Hello everyone, :wave::skin-tone-4: I’ve had a loo...

# serialization

[Helio]

Hello everyone, 👋🏽
I’ve had a look at Kotlinx.Serialization documentation, and also looked for examples, but I couldn’t find the best practice for the case I’m going to describe. I wonder if anyone would be able to provide any insight. Also, I’m not an advanced user of the library.

I have an server that return a JSON Payload containing a single Status property:

{
  "status": "OneOf<Pending|Queued|InProgress|Finished|NotBuilt>"
}

If I want to serialise it to Enum, I would have:

@Serializable
enum class Status {
    @SerialName("Pending") PENDING,
    @SerialName("Queued") QUEUED,
    @SerialName("InProgress") IN_PROGRESS,
    @SerialName("Finished") FINISHED,
    @SerialName("NotBuilt") NOT_BUILT,
}

@Serializable
data class ServerResponseModel(val status: Status)

However, when I get a response from the server, let’s say InProgress all I need to do is build a new Model and return the status as being IN_PROGRESS .

What would be the best way to achieve that? Do I need to write a custom serialisation in this case? Also, does it makes sense to create an Enum class for ServerResponseModel?

Thanks for your assistance.

[Paul Griffith]

I think an enum would be fine, and it should "just work" (no custom serializers required) based on your example

[Paul Griffith]

If you might in the future have additional information (that's different) in each response type, you could use a sealed class hierarchy instead - then each inner class would be able to hold different information (I've found that's a pretty common pattern with REST APIs driven by more dynamic languages)

[Helio]

Thanks for your help Paul!

I’ll probably have to do the sealed class hierarchy as you mentioned… I was trying to avoid that since it requires a bit more of boilerplate.

[Helio]

If I stick with enums, I would need to have 2 enum classes . The 1st enum would map the responses from Server, which returns: InProgress. And another that enum that maps a response from Server to InProgress to IN_PROGRESS which is the response I want to send.

[Paul Griffith]

hmm I haven't actually used it myself, but maybe you could have one enum, but use the new @JsonNames annotation?

[Paul Griffith]

Oh, nevermind... https://github.com/Kotlin/kotlinx.serialization/issues/1458

[Helio]

Thanks for pointing this. 🙂

[Helio]

@Paul Griffith, not sure if you would be interested, but I ended up doing something like this as a workaround. :(

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