Asset ID – Asset stamping and uploading to S3 for Rails
Uploads static assets to Amazon S3 with unique identifiers encoded into the path of the asset.
Only works with Rails 3.x because Rails 3 makes doing this sort of thing a lot easier and
that is all I needed it for.
This library takes standard Rails asset paths such as
/stylesheets/main.css?1288717704 and converts them
It uses an MD5 hash of the file contents to produce the id so the same asset will always have the same ID.
In my quest to achieve a Google Page Speed score of 100, this library achieves the following:
- Assets served from a cookie-less domain
- Unique identifier is not encoded into a query parameter (so it is cacheable by proxy servers)
- All assets have far-future expires headers for caching
- Assets have the Cache-Control: public header for caching
As an added bonus, all your assets are available over
https:// as well.
Add the gem to your
config/environments/production.rb to use Amazon S3 as the asset host
and to use the id-stamped asset paths in helpers
config.action_controller.asset_host = Proc.new do |source| 'http://my_bucket.s3.amazonaws.com' end config.action_controller.asset_path = Proc.new do |source| AssetID::Asset.fingerprint(source) end
Add your Amazon S3 configuration details to
production: access_key_id: 'MY_ACCESS_KEY' secret_access_key: 'MY_ACCESS_SECRET' bucket: "my_live_bucket"
Optionally create a rake task in
perform the upload for use in your deploy scripts
namespace :asset do namespace :id do desc "uploads the current assets to s3 with stamped ids" task :upload do AWS::S3::DEFAULT_HOST.replace "s3-eu-west-1.amazonaws.com" # If using EU bucket AssetID::Asset.asset_paths += ['favicon.png'] # Configure additional asset paths AssetID::S3.upload end end end
If you want to use the SSL host in your configuration you can do so in
config.action_controller.asset_host = Proc.new do |source| request.ssl? 'https://my_bucket.s3.amazonaws.com' : 'http://my_bucket.s3.amazonaws.com' end
By default any relative CSS images that match files on the filesystem are converted to AssetID paths as well.
For S3, if you don’t specify a
prefix it will use the
http:// bucket URL by default. You can override this in
config/asset_id.yml. For example if you wanted to use the
production: access_key_id: 'MY_ACCESS_KEY' secret_access_key: 'MY_ACCESS_SECRET' bucket: "my_live_bucket" prefix: "https://my_bucket.s3.amazonaws.com"
Using Amazon CloudFront Content Delivery Network (CDN)
To use Amazon CloudFront as a CDN for your assets all you need to do is create a CloudFront distribution for the bucket you have defined your configuration and then substitute your unique CloudFront domain name in
config.action_controller.asset_host = Proc.new do |source| 'http://my_domain.d374pjuyllr15e.cloudfront.net' end
SSL works fine here as well.