Serving static assets #

Static assets refer to JavaScript, stylesheets, images, fonts, etc. that are used in your views.

Setting up a directory to serve can be accomplished using the relevant version of router.path() that accepts an instance of StaticHandlerOptions:

void configure(Router router) {
 router.path('/public/*', serve('public'))   
}

This makes the contents of {PWD}/public available at /public/*.

You can also be more explicit by using regular expressions in the route path:

router.pathRegex('\\.(css|js|jpe?g|png)$', serve('public'))

The serve method in diego.Application will serve a directory using smart defaults depending on the application environment (the value for app.env). These defaults are as follows:

Diego uses Vert.x Web’s StaticHandler under the hood. Check out their official docs for more information on how it operates.

If you store your assets in a public directory in your project root during development, you’ll be able to see changes to assets immediately without rebuilding your app. This is handy when working with front end build tools like Vite, WebPack and Gulp. At deploy time, copy the public directory to src/main/resources to include it as part of your JAR.

Customizing Caching Behaviour #

If you wish to customize the automatic caching behaviour, you can do so by providing your own instance of StaticHandlerOptions to the Application.serve method.

router.path('/public/*', serve(dir: 'public', cacheEnabled: true, maxAge: '365d', maxCacheSize: 100))

Further customization #

If you require even more control of the underlying StaticHandler, consider using a variation of router.use or router.path that supports a io.vertx.core.Handler<RouteContext>. This way you can mount a custom StaticHandler.

WebJars #

WebJars are served at /webjars/* and are cached in all environments for the maximum time allowed by the browser. There is no additional configuration required.

Next: Forms