Address WebApiControllerBase Error Handling Issues

DeviceAdministration/Web/WebApiControllers/WebApiControllerBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
 using System.Net;
@@ -18,6 +19,11 @@ namespace Microsoft.Azure.Devices.Applications.RemoteMonitoring.DeviceAdmin.Web.
     {
         protected async Task<HttpResponseMessage> GetServiceResponseAsync(Func<Task> getData)
         {
+            if (getData == null)
+            {
+                throw new ArgumentNullException("getData");
+            }
+
             return await GetServiceResponseAsync<object>(async () =>
             {
                 await getData();
@@ -34,6 +40,11 @@ namespace Microsoft.Azure.Devices.Applications.RemoteMonitoring.DeviceAdmin.Web.
         /// <returns></returns>
         protected async Task<HttpResponseMessage> GetServiceResponseAsync<T>(Func<Task<T>> getData)
         {
+            if (getData == null)
+            {
+                throw new ArgumentNullException("getData");
+            }
+
             return await GetServiceResponseAsync(getData, true);
         }
 
@@ -49,24 +60,41 @@ namespace Microsoft.Azure.Devices.Applications.RemoteMonitoring.DeviceAdmin.Web.
         {
             ServiceResponse<T> response = new ServiceResponse<T>();
 
+            if (getData == null)
+            {
+                throw new ArgumentNullException("getData");
+            }
+
             try
             {
-                response.Data = await getData();    
+                response.Data = await getData();
             }
             catch (ValidationException ex)
             {
-                foreach (string error in ex.Errors)
+                if (ex.Errors == null)
                 {
-                    response.Error.Add(new Error(error));
+                    response.Error.Add(new Error(ex.Message));
+                }
+                else
+                {
+                    foreach (string error in ex.Errors)
+                    {
+                        response.Error.Add(new Error(error));
+                    }
                 }
             }
             catch (DeviceAdministrationExceptionBase ex)
             {
                 response.Error.Add(new Error(ex.Message));
             }
+            catch (HttpResponseException ex)
+            {
+                throw ex;
+            }
             catch (Exception ex)
             {
                 response.Error.Add(new Error(ex));
+                Debug.Write(FormatExceptionMessage(ex), " GetServiceResponseAsync Exception");
             }
 
             // if there's an error or we've been asked to use a service response, then return a service response
@@ -76,7 +104,7 @@ namespace Microsoft.Azure.Devices.Applications.RemoteMonitoring.DeviceAdmin.Web.
                         response.Error != null && response.Error.Any() ? HttpStatusCode.BadRequest : HttpStatusCode.OK,
                         response);
             }
-            
+
             // otherwise there's no error and we need to return the data at the root of the response
             return Request.CreateResponse(HttpStatusCode.OK, response.Data);
         }
@@ -93,15 +121,38 @@ namespace Microsoft.Azure.Devices.Applications.RemoteMonitoring.DeviceAdmin.Web.
         {
             ServiceResponse<T> response = new ServiceResponse<T>();
 
-            string errorMessage = 
+            string errorMessage =
                 String.Format(
                     CultureInfo.CurrentCulture,
-                    Strings.RequestFormatError, 
+                    Strings.RequestFormatError,
                     parameterName, type);
 
             response.Error.Add(new Error(errorMessage));
 
             return Request.CreateResponse(HttpStatusCode.BadRequest, response);
         }
+
+        protected void TerminateProcessingWithMessage(HttpStatusCode statusCode, string message)
+        {
+            HttpResponseMessage responseMessage = new HttpResponseMessage()
+            {
+                StatusCode = statusCode,
+                ReasonPhrase  = message
+            };
+
+            throw new HttpResponseException(responseMessage);
+        }
+
+        private static string FormatExceptionMessage(Exception ex)
+        {
+            Debug.Assert(ex != null, "ex is a null reference.");
+
+            // TODO: Localize string if neccessary.
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                "{0}{0}*** EXCEPTION ***{0}{0}{1}{0}{0}",
+                Console.Out.NewLine,
+                ex);
+        }
     }
 }