   ActiveSupport::Proxy.new([user_n, user_e, user_s, user_w]) do     def owner(card)       ...     end   end end

I can try to write something, but I'd like to know if it's worth spending few hours on it. What do you think about it?

Cheers, Kuba.

2

Note that arrays have a metaclass, just like everything else:

def users    result = [user_n, user_e, user_s, user_w]    def result.owner(card)      # define something; 'self' will be the array    end    result end

But I'm not really sure why writing @board.users.owner(card) is in any way preferable to just defining 'owner' on Board - @board.owner(card)...

--Matt Jones

3

That's what I did: http://codaset.com/qoobaa/libre/source/master/blob/app/models/board.rb

But I need to access the parent (Board) class from the extension method. Probably I could use the JS version: to define that = self before the definition. Anyway - it'd be really great to have Proxy class in ActiveSupport I think.

Thanks, Kuba.

4

Hi

I was also looking for similar 'proxy' mechanism. What I came up with was:

module Proxy   def Proxy.included(base)     @@b = base   end   def proxy(o, &class_body)     def o.parent() @@b end     o.extend(Module.new(&class_body))   end end

class Foo   include Proxy

  def initialize     @user = ['john', 'doe']   end

  def user_proxy     proxy(@user) do       def hi         "Hello #{self.join(' ')} from class #{parent}"       end     end   end

end

puts Foo.new.user_proxy.hi # => Hello john doe from class Foo

However, it would make more sense to use logic from AssociationProxy, if it's already there.

5

I don’t think this is a good place to discuss about this. Try here: http://groups.google.com/group/rubyonrails-talk