The document discusses the Rails asset pipeline and Sprockets gem. It summarizes that the asset pipeline packages and minifies JavaScript and CSS assets, manages dependencies between assets, and provides a preprocessor pipeline. It also describes Sprockets directives like //= require that search for and include assets. Gems like turbo-sprockets-rails3 and quiet_assets can improve the asset pipeline by speeding up asset precompilation and hiding asset requests in logs.

1. Rails Asset Pipeline
Nathan Broadbent
Onboard Coding Ltd.
https://twitter.com/ndbroadbent
http://github.com/ndbroadbent

2. Sprockets
● Packages and minifies your JavaScript and
CSS assets
● Dependency management
● Pre-processor pipeline
– CoffeeScript
– SCSS / LESS
– Minification

3. Sprockets Directives
● //= require example_asset
– searches app/assets/, vendor/assets, lib/assets,
<gem>/app/assets
– will find:
● example_asset.js
● example_asset.js.coffee
● example_asset.js.coffee.erb
● //= require_tree .
– recursively requires all assets in the current directory,
including subdirectories

4. Gems to improve
the asset pipeline

5. turbo-sprockets-rails3
● Speeds up rake assets:precompile by only
recompiling changed assets, based on a hash
of their source files
● Only compiles once to generate both
fingerprinted and non-fingerprinted assets

6. turbo-sprockets-rails3
Benchmark on a small Rails app:
● Uninstalled: 26.993s
● Installed
– first run: 18.525s
– unchanged assets: 9.386s

7. quiet_assets
● Hide asset requests in your Rails logs.
● Lets you focus on SQL queries and rendering
● Just add gem 'quiet_assets' to Gemfile

8. assets_precompile_enforcer
● Raises an exception if an asset is not found in
config.assets.precompile
● Avoid 500 errors in production due to
uncompiled assets

9. Assets in Rails 4
● Much faster, don't need turbo-sprockets-rails3
● Non-digest assets are no longer compiled if
fingerprints enabled
● Source maps support: Easily debug errors in
minified javascript
– http://www.html5rocks.com/en/tutorials/developert
ools/sourcemaps/
– If you give your asset source maps to Errbit, it
could show you where a production error occurred
in the original (unminified) JavaScript

10. Questions or
Comments?