Hi! Say you have: ```@Serializable data class PagedData<T>(val data: T, val page: Int, val tot...

# serialization

[Lamberto Basti]

Hi! Say you have:

@Serializable
data class PagedData<T>(val data: T, val page: Int, val totalPages: Int, val pageSize: Int)

Where you know for sure that T is a class that has the annotations @Serializable or a list of a type that is annotated with @Serializable.

Why the serialization runtime is not able to infer what to use? Also, I am using Ktor, it would be kind of pointless to explicitly build a serializer before every response as such.

[Dominaezzz]

The issue here is because of type erasure. Not too long ago even List<T> had to have it's serializers explicitly created. This was "fixed" for bult-in types using the typeOf api.
I believe support is being added to non built-in types is planned.

[Lamberto Basti]

Oh ok, thanks for the reply! Is there some workaround?

[Dominaezzz]

My current workaround is to get the String from ktor the deserialize it myself with the explicitly created serializer.

[Lamberto Basti]

That may be ok for deserialization, but if I have to serialize, how do I handle the content-type header if i return just a string?

[Dominaezzz]

Are you using client or server?

[Lamberto Basti]

Server, the incriminated line is:

call.respond(PagedData(data, page, pageSize, totalPages))

[Dominaezzz]

Ah. I was assuming client.

[Dominaezzz]

You could serialize it to a string yourself and respondText with content-type of json.

[Lamberto Basti]

Yeah I'll try:

call.respondText(
    deserializer.stringify(
        PagedData.serializer(ElaboratedTweet.serializer().list),
        PagedData(data, page, pageSize, totalPages)
    ),
    ContentType.Application.Json
)

Thanks :)