RESTful has_many :through

Rails
1

Okay, I think I get the concept of a RESTful many-to-many association
controller, but I’ve hit a bit of a wall actually implementing it. I’ve
been Googling for a while, but this simple question is starting to take
up too much time:

Heres where I am:

I have a Meeting model related to Users through Attendees. Simple enough
so far. I need to be able to create, update and destroy meeting
attendees:

in the controller I, of course have create, update and destroy actions
and the attendees are nested under meetings giving the following route:
POST /meetings/1/attendees (for create action).

def create
@meeting = Meeting.find(params[:meeting_id]) # actually in
before_filter
@meeting.users << current_user
…
…
end

Okay so far, however I also need to set additional attributes on the
Attendee object:

attendee.rsvp = “Yes” # for example

So rather than using << to associate the logged in user directly to the
meeting should I instead create the Attendee model directly set the
attributes and save?

def create
attendee = Attendee.new(:meeting_id => params[:meeting_id], :user_id
=> current_user.id, rsvp => params[:rsvp])
if attendee.save
…
else
…
end
end

Or am I way off base and there’s a smart and simple way to accomplish
this?

2

Have a look at has_many :through…

I would see this to be a meeting has_many :users :through attenders/
attendees or maybe attendance

3

heimdull wrote:

Have a look at has_many :through…

I would see this to be a meeting has_many :users :through attenders/
attendees or maybe attendance

The model I understand and that all works fine. I actually have it
modeled like so:

class Meeting < ActiveRecord::Base
has_many :attendees, :dependent => :destroy
has_many :users, :through => :attendees
end

class User < ActiveRecord::Base
has_many :attendances, :class_name => “Attendee”, :dependent =>
:destroy
has_many :meetings, :through => : attendances
end

class Attendee < ActiveRecord::Base
belongs_to :meeting
belongs_to :user
end

It’s the controller create and update methods that are tripping me up. I
was just trying to find out how the “experts” handled many-to-many
associations in controllers. I actually end up using something like
this:

class AttendeesController < ApplicationController
before_filter :require_login
before_filter :load_meeting

def create
@attendee = Attendee.new(:meeting_id => @meeting.id, :user_id =>
current_user.id, :rsvp => params[:rsvp])
…
end

protected
def load_meeting
@meeting = Meeting.find(params[:meeting_id])
end
end

I’m guessing that’s the most straight forward way to do this? I’m not
exactly sure if setting the foreign keys directly like that is best
practice, but it I haven’t figured out a clean way to handle this using
the associations.

Adding the user to the meeting would create the association
(@meeting.users << current_user), but then I wouldn’t have access to the
attendee object in order to set the extra “rsvp” attribute. I’d have to
go back and fetch it something like @attendee =
@meeting.attendees.find_by_user_id(current_user.id).

So this is why I was hoping to get some insight from the community.