Asked i serialization channel nobody replied maybe someone k

Question

Asked i serialization channel nobody replied maybe someone knows here Does anyone know if I can somehow register a serializer in ktor using kotlinx serialization I am writing a Ktor sever and I need to return a data class from a 3rd party library so I can t annotate it with Serializable I can write a serializer for it but how to tell Ktor to use this serializer

David Eriksson · Answer

Ivan Brko · Answer

Thanks for the answer Maybe I m missing something obvious here but all I can see here is call to register method If I m using kotlinx serialization isn t that handled internally when I call json

David Eriksson · Answer

Maybe I misinterpreted your question wink

Ivan Brko · Answer

Sorry accidentally sent unfinished message above so I edited it

David Eriksson · Answer

``` application install ContentNegotiation register ContentType Application Json SerializationConverter application routing val model = MyEntity 777 Cargo listOf ChildEntity Qube 1 ChildEntity Sphere 2 ChildEntity uc 3 get call respond model ```

David Eriksson · Answer

From <https github com ktorio ktor blob d85573f5f1bb1c3d0035804f7db1925258e9f119 ktor features ktor serialization jvm test io ktor tests serialization SerializationTest kt L245>

David Eriksson · Answer

But yes MyEntity and ChildEntity have Serializable

David Eriksson · Answer

So you might need to go this route <https github com Kotlin kotlinx serialization blob master docs custom serializers md external serializers for library classes>

David Eriksson · Answer

External serializers for library classes

Ivan Brko · Answer

Thanks I know how to write my own serializer I just don t know how to register that KSerializer in Ktor so that it uses it when it is trying to serialize or deserialize data in API For example when using KMongo with kotlinx serialization there is a method registerSerializer where I can register any non existing serializer

Ivan Brko · Answer

I ll check the samples you gave above in more detail but I have to admit I still don t understand what will hapen when I write something like this ```install ContentNegotiation json register ContentType Application Json SerializationConverter ``` Both json and I call register directly here for Json content That is OK with Ktor

David Eriksson · Answer

Can t say for sure sorry

Ivan Brko · Answer

Ok great Thanks for the help

David Eriksson · Answer

But the Serializable annotations should be picked up by the compiler plugin

Ivan Brko · Answer

Yes but the problem is when I can t annotate the data class as it is not in my code

David Eriksson · Answer

``` Imagine that MyData is a third party library class Plugin will try to automatically serialize all constructor properties and public vars Serializer forClass = MyData class object DataSerializer ```