JSON to Model property binding using JsonProperty

Question

I'm bound by agreements between my party and the client to use json parameters containing dashes. Since it's not possible to use that in property names in C#, I need to map to the desired property.

What I do now:

The below code is simplified for convenience.

Model

public class MyRequest
{
    [JsonProperty("request-number")]
    public string RequestNumber { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }
}

Controller

[HttpGet]
[Route("api/load-stuff")]
public Stuff LoadStuff([FromUri]MyRequest request)
{
    return BackEnd.LoadStuff(request);
}

Call to the API from client

The above controller is targeted using this uri:

http://localhost:12345/api/load-stuff?request-number=X123&name=requestName

My question

If I put a breakpoint at the BackEnd.LoadStuff line I can see the call arrives, but the request isn't mapped correctly.

Name contains what I expect: requestName, but RequestNumber is null, so the mapping didn't work.

What's going wrong?

Answer 1

ASP.NET's default model binder doesn't take the JsonPropertyAttribute into account when attempting to bind request parameters to a model (it can't, since it doesn't know about JsonPropertyAttribute and the rest of NewtonSoft.Json). Given your scenario (property names that aren't legal identifiers in C#), the only way to achieve what you want is via a custom model binder that does read JsonPropertyAttribute.

If you did have property names that were legal identifiers (for example request_number) then you could create a request model with those named properties, then map it to a separate model with the correctly-named properties, e.g.:

public class MyController : ApiController
{
    [HttpGet]
    [Route("api/load-stuff")]
    public Stuff LoadStuff([FromUri]MyRequest request)
    {
        return BackEnd.LoadStuff(request.ToMyPrettyRequest());
    }
}

public class MyRequest
{
    public string request_number { get; set; }

    public string name { get; set; }

    MyPrettyRequest ToMyPrettyRequest()
    {
        return new MyPrettyRequest
        {
            RequestNumber = request_number,
            Name = name,
        };
    }
}

public class MyPrettyRequest
{
    public string RequestNumber { get; set; }

    public string Name { get; set; }
}