Is there a reason why `io.ktor.http.URL` isn’t `@Serializable`? Seems like a good way to avoid <pri...

# ktor

[Rescribet]

Is there a reason why io.ktor.http.URL isn’t @Serializable?

Seems like a good way to avoid

primitive obsession▾

and a quick win to get basic validation:

@Serializable
data class Person(
    val name: String,
    val friends: String,
)
val p = Person("Abbey", "<http://ex.com/abbey/friends>")
Json.encodeToString(p) // { "name": "Abbey", "friends": "<http://ex.com/abbey/friends>" }

val err = """
	{ "name": "Abbey", "friends": "abbey/friends" }
"""
Json.decodeFromString<Person>(err) // MalformedUrlException : SerializationException

[Dominaezzz]

You can always add a simple custom serializer.

[Dominaezzz]

I don't think ktor-core wants to depend on kotlinx.serialization.

[Rescribet]

That would work. I didn’t know that’s an option for external classes

[Dominaezzz]

Now you know. It would look something like this.

@Serializable
data class Person(
    val name: String,
    val friends: @Serializable(MyCustomSerializer::class) Url,
)

[Rescribet]

That was quite trivial:

object UrlSerializer : KSerializer<Url> {
    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("Url", PrimitiveKind.STRING)

    override fun serialize(encoder: Encoder, value: Url) = encoder.encodeString(value.toString())

    override fun deserialize(decoder: Decoder): Url = Url(decoder.decodeString())
}