Allow an HttpClientFactory to be assigned to OpenAIAPI

OpenAI_API/EndpointBase.cs

@@ -59,16 +59,18 @@ protected HttpClient GetClient()
 			{
 				throw new AuthenticationException("You must provide API authentication.  Please refer to https://github.com/OkGoDoIt/OpenAI-API-dotnet#authentication for details.");
 			}
-
-			/*
-			if (_Api.SharedHttpClient==null)
+
+			HttpClient client;
+			var clientFactory = _Api.HttpClientFactory;
+			if (clientFactory != null)
+			{
+				client = clientFactory.CreateClient();
+			}
+			else
 			{
-				_Api.SharedHttpClient = new HttpClient();
-				_Api.SharedHttpClient.
+				client = new HttpClient();
 			}
-			*/
 
-			HttpClient client = new HttpClient();
 			client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _Api.Auth.ApiKey);
 			// Further authentication-header used for Azure openAI service
 			client.DefaultRequestHeaders.Add("api-key", _Api.Auth.ApiKey);

OpenAI_API/OpenAIAPI.cs

@@ -5,7 +5,7 @@
 using OpenAI_API.Images;
 using OpenAI_API.Models;
 using OpenAI_API.Moderation;
-using System.Xml.Linq;
+using System.Net.Http;
 
 namespace OpenAI_API
 {
@@ -31,6 +31,11 @@ public class OpenAIAPI : IOpenAIAPI
 		/// </summary>
 		public APIAuthentication Auth { get; set; }
 
+		/// <summary>
+		/// Optionally provide an IHttpClientFactory to create the client to send requests.
+		/// </summary>
+		public IHttpClientFactory HttpClientFactory { get; set; }
+
 		/// <summary>
 		/// Creates a new entry point to the OpenAPI API, handling auth and allowing access to the various API endpoints
 		/// </summary>
@@ -96,6 +101,5 @@ public static OpenAIAPI ForAzure(string YourResourceName, string deploymentId, A
 		/// The API lets you do operations with images. You can Given a prompt and/or an input image, the model will generate a new image.
 		/// </summary>
 		public ImageGenerationEndpoint ImageGenerations { get; }
-
 	}
 }

OpenAI_API/OpenAI_API.csproj

@@ -42,10 +42,15 @@
 		</None>
 	</ItemGroup>
 
+	<ItemGroup>
+		<InternalsVisibleTo Include="OpenAI_Tests" />
+	</ItemGroup>
+
 	<ItemGroup>
 		<PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="1.1.1" />
 		<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
 		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
+		<PackageReference Include="Microsoft.Extensions.Http" Version="1.1.1" />
 	</ItemGroup>
 
 </Project>

OpenAI_Tests/HttpClientResolutionTests.cs

@@ -0,0 +1,66 @@
+using Microsoft.Extensions.Options;
+using Moq;
+using NUnit.Framework;
+using OpenAI_API;
+using System;
+using System.Linq;
+using System.Net.Http;
+
+namespace OpenAI_Tests
+{
+    public class HttpClientResolutionTests
+    {
+        [Test]
+        public void GetHttpClient_NoFactory()
+        {
+            var api = new OpenAIAPI(new APIAuthentication("fake-key"));
+            var endpoint = new TestEndpoint(api);
+
+            var client = endpoint.GetHttpClient();
+            Assert.IsNotNull(client);
+        }
+
+        [Test]
+        public void GetHttpClient_WithFactory()
+        {
+            var expectedClient1 = new HttpClient();
+            var mockedFactory1 = Mock.Of<IHttpClientFactory>(f => f.CreateClient(Options.DefaultName) == expectedClient1);
+
+            var expectedClient2 = new HttpClient();
+            var mockedFactory2 = Mock.Of<IHttpClientFactory>(f => f.CreateClient(Options.DefaultName) == expectedClient2);
+
+            var api = new OpenAIAPI(new APIAuthentication("fake-key"));
+            var endpoint = new TestEndpoint(api);
+
+            api.HttpClientFactory = mockedFactory1;
+            var actualClient1 = endpoint.GetHttpClient();
+
+            api.HttpClientFactory = mockedFactory2;
+            var actualClient2 = endpoint.GetHttpClient();
+
+            Assert.AreSame(expectedClient1, actualClient1);
+            Assert.AreSame(expectedClient2, actualClient2);
+
+            api.HttpClientFactory = null;
+            var actualClient3 = endpoint.GetHttpClient();
+
+            Assert.NotNull(actualClient3);
+            Assert.AreNotSame(expectedClient1, actualClient3);
+            Assert.AreNotSame(expectedClient2, actualClient3);
+        }
+
+        private class TestEndpoint : EndpointBase
+        {
+            public TestEndpoint(OpenAIAPI api) : base(api)
+            {
+            }
+
+            protected override string Endpoint => throw new System.NotSupportedException();
+
+            public HttpClient GetHttpClient()
+            {
+                return base.GetClient();
+            }
+        }
+    }
+}

OpenAI_Tests/OpenAI_Tests.csproj

@@ -8,6 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="FluentAssertions" Version="6.9.0" />
+    <PackageReference Include="Moq" Version="4.18.4" />
     <PackageReference Include="nunit" Version="3.13.3" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.3.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.1" />