Added Viewer and

change to App Setting File from Constants

Viewer/Controllers/ErrorHandlerController.cs

@@ -0,0 +1,32 @@
+using Microsoft.AspNetCore.Diagnostics;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+
+namespace OI.Metrology.Viewer.Controllers;
+
+[Route("/error")]
+public class ErrorHandlerController : Controller
+{
+    private readonly ILogger _Logger;
+
+    public ErrorHandlerController(ILogger<ErrorHandlerController> logger) => _Logger = logger;
+
+    public IActionResult Index()
+    {
+        IExceptionHandlerFeature error = HttpContext.Features.Get<IExceptionHandlerFeature>();
+        if (error == null)
+        {
+            return Redirect("~/");
+        }
+        else
+        {
+            _Logger.LogError("Unhandled exception: " + error.Error.ToString());
+            dynamic r = new
+            {
+                Message = error.Error == null ? "Error" : error.Error.Message
+            };
+            return StatusCode(StatusCodes.Status500InternalServerError, r);
+        }
+    }
+}