DefaultConversionService issue with enums

[Bluexin]

I noticed DefaultConversionService#convert uses Enum#name and not Enum#toString.
The issue with this in locations comes with how most conventions have enum constants be uppercased, while paths are usually lowercased.
Therefore, using #toString would let the developer decide for themselves.

[cy6erGn0m]

On the other hand such enum name to web parameters values mapping increases code cohesion and doesn't look obvious. For example one could amend toString for debugging purposes and accidentally break web endpoint from other system component. It should be some other way to do it

[cy6erGn0m]

Currently the only way to fix it is to provide custom enum conversion:

    enum class LocationEnum {
        A, B, C
    }

    @Location("/") class LocationWithEnum(val e: LocationEnum)

    @Test fun `location class with custom enum value`() = withLocationsApplication {
        application.install(DataConversion) {
            convert(LocationEnum::class) {
                encode { if (it == null) emptyList() else listOf((it as LocationEnum).name.toLowerCase()) }
                decode { values, type -> LocationEnum.values().first { it.name.toLowerCase() in values } }
            }
        }
        application.routing {
            get<LocationWithEnum> {
                call.respondText(call.locations.resolve<LocationWithEnum>(LocationWithEnum::class, call).e.name)
            }
        }

        urlShouldBeHandled("/?e=a", "A")
        urlShouldBeHandled("/?e=b", "B")
    }

However it looks too ugly for end-users. Perhaps we can provide enum data converter that does handle lower cases so one can easily plug it for particular enums

[Bluexin]

Right, I missed the article on data conversions, thanks.
However as you said it is kind of ugly for end-users, and having all the converters where you install them might be less obvious for the developer.
Maybe doing it like other serializers (like json ones) where you can specify custom (de)serializers using an annotation to register it would allow for most flexibility ?

[oleg-larshin]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.