ASP .NET Web API 如何在不支持的媒体类型上返回错误

Question

My Web API controller deals with some third party class in one of its methods

[HttpPost]
public IHttpActionResult CreateJob([FromBody] ThirdPartyCustomType item)
{
  //Something useful done here
}

It is parsed using custom media type formatter and has it's own media type "application/json+customType".

The problem is that when parameter content type is specified incorrectly(for example "application/json"). Web API uses another formatter to parse request body and then when it tries to create instance of ThirdPartyCustomType it fails some internal validation and throws NullReferenceException.

How can I tell Web API not to try and parse request body when content type is wrong?

EDIT: As guys in comments suggested I created a middleware class, now the thing is that all requests are getting caught there and I need this validation to work only for one. I think that I can check Request.Path in my middleware and act only if it corresponds to my request but that does not seems like good solution.

Another edit Finally it looks like this:

public class ContentTypeCheckMiddleWare : OwinMiddleware
{
    public ContentTypeCheckMiddleWare(OwinMiddleware next) : base(next)
    {
    }

    public async override Task Invoke(IOwinContext context)
    {
        if (context.Request.Path.Value.EndsWith("myRouteSuffix") && context.Request.Method == "POST")
        {
            var contentType = context.Request.ContentType;

            if (contentType != "application/json+customType")
            {
                context.Response.StatusCode = 416;
                await context.Response.WriteAsync(
                    "Invalid content type.");
            }
        }
        else
        {
            await Next.Invoke(context);
        }
    }
}

Is there any better way?

Answer 1

当返回类型为 IHttpActionResult 时，您可以使用内置响应类型，例如 Ok()、BadRequest() 或 NotFound()，对于其余状态代码，您可以使用 StatusCode(HttpStatusCode statuscode) 方法。

return StatusCode(HttpStatusCode.UnsupportedMediaType);