custom400.kt

import org.http4k.contract.PreFlightExtraction
import org.http4k.contract.contract
import org.http4k.contract.meta
import org.http4k.core.Body
import org.http4k.core.Filter
import org.http4k.core.Method.POST
import org.http4k.core.Request
import org.http4k.core.Response
import org.http4k.core.Status.Companion.BAD_REQUEST
import org.http4k.core.Status.Companion.OK
import org.http4k.core.then
import org.http4k.format.Jackson.auto
import org.http4k.lens.LensFailure
import org.http4k.lens.Path

data class Blob(val name: String)

fun main() {

    val lens = Body.auto<Blob>().toLens()

    val filter = Filter { next ->
        {
            try {
                next(it)
            } catch (e: LensFailure) {
                Response(BAD_REQUEST).body(e.cause?.localizedMessage ?: "")
            }
        }
    }

    val app = contract {
        val value = Path.of("foo") meta {
            receiving(lens)
            preFlightExtraction = PreFlightExtraction.IgnoreBody
        } bindContract POST to {
            filter.then { Response(OK).body(lens(it).toString()) }
        }
        routes += value
    }

    println(app(Request(POST, "/foo").body("{\"name\":\"}")))
}