Adding an action to an existing controller (Ruby o

问题:

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.

回答1:

Your routing isn't set up to allow that route. Assuming you're using the default scaffolding, put this line before the map.resources :posts line in config/routes.rb:

map.connect "posts/:action", :controller => 'posts', :action => /[a-z]+/i

The regex for :action restricts it to just a-z (to avoid catching things like /posts/1). It can be improved if you need underscores or numbers in your new actions.

回答2:

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.

回答3:

On Rails 4.x use:

get '/posts/start', :controller => 'posts', :action => 'start'

On Rails 3.x use:

match '/posts/start', :controller => 'posts', :action => 'start'

instead of

map.connect '/posts/start', :controller => 'posts', :action => 'start'

it solved my issue.

回答4:

Try this if you are using rails 3.0.3

in your route.rb

 resource :posts do
   collection do
     get 'start'
   end
 end

this might help

回答5:

I want to say, sometimes Rails gets sticky with routes-caching, even in the development environment.

It may help to restart your Rails server. This has worked for me more times than I can count when receiving this error.

回答6:

This works:

map.resource :post, :collection => { :my_action => :get}

回答7:

I found the solution to my problem, in the routes.rb file where

map.resource :post

I added with collection argument, so it stayed this way:

map.resource :post, :collection => { :my_action => :get}