Question

Ok, I have a simple question. I am new to RoR and I created a scaffold for an item. I then wanted to add a link that, when pressed, incremented a counter. What I am having trouble with is routing. I modeled this functionality after the destroy/delete link and method. Here is my code:

index.html.erb:

  ...
  <td><%= link_to 'Destroy', post, method: :delete %></td>
  <td><%= link_to 'increment', post, method: :increment%></td>
  ...

post_controller.rb:

  def vote
    @post = Post.find(params[:id])
    @post.counts = @post.counts + 1
    @post.save

    respond_to do |format|
      format.html { redirect_to post_url }
      format.json { head :ok }
    end
  end

When I try and click on the link, I get a routing error:

Routing Error

No route matches [POST] “/posts/25”

is there a step I am missing? Do I have to add some routing stuff to get this working?

Answer 1

Ok, hang in here with me, there’s a few fixes needed:

The :method param in the link_to function is not referring to the controller method, it is referring to the HTTP method. So acceptable values would be ‘:post’, ‘:delete’ etc.

More info: http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to

In this case we probably want to set :method to :post for the increment link, which we will need to match with the route we will create now.

To access the vote action you have created, we need to add it to the routes file. You probably have something like this:

 resources :posts

We need to add an action (vote), that will apply to a member of the posts resource, so we change that to this:

resources :posts do
  member do
    post 'vote'
  end
end

Now that we have the correct route, we can use the route helper method in the link_to helper (to see a full list of routes run rake routes at the command line). So in your link_to replace post with vote_post_path(post). If we include our earlier change about the :method we get:

<%= link_to 'increment', vote_post_path(post), method: :post %>

Hope this helps to fill in some blanks for you!