Fix meta header and support rest api compatibility (#59)

* Fix meta header client version detection

* Support default mime type and ES rest API compatibility

src/Elastic.Transport/Components/Pipeline/DefaultResponseBuilder.cs

@@ -125,8 +125,12 @@ IReadOnlyDictionary<TcpState, int> tcpStats
 					.StatusCodeToResponseSuccess(requestData.Method, statusCode.Value);
 		}
 
+		// TODO: Perf - avoid extra allocation by comparing spans.
+		var trimmedMimeType = mimeType?.Replace(" ", "");
+		var trimmedAccept = requestData.Accept.Replace(" ", ""); 
+
 		//mimeType can include charset information on .NET full framework
-		if (!string.IsNullOrEmpty(mimeType) && !mimeType.StartsWith(requestData.Accept))
+		if (!string.IsNullOrEmpty(trimmedMimeType) && !trimmedMimeType.StartsWith(trimmedAccept))
 			success = false;
 
 		var details = new ApiCallDetails
@@ -191,7 +195,11 @@ private TResponse SetBody<TResponse>(ApiCallDetails details, RequestData request
 					return response;
 				}
 
-				return mimeType == null || !mimeType.StartsWith(requestData.Accept, StringComparison.Ordinal)
+				// TODO: Perf - avoid extra allocation by comparing spans.
+				var trimmedMimeType = mimeType?.Replace(" ", "");
+				var trimmedAccept = requestData.Accept.Replace(" ", "");
+
+				return trimmedMimeType == null || !trimmedMimeType.StartsWith(trimmedAccept, StringComparison.Ordinal)
 					? null
 					: serializer.Deserialize<TResponse>(responseStream);
 			}
@@ -283,7 +291,11 @@ CancellationToken cancellationToken
 					return response;
 				}
 
-				return mimeType == null || !mimeType.StartsWith(requestData.Accept, StringComparison.Ordinal)
+				// TODO: Perf - avoid extra allocation by comparing spans.
+				var trimmedMimeType = mimeType?.Replace(" ", "");
+				var trimmedAccept = requestData.Accept.Replace(" ", "");
+
+				return trimmedMimeType == null || !trimmedMimeType.StartsWith(trimmedAccept, StringComparison.Ordinal)
 					? default
 					: await serializer
 						.DeserializeAsync<TResponse>(responseStream, cancellationToken)

src/Elastic.Transport/Components/Pipeline/RequestData.cs

@@ -61,8 +61,8 @@ MemoryStreamFactory memoryStreamFactory
 
 		Pipelined = local?.EnableHttpPipelining ?? global.HttpPipeliningEnabled;
 		HttpCompression = global.EnableHttpCompression;
-		RequestMimeType = local?.ContentType ?? MimeType;
-		Accept = local?.Accept ?? MimeType;
+		ContentType = local?.ContentType ?? global.ProductRegistration.DefaultMimeType ?? MimeType;
+		Accept = local?.Accept ?? global.ProductRegistration.DefaultMimeType ?? MimeType;
 
 		if (global.Headers != null)
 			Headers = new NameValueCollection(global.Headers);
@@ -160,8 +160,7 @@ public Node Node
 	public string ProxyAddress { get; }
 	public string ProxyPassword { get; }
 	public string ProxyUsername { get; }
-	// TODO: rename to ContentType in 8.0.0
-	public string RequestMimeType { get; }
+	public string ContentType { get; }
 	public TimeSpan RequestTimeout { get; }
 	public string RunAs { get; }
 	public IReadOnlyCollection<int> SkipDeserializationForStatusCodes { get; }

src/Elastic.Transport/Components/TransportClient/Content/RequestDataContent.cs

@@ -41,7 +41,9 @@ public RequestDataContent(RequestData requestData)
 	{
 		_requestData = requestData;
 		_token = default;
-		Headers.ContentType = new MediaTypeHeaderValue(requestData.RequestMimeType);
+
+		Headers.TryAddWithoutValidation("Content-Type", requestData.ContentType);
+
 		if (requestData.HttpCompression)
 			Headers.ContentEncoding.Add("gzip");
 
@@ -61,7 +63,9 @@ public RequestDataContent(RequestData requestData, CancellationToken token)
 	{
 		_requestData = requestData;
 		_token = token;
-		Headers.ContentType = new MediaTypeHeaderValue(requestData.RequestMimeType);
+
+		Headers.TryAddWithoutValidation("Content-Type", requestData.ContentType);
+
 		if (requestData.HttpCompression)
 			Headers.ContentEncoding.Add("gzip");
 

src/Elastic.Transport/Components/TransportClient/HttpTransportClient.cs

@@ -364,7 +364,7 @@ private static HttpRequestMessage CreateRequestMessage(RequestData requestData)
 
 		requestMessage.Headers.Connection.Clear();
 		requestMessage.Headers.ConnectionClose = false;
-		requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(requestData.Accept));
+		requestMessage.Headers.TryAddWithoutValidation("Accept", requestData.Accept);
 
 		var userAgent = requestData.UserAgent?.ToString();
 		if (!string.IsNullOrWhiteSpace(userAgent))
@@ -417,7 +417,7 @@ private static void SetContent(HttpRequestMessage message, RequestData requestDa
 			if (requestData.HttpCompression)
 				message.Content.Headers.ContentEncoding.Add("gzip");
 
