android - Is there a way to handle dynamic SerialName annotations for Kotlin Serializer? - Stack Overflow

I'm having an issue that my field name changes depending on my response from other items. In Kotlin Serialization I know we can serialize fields and such like this

@Serializable data class WeatherResponse (@SerialName("some_weather_id") val weatherData:WeatherData )

However, in my case "some_weather_id" annotation can change based on previous data and api responses. It can be "another_weather_id" etc.

My question is how can we change that or make the annotation dynamic?

I tried implementing a custom serializer, but I get the error

Field 'weatherData' is required for type with serial name 'com.test.WeatherResponse', but it was missing at path: $

Here is my custom serializer in case I'm doing something incorrect

object SerialNameSerializer : KSerializer<String> {
    override val descriptor = PrimitiveSerialDescriptor("DynamicSerialName", PrimitiveKind.STRING)

    override fun serialize(encoder: Encoder, value: String) {
        val dynamicName = getWeatherID()
        encoder.encodeStructure(descriptor){
            encodeStringElement(descriptor, 0, dynamicName)
            encodeStringElement(descriptor,1,value)
        }
    }

    override fun deserialize(decoder: Decoder): String {
        val dynamicName = getWeatherID()
        decoder.decodeStructure(descriptor){
            val name = decodeStringElement(descriptor,0)
            if(name != dynamicName) {
                throw SerializationException("Unexpected field name: $name")
            }
            return@decodeStructure decodeStringElement(descriptor, 1)
        }
        return dynamicName
    }

    private fun getWeatherID(): String {
        return "some_weather_id"
    }
}

I'm having an issue that my field name changes depending on my response from other items. In Kotlin Serialization I know we can serialize fields and such like this

@Serializable data class WeatherResponse (@SerialName("some_weather_id") val weatherData:WeatherData )

However, in my case "some_weather_id" annotation can change based on previous data and api responses. It can be "another_weather_id" etc.

My question is how can we change that or make the annotation dynamic?

I tried implementing a custom serializer, but I get the error

Field 'weatherData' is required for type with serial name 'com.test.WeatherResponse', but it was missing at path: $

Here is my custom serializer in case I'm doing something incorrect

object SerialNameSerializer : KSerializer<String> {
    override val descriptor = PrimitiveSerialDescriptor("DynamicSerialName", PrimitiveKind.STRING)

    override fun serialize(encoder: Encoder, value: String) {
        val dynamicName = getWeatherID()
        encoder.encodeStructure(descriptor){
            encodeStringElement(descriptor, 0, dynamicName)
            encodeStringElement(descriptor,1,value)
        }
    }

    override fun deserialize(decoder: Decoder): String {
        val dynamicName = getWeatherID()
        decoder.decodeStructure(descriptor){
            val name = decodeStringElement(descriptor,0)
            if(name != dynamicName) {
                throw SerializationException("Unexpected field name: $name")
            }
            return@decodeStructure decodeStringElement(descriptor, 1)
        }
        return dynamicName
    }

    private fun getWeatherID(): String {
        return "some_weather_id"
    }
}

• android
• kotlin
• serialization

Share Improve this question Follow asked Jan 30 at 21:49 OdinsBeardOdinsBeard 3955 bronze badges

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1 Answer 1

Sorted by: Reset to default 1

If the names are known, you can use JsonNames like:

@Serializable 
data class WeatherResponse(
  @JsonNames("some_weather_id", "another_weather_id") val weatherData: WeatherData
)

More examples: https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/json.md#alternative-json-names