Question

In my app:

A song has many setlists through allocations
A setlist has many songs through allocations
allocations belong to setlists and songs

I’m trying to add a song from the existing library to a set list using the following form:

 <% @songs.each do |song| %>
            <tr>
               <%= nested_form_for(@setlist.allocations.build(song_id: song.id)) do |f| %>
               <td><%= song.title %></td>
               <td><%= song.artist %></td>
               <td><%= song.key %></td>
               <td>
                     <div><%= f.hidden_field :song_id %></div>
                  <%= f.submit "ADD", class: "btn btn-small btn-primary" %>
                  <% end %>

               </td>
            </tr>
          <% end %>

In my setlists controller I have:

def edit
    @songs = Song.all(order: 'title')
    @setlist = Setlist.find(params[:id])
    @setSongs = @setlist.songs
    @allocations = Allocation.where("setlist_id =?", @setlist) 
  end

  def update
    @setlist = Setlist.find(params[:id])
    song = Song.find(params[:song_id])
    @setlist.allocate!(song)
    if @setlist.update_attributes(params[:setlist])
      # Handle a successful update.
      flash[:success] = "SAVED!"
      redirect_to setlists_path
    else
      render 'edit'
    end
  end

The allocate method is specified in the setlist model as:

 def allocate!(song)
    allocations.create!(song_id: song.id)
  end

At the moment it returns the following whenever I click to add songs to the setlist.

NoMethodError in SetlistsController#update
undefined method `id’ for :song:Symbol

The bug is also wierd in that it only does the error above for the first record in the table, whilst all the others render the “error” page for when a record hasn’t been added.

Any pointers would be appreciated. Thanks very much in advance

Answer 1

You are passing the Symbol :song to allocate! in

@setlist.allocate!(:song)

when allocate! is expecting an instance of Song to be passed. The :song symbol has no method .id, hence the error.

If you’re trying to pass the Song related to

<%= f.hidden_field :song_id %>

you must first get the Song.

song = Song.find(params[:allocation][:song_id])
@setlist.allocate!(song)