Rails ajax form with join table associations - ruby-on-rails

Question

I am trying to build a 'ajaxy' form between two models in rails. here are the relevant files and code snippets...
my models
ActiveRecord::Schema.define(:version => 20140214134314) do
create_table "group_shots", :force => true do |t|
t.integer "shot_id"
t.integer "group_id"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "groups", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "shots", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
end
app/views/groups/show.html.erb
<b>Name:</b>
<%= #group.name %>
<%= link_to 'New Shot', new_shot_path, id: "new_shot", remote: true %></br>
app/views/shots/new.js.erb
$('#new_shot').hide().after('<%= j render("form") %>');
app/controllers/shots_controller.rb
def create
#shot = Shot.new(params[:shot])
respond_to do |format|
if #shot.save
GroupShot.create! :shot_id => #shot.id
def new
#shot = Shot.new
end
My end goals is when a user is viewing a group (show action/view) that they can add a shot that is associated with that group, and consequently when the user adds the shot, the correct entries are made in the group_shot table.
You can see in the shots controller, when the shot is saved I am creating a new entry in the group/shots table successfully. I am getting the shot_id, but not the group_id. So that is the question, how do I get the group_id in this view/controller. Any help appreciated.

Answer 1

My suggestion is to pass the group_id as a parameter to the call to new_shot_path in your groups_controller#show view:
new_shot_path(group_id: #group)
then include it as a hidden field in the form you're using in your shots_controller#new view, using hidden_field_tag:
<%= hidden_field_tag 'group_id', #group.id %>
and then include it in your call to GroupShot#create in the shots_controller#create method:
GroupShot.create! :shot_id => #shot.id, :group_id => params[:group_id]
Just keep in mind that you're doing two things in shots_controller#create -- both creating the shot and associating it back to the group, which is perhaps a little unorthodox. From your code, it appears that a Shot is never created without an associated Group. If your starting point is always from viewing groups (then adding shots to a selected group), you may want to consider moving this to the groups_controller as something like #add_shot, but that's going to be depend on how the rest of your application is architected.