I’m not sure if I understand how to use Ktor properly. Unless I get an HTTP 200 Ok, it throws an exc...

# ktor

[hellman]

I’m not sure if I understand how to use Ktor properly. Unless I get an HTTP 200 Ok, it throws an exception unless I set expectSuccess to false. But if I do that, I can’t get the deserialized body.

This means that when I get a valid response, like 302 Found, I still get an exception.

How is this meant to be used?

[Rustam Siniukov]

what do you mean by you can’t get deserialized body?

[hellman]

If I do like this:

val thing = try {
    <http://client.post|client.post><Thing>(url)
} catch (e: RedirectResponseException) { // 3xx response code
    // can't get deserialized body here!
}

[Rustam Siniukov]

e.response.receive<YourDataClass>() doesn’t work for you? what is the error?

[hellman]

The exception only have the ByteReadChannel so I have to do the deserialization myself

[hellman]

Hmmm

[hellman]

Oh, that should probably go into the docs! 😄

[Rustam Siniukov]

yes, we are improving API discoverability here. should be better in next minor/major releases

[hellman]

Ok, so now I got a different error:

NoTransformationFoundException: No transformation found: class io.ktor.utils.io.ByteBufferChannel (Kotlin reflection is not available) -> class com.Thing (Kotlin reflection is not available)

[hellman]

It doesn’t seem like it uses the serializer?

[Rustam Siniukov]

is it possible that response do not has ContentType header?

[hellman]

hm. you’re right, it doesn’t

[hellman]

Can I force that?

[Rustam Siniukov]

not in a simple way. you can create interceptor that will add header to the response, but that’s a bit hacky

[hellman]

Ok. Too bad. That will probably break at a lot of API integrations.. 😕

[Rustam Siniukov]

please create an issue with your concerns, we will take a look at it

[hellman]

Will do!

[hellman]

Is there an example of how to intercept the response?

[Rustam Siniukov]

something like this is what you need

scope.receivePipeline.intercept(HttpReceivePipeline.After) { response ->
    context.response = object : HttpResponse() {
        override val call: HttpClientCall = response.call
        override val status: HttpStatusCode = response.status
        override val version: HttpProtocolVersion = response.version
        override val requestTime: GMTDate = response.requestTime
        override val responseTime: GMTDate = response.responseTime
        override val content: ByteReadChannel = response.content
        override val headers: Headers = Headers.build { appendAll(response.headers); append(/* you headers*/) }
        override val coroutineContext: CoroutineContext = response.coroutineContext
    }
    proceedWith(context.response)
}

[hellman]

hmm.. context.response only has an internal setter. 😕

[hellman]

Oh, I don’t need to set it!

[Rustam Siniukov]

as another option, you may configure the json feature so that it accepts all responses

[Rustam Siniukov]

this can be better solution depending on your use case

[hellman]

Yep. That solved it. Thanks!

I consider this as a bug in our backend so I will file an issue there first. :)