Adding an action to an existing controller (Ruby on Rails)

Question

I am new to Ruby on Rails, I have completed the Blog Tutorial.

I am now trying to add an additional action to the controller, called 'start'.

def start
end

I have added a view page "app/views/posts/start.html.erb" containing nothing but simple html.

When I go to /posts/start i get the following error.

ActiveRecord::RecordNotFound in PostsController#show 
Couldn't find Post with ID=start

I understand the error, the show action is being executed and start is not a valid ID. Why doesn't the start action get executed, is there some part of the MVC architecture or configuration I am missing ?

Below is my posts_controller.rb

class PostsController < ApplicationController

  # GET /posts/start
  def start
  end

  # GET /posts
  # GET /posts.xml
  def index
    @posts = Post.find(:all)
    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @posts }
    end
  end

  # GET /posts/1
  # GET /posts/1.xml
  def show
    @post = Post.find(params[:id])
    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @post }
    end
  end

end

Yes I have restarted the server and tried it with Mongrel and webrick.

Answer 1

The error you're making is actually a pretty common one.

Basically, Rails automatically maps URLs for your scaffolds. So when you created the Posts scaffolds, Rails is mapping the URL routes for it. One such route is the URL for viewing a single post: /posts/(post_id)

So, when you're entering the URL /posts/start Rails thinks you're saying "Hey, give me the post with ID = start. So Rails complains that the show method can't find a post with such ID.

One quick way to fix this is to make sure your config/routes.rb has the route for the start action before the scaffolding routes:

# Route for start action
map.connect '/posts/start', :controller => 'posts', :action => 'start'
# Default mapping of routes for the scaffold
map.resources :posts

Anyway, hope that helps.