Customizing “No http resource was found that matches the request uri” message

Question

Is there a simple way to modify the default 404 message returned by Web API?

No http resource was found that matches the request uri

Answer 1

You need to override the DelegatingHandler abstract class.

see more here Uniform, consistent error responses from ASP.Net Web API 2

and here, ASP.NET Web API Exception Handling

Answer 2

The simple way to do that is by "DelegatingHandler"

1. First Step is to create a new class inherits from DelegatingHandler:

     public class ApiGatewayHandler : DelegatingHandler { protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { var response = await base.SendAsync(request, cancellationToken); if (response!=null && response.StatusCode == HttpStatusCode.NotFound) { var msg = await response.Content.ReadAsStringAsync(); //you can change the response here if (msg != null && msg.Contains("No HTTP resource was found")) { return new HttpResponseMessage { StatusCode = HttpStatusCode.NotFound, Content = new ObjectContent(typeof(object), new { Message = "New Message..No HTTP resource was found that matches the request URI" }, new JsonMediaTypeFormatter()) }; } } return response; return response; } 

   }

2. Then Register this class in the web api Register config file

    public static void Register(HttpConfiguration config){ public static void Register(HttpConfiguration config) { // you config and routes here config.MessageHandlers.Add(new ApiGatewayHandler()); //.... } } 

That is it. Same way if you need to change any other error message.