Hi! I'm new at Ktor and kotlinx.serialization so this may be a very dumb question, sorry if that's the case... I'm trying to setup a multiplatform client to access some REST API. My example is an endpoint (

/account/auth/

) which I should send a JSON object to, which contains a field

username

and a field

password

. It should return a JSON object that contains a

token

field. I want to use Kotlinx.Serialization to generate the JSON objects, so I started with:

@Serializable
private data class ApiUsernamePassword(val username: String, val password: String)

and I do my request like this:

val client = HttpClient() {
    install(JsonFeature) {
        serializer = KotlinxSerializer()
    }
}

val res = <http://client.post|client.post><String> {
    url("<http://localhost:8000/account/auth/>")

    body = ApiUsernamePassword(username, password)
}

On the JVM, I get this error:

Companion
java.lang.NoSuchFieldError: Companion
	at io.ktor.client.features.json.serializer.KotlinxSerializer.<init>(KotlinxSerializer.kt:22)

(I can send the full stacktrace if needed) On JS, I get this error:

TypeError: Cannot read property 'plain' of undefined

    at new KotlinxSerializer (<http://localhost:9876/absolute/[REDACTED]/adapter-browser.js?fb6a5f1e12e8cc2bf794189b2b55f22def38ca94:157371:29>)

I've tried Googling it but I don't get any meaningul/related results for both of those errors... Did anyone encounter this before? I also tried adding an empty companion object to my serializable class but it didn't change anything. (all of the above is in the common module, if that's relevant)

What version of ktor & serializable do you use?

Kotlin 1.3.70 Ktor 1.3.1 Serialization 0.20.0

serialization 0.20.0 is not yet supported. Try 0.14.0

Ok, I'm trying

Add

contentType(ContentType.Application.Json)

before

body = …

@ribesg @gabin It works, thanks a lot!