Question

So I’ve been following this guide to make a status feed based on what members you’re following (also in the guide) but I’m getting an undefined method error on “join” which I don’t see in the code.

This is what’s in my model (or what would be my microposts model)

    **tattoo.rb**
          #def self.from_members_followed_by(member)
          #  where(:member_id => member.following.push(member))
          #end

          default_scope :order => 'tattoos.created_at DESC'
- Error 2-  scope :from_members_followed_by, lambda { |member| followed_by(member) }


          private

            def self.followed_by(member)
              following_ids = %(SELECT followed_id FROM relationships WHERE follower_id = :member_id)
-Error 1 -     where("member_id IN (#{following_ids}) OR member_id = :member_id", { :member_id => member })
            end

    **member.rb**
          def feed
- Error 3-   Tattoo.from_members_followed_by(self)
          end

I guess the scope :from_members_followed_by replaces the commented out function which is why I commented it out.

The stack trace has the error at:

    app/models/tattoo.rb:50:in `followed_by' - Error 1
    app/models/tattoo.rb:43:in `block in <class:Tattoo>' - Error 2
    app/models/member.rb:90:in `feed' - Error 3
    app/controllers/members_controller.rb:15:in `home'

Answer 1

Ha! I think I got it.

First up: there is no need for the extra scope that just calls the followed_by function. Secondly: the parameter to your scope should be a member.id, and you throw in the complete member.

You can fix this in two ways. Either, in member.rb

def feed
  Tattoo.followed_by(self.id)
end

or, in tattoo.rb write:

def self.followed_by(member)
  following_ids = %(SELECT followed_id FROM relationships WHERE follower_id = :member_id)
  where("member_id IN (#{following_ids}) OR member_id = :member_id", { :member_id => member.id })
end

Hope this helps.