Hey guys! I would like to make a mapper from a

HttpResponse

to a

Result<T>

But I can't get it to work?!

class ResponseMapper {
    fun <T> map (httpResponse: HttpResponse) : Result<T> {
        return if (httpResponse.status.isSuccess()){
            Result.success(httpResponse.body()) // This is not allowed?
        } else if (httpResponse.status.value == 401) {
            Result.failure(exception = AuthException())
        } else {
            Result.failure(BackendException(errorCode = httpResponse.status.value))
        }
    }
}

Cannot use 'T' as reified type parameter. Use a class instead.

Can you make this method inline? You'll need it to be inline so it can get the type.

It want to be:

suspend inline fun <reified T> map

That looks right. The body method uses a reified T, and since your T is not reified, it can't use it.

I want to make map a

HttpResponse

that is returned from my

ktor.request

method:

val response = ktor.request(PokemonApi.getAllPokemon(BATCH_SIZE, batch * BATCH_SIZE))
val entity = responseMapper.map(response)

It doesn't know what type 'entity' should be. Either specify a type on entity or use brackets in map and specify a type.

Is their a way that just does:

ResponseMapper.map(response)

?

How would it know what the type is? You can specify the type of entity as in my first example (replace the ... with your response mapper).

We normally use

Retrofit

and the

ResponseMapper

looked like this:

fun <T> map(response: Response<T>): Result<T> = when {
    response.isSuccessful -> response.body()?.let(Result.Companion::success) ?: Result.failure(
        exception = Throwable("Http body is empty. HttpMessage: ${response.message()} HttpCode: ${response.code()}")
    )
    response.code() == 401 -> Result.failure(
        exception = AuthException()
    )
    else -> Result.failure(
        BackendException(
            errorCode = response.code()
        )
    )
}

That code gets the type from the retrofit Response<T>.

Is that possible to do with Ktor?

If you have a Response<T> in your old code, then T is known in the scope where you create the response. You'll want to just specify the type for your mapper instead.