Kotlin Webjars Locator Ktor Gradle

README.md

This is how I like to use webjars in kotlin.

build.gradle.kts dependencies:

dependencies {
    // webjars
    implementation("org.webjars:webjars-locator:0.46")
    implementation("org.webjars.npm:htmx.org:1.9.2")
}

endpoint:

val htmx = textFromWebJar("htmx.js")
routing {
  get("/asset/htmx.js") { call.respondText(htmx, ContentType.Application.JavaScript)  }
}

io.kt

package util

import org.webjars.WebJarAssetLocator
import java.nio.charset.Charset

private val locator by lazy { WebJarAssetLocator() }

// Do not use a trailing / for resource paths
// IMPORTANT: Must use getSystemResourceAsStream to load a resource from a jar
internal fun textFromResource(name: String, charset: Charset = Charset.forName("UTF-8")) =
    ClassLoader.getSystemResourceAsStream(name)!!.bufferedReader(charset).readText()

internal fun fullPathForWebjar(trailingPath: String) = locator.getFullPath(trailingPath)

internal fun textFromWebjar(trailingPath: String) = locator
    .getFullPath(trailingPath)
    .let(::textFromResource)

internal fun textFromWebjar(artifactId: String, trailingPath: String) = locator.allWebJars.values
    .first { it.artifactId == artifactId }.contents
    .first { it.contains(trailingPath) }
    .let(::textFromResource)