CdnAssets.scala is a simple replacement for Play Framework’s Assets.at() to enable loading static assets such as JavaScript, CSS, images etc. from a content delivery network (e.g. CloudFront). Whilst in development mode assets are loaded from localhost with an added timestamp as query string to prevent assets from being cached.

CdnAssets has been used successfully with Play Framework 2.2 and 2.3.

The following instructions apply to a standard Play Framework 2.x installation.

• Copy CdnAssets.scala to /app/controllers/.
• In your views replace @Assets.at("filename") with @CdnAssets.at("filename") (see sample-view.scala.html).
• Add assetscdn="//xxxxxxxxxxx.cloudfront.net" and assetsversion="1" to your /conf/application.conf (see sample.conf).
• Make sure your development assets are stored in /public/dev/.
• Make sure your production assets are stored in /public/1/.

Whenever you deploy a new version of your assets, bump the assetsversion number in the config file and store the new assets in /public/{version number}/. A Grunt task can make this a simple task.

The benefits of putting an assets version number into the path is, old assets will no longer be loaded from cache – neither from browser cache nor from the CDN’s caches. You don’t have to invalidate the objects of the CDN, which can take a very long time and may involve cost. You can increase max-age cache headers of your assets for better performance.

There is no equivalent for Assets.at(path: String, file: String).