Half Pipe

Stories in Ready

Gem to replace the Rails asset pipeline with a Grunt.js-based workflow, providing dependencies via Bower.

Half Pipe is a generator to get you up and running quickly with a Grunt setup for building client-side code in Rails apps. We believe that your asset workflow is yours and you should be able to configure it however you need to.

Who is this For?

This initial release assumes you have been using Grunt.js in non-Rails apps and would like to start using it in Rails as well. It uses Bower for dependency management, RequireJS for Javascript modules and Sass for CSS. If you use alternatives to these tools, we'd love to hear from you.

Looking for Contributors

If you take a look at our issue board on waffle.io you'll see that we have some big plans for future releases of Half Pipe. If you are interested in working on a feature or fixing a bug, please feel free to move the issue to "In Progress" and send a PR when you're ready. If you have ideas or questions, please feel free to open an issue.

Getting Started

Directory Structure

We believe that the directory structured imposed by the Rails asset pipeline was a step in the right direction, but did not go far enough in making client code a first-class part of your application. Given that, we have put assets at the same level as the rest of your Ruby code:

  • app/scripts - Javascript files (currently all RequireJS modules)
  • app/styles - Sass templates

Rails Generator

In a Rails app, use rails g half_pipe:install to get started. This will generate the directory structure and any files necessary for your Grunt workflow.

Generated Purpose
Gruntfile.js Main configuration for your Grunt tasks
bower.json 3rd-party asset dependencies (includes normalize-css, requirejs, and html5shiv by default)
package.json NPM dependencies (ie. Bower, Grunt, any Grunt tasks)
.jshintrc Linting configuration for Javascript
app/scripts/application.js Entry point for requirejs; includes requirejs configuration, main module require and bootstraps page
app/scripts/main.js Main module for your app; includes page initialization and requires any modules necessary for initialization
config/initializers/sass.rb Bootstraps Sass with bower importer

Beyond these files, the generator also removes sprockets from config/application.rb and replaces javascript_include_tag "application" in your application layout with requirejs_include_tag "/scripts/application.js".

Post-generator Tasks

If you're in an app with existing assets, the generator DOES NOT touch them. It is up to you to move them into their new homes and incorporate any existing Javascript files into requirejs modules.

Building Assets

Build assets by running grunt build. This will compile Javascripts to public/scripts and stylesheets to public/styles.


In this early release if you want to configure anything, you'll have to manually change Gruntfile.js. We'd like to make this more invisible in the future; please post any use cases for configuration as Github issues.


07/22/2013 v0.2.0

  • Removes dependency on rack-asset-compiler and embeds the code in this gem

07/19/2013 v0.1.0

  • Override Rails' rake assets:precompile to run grunt build for easier deployments
  • Allow for configuring asset server with config.half_pipe.serve_assets = true|false
  • Use Almond for requirejs optimization so as not to need requirejs in production


  • v0.2 - Asset fingerprinting

Future Features

  • Precompilation of client-side templates
  • Javascript module generator
  • Configurable asset directories
  • Configurable build directories
  • Better support for images
  • Support for additional module loaders (including ES6 modules)
  • Padrino support
  • Middleman support
  • Support for most popular AltJS languages
  • BYO support for less common languages
  • Automatic symlinking of CSS files within bower to SCSS partials within app/styles
  • Read .bowerrc for Bower directory