Hi all, I'm using Ktor with Json content serialize...

# ktor

[Mateu]

Hi all,
I'm using Ktor with Json content serializer. Everything is perfect but now I want to be able to return Eithers form Arrow. The serializers are given by Arrow team but I don't know how to configure them (the either is directly the return of the service).
Anyone knows how to add a custom serializer for a return type?
Thanks,

[Aleksei Tirman [JB]]

Can you please illustrate your question with some code?

[Mateu]

I've simplified it to:

get<Either<String, String>>{
    val result : Either<String, String> = "a".right()
    call.respond(result)
}

[phldavies]

Generally you wouldn't want to serialize/respond with the Left of an either the same way you would the Right (as you'd likely want a different status code or body for different domain errors)

[phldavies]

An example way of handling an Either from a route would be to have an extension on PipelineContext<Unit, ApplicationCall> that would handle calling the appropriate call.respond based on if the either is Left or Right

[phldavies]

https://github.com/nomisRev/ktor-arrow-example/blob/main/src/main/kotlin/io/github/nomisrev/routes/error.kt shows this pattern, albeit using context receivers.

[Mateu]

I know is kind of "dirty". The thing is that I'm building the client and server. If I return and recieve an Either I don't need to do the transform and untransform.