From 8a50d96da0ef10574618cd7a2b2f48699bd66779 Mon Sep 17 00:00:00 2001
From: Marty Tippin <120425148+tippmar-nr@users.noreply.github.com>
Date: Fri, 27 Oct 2023 16:02:49 -0500
Subject: [PATCH] POC - razor page instrumentation. Needs work in transaction /
 segment naming

---
 .../Agent/Core/Utilities/ExtensionsLoader.cs  |  1 +
 .../AspNetCore6Plus/Instrumentation.xml       |  5 ++
 ...ageActionInvokeHandlerAsyncWrapper6Plus.cs | 66 +++++++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/PageActionInvokeHandlerAsyncWrapper6Plus.cs

diff --git a/src/Agent/NewRelic/Agent/Core/Utilities/ExtensionsLoader.cs b/src/Agent/NewRelic/Agent/Core/Utilities/ExtensionsLoader.cs
index d97693468b..c274e15281 100644
--- a/src/Agent/NewRelic/Agent/Core/Utilities/ExtensionsLoader.cs
+++ b/src/Agent/NewRelic/Agent/Core/Utilities/ExtensionsLoader.cs
@@ -40,6 +40,7 @@ public static void Initialize(string installPathExtensionsDirectory)
                 { "BuildCommonServicesWrapper6Plus",                                                                Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
                 { "GenericHostWebHostBuilderExtensionsWrapper6Plus",                                                Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
                 { "InvokeActionMethodAsyncWrapper6Plus",                                                            Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
+                { "PageActionInvokeHandlerAsyncWrapper6Plus",                                                       Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
 
                 { "ResolveAppWrapper",                                                                              Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.Owin.dll") },
 
diff --git a/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/Instrumentation.xml b/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/Instrumentation.xml
index da76c6e9e4..e81652b6e3 100644
--- a/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/Instrumentation.xml
+++ b/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/Instrumentation.xml
@@ -20,5 +20,10 @@ SPDX-License-Identifier: Apache-2.0
         <exactMethodMatcher methodName="InvokeActionMethodAsync" />
       </match>
     </tracerFactory>
+    <tracerFactory name="PageActionInvokeHandlerAsyncWrapper6Plus">
+      <match assemblyName="Microsoft.AspNetCore.Mvc.RazorPages" className="Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker" minVersion="6.0.0.0">
+        <exactMethodMatcher methodName="InvokeHandlerMethodAsync" />
+      </match>
+    </tracerFactory>
   </instrumentation>
 </extension>
diff --git a/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/PageActionInvokeHandlerAsyncWrapper6Plus.cs b/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/PageActionInvokeHandlerAsyncWrapper6Plus.cs
new file mode 100644
index 0000000000..c900d187d8
--- /dev/null
+++ b/src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/PageActionInvokeHandlerAsyncWrapper6Plus.cs
@@ -0,0 +1,66 @@
+// Copyright 2020 New Relic, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using NewRelic.Agent.Api;
+using NewRelic.Agent.Api.Experimental;
+using NewRelic.Agent.Extensions.Providers.Wrapper;
+using NewRelic.Reflection;
+
+namespace NewRelic.Providers.Wrapper.AspNetCore6Plus
+{
+    public class PageActionInvokeHandlerAsyncWrapper6Plus : IWrapper
+    {
+        private static Func<object, PageContext> _getPageContext;
+
+        static PageActionInvokeHandlerAsyncWrapper6Plus()
+        {
+            _getPageContext = VisibilityBypasser.Instance.GenerateFieldReadAccessor<PageContext>("Microsoft.AspNetCore.Mvc.RazorPages",
+                "Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker", "_pageContext");
+        }
+
+        public bool IsTransactionRequired => true;
+
+        public CanWrapResponse CanWrap(InstrumentedMethodInfo methodInfo)
+        {
+            return new CanWrapResponse("PageActionInvokeHandlerAsyncWrapper6Plus".Equals(methodInfo.RequestedWrapperName));
+        }
+
+        public AfterWrappedMethodDelegate BeforeWrappedMethod(InstrumentedMethodCall instrumentedMethodCall, IAgent agent, ITransaction transaction)
+        {
+            if (instrumentedMethodCall.IsAsync)
+            {
+                transaction.AttachToAsync();
+            }
+
+            var pageContext = _getPageContext(instrumentedMethodCall.MethodCall.InvocationTarget);
+
+            var actionDescriptor = pageContext.ActionDescriptor;
+
+            var transactionName = CreateTransactionName(actionDescriptor);
+
+            transaction.SetWebTransactionName(WebTransactionType.Action, transactionName, TransactionNamePriority.FrameworkHigh);
+
+            var actionDescriptorPageTypeInfo = actionDescriptor.PageTypeInfo;
+            var pageTypeName = actionDescriptorPageTypeInfo.Name;
+
+            var segment = transaction.StartMethodSegment(instrumentedMethodCall.MethodCall, pageTypeName, "uhh_what_goes_here");
+
+            var segmentApi = segment.GetExperimentalApi();
+            segmentApi.UserCodeNamespace = actionDescriptorPageTypeInfo.FullName;
+            segmentApi.UserCodeFunction = "uhh_what_goes_here";
+
+            return Delegates.GetAsyncDelegateFor<Task>(agent, segment, TaskContinueWithOption.None);
+        }
+
+        private static string CreateTransactionName(CompiledPageActionDescriptor actionDescriptor)
+        {
+            var transactionName = $"Pages{actionDescriptor.DisplayName}";
+
+            return transactionName;
+        }
+    }
+}