(Which is stupid)

{
    "results": [...]
}

That’s how you should do it. There are various reasons for that... but in the real world there are APIs who return arrays. But the folks working on

kotlinx.serialization

don’t really care about the real world. It’s the same for the

null

problem.

I’m not sure how generics would work there, but it doesn’t work on native so I didn’t try

If you’re just on the JVM you could try

Shoot, that just brings me back to last week's problem 😔

What's your opinion on this solution (this is just a start, still need to figure out how to ensure

T

is serializable, and add proper handling for request settings):

@ImplicitReflectionSerializer
    suspend inline fun <reified T : Any> HttpClient.getList(): List<T> = request<HttpResponse> {
        // other settings: url, etc
        method = HttpMethod.Get
    }.use {
        if (it.status.isSuccess()) {
            Json.parse(T::class.serializer().list, it.readText())
        } else {
            throw BadResponseStatusException(it.status, it)
        }
    }

This allows me to perform the request as follows:

actual suspend fun getAll(): List<PersonDTO> = client.getList(/*request settings*/)

?

A very quick google search returns this one for example https://haacked.com/archive/2009/06/25/json-hijacking.aspx/

All the vulnerabilities are nice, but my favorite reason is the fact that arrays can’t evolve. When you return an object, you can add a new entry to the returned payload without breaking every client. You can’t do that when your root element is an array.

Nowadays you could implement your API returning arrays and objects, and use versioning for evolution. But for historical reasons it’s still best to use only objects today. Even a deserializer as young as

kotlinx.serialization

doesn’t support top level arrays... Do you think it’s the only one?

Just look where we are and why we’re here: the developers of

kotlinx.serialization

ever forgot that top level arrays were a thing, or thought it was not something important to implement. There are reasons behind this, conscious or not