Opal Sprockets

Adds sprockets support for Opal.

Installation

Add to your Gemfile:

gem "opal-sprockets"

A note on the version number

The version number is an attempt to keep track and support different combinations of both opal and sprockets without cluttering the code with giant ifs and conditional requires. The structure is roughly as follows:

<basic version number>.<opal version number>.<sprockets version numbers>

For example version 0.4.1.0.11.0.rc1.3.1 is build taking into account the following components:

BASE_VERSION = '0.4.1'
OPAL_VERSION = '0.11.0.rc1'
SPROCKETS_VERSION = '3.1'

Usage

Sprockets uses a set of load paths to resolve dependencies. This gem extends sprockets to provide opal load paths to sprockets. opal-sprockets provides a template processor for all files with .rb or .opal extensions.

#= require opal

puts "opal running in sprockets!"

Improved require support

By default, sprockets will examine your code for processor directive comments to handle requires, e.g. #= require opal. Opal takes this one step futher by extending the opal processor to automatically detect and register any require call made inside your ruby code:

require "opal"
require "opal-jquery"

puts "opal-jquery is now available!"

Opal cannot require files at runtime, so this trick allows ruby code to use the nicer ruby syntax for requiring dependencies.

Example

Sprockets uses a load path for code files, so make a simple app/ directory with some code inside app/application.rb:

# app/application.rb

require "opal"

puts "hello, world"

The opal corelib and runtime can be included in your app simply by adding require "opal". We also need an html file to test the application with, so add index.html:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <script src="/assets/application.js"></script>
</head>
<body>
</body>
</html>

Running Application

opal-sprockets comes with a simple Server class that can be used to easily configure applications inside config.ru:

# config.ru

require 'bundler'
Bundler.require

run Opal::Sprockets::Server.new { |s|
  s.append_path 'app'
  s.main = 'application'

  # This can be used to provide a custom index file.
  # s.index_path = 'my_index.erb'
}

This just adds the app/ directory to the load path, and tells sprockets that application.rb will be the main file to load.

Now just run the rack app:

$ bundle exec rackup

And then visit http://127.0.0.1:9292 in any browser.

Source Maps

opal-sprockets will create source maps for all assets by default. You can disable this with:

Opal::Config.source_map_enabled = false

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

opal/opal-sprockets