feat: Simplify setting the HttpClient timeout

Src/Support/Google.Apis.Core/Util/HttpTimeoutInitializer.cs

@@ -0,0 +1,45 @@
+/*
+Copyright 2024 Google Inc
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+using Google.Apis.Http;
+using System;
+
+namespace Google.Apis.Core;
+
+/// <summary>
+/// Used for specifying a custom timeout for a <see cref="ConfigurableHttpClient"/>.
+/// </summary>
+public sealed class HttpTimeoutInitializer : IConfigurableHttpClientInitializer
+{
+    /// <summary>
+    /// The timeout to set on <see cref="ConfigurableHttpClient"/> instances on which this initializer is applied.
+    /// </summary>
+    public TimeSpan HttpClientTimeout { get; }
+
+    /// <summary>
+    /// Creates a new instance with the given timeout.
+    /// </summary>
+    /// <remarks>
+    /// This initializer relies on <see cref="ConfigurableHttpClient"/> for validation.
+    /// That means that <paramref name="httpClientTimeout"/> is not validated in this constructor.
+    /// It's when this initializer is applied to a <see cref="ConfigurableHttpClient"/>
+    /// that the value will be validated and an exception possibly thrown.
+    /// </remarks>
+    public HttpTimeoutInitializer(TimeSpan httpClientTimeout) => HttpClientTimeout = httpClientTimeout;
+
+    /// <inheritdoc/>
+    public void Initialize(ConfigurableHttpClient httpClient) => httpClient.Timeout = HttpClientTimeout;
+}

Src/Support/Google.Apis.Tests/Apis/Services/BaseClientServiceTest.cs

@@ -372,6 +372,19 @@ public void InvalidApplicationName()
             }));
         }
 
+        [Fact]
+        public void HttpClientTimeout()
+        {
+            var timeout = TimeSpan.FromHours(10);
+            var service = new MockClientService(new BaseClientService.Initializer
+            {
+                HttpClientTimeout = timeout
+            });
+
+            Assert.Equal(timeout, service.HttpClientTimeout);
+            Assert.Equal(timeout, service.HttpClient.Timeout);
+        }
+
         [Fact]
         public void VersionHeader()
         {

Src/Support/Google.Apis/Services/BaseClientService.cs

@@ -14,6 +14,7 @@ You may obtain a copy of the License at
 limitations under the License.
 */
 
+using Google.Apis.Core;
 using Google.Apis.Discovery;
 using Google.Apis.Http;
 using Google.Apis.Json;
@@ -123,6 +124,13 @@ public class Initializer
             /// </remarks>
             public string UniverseDomain { get; set; }
 
+            /// <summary>
+            /// The timeout to set on <see cref="HttpClient"/> instances used by the service.
+            /// May be null, in which case the default timeout values on <see cref="HttpClient"/> instances
+            /// used by this service will be left unchanged.
+            /// </summary>
+            public TimeSpan? HttpClientTimeout { get; set; }
+
             /// <summary>
             /// Builder for the x-goog-api-client header, collecting version information.
             /// Services automatically add the API library version to this.
@@ -180,6 +188,7 @@ protected BaseClientService(Initializer initializer)
             ApplicationName = initializer.ApplicationName;
             BaseUriOverride = initializer.BaseUri;
             UniverseDomain = initializer.UniverseDomain;
+            HttpClientTimeout = initializer.HttpClientTimeout;
             ValidateParameters = initializer.ValidateParameters;
             if (ApplicationName == null)
             {
@@ -213,6 +222,13 @@ protected BaseClientService(Initializer initializer)
         /// </remarks>
         public string UniverseDomain { get; set; }
 
+        /// <summary>
+        /// The timeout to set on <see cref="HttpClient"/> instances used by the service.
+        /// May be null, in which case the default timeout values on <see cref="HttpClient"/> instances
+        /// used by this service will be left unchanged.
+        /// </summary>
+        public TimeSpan? HttpClientTimeout { get; }
+
         /// <summary>Returns <c>true</c> if this service contains the specified feature.</summary>
         private bool HasFeature(Features feature)
         {
@@ -244,6 +260,12 @@ private ConfigurableHttpClient CreateHttpClient(Initializer initializer, string
                     CreateBackOffHandler));
             }
 
+            // Add HTTP client timeout initializer if necessary.
+            if (HttpClientTimeout is not null)
+            {
+                args.Initializers.Add(new HttpTimeoutInitializer(HttpClientTimeout.Value));
+            }
+
             var httpClient = factory.CreateHttpClient(args);
             if (initializer.MaxUrlLength > 0)
             {