Hey, can you use a custom serializer for a specifi...

# serialization

[hfhbd]

Hey, can you use a custom serializer for a specific format? I want to write one class and use it with different formats, like Json and my own format.

@Serializable
data class Foo(@MyFormat(Custom::class) val bar: Int)

object Custom: KSerializer<Int> { .. }

With Json, I want to use native integer handling: {"bar": 42}` but my format should produce 4242.

[hfhbd]

There is an option to use @Contextual but this only works only on a type, eg Int but you can't use different contextual serializers for the same type, eg Int.

@Serializable
data class Foo(@Contextual val bar: Int, @Contextual val other: Int)

object BarCustom: KSerializer<Int> { .. }
object OtherCustom: KSerializer<Int> { .. }

MyFormat(serializerModule = SerializersModule {
  contextual(Int::class, BarCustom)
}

[Derek Ellis]

You could probably have a custom serializer that delegates to another encoder depending on the type of encoder that is being passed in? (i.e. checking if encoder is JsonEncoder and doing something different than if encoder is MyFormatEncoder)

[hfhbd]

Okay, this would work but results writing a custom serializer for each class.