Returning Error Code from Controller with System.Web.Http

Question

I have a very light weight REST API that I wrote that validates a user. I want to return the validation as a JSON object, which I can, but if there are missing arguments, I want to kick back an error with some information. Here is my controller

    public class GraphAccessController : ApiController
    {
        private UserValidation _userValidation;
        private UserPermissions _userPermissions;
        string _application;

        public GraphAccessController()
        {
            _userValidation = new UserValidation();
            _userPermissions = new UserPermissions();
        }
        public object GetUserValidation(string application)
        {

            if (string.IsNullOrEmpty(application))
            {
                return StatusCode(HttpStatusCode.MethodNotAllowed);
                //return new HttpResponseException(HttpStatusCode.MethodNotAllowed);
            }
            try
            {
                _application = application;
                ValidateUser(WindowsIdentity.GetCurrent(), application);
                return _userValidation;
            }
            catch (HttpResponseException e)
            {
                string error = e.ToString();
                return StatusCode(HttpStatusCode.InternalServerError);

            }
        }....(other private calls for validation)
{

When the "application" is passed in, I get a nice JSON object back. However, when I am trying to return an error to the user while checking for IsNullOrEmpty, if I just call with PostMan:

return StatusCode(HttpStatusCode.MethodNotAllowed)

the status is set to "405 Method Not Allowed" but I would like to pass down some text to indicate why it failed. So I tried:

throw new HttpResponseException(HttpStatusCode.MethodNotAllowed);

and this just stops execution in my control. So I did a return instead of throw I get a status of 200 (indicating everything was fine) but the JSON header data:

{ "Response": { "Version": { "_Major": 1, "_Minor": 1, "_Build": -1, "_Revision": -1 }, "Content": null, "StatusCode": 405, "ReasonPhrase": "Method Not Allowed", "Headers": [], "RequestMessage": null, "IsSuccessStatusCode": false }, "Message": "Processing of the HTTP request resulted in an exception. Please see the HTTP response returned by the 'Response' property of this exception for details.", "Data": {}, "InnerException": null, "TargetSite": null, "StackTrace": null, "HelpLink": null, "Source": null, "HResult": -2146233088 }

As you can see from the code in the catch I am also trying to do the same type of thing. How do you return a StatusCode with corresponding information text to the caller so they can check the status and if it isn't 200, check the body for error text?

Thanks

Have you checked this: https://learn.microsoft.com/en-us/aspnet/web-api/overview/getting-started-with-aspnet-web-api/action-results ? I think that using `HttpResponseMessage` is the proper way to handle that you want. — Christos, Dec 11 '18 at 21:53
I looked at this and tried with this code: string error = "Application cannot be empty"; HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.NotImplemented, Encoding.Unicode); response.Content = new StringContent(error); return response; But when I do I get this error: "ExceptionMessage": "Method not found: 'System.Net.Http.HttpRequestMessage System.Web.Http.ApiController.get_Request()'.", — john, Dec 11 '18 at 22:13

score 2 · Accepted Answer · answered Dec 11 '18 at 22:17

2

Try returning a content response with the desired HttpStatusCode like this:

catch (HttpResponseException e)
        {
            string error = e.ToString();
            return Content(HttpStatusCode.MethodNotAllowed, error);
        }

answered Dec 11 '18 at 22:17

Phil

131
6

1

Thank you! This did it. I wasn't returning content. – john Dec 11 '18 at 22:26

Returning Error Code from Controller with System.Web.Http

1 Answers1