asp.net web api - F#, Json.NET 6.0 and WebApi - serialization of record types

Question

Json.NET 6.0.1 adds F# support for records and discriminated unions. When serializing a F# record type using Json.NET I now get nicely formatted JSON.

The serialization is done as follow:

let converters = [| (new StringEnumConverter() :> JsonConverter) |]
JsonConvert.SerializeObject(questionSet, Formatting.Indented, converters)

However, when I try to expose my F# types through a ASP.NET WebApi 5.0 service, written in C#, the serialized JSON includes an @-sign infront of all properties. The @-sign comes from the internal backing field for the record type (this used to be a known problem with Json.Net and F#).

But - since I'm using the updated version of Json.NET, shouldn't the result be the same as when calling JsonConvert? Or is JsonConvert behaving differently than JsonTextWriterand JsonTextReader?

As far as I can tell from reading the JsonMediaTypeFormatter in the WebApi source JsonTextWriterand JsonTextReader is used by WebApi.

Answer 1

You can adorn your records with the [<CLIMutable>] attribute:

[<CLIMutable>]
type MyDtr = {
    Message : string
    Time : string }

That's what I do.

---

For nice XML formatting, you can use:

GlobalConfiguration.Configuration.Formatters.XmlFormatter.UseXmlSerializer <- true

For nice JSON formatting, you can use:

config.Formatters.JsonFormatter.SerializerSettings.ContractResolver <-
    Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()