Question

I am just beginning to work with Rails. I have a model, “User” and it has many “List”. On the user show view I have created a form to create a list for the current user. When the form is submitted I get the following error:

Couldn’t find User without an ID

I assume that there is something wrong with the way I have setup the nested List form.

User -> show.html.erb

    <p id="notice"><%= notice %></p>

<p>
  <b>Username:</b>
  <%= @user.username %>
</p>

<p>
  <b>Password:</b>
  <%= @user.password %>
</p>

<p>
  <b>Email:</b>
  <%= @user.email %>
</p>

<h2>Add a List</h2>
 <%= form_for([@user, @user.lists.build]) do |f| %>
 <div class ="field">
    <%= f.label :title %><br />
    <%= f.text_field :title %>
</div>
<div class="field">
    <%=f.label :description%><br />
    <%=f.text_field :description%>
</div>
<div class="actions">
    <%= f.submit %>
</div>

<% end %>



<%= link_to 'Edit User', edit_user_path(@user) %> |
<%= link_to 'Back to Users', users_path %>

This is the list ‘create’ controller action.

 class ListsController < ApplicationController
    def create
        @user = User.find(params[:id])
        @list = @user.lists.create(params[:list])
        redirect_to user_path(@user)        
    end
end

Update: show method on UserController

 # GET /users/1
  # GET /users/1.json
  def show
    @user = User.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @user }
    end
  end

Update: My routes

    resources :users do
      resources :lists
  end

  get "home/index"

So is params[:id] nil somehow? What am I missing?

Thanks!

Answer 1

Make sure you are using params[:user_id] in create action, not params[:id]

class ListsController < ApplicationController
    def create
        @user = User.find(params[:user_id]) 
        @list = @user.lists.create(params[:list])
        redirect_to user_path(@user)        
    end
end