Sprockets preprocessor for Google's Closure tools + Closure-templates (soy) compiler + Closure stylesheets (gss) compiler.

If you want to use closure as your Javascript library in Rails 3, add this gem to your Gemfile:

gem 'closure-sprockets'

The gem ships with a Railtie which will automatically register a Closure preprocessor. From here, two more steps:

• Download the latest version of closure library from Google and put it in vendor/assets
• Write some closure code!

// in one of your javascript files
goog.require('goog.dom');

function sayHello() {
  newHeader = goog.dom.createDom('h1', {}, 'Hello world!');
  goog.dom.appendChild(document.body, newHeader);
};

window.onload = sayHello;

You can also add a name.soy template in your assets folder, and it will be automatically compiled to Javascript for you! Ex:

/** hello.soy */

{namespace examples.simple}

/**
 * Says hello to the world.
 */
{template .helloSoy}
  Hello from Soy!
{/template}

var soy = goog.dom.createDom('h1', {'style': 'background-color:#EEE'}, examples.simple.helloSoy());
goog.dom.appendChild(document.body, soy);

That's it! Point your browser at your page and you should have a hello world greeting from Google Closure, preprocessed by the Rails 3 Asset Pipeline and without any external Python dependencies or dynamic Javascript loading.

You can use also closure stylesheets in .gss files

/** style.gss **/

@def BG_COLOR              rgb(235, 239, 249);

@def DIALOG_BORDER_COLOR   rgb(107, 144, 218);
@def DIALOG_BG_COLOR       BG_COLOR;

body {
  background-color: BG_COLOR;
}

.dialog {
  background-color: DIALOG_BG_COLOR;
  border: 1px solid DIALOG_BORDER_COLOR;
}

GSS files will be compiled automatically to CSS:

body {
  background-color: #ebeff9;
}
.dialog {
  background-color: #ebeff9;
  border: 1px solid #6b90da;
}

If you decided to put your closure-library directory somewhere other than vendor/assets, then you'll have to update your environment config with the right path:

config.closure.lib = 'vendor/assets/path/to/closure-library'

Closure also provides its own Javascript compressor. If you wish to use it, pull in the closure-compiler gem:

# in your Gemfile
gem 'closure-compiler'

# in your environment configuration
config.assets.js_compressor = Closure::Compiler.new

If you are not using the closure compiler, then you may want to disable the dynamic deps.js loading. To do so, add the following snippet in application.html.erb above the javascript_include tag:

    <script type="text/javascript">
      var CLOSURE_NO_DEPS = true;
    </script>

(MIT License) - Copyright (c) 2011 Ilya Grigorik