Vert.x + Kotlin + JTE + HTMX

build.gradle.kts

plugins {
  id("gg.jte.gradle") version "2.2.2"
}

jte {
  precompile()
}

tasks.withType<ProcessResources> {
  dependsOn(tasks.withType<CompileSass>())
  exclude("**/.gitkeep")
}

tasks.jar {
  dependsOn(tasks.precompileJte)
  from(fileTree("jte-classes")) {
    include("**/*.class")
    include("**/*.bin") // Only required for binary templates
  }
}

mainVerticle.kt

// templates in /src/main/jte
override val templateEngine: TemplateEngine by lazy {
  val path = Path.of("src", "main", "jte")
  TemplateEngine.create(DirectoryCodeResolver(path), ContentType.Html)
    .apply { setBinaryStaticContent(true) }
}

webHandlers.kt

interface TemplateEngineProvider {
  val templateEngine: TemplateEngine
}

context(TemplateEngineProvider)
suspend fun RoutingContext.endWithHTMX(
  templateName: String,
  model: Map<String, Any> = emptyMap(),
) {
  val enrichedModel = model + mapOf("htmx" to isHTMXRequest)
  val output = Utf8ByteOutput()

  templateEngine.render("$templateName.jte", enrichedModel, output)

  response()
    .putHeader(HttpHeaders.CONTENT_TYPE, "text/html")
    .end(output.toBuffer())
    .await()
}

private fun Utf8ByteOutput.toBuffer(): Buffer {
  val buffer = Buffer.buffer(contentLength)
  writeTo(buffer::appendBytes)
  return buffer
}

private val HTMX_HEADER = HttpHeaders.createOptimized("HX-Request")
private val RoutingContext.isHTMXRequest
  get() = request().getHeader(HTMX_HEADER).toBoolean()