Implement your own clients

http4k Connect

It is very easy to implement your own clients to follow the pattern. For the system MySystem, you would need to:

Depend on the http4k-connect-core artifact
Add an Action interface and implementation:

interface MySystemAction<R> : Action<R>

data class Echo(val value: String) : MySystemAction<Echoed> {
    override fun toRequest() = Request(GET, "echo").body(value)
    override fun toResult(response: Response) = Echoed(response.bodyString())
}

data class Echoed(val value: String)

Add your client interface and HTTP implementation:

interface MySystem {
    operator fun <R : Any> invoke(action: MySystemAction<R>): R

    companion object
}

fun MySystem.Companion.Http(http: HttpHandler) = object : MySystem {
    override fun <R : Any> invoke(action: MySystemAction<R>) = action.toResult(http(action.toRequest()))
}

See also the guide on using KSP to generate extension functions for your clients!