CODEWITHSUNDEEP
jacksonspring-amqpkotlinx.serialization
Rostyslav Khoptiy
Rostyslav Khoptiy

Reputation: 3

How to use kotlinx serialization with Spring AMQP?

It seems that spring AMQP has built-in MessageConverter support for Jackson with the Jackson2JsonMessageConverter class, but is there an equivalent for the kotlinx serialization lib, or would it be necessary to write a custom message converter for it?

Trying to deserialize a JSON AMQP message without providing a MessageConverter Bean will cause an exception

Upvotes: 0

Views: 476

Answers (2)

Odin
Odin

Reputation: 682

I faced this issue myself while working with Spring boot and Kotlin as well. I ended up creating my own converter like Artem said in his response.

An implementation of that would be like:

class KotlinConverter : MessageConverter {
   override fun toMessage(model: Any, messageProperties: MessageProperties): Message {
       val serializer = Json.serializersModule.serializer(model.javaClass)
       val message = Json.encodeToString(serializer, model)
       return Message(
          message.toByteArray(),
          messageProperties
      )
   }

   override fun fromMessage(message: Message): Any {
      return Json.decodeFromString(message.body.toString())
   }
}

encodeToString needed more context to encode a model with Any type so I had to get the serializer from the model's class type.

I haven't tested the fromMessage part since I don't receive any messages from Rabbit but toMessage works fine.

And then set Rabbit's message converter like:

rabbitTemplate.messageConverter = KotlinConverter()

Upvotes: 1

Artem Bilan
Artem Bilan

Reputation: 121382

Yes, you have to write your own org.springframework.amqp.support.converter.MessageConverter implementation for Kotlin Serialization.

It looks like we can borrow ideas from the org.springframework.messaging.converter.KotlinSerializationJsonMessageConverter.

However you also can use a org.springframework.amqp.support.converter.MessagingMessageConverter with a delegate to the mentioned KotlinSerializationJsonMessageConverter.

See AbstractRabbitListenerContainerFactory.setMessageConverter(MessageConverter messageConverter).

Upvotes: 1

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