Refactored out the filter functions

src/Infrastructure.Web.Api.Common/Endpoints/ApiUsageFilter.cs

@@ -94,8 +94,7 @@ private void TrackResponse(EndpointFilterInvocationContext context, ICallerConte
     }
 
     private static Dictionary<string, object> PopulatePropertiesFromRequest(HttpContext httpContext,
-        IWebRequest request,
-        ICallerContext caller)
+        IWebRequest request, ICallerContext caller)
     {
         var requestName = request.GetType().Name.ToLowerInvariant();
         var route = httpContext.GetEndpoint()!.DisplayName!;
@@ -126,14 +125,8 @@ private static Dictionary<string, object> PopulatePropertiesFromRequest(HttpCont
 
     private static IWebRequest? GetRequest(EndpointFilterInvocationContext context)
     {
-        var arguments = context.Arguments;
-        if (arguments.Count < 2)
-        {
-            return null;
-        }
-
-        var request = context.Arguments[1]!;
-        if (request is not IWebRequest webRequest)
+        var webRequest = context.GetRequestDto();
+        if (webRequest.NotExists())
         {
             return null;
         }

src/Infrastructure.Web.Api.Common/Endpoints/EndpointFilterExtensions.cs

@@ -0,0 +1,29 @@
+using Infrastructure.Web.Api.Interfaces;
+using Microsoft.AspNetCore.Http;
+
+namespace Infrastructure.Web.Api.Common.Endpoints;
+
+public static class EndpointFilterExtensions
+{
+    /// <summary>
+    ///     Determines the request DTO of the current HTTP request.
+    ///     We expect that all <see cref="RequestDelegate" /> are of this form: (IMediatr mediatr, IWebRequest request)
+    ///     where the second parameter is an instance of a <see cref="IWebRequest{TResponse}" />
+    /// </summary>
+    public static IWebRequest? GetRequestDto(this EndpointFilterInvocationContext context)
+    {
+        var arguments = context.Arguments;
+        if (arguments.Count < 2)
+        {
+            return null;
+        }
+
+        var request = context.Arguments[1]!;
+        if (request is not IWebRequest webRequest)
+        {
+            return null;
+        }
+
+        return webRequest;
+    }
+}

src/Infrastructure.Web.Api.Common/Endpoints/HttpRecordingFilter.cs

@@ -49,7 +49,7 @@ public HttpRecordingFilter(IRecorder recorder, ICallerContextFactory callerConte
         return response;
     }
 
-    private void TraceRequest(IRecorder recorder, ICallerContext caller, string requestDescriptor)
+    private static void TraceRequest(IRecorder recorder, ICallerContext caller, string requestDescriptor)
     {
         recorder.TraceInformation(caller.ToCall(),
 #if TESTINGONLY
@@ -60,8 +60,8 @@ private void TraceRequest(IRecorder recorder, ICallerContext caller, string requ
             requestDescriptor);
     }
 
-    private void TraceResponse(IRecorder recorder, ICallerContext caller, EndpointFilterInvocationContext context,
-        string requestDescriptor, object response)
+    private static void TraceResponse(IRecorder recorder, ICallerContext caller,
+        EndpointFilterInvocationContext context, string requestDescriptor, object response)
     {
         var httpResponse = context.HttpContext.Response;
         var statusCode = httpResponse.StatusCode;