ktor receive json body twice - exception

Question

I cannot receive the json body of the ktor HttpClient twice.
For the server there is a DoubleReceive feature but I don't see how I can use this when doing client calls.
I want to call a different microservice which either returns some json or when there is an error it return e.g. status 500 and a error description a json payload.
so I tried to HttpResponseValidator and in this only allows a readBytes with this code
HttpResponseValidator {
validateResponse { response ->
val statusCode = response.status.value
val originCall = response.call
if (statusCode < 300 || originCall.attributes.contains(ValidateMark)) return#validateResponse
response.use {
val exceptionCall = originCall.save().apply {
attributes.put(ValidateMark, Unit)
}
//try parse error from json payload which other microservice usually send
exceptionCall.response.receiveError()?.also { throw mapErrors(response, it) }
//default ktor exception mapping
when (statusCode) {
in 300..399 -> throw RedirectResponseException(response)
in 400..499 -> throw ClientRequestException(response)
in 500..599 -> throw ServerResponseException(response)
}
if (statusCode >= 600) {
throw ResponseException(response)
}
}
}
}
receiveError can be used as JacksonConfig.defaultMapper.readValue<ServiceErrorResponse>(this.readBytes()) but will throw a DoubleReceivException if you just call response.receive<ServiceErrorResponse>()
The reason for this is that the receive function first checks a received atomicBoolean.
TL;DR
Now I wonder if there are any ideas on how you handle error payloads or do you just not use them? I am new to microservice in such a manner and it was a requirement to add them. Ktor is a new addition. How do you communicate error infromation between services?
Also is there a way to use the DoubleReceive feature in the client. Because HttpClient(){install(DoubleReceive)} does not work as it is not an ApplicationFeature and not a ClientFeature.

Answer 1

Ktor has developed an experimental plugin called Double Receive, you can use it to receive request body as much as you want.
Read more: https://ktor.io/docs/double-receive.html