-			message.Content.Headers.ContentType = new MediaTypeHeaderValue(requestData.RequestMimeType);
+			message.Content.Headers.TryAddWithoutValidation("Content-Type", requestData.ContentType);
 		}
 	}
 
@@ -455,7 +455,7 @@ private static async Task SetContentAsync(HttpRequestMessage message, RequestDat
 			if (requestData.HttpCompression)
 				message.Content.Headers.ContentEncoding.Add("gzip");
 
-			message.Content.Headers.ContentType = new MediaTypeHeaderValue(requestData.RequestMimeType);
+			message.Content.Headers.TryAddWithoutValidation("Content-Type", requestData.ContentType);
 		}
 	}
 

src/Elastic.Transport/Components/TransportClient/HttpWebRequestTransportClient.cs

@@ -288,7 +288,7 @@ private static HttpWebRequest CreateWebRequest(RequestData requestData)
 		var request = (HttpWebRequest)WebRequest.Create(requestData.Uri);
 
 		request.Accept = requestData.Accept;
-		request.ContentType = requestData.RequestMimeType;
+		request.ContentType = requestData.ContentType;
 #if !DOTNETCORE
 		// on netstandard/netcoreapp2.0 this throws argument exception
 		request.MaximumResponseHeadersLength = -1;

src/Elastic.Transport/Products/DefaultProductRegistration.cs

@@ -51,6 +51,9 @@ public sealed class DefaultProductRegistration : ProductRegistration
 	/// <inheritdoc cref="ProductRegistration.ResponseBuilder"/>
 	public override ResponseBuilder ResponseBuilder => new DefaultResponseBuilder<EmptyError>();
 
+	/// <inheritdoc cref="ProductRegistration.DefaultMimeType"/>
+	public override string DefaultMimeType => null;
+
 	/// <inheritdoc cref="ProductRegistration.HttpStatusCodeClassifier"/>
 	public override bool HttpStatusCodeClassifier(HttpMethod method, int statusCode) =>
 		statusCode >= 200 && statusCode < 300;

src/Elastic.Transport/Products/Elasticsearch/ElasticsearchProductRegistration.cs

@@ -20,6 +20,7 @@ public class ElasticsearchProductRegistration : ProductRegistration
 {
 	private readonly HeadersList _headers;
 	private readonly MetaHeaderProvider _metaHeaderProvider;
+	private readonly int? _clientMajorVersion;
 
 	/// <summary>
 	/// Create a new instance of the Elasticsearch product registration.
@@ -30,7 +31,12 @@ public class ElasticsearchProductRegistration : ProductRegistration
 	/// 
 	/// </summary>
 	/// <param name="markerType"></param>
-	public ElasticsearchProductRegistration(Type markerType) : this() => _metaHeaderProvider = new DefaultMetaHeaderProvider(markerType, "es");
+	public ElasticsearchProductRegistration(Type markerType) : this()
+	{
+		var clientVersionInfo = ReflectionVersionInfo.Create(markerType);
+		_metaHeaderProvider = new DefaultMetaHeaderProvider(clientVersionInfo, "es");
+		_clientMajorVersion = clientVersionInfo.Version.Major;
+	}
 
 	/// <summary> A static instance of <see cref="ElasticsearchProductRegistration"/> to promote reuse </summary>
 	public static ProductRegistration Default { get; } = new ElasticsearchProductRegistration();
@@ -53,6 +59,9 @@ public class ElasticsearchProductRegistration : ProductRegistration
 	/// <inheritdoc cref="ProductRegistration.ResponseBuilder"/>
 	public override ResponseBuilder ResponseBuilder => new ElasticsearchResponseBuilder();
 
