receiveOrNull susceptible to type erasure

https://github.com/ktorio/ktor/blob/84f213a320f38e11ffaafe7b5e7f321a6b7adaab/ktor-server/ktor-server-core/src/io/ktor/request/ApplicationReceiveFunctions.kt#L70

The highlighted code is susceptible to type erasure. If I want to receiveOrNull<Map<String, List<String>>>(), for instance, at runtime I will only have access to Map<*, *>::class. This is a problem for a lot of serializations frameworks, like jackson, who use TypeTokens or the like.

[nikolajakshic]

@tylerbobella Same thing happens with Gson as well. And for workaround, well you can still take the whole string and convert it with jackson/gson manually.

With Gson, instead of:

val items = call.receive<List<MyType>>()

use

val items = Gson().fromJson<List<MyType>>(call.receiveText(), object : TypeToken<List<MyType>>() {}.type)

You can write extension function and make it look prettier.

[cy6erGn0m]

Since 1.3.0 KType is available (from typeOf() and kotlinx.serialization support should work as well. You may check it in version 1.3.0-rc