Krpc

Disclaimer

I am very early in development and actively experimenting with how I want to solve this problem aswell as learning new things alongside. Therefore, nothing is final and the code in this repository might not have the highest quality yet.

Introduction

The aim of this repository is to deepen my knowledge of Kotlin while trying to create something that I miss dearly from fullstack Typescript.

What

In fullstack Typescript there is this fullstack type safety term which came up some time ago. It describes the pursuit of closing the air gap between the client and server. Here I am trying to bring this feeling to Kotlin. My goal is for the API declaration on the server to be the single source of truth for how the API and the DTO's coming in and out of the server are shaped. To archive this, I want to generate a client from this API description. Regarding developer experience, I am looking at trpc and Orpc from the Typescript ecosystem.

in Goals I will show a bit more how I want things to look and feel.

Why

I am a big fan of the idea of fullstack type safety. Starting my career with Java development, and to be honest sometimes later as well, I worked in projects where the client and server were virtually air gapped. They both had their own set of DTO's written and drift between these DTO's happened always.

At the time I discovered that something like trpc exists I was delighted and wondered why it is not as big a deal in the JVM ecosystem. Recently I was able to use some of these tools in a work context. This strengthened my belief that fullstack type safety is something worth considering and adopting at least some parts of it.

Goals

My goal for this project is to be able to write code roughly like this using a Ktor server

val api = router {
    krpcRoute("/") {
        krpcRoute("action") {
            get<Out> {
                Out("Hello", "Peter")
            }
            post<String, Out> { input ->
                Out("POST", input)
            }
        }
    }
}

fun Application.module() {
    routing {
        api.installInto(this)
    }
}

and be able to import, instantiate, and use a client straight away with the same DTOs used in the route handlers.

import krpc.generated.Client

val client = Client("https://my.server.domain.com")

val result = client.action.get()