+	/// <inheritdoc cref="ProductRegistration.DefaultMimeType"/>
+	public override string DefaultMimeType => _clientMajorVersion.HasValue ? $"application/vnd.elasticsearch+json;compatible-with={_clientMajorVersion.Value}" : null;
+
 	/// <summary> Exposes the path used for sniffing in Elasticsearch </summary>
 	public const string SniffPath = "_nodes/http,settings";
 

src/Elastic.Transport/Products/ProductRegistration.cs

@@ -23,6 +23,11 @@ namespace Elastic.Transport.Products;
 /// </summary>
 public abstract class ProductRegistration
 {
+	/// <summary>
+	/// The default MIME type used for Accept and Content-Type headers for requests.
+	/// </summary>
+	public abstract string DefaultMimeType { get; }
+
 	/// <summary>
 	/// The name of the current product utilizing <see cref="HttpTransport{TConnectionSettings}"/>
 	/// <para>This name makes its way into the transport diagnostics sources and the default user agent string</para>

src/Elastic.Transport/Requests/MetaData/DefaultMetaHeaderProvider.cs

@@ -26,6 +26,15 @@ public DefaultMetaHeaderProvider(Type clientType, string serviceIdentifier)
 		_syncMetaDataHeader = new MetaDataHeader(clientVersionInfo, serviceIdentifier, false);
 	}
 
+	/// <summary>
+	/// 
+	/// </summary>
+	internal DefaultMetaHeaderProvider(ReflectionVersionInfo reflectionVersionInfo, string serviceIdentifier)
+	{
+		_asyncMetaDataHeader = new MetaDataHeader(reflectionVersionInfo, serviceIdentifier, true);
+		_syncMetaDataHeader = new MetaDataHeader(reflectionVersionInfo, serviceIdentifier, false);
+	}
+
 	/// <summary>
 	/// 
 	/// </summary>

src/Elastic.Transport/Requests/MetaData/ReflectionVersionInfo.cs

@@ -37,7 +37,7 @@ private static string DetermineVersionFromType(Type type)
 	{
 		try
 		{
-			var productVersion = "8.0.0-alpha.8+02b315d290415a4eb153beb827a879d037e904f6 (Microsoft Windows 10.0.19044; .NET 6.0.4; Elastic.Clients.Elasticsearch)"; //FileVersionInfo.GetVersionInfo(type.GetTypeInfo().Assembly.Location)?.ProductVersion ?? EmptyVersion;
+			var productVersion = FileVersionInfo.GetVersionInfo(type.GetTypeInfo().Assembly.Location)?.ProductVersion ?? EmptyVersion;
 
 			if (productVersion == EmptyVersion)
 				productVersion = Assembly.GetAssembly(type).GetName().Version.ToString();

tests/Elastic.Transport.IntegrationTests/Elastic.Transport.IntegrationTests.csproj

@@ -8,6 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Elastic.Clients.Elasticsearch" Version="8.0.2" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="5.0.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
     <PackageReference Include="xunit" Version="2.4.1" />

tests/Elastic.Transport.IntegrationTests/Http/MetaHeaderTests.cs

@@ -0,0 +1,54 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System.Linq;
+using System.Threading.Tasks;
+using Elastic.Transport.IntegrationTests.Plumbing;
+using Elastic.Transport.IntegrationTests.Plumbing.Stubs;
+using Elastic.Transport.Products.Elasticsearch;
+using FluentAssertions;
+using Microsoft.AspNetCore.Mvc;
+using Xunit;
+
+namespace Elastic.Transport.IntegrationTests.Http;
+
+/// <summary>
+/// Tests that the test framework loads a controller and the exposed transport can talk to its endpoints.
+/// Tests runs against a server that started up once and its server instance shared among many test classes
+/// </summary>
+public class MetaHeaderTests : AssemblyServerTestsBase
+{
+	public MetaHeaderTests(TransportTestServer instance) : base(instance) { }
+
+	[Fact]
+	public async Task AddsExpectedMetaHeader()
+	{
+		var connection = new TestableHttpConnection(responseMessage =>
+		{
+			responseMessage.RequestMessage.Content.Headers.ContentType.MediaType.Should().Be("application/vnd.elasticsearch+json");
+			var parameter = responseMessage.RequestMessage.Content.Headers.ContentType.Parameters.Single();
+			parameter.Name.Should().Be("compatible-with");
+			parameter.Value.Should().Be("8");
+
+			var acceptValues = responseMessage.RequestMessage.Headers.GetValues("Accept");
+			acceptValues.Single().Replace(" ", "").Should().Be("application/vnd.elasticsearch+json;compatible-with=8");
+
+			var contentTypeValues = responseMessage.RequestMessage.Content.Headers.GetValues("Content-Type");
+			contentTypeValues.Single().Replace(" ", "").Should().Be("application/vnd.elasticsearch+json;compatible-with=8");
+		});
+
+		var connectionPool = new SingleNodePool(Server.Uri);
+		var config = new TransportConfiguration(connectionPool, connection, productRegistration: new ElasticsearchProductRegistration(typeof(Clients.Elasticsearch.ElasticsearchClient)));
+		var transport = new DefaultHttpTransport(config);
+
+		var response = await transport.PostAsync<StringResponse>("/metaheader", PostData.String("{}"));
+	}
+}
+
+[ApiController, Route("[controller]")]
+public class MetaHeaderController : ControllerBase
+{
+	[HttpPost()]
+	public async Task<int> Post() => await Task.FromResult(100);
+}