feat: forward request options to Kiota's default handlers

src/Microsoft.Graph.Core/Requests/GraphClientFactory.cs

@@ -13,6 +13,7 @@ namespace Microsoft.Graph
     using System.Threading;
     using Azure.Core;
     using Microsoft.Graph.Authentication;
+    using Microsoft.Kiota.Abstractions;
     using Microsoft.Kiota.Abstractions.Authentication;
     using Microsoft.Kiota.Http.HttpClientLibrary;
     using Microsoft.Kiota.Http.HttpClientLibrary.Middleware;
@@ -170,7 +171,21 @@ public static HttpClient Create(
         /// <returns></returns>
         public static IList<DelegatingHandler> CreateDefaultHandlers(GraphClientOptions graphClientOptions = null)
         {
-            var handlers = KiotaClientFactory.CreateDefaultHandlers();
+            return CreateDefaultHandlers(graphClientOptions, null);
+        }
+
+        /// <summary>
+        /// Create a default set of middleware for calling Microsoft Graph, letting callers configure the
+        /// underlying Kiota handlers (for example a custom <see cref="Microsoft.Kiota.Http.HttpClientLibrary.Middleware.Options.RetryHandlerOption"/>)
+        /// without having to remove and reinsert a handler afterwards.
+        /// </summary>
+        /// <param name="graphClientOptions">The <see cref="GraphClientOptions"/> to use with the client</param>
+        /// <param name="optionsForHandlers">The request options to configure the default Kiota handlers with. See
+        /// <see cref="KiotaClientFactory.CreateDefaultHandlers(IRequestOption[])"/> for the handlers that read these options.</param>
+        /// <returns></returns>
+        public static IList<DelegatingHandler> CreateDefaultHandlers(GraphClientOptions graphClientOptions, IRequestOption[] optionsForHandlers)
+        {
+            var handlers = KiotaClientFactory.CreateDefaultHandlers(optionsForHandlers);
             handlers.Add(new GraphTelemetryHandler(graphClientOptions));// add the telemetry handler last.
 
             return handlers;

tests/Microsoft.Graph.DotnetCore.Core.Test/Requests/GraphClientFactoryTests.cs

@@ -10,9 +10,11 @@ namespace Microsoft.Graph.DotnetCore.Core.Test.Requests
     using System.Net;
     using System.Net.Http;
     using System.Net.Http.Headers;
+    using System.Reflection;
     using System.Threading;
     using System.Threading.Tasks;
     using Azure.Core;
+    using Microsoft.Kiota.Abstractions;
     using Microsoft.Kiota.Abstractions.Authentication;
     using Microsoft.Kiota.Http.HttpClientLibrary.Middleware;
     using Microsoft.Kiota.Http.HttpClientLibrary.Middleware.Options;
@@ -148,6 +150,30 @@ public void CreatePipeline_Should_Throw_Exception_With_Duplicate_Handlers()
             Assert.Contains($"{typeof(GraphTelemetryHandler)} has a duplicate handler.", exception.Message);
         }
 
+        [Fact]
+        public void CreateDefaultHandlers_Should_Forward_RetryHandlerOption_To_RetryHandler()
+        {
+            var retryOption = new RetryHandlerOption
+            {
+                MaxRetry = 7,
+                Delay = 3
+            };
+
+            var defaultHandlers = GraphClientFactory.CreateDefaultHandlers(new GraphClientOptions(), new IRequestOption[] { retryOption });
+
+            var retryHandler = defaultHandlers.OfType<RetryHandler>().Single();
+
+            // RetryHandler.RetryOption is internal to the Kiota library, so we reach it with reflection
+            // to prove the option we passed in is the one the handler ended up with.
+            var retryOptionProperty = typeof(RetryHandler).GetProperty("RetryOption", BindingFlags.NonPublic | BindingFlags.Instance);
+            Assert.NotNull(retryOptionProperty);
+            var actualRetryOption = (RetryHandlerOption)retryOptionProperty.GetValue(retryHandler);
+
+            Assert.Same(retryOption, actualRetryOption);
+            Assert.Equal(7, actualRetryOption.MaxRetry);
+            Assert.Equal(3, actualRetryOption.Delay);
+        }
+
         [Fact]
         public void CreateClient_CustomHttpHandlingBehaviors()
         {