baratox/play-requirejs

This project is an experiment with recreating the requirejs/example-multipage-shim application with Play! Framework 2.1.0. The main goals are:

Goal	Dev Mode	Prod Mode	Status
Modules	Served in full source code, each in its own file, as they are.	Served after optimized: minified and combined into fewer files.	50%
Libraries	Served in full source code	Served after minified. The minified version should be the official.	50%
CDN	Served locally.	Serve libraries from a CDN, such as Google's;	50%

Running and building

To start the application in development mode, run:

play run

To start in production mode, run:

play start

To optimize the scripts using the Require.Js Optimizer directly, run:

node tools/r.js -o tools/build.js

That build command creates an optimized version of the project in a public/javascripts-built directory. The common.js file will contain all the common modules. app/main1.js will contain the main1-specific modules, app/main2.js will contain the main2-specific modules.

This means that for page 1, after an optimization, the loaded scripts would be:

• common.js
• app/main1.js
• and third-party libraries

Details

Modules

In dev mode, files are served as they are. Nice.

For prod mode, the optimization step needs to be improved. Access to optimizer options are limited to:

• Module names, defined with requireJs in Build.scala.
• mainConfigFile, defined with requireJsShim in Build.scala.

In order to create the best optimization, we need to be able to specify additional options. Ideally, we should be able to specify a complete build script, like the build.js.

Check the difference with Play's optimization and the custom, optimal solution:

common.js                          custom build.js
--------------------------------------------------
common.js                   common.js
                            app/lib.js
                            app/controller/Base.js
                            app/model/Base.js

app/main1.js
--------------------------------------------------
app/lib.js
app/controller/Base.js
app/controller/c1.js        app/controller/c1.js
app/model/Base.js
app/model/m1.js             app/model/m1.js
app/main1.js                app/main1.js

app/main2.js
--------------------------------------------------
app/lib.js
app/controller/Base.js
app/controller/c2.js        app/controller/c2.js
app/model/Base.js
app/model/m2.js             app/model/m2.js
app/main2.js                app/main2.js

In order to serve different versions depending on the mode, the Application.javascripts() method is routed from GET /assets/javascripts/*file controllers.Application.javascripts(file)

Libraries

I couldn't easily keep both, a full source code for dev and a minified version for prod. Even if there already is a public/javascripts-min/lib/jquery.js, Play's optimization overrides it with its own minified version.

There are two main reasons to use the official minified version rather than Play's:

• Play's minified version of jQuery is ~96kb, against ~32kb for the official.
• Minification takes a considerable time.

One way to do this is to have the minified files in a different folder (to avoid re-minification), and use a different route. Similar to what is used for the /assets/javascripts.

CDN

Serving libraries from a CDN in production is trivial, just setup the paths correctly in the requirejs.config(). See the configuration of jQuery in common.js.

But then, libraries are served from the CDN even in dev mode.