Question

I have this relationship where User can create a document(trip) and invite other users to a group that belongs to that document. My relationship indicates that “Group” has a user_id and trip_id column, so for every user I invite, a new Group record will be created in the database.

When I am inviting other users, I only want users who are NOT in the group to appear. Users who are already in the group should not show up, but my view still shows the users.

I’ve been playing around with <% if !friend.trips.include?(@trip)%>, but I can’t seem to get the correct view. The record is being created in the database correctly.

Also, when I am viewing groups/new.html.erb, this is the url http://localhost:3000/groups/new?id=2, where the id is the trip_id.

My question:

1. Am I using restful convention? That is, should I be using the new method here (as is) or should I be using the index method instead?
2. How do I iterate through each friend’s groups to make sure that none of the group’s trip_id is equivalent to @trip.id?

Thanks!

view (/groups/new.html.erb)

<% if !@friends.blank? %>
  <% @friends.each do |friend| %>
     <% if !friend.trips.include?(@trip)%>
          <%= link_to groups_path(:user_id => friend.id, :trip_id => @trip.id), 
                                  :method => :post, :action => 'create' do %>
            <div id="addfriend_totrip_button_groupsnew">add friend to trip</div>
          <% end %>
    <% end %>   
  <% end %>
<% end %>

groups_controller.rb

class GroupsController < ApplicationController
before_filter :authenticate, :only => [:update, :create, :destroy]

  def new
   @trip = Trip.find(params[:id])
   @user = User.find(current_user)
   @group = Group.new
   @friends = @user.friends.all 
  end

  def create
    @trip = Trip.find(params[:trip_id])
    @user = User.find(params[:user_id])
    @group = Group.create(:user_id => @user.id, :trip_id => @trip.id)

    if @group.save
      flash[:success] = "Friend added to group."
      redirect_to groups_path(:id => @trip.id)
    else
      flash[:error] = "Could not add friend."
      redirect_to root_path
    end
  end

end

user.rb

class User < ActiveRecord::Base
  has_many :trips, :through => :groups
  has_many :trips, :dependent => :destroy
  has_many :groups
end

trip.rb

class Trip < ActiveRecord::Base
  belongs_to :user
  belongs_to :traveldeal
  has_many :groups

  has_many :users, :through => :groups
end

group.rb

class Group < ActiveRecord::Base
  belongs_to :trip
  belongs_to :user
end

Answer 1

First of all, you have has_many :trips called twice in your User model. I understand you have two different types of User–Trip relationships (one directly, and one through Group), but you can’t give both the same name, otherwise one will hide the other. Try defining your User model like this:

class User < ActiveRecord::Base
  has_many :group_trips, :through => :groups,
                         :class_name   => "Trip"
  has_many :trips, :dependent => :destroy
  has_many :groups

  def all_trips
    Trip.joins(:groups).where({:user_id => self.id} | {:groups => {:user_id => self.id}})
  end
end

There’s also the problem that you’re searching the friend‘s list of groups for a Trip object. Try changing that line to:

<% if !friend.all_trips.include?(@trip) %>

Or without the new method, something like this should work:

<% if !friend.groups.where(:trip_id => @trip.id).first %>

I don’t see anything un-RESTful about your approach. RESTful in general means stateless. I.e. the only thing a response depends on is the HTTP method and the address. So as long as your not keeping state information in, say, the session, you should be following REST.