From 03182fef6f6a3188efce6ef4d3bea41a8c721ed0 Mon Sep 17 00:00:00 2001
From: Drew Gillies <drewgil@microsoft.com>
Date: Mon, 24 Jun 2024 11:26:57 +1000
Subject: [PATCH] WIP

---
 .../NuGetGallery.Core.csproj                  |  3 +
 .../Diagnostics/ElmahHandleErrorAttribute.cs  | 64 +++++++++++++++++++
 .../SendErrorsToTelemetryAttribute.cs         |  7 +-
 src/NuGetGallery/App_Start/AppActivator.cs    |  1 +
 4 files changed, 73 insertions(+), 2 deletions(-)
 create mode 100644 src/NuGetGallery.Services/Diagnostics/ElmahHandleErrorAttribute.cs

diff --git a/src/NuGetGallery.Core/NuGetGallery.Core.csproj b/src/NuGetGallery.Core/NuGetGallery.Core.csproj
index 221a3609d7..4b8b74c4b4 100644
--- a/src/NuGetGallery.Core/NuGetGallery.Core.csproj
+++ b/src/NuGetGallery.Core/NuGetGallery.Core.csproj
@@ -65,6 +65,9 @@
     <PackageReference Include="NuGet.Services.Validation.Issues">
       <Version>$(ServerCommonPackageVersion)</Version>
     </PackageReference>
+    <PackageReference Include="NuGet.StrongName.elmah.corelibrary">
+      <Version>1.2.2</Version>
+    </PackageReference>
     <PackageReference Include="Microsoft.Data.Services.Client">
       <Version>5.8.4</Version>
     </PackageReference>
diff --git a/src/NuGetGallery.Services/Diagnostics/ElmahHandleErrorAttribute.cs b/src/NuGetGallery.Services/Diagnostics/ElmahHandleErrorAttribute.cs
new file mode 100644
index 0000000000..ee50f25e41
--- /dev/null
+++ b/src/NuGetGallery.Services/Diagnostics/ElmahHandleErrorAttribute.cs
@@ -0,0 +1,64 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Web;
+using System.Web.Mvc;
+using Elmah;
+
+namespace NuGetGallery.Diagnostics
+{
+    /// <summary>
+    /// Source: http://stackoverflow.com/a/779961/52749
+    /// </summary>
+    public class ElmahHandleErrorAttribute : HandleErrorAttribute
+    {
+        public override void OnException(ExceptionContext context)
+        {
+            base.OnException(context);
+            if (!context.ExceptionHandled       // if unhandled, will be logged anyhow
+                || TryRaiseErrorSignal(context) // prefer signaling, if possible
+                || IsFiltered(context))         // filtered?
+                return;
+
+            LogException(context);
+        }
+
+        private static bool TryRaiseErrorSignal(ExceptionContext context)
+        {
+            var httpContext = GetHttpContextImpl(context.HttpContext);
+            if (httpContext == null)
+                return false;
+            var signal = ErrorSignal.FromContext(httpContext);
+            if (signal == null)
+                return false;
+            signal.Raise(context.Exception, httpContext);
+            return true;
+        }
+
+        private static bool IsFiltered(ExceptionContext context)
+        {
+            var config = context.HttpContext.GetSection("elmah/errorFilter")
+                            as ErrorFilterConfiguration;
+
+            if (config == null)
+                return false;
+
+            var testContext = new ErrorFilterModule.AssertionHelperContext(
+                                  context.Exception,
+                                  GetHttpContextImpl(context.HttpContext));
+            return config.Assertion.Test(testContext);
+        }
+
+        private static void LogException(ExceptionContext context)
+        {
+            var httpContext = GetHttpContextImpl(context.HttpContext);
+            var error = new Error(context.Exception, httpContext);
+            ErrorLog.GetDefault(httpContext).Log(error);
+        }
+
+        private static HttpContext GetHttpContextImpl(HttpContextBase context)
+        {
+            return context.ApplicationInstance.Context;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/NuGetGallery.Services/Diagnostics/SendErrorsToTelemetryAttribute.cs b/src/NuGetGallery.Services/Diagnostics/SendErrorsToTelemetryAttribute.cs
index 5003847ea9..069f10e286 100644
--- a/src/NuGetGallery.Services/Diagnostics/SendErrorsToTelemetryAttribute.cs
+++ b/src/NuGetGallery.Services/Diagnostics/SendErrorsToTelemetryAttribute.cs
@@ -8,10 +8,13 @@
 namespace NuGetGallery.Diagnostics
 {
     [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
-    public sealed class SendErrorsToTelemetryAttribute : Attribute
+    public sealed class SendErrorsToTelemetryAttribute : 
+        ElmahHandleErrorAttribute
     {
-        public void OnException(ExceptionContext context)
+        public override void OnException(ExceptionContext context)
         {
+            base.OnException(context);
+
             if (context != null)
             {
                 try
diff --git a/src/NuGetGallery/App_Start/AppActivator.cs b/src/NuGetGallery/App_Start/AppActivator.cs
index 1e6d8cfa2d..e35e692ca1 100644
--- a/src/NuGetGallery/App_Start/AppActivator.cs
+++ b/src/NuGetGallery/App_Start/AppActivator.cs
@@ -252,6 +252,7 @@ private static void AppPostStart(IAppConfiguration configuration)
             Routes.RegisterRoutes(RouteTable.Routes, configuration.FeedOnlyMode, configuration.AdminPanelEnabled);
             AreaRegistration.RegisterAllAreas();
 
+            GlobalFilters.Filters.Add(new SendErrorsToTelemetryAttribute { View = "~/Views/Errors/InternalError.cshtml" }); 
             GlobalFilters.Filters.Add(new ReadOnlyModeErrorFilter());
             GlobalFilters.Filters.Add(new AntiForgeryErrorFilter());
             GlobalFilters.Filters.Add(new UserDeletedErrorFilter());