WebAPI is not returning error message with statuscode in Asp.net mvc

Question

I'm working on asp.net mvc webapi which returns result in json format. I'm trying to set the Response.StatusCode in which I'm partially succeed. When I hit the API on localhost with Postman it returns the status code and error message which I have set manually, but when I hit the API using published link it returns only StatusCode.

public JsonResult Demo(string Fordate)
{ 
    if (string.IsNullOrEmpty(Fordate))
    {
        errorMsg = "For Date is invalid, please correct";
        ControllerContext.HttpContext.Response.StatusCode = Convert.ToInt32(HttpStatusCode.Unauthorized); 
        return Json(new { Response = errorMsg }, JsonRequestBehavior.AllowGet);
    }
}

When I run above code on localhost using Postman it gives following output which is expected output:

But when I tried it with my published link it displays below Output in Postman:

I have tried following line of code also but it does not work if there is a try-catch block. If I put this line of code in try-catch block it gives the error:

Cannot use local variable 'Response' before it is declared

Response.StatusCode = Convert.ToInt32(HttpStatusCode.Forbidden);
return Json(new { Response.StatusCode, Response = error }, JsonRequestBehavior.AllowGet);

From the image you shared, your call never reaches to your method because of unauthorized user. Are you sending the token with that API call too? — ArslanIqbal, Jul 29 '19 at 14:00

score 1 · Answer 1 · answered Jul 29 '19 at 14:04

1

Your error message clearly says that unauthorized access is denied due to invalid credentials. Read this article as this explains clearly.

https://support.microsoft.com/en-in/help/871179/you-receive-an-http-error-401-1-unauthorized-access-is-denied-due-to-i

answered Jul 29 '19 at 14:04

Thameem

537
7
24

Thank you, but I want to show my custom error message with StatusCode. – Suchir Patel Jul 30 '19 at 05:47

user1477388 · Answer 2 · 2019-07-29T14:22:04.197

This happens because the 401 error is a server error. As such, the request never reaches your GET action.

Does your controller have the [Authorize] attribute? If so, you can replace it with a custom attribute (recommended) as described here or just remove it and let your action handle it (not recommended):

throw new HttpResponseException(HttpStatusCode.Unauthorized);

An even better solution, if you are using .NET Core, might be to configure your Startup.cs class like so (you may need to configure this to your liking):

services.AddIdentity<User, IdentityRole>(options =>
{
    options.Cookies.ApplicationCookie.Events = new CookieAuthenticationEvents
    {
        OnRedirectToLogin = ctx =>
        {
           if (ctx.Request.Path.StartsWithSegments("/api") &&
               ctx.Response.StatusCode == (int) HttpStatusCode.OK)
           {
               ctx.Response.StatusCode = (int) HttpStatusCode.Unauthorized;
           }
           else
           {
               ctx.Response.Redirect(ctx.RedirectUri);
           }
           return Task.FromResult(0);
        }
    };
});

Ref. https://devblog.dymel.pl/2016/07/07/return-401-unauthorized-from-asp-net-core-api/

In later versions of .NET Core (and Identity) you may want to use something like this (again, you will want to customize this to suit your requirements):

services.ConfigureApplicationCookie(options =>
{
    options.LoginPath = new PathString("/Account/Login");
    options.LogoutPath = new PathString("/Account/Logout");

    options.Events.OnRedirectToLogin = context =>
    {
        if (context.Request.Path.StartsWithSegments("/api")
            && context.Response.StatusCode == StatusCodes.Status200OK)
        {
            context.Response.Clear();
            context.Response.StatusCode = StatusCodes.Status401Unauthorized;
            return Task.FromResult<object>(null);
        }
        context.Response.Redirect(context.RedirectUri);
        return Task.FromResult<object>(null);
    };
});

Ref. https://stackoverflow.com/a/47240601/1477388

My controller does not have the [Authorize] attribute And I'm not using .NET Core.How can I display My error message which I'm manually setting with those StatusCode as I have to display the error message also with statuscode — Suchir Patel, Jul 30 '19 at 05:39
What versions of .NET, MVC and Identity are you using? You can find these answers in the References folder of your solution under Solution Explorer. Right-click each dependency and select "Properties" to find the version. — user1477388, Jul 30 '19 at 12:57

WebAPI is not returning error message with statuscode in Asp.net mvc

2 Answers2