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Static Assets

Example application

Http4k provides out of the box a set of components for serving static assets, and Invirt only adds a few utilities to make caching and versioning easier.

val staticAssetsVersion = gitCommitId()!!
val devMode = Environment.ENV.developmentMode

Invirt.configure(
    developmentMode = devMode,
    pebble = InvirtPebbleConfig(
        globalVariables = mapOf("staticAssetsVersion" to staticAssetsVersion)
    )
)

val appHandler = routes(
    "/" GET { request -> renderTemplate(request, "index") },
    "/static/${staticAssetsVersion}" bind cacheDays(365).then(staticAssets(devMode))
)

Assets version​

staticAssetsVersion is exposed as a Pebble global variable, so templates can include assets dynamically:

<script src="/static/{{ staticAssetsVersion }}/app.js"></script>

In the snippet above we use the Git commit id, retrieved by Invirt's gitCommitId().

Caching​

cacheDays(days) is a thin convenience over http4k's built-in caching filter:

CachingFilters.CacheResponse.MaxAge(Duration.ofDays(days.toLong()))

A cacheOneYear() shorthand is also available for the common case.

Hot reload vs classpath loading​

staticAssets(...) wraps http4k's static asset wiring and switches between hot-reload (filesystem) and caching (classpath) loading, mirroring how views are loaded.

fun staticAssets(
    developmentMode: Boolean,
    classpathLocation: String = "webapp/static",
    directory: String = "src/main/resources/webapp/static"
): RoutingHttpHandler