Question

I have a problem with Rails and Jquery. Im using AJAX to add comments to articles without reloading them. The following code got automatically included in my views/application.html:

  <%= javascript_include_tag "application" %>
  <%= javascript_include_tag :all %>
  <%= javascript_include_tag "http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" %>
  <%= javascript_include_tag  "http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js" %>

Everything seemed to work fine, until i realised that the server console shows the following error:

ActionController::RoutingError (No route matches [GET] "assets/all.js")

So since this line doesn’t seem to add anything to the application other than an error i deleted it. Next time I started the server and used the application all of a sudden every comment gets posted twice!? Otherwise everything still worked fine. So I added the deleted line again and I have no idea why but when I add the line

<%= javascript_include_tag :all %>

again everythings works fine again, only one comment gets posted as intended. However I dont want to keep this in the code since it throws an error. Can someone explain this behaviour and tell me how to fix this?

Answer 1

Rails 3.1 uses sprockets to bundle javascript and css files. This makes the :all option deprecated. Sprockets use ‘magical’ comments to manage which javascripts are included.

So your application.js should look something like this:

//= require jquery
//= require jquery_ujs
//= require jquery-ui
//= require_tree .

The first line also includes jQuery itself, so you don’t need the other script tags. All you need to to is to point to application.

<%= javascript_include_tag "application" %>

If you’re deploying to production, you’ll need to run rake assets:precompile.

There is a Railscasts episode on assets, which is a must see.