Iterating over has_many objects with the :through association together

rubyonrails-core
1

It is often the case when I iterate over an array of objects in a has_many_through association that I want access to both the :has_many objects and the :through objects. There is generally something in that join object that is useful to get at, but enumerating with the each method, I don't have easy access to that join object.

Example:

class User < ActiveRecord::Base    has_many :memberships    has_many :groups, :through => :memberships end

# ugly way user.groups.each do |group|   membership = user.memberships.detect { |memberships| memberships.group_id == group.id}   # or   membership = user.memberships.find(:first, :conditions => ["memberships.group_id = ?", group.id]}   puts "#{group.name}, #{membership.status}" end

# a better way user.groups.each_with_join do |group, membership|   puts "#{group.name}, #{membership.status}" end

I created a ticket with a patch (tested) in lighthouse: http://rails.lighthouseapp.com/projects/8994/tickets/82-iterate-over-has_many-array-with-the-join-through-model

Let me know what you think!

Daniel

2

I was hoping this ticket could be resolved in time for 2.1, it's complete with tests that show the failure.

http://dev.rubyonrails.org/ticket/11565

3

But your ticket has nothing to do with the one I was proposing, so let's not lump them together.

4

Sorry about that. Wasn't my intent.

5

It is often the case when I iterate over an array of objects in a has_many_through association that I want access to both the :has_many objects and the :through objects. There is generally something in that join object that is useful to get at, but enumerating with the each method, I don't have easy access to that join object.

Example:

class User < ActiveRecord::Base    has_many :memberships    has_many :groups, :through => :memberships   end

# ugly way user.groups.each do |group|   membership = user.memberships.detect { |memberships| memberships.group_id == group.id}   # or   membership = user.memberships.find(:first, :conditions => ["memberships.group_id = ?", group.id]}   puts "#{group.name}, #{membership.status}" end

# a better way user.groups.each_with_join do |group, membership|   puts "#{group.name}, #{membership.status}" end

This should really just be:

user.memberships.each do |membership|   puts membership.status, membership.group.name end

So I can't the need for this feature.