Issue #44

src/GraphQL.Client/Http/GraphQLHttpClient.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Threading;
 using System.Threading.Tasks;
@@ -89,6 +90,16 @@ public GraphQLHttpClient(GraphQLHttpClientOptions options) {
 			this.graphQLHttpHandler = new GraphQLHttpHandler(options);
 		}
 
+		internal GraphQLHttpClient(GraphQLHttpClientOptions options,HttpClient httpClient) {
+			if (options == null) { throw new ArgumentNullException(nameof(options)); }
+			if (options.EndPoint == null) { throw new ArgumentNullException(nameof(options.EndPoint)); }
+			if (options.JsonSerializerSettings == null) { throw new ArgumentNullException(nameof(options.JsonSerializerSettings)); }
+			if (options.HttpMessageHandler == null) { throw new ArgumentNullException(nameof(options.HttpMessageHandler)); }
+			if (options.MediaType == null) { throw new ArgumentNullException(nameof(options.MediaType)); }
+
+			this.graphQLHttpHandler = new GraphQLHttpHandler(options,httpClient);
+		}
+
 		public async Task<GraphQLResponse> SendQueryAsync(string query, CancellationToken cancellationToken = default) =>
 			await this.SendQueryAsync(new GraphQLRequest { Query = query }, cancellationToken).ConfigureAwait(false);
 

src/GraphQL.Client/Http/HttpClientExtensions.cs

@@ -0,0 +1,21 @@
+using System.Net.Http;
+
+namespace GraphQL.Client.Http {
+
+	/// <summary>
+	/// Extensions for <see cref="HttpClient"/>
+	/// </summary>
+	public static class HttpClientExtensions {
+
+		/// <summary>
+		/// Creates a <see cref="GraphQLHttpClient"/> from a <see cref="HttpClient"/>
+		/// </summary>
+		/// <param name="httpClient"></param>
+		/// <param name="graphQLHttpClientOptions"></param>
+		/// <returns></returns>
+		public static GraphQLHttpClient AsGraphQLClient(this HttpClient httpClient, GraphQLHttpClientOptions graphQLHttpClientOptions) =>
+			new GraphQLHttpClient(graphQLHttpClientOptions, httpClient);
+
+	}
+
+}

src/GraphQL.Client/Http/Internal/GraphQLHttpHandler.cs

@@ -26,6 +26,16 @@ public GraphQLHttpHandler(GraphQLHttpClientOptions options) {
 			this.HttpClient = new HttpClient(this.Options.HttpMessageHandler);
 		}
 
+		public GraphQLHttpHandler(GraphQLHttpClientOptions options, HttpClient httpClient) {
+			this.Options = options ?? throw new ArgumentNullException(nameof(options));
+			if (options.EndPoint == null) { throw new ArgumentNullException(nameof(options.EndPoint)); }
+			if (options.JsonSerializerSettings == null) { throw new ArgumentNullException(nameof(options.JsonSerializerSettings)); }
+			if (options.HttpMessageHandler == null) { throw new ArgumentNullException(nameof(options.HttpMessageHandler)); }
+			if (options.MediaType == null) { throw new ArgumentNullException(nameof(options.MediaType)); }
+
+			this.HttpClient = httpClient;
+		}
+
 		/// <summary>
 		/// Send a <see cref="GraphQLRequest"/> via GET
 		/// </summary>

tests/GraphQL.Client.Tests/Http/HttpClientExtensionsTest.cs

@@ -0,0 +1,100 @@
+using System;
+using System.Net.Http;
+using GraphQL.Client.Http;
+using GraphQL.Common.Request;
+using GraphQL.Common.Tests.Model;
+using Xunit;
+
+namespace GraphQL.Client.Tests.Http {
+
+	public class HttpClientExtensionsTest : BaseGraphQLClientTest {
+
+		public GraphQLHttpClient GraphQLHttpClient => new HttpClient().AsGraphQLClient(new GraphQLHttpClientOptions {EndPoint=new Uri( "https://swapi.apis.guru/") });
+
+		[Fact]
+		public async void QueryGetAsyncFact() {
+			var graphQLRequest = new GraphQLRequest {
+				Query = @"
+				{
+					person(personID: ""1"") {
+						name
+					}
+				}"
+			};
+			var response = await this.GraphQLHttpClient.SendQueryAsync(graphQLRequest).ConfigureAwait(false);
+
+			Assert.Equal("Luke Skywalker", response.Data.person.name.Value);
+			Assert.Equal("Luke Skywalker", response.GetDataFieldAs<Person>("person").Name);
+		}
+
+		[Fact]
+		public async void OperationNameGetAsyncFact() {
+			var graphQLRequest = new GraphQLRequest {
+				Query = @"
+				query Person{
+					person(personID: ""1"") {
+						name
+					}
+				}
+
+				query Planet {
+					planet(planetID: ""1"") {
+						name
+					}
+				}",
+				OperationName = "Person"
+			};
+			var response = await this.GraphQLHttpClient.SendQueryAsync(graphQLRequest).ConfigureAwait(false);
+
+			Assert.Equal("Luke Skywalker", response.Data.person.name.Value);
+			Assert.Equal("Luke Skywalker", response.GetDataFieldAs<Person>("person").Name);
+		}
+
+		[Fact]
+		public async void VariablesGetAsyncFact() {
+			var graphQLRequest = new GraphQLRequest {
+				Query = @"
+				query Person($personId: ID!){
+					person(personID: $personId) {
+						name
+					}
+				}",
+				Variables = new {
+					personId = "1"
+				}
+			};
+			var response = await this.GraphQLHttpClient.SendQueryAsync(graphQLRequest).ConfigureAwait(false);
+
+			Assert.Equal("Luke Skywalker", response.Data.person.name.Value);
+			Assert.Equal("Luke Skywalker", response.GetDataFieldAs<Person>("person").Name);
+		}
+
+		[Fact]
+		public async void OperationNameVariableGetAsyncFact() {
+			var graphQLRequest = new GraphQLRequest {
+				Query = @"
+				query Person($personId: ID!){
+					person(personID: $personId) {
+						name
+					}
+				}
+
+				query Planet {
+					planet(planetID: ""1"") {
+						name
+					}
+				}",
+				OperationName = "Person",
+				Variables = new {
+					personId = "1"
+				}
+			};
+			var response = await this.GraphQLHttpClient.SendQueryAsync(graphQLRequest).ConfigureAwait(false);
+
+			Assert.Equal("Luke Skywalker", response.Data.person.name.Value);
+			Assert.Equal("Luke Skywalker", response.GetDataFieldAs<Person>("person").Name);
+		}
+
+	}
+
+}