Call ExceptionHandler for Ktor

KtorExceptionHandler.kt

import io.ktor.application.*
import io.ktor.http.HttpStatusCode
import io.ktor.response.respond
import io.ktor.util.AttributeKey
import io.ktor.util.pipeline.PipelinePhase

typealias DoHandlerExp = suspend (ApplicationCall, Throwable) -> Unit

class ExceptionHandler(
        private val onHandler: DoHandlerExp
) {

    class Configuration {
        internal var onHandler: DoHandlerExp = { call, it ->
            call.respond(HttpStatusCode.OK, it.message ?: "$it")
        }

        fun onHandler(handler: DoHandlerExp) {
            onHandler = handler
        }
    }

    companion object Feature : ApplicationFeature<Application, Configuration, ExceptionHandler> {
        override val key: AttributeKey<ExceptionHandler> = AttributeKey("Exception Handler")

        override fun install(pipeline: Application, configure: Configuration.() -> Unit): ExceptionHandler {
            val handlerPhase = PipelinePhase("ExceptionHandler")
            val configuration = Configuration().apply(configure)
            val feature = ExceptionHandler(configuration.onHandler)

            pipeline.insertPhaseBefore(ApplicationCallPipeline.Monitoring, handlerPhase)
            pipeline.intercept(handlerPhase) {
                kotlin.runCatching {
                    proceed()
                }.onFailure {
                    it.printStackTrace()
                    feature.onHandler(call, it)
                }
            }
            return feature
        }
    }
}

install(ExceptionHandler) {
    onHandler { call, err ->
        call.failed(500, err.message ?: "$err")
    }
}