Record Types and Serialization -> F# to C#

I was working on an exercise where I have a F# component being consumed by an MVC web application written in C#.   As I already asked about here, the CLIMutable is a great feature to the F# language spec.  I created a basic record type with the CLIMutable attribute like so:

1 [<CLIMutable>] 2 type Account = {Number:int; Holder:string; Amount:float}

I then create an instance of that type in the controller written in C#:

1 public class AccountController : ApiController 2 { 3 [HttpGet] 4 public Account Index() 5 { 6 var account = new Account(); 7 account.Amount = 100; 8 account.Holder = "Homer"; 9 account.Number = 1; 10 return account; 11 } 12 }

When I write the site and call the method via Fiddler, I get a nasty “@” symbol added to the end of the name:


which is no good.  I then thought of my question on SO and Mark Seeman’s blog post on this topic found here.  I added this to the WebApiConfig class

1 public static void Register(HttpConfiguration config) 2 { 3 // Web API configuration and services 4 GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ContractResolver = 5 new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver(); 6 7 // Web API routes 8 config.MapHttpAttributeRoutes(); 9 10 config.Routes.MapHttpRoute( 11 name: "DefaultApi", 12 routeTemplate: "api/{controller}/{id}", 13 defaults: new { id = RouteParameter.Optional } 14 ); 15 }

And the “@” symbol goes away


The next task was to add in option types.  I updated the class like so:

1 [<CLIMutable>] 2 type Account = {Number:int;Holder:string option;Amount:float}

I then added a F# class to do the assignment of the value

1 type AccountRepository() = 2 member this.GetAccount() = 3 {Number=1;Holder=Some "Homer"; Amount=100.}

And then updated the controller:

1 [HttpGet] 2 public Account Index() 3 { 4 AccountRepository repository = new AccountRepository(); 5 return repository.GetAccount(); 6 }

And I get this:


Which is not what my UI friends want.  They want the same value for the json –> they want to ignore the existence of the option type.  Fair enough. I hit up stack overflow here and Sven had a great answer pointing me to Isaac Abraham’s serializer found here.  I popped that puppy into the project and updated the WebApiConfig like so:

1 var formatter = GlobalConfiguration.Configuration.Formatters.JsonFormatter; 2 formatter.SerializerSettings.ContractResolver = new DefaultContractResolver(); 3 formatter.SerializerSettings.Converters.Add(new IdiomaticDuConverter());

And boom goes the dynamite.


One Response to Record Types and Serialization -> F# to C#

  1. Pingback: F# Weekly #6, 2015 | Sergey Tihon's Blog

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