/torba

Bundler for Sprockets

Primary LanguageRubyMIT LicenseMIT

Torba

Build Status Gem version

Torba is a Bower-less asset manager for Sprockets. It makes a local copy of a JS/CSS library and puts it under Sprockets' load path.

Name origin

"Торба" [tǒːrba] in Ukrainian and "torba" in Polish, Turkic languages can mean "duffel bag", "gunny sack" or, more generally, any flexible container.

Status

Production ready.

Documentation

Released version

Why

De facto approach, i.e. wrapping JS and CSS libraries in a gem, requires from a maintainer to constantly track changes in upstream repository. Even more, if the maintainer stops using this gem itself, it will eventually become abandoned. Many libraries still have no gem wrappers.

Among other alternatives:

Problems with the Bower:

  • it is not a part of Ruby ecosystem,
  • frontend JS libraries are usually standalone (except for jQuery dependency), so there's no need for complex Bundler-like solution with tree-dependency resolution,
  • often we can't use optimistic version constraints, because JS community still doesn't fully grasp the idea of Semver. By specifying strict versions we use Bower as a complex facade for functionality that could be done by curl.

External dependencies

  • curl
  • unzip
  • gzip
  • tar

Design limitations

  • Torba doesn't do any version dependency resolution, it's up to you to specify correct version of each asset package,
  • Torba doesn't do any builds, use remote sources with pre-built assets.

Installation

Add this line to your application's Gemfile and run bundle:

gem 'torba'

Rails

in boot.rb

 require 'bundler/setup' # Set up gems listed in the Gemfile.
+require 'torba/verify'

it config/application.rb

 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
+
+require 'torba/rails'

Usage

  1. Create Torbafile at the project root and commit it.

  2. Run bundle exec torba pack.

  3. Add "require" Sprockets directives to your "application.js" and/or "@import" Sass directives to "application.css".

  4. Non JS/CSS assets are automatically added to precompile list, nothing to do here.

If any changes made to the Torbafile, run bundle exec torba pack again.

Torbafile

Torbafile is an assets specification. It is a plain text file that contains one or more sections, each of them describes one remote source of assets.

Currently only zip, tar.gz archives, Github releases and npm packages are supported.

Zip archive package

Allows to download and unpack asset package from any source accessible by curl.

The syntax is:

zip "name", url: "..." [, import: %w(...)]

where "name" is an arbitrary name for the package, more on "import" below. For example,

zip "scroll_magic", url: "https://github.com/janpaepke/ScrollMagic/archive/v2.0.0.zip"

Tar.gz archive package

The syntax is same as for a zip package:

targz "name", url: "..." [, import: %w(...)]

for example,

targz "scroll_magic", url: "https://github.com/janpaepke/ScrollMagic/archive/v2.0.0.tar.gz"

Github release package

This is a more readable version/shortcut for "https://github.com/.../archive/..." URLs.

The syntax is:

gh_release "name", source: "...", tag: "..." [, import: %w(...)]

where "source" is the user + repository and "tag" is the repository tag (exactly as on Github, i.e. with "v" prefix if present), more on "import" below. For example,

gh_release "scroll_magic", source: "janpaepke/ScrollMagic", tag: "v.2.0.0"

You can omit the name, it will be equal to the repository name:

gh_release source: "janpaepke/ScrollMagic", tag: "v.2.0.0" # "ScrollMagic" is assumed

npm package

Allows to download packages from npm registry.

The syntax is:

npm "name", package: "...", version: "..." [, import: %w(...)]

where "package" is the package name as published on npm registry and "version" is its version, more on "import" below. For example,

npm "coffee", package: "coffee-script", version: "1.9.2"

You can omit the name, it will be equal to the package name:

npm package: "coffee-script", version: "1.9.2"

"Packing the torba" process

When you run torba pack the following happens:

  1. All remote sources are cached locally.

  2. Archives are unpacked with top level directory removed. This is done for good cause it usually contains package version, e.g. "react-0.13.2", and you don't want to reference versions inside your application code (except Torbafile).

  3. Remote source's content is copied as is to the Torba.home_path location with package name used as a namespace.

    This is also done for good in order to avoid name collisions (since many JS projects can have assets with the same names and all packages are placed into shared Sprockets' virtual filesystem). The downside is that you have to use namespace in each require directive, which can lead to duplication:

    // application.js
//= require 'underscore/underscore'

    Hint: use "require_directory" if you're strongly against such duplication:

    //= require_directory 'underscore'

  4. Stylesheets (if any) are converted to ".css.erb" with "asset_path" helpers used in "url(...)" statements.

:import option

Copying whole remote source's content has one disadvantage of using remote source specific paths in your require/import directives. For example, if an archive contains file in "dist/css" directory, you'll have to mention it:

/* application.css */
@import 'lightslider/dist/css/lightslider';

To mitigate this you can cherry-pick files from the source via "import" option, for example:

gh_release "lightslider", source: "sachinchoolur/lightslider", tag: "1.1.2", import: %w[
  dist/css/lightslider.css
]

Such files will be copied directly to the package root (i.e. file tree becomes flatten), thus you can omit unnecessary paths:

@import 'lightslider/lightslider';

You can use any Dir.glob pattern:

gh_release "lightslider", source: "sachinchoolur/lightslider", tag: "1.1.2", import: %w[
  dist/css/lightslider.css
  dist/img/*.png
]

In addition to this "path/" is treated as a shortcut for "path/**/*" glob pattern.

Be careful to import only that you really need. Everything that is non JS or CSS asset is going to be precompiled by Sprockets and accessible publicly. See Rails ticket that explains this problem (and why Rails >= 4 precompiles only application.js/css in vendor by default), except that Torba does have a way to specify exact list of files to import.

Deployment

  1. Specify TORBA_HOME_PATH env variable pointing to a persistent directory writable by your deploy user. For Capistrano it should be shared/.
  2. Add bundle exec torba pack to your deployment script right after bundle install. It's safe and fairly cheap to run it unconditionally on each deployment.