Use HttpMessageHandler on HttpConnection (#3648)

* Use HttpMessageHandler

Fixes #3415

* Use MemoryStreamFactory

This commit uses the MemoryStreamFactory to create a Memory Stream
when the response is an Elasticsearch.Net response type

* Use StringBuilder to build query string

This commit replaces the use of string.join and the capturing delegate to instead use
a StringBuilder and for loop. It also uses a simple heuristic to intialize the StringBuilder capacity.

* Avoid allocating Headers if unused

This commit avoids allocating a NameValueCollection for Headers if there
are no headers to send

Author: russcam

src/Elasticsearch.Net/Connection/HttpConnection.cs

@@ -74,7 +74,7 @@ public virtual TResponse Request<TResponse>(RequestData requestData)
 			}
 			responseStream = responseStream ?? Stream.Null;
 			var response = ResponseBuilder.ToResponse<TResponse>(requestData, ex, statusCode, warnings, responseStream, mimeType);
-			//var response = builder.ToResponse();
+
 			//explicit dispose of response not needed (as documented on MSDN) on desktop CLR
 			//but we can not guarantee this is true for all HttpMessageHandler implementations
 			if (typeof(TResponse) != typeof(ElasticsearchResponse<Stream>)) responseMessage?.Dispose();
@@ -150,7 +150,7 @@ private HttpClient GetClient(RequestData requestData)
 			return client;
 		}
 
-		protected virtual HttpClientHandler CreateHttpClientHandler(RequestData requestData)
+		protected virtual HttpMessageHandler CreateHttpClientHandler(RequestData requestData)
 		{
 			var handler = new HttpClientHandler
 			{
@@ -212,7 +212,12 @@ protected virtual HttpRequestMessage CreateRequestMessage(RequestData requestDat
 			var method = ConvertHttpMethod(requestData.Method);
 			var requestMessage = new HttpRequestMessage(method, requestData.Uri);
 
-			foreach (string key in requestData.Headers) requestMessage.Headers.TryAddWithoutValidation(key, requestData.Headers.GetValues(key));
+			if (requestData.Headers != null)
+			{
+				foreach (string key in requestData.Headers)
+					requestMessage.Headers.TryAddWithoutValidation(key, requestData.Headers.GetValues(key));
+			}
+
 			requestMessage.Headers.Connection.Clear();
 			requestMessage.Headers.ConnectionClose = false;
 			requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(requestData.Accept));

src/Elasticsearch.Net/Transport/Pipeline/RequestData.cs

@@ -4,6 +4,7 @@
 using System.IO;
 using System.Linq;
 using System.Security.Cryptography.X509Certificates;
+using System.Text;
 
 namespace Elasticsearch.Net
 {
@@ -42,10 +43,17 @@ IMemoryStreamFactory memoryStreamFactory
 			HttpCompression = global.EnableHttpCompression;
 			RequestMimeType = local?.ContentType ?? MimeType;
 			Accept = local?.Accept ?? MimeType;
-			Headers = global.Headers != null ? new NameValueCollection(global.Headers) : new NameValueCollection();
+
+			if (global.Headers != null)
+				Headers = new NameValueCollection(global.Headers);
 
 			if (!string.IsNullOrEmpty(local?.OpaqueId))
+			{
+				if (Headers == null)
+					Headers = new NameValueCollection();
+
 				Headers.Add(OpaqueIdHeader, local.OpaqueId);
+			}
 
 			RunAs = local?.RunAs;
 			SkipDeserializationForStatusCodes = global?.SkipDeserializationForStatusCodes;
@@ -54,7 +62,7 @@ IMemoryStreamFactory memoryStreamFactory
 			RequestTimeout = local?.RequestTimeout ?? global.RequestTimeout;
 			PingTimeout =
 				local?.PingTimeout
-				?? global?.PingTimeout
+				?? global.PingTimeout
 				?? (global.ConnectionPool.UsingSsl ? ConnectionConfiguration.DefaultPingTimeoutOnSSL : ConnectionConfiguration.DefaultPingTimeout);
 
 			KeepAliveInterval = (int)(global.KeepAliveInterval?.TotalMilliseconds ?? 2000);
@@ -86,7 +94,7 @@ IMemoryStreamFactory memoryStreamFactory
 		public bool MadeItToResponse { get; set; }
 		public IMemoryStreamFactory MemoryStreamFactory { get; }
 
-		public HttpMethod Method { get; private set; }
+		public HttpMethod Method { get; }
 
 		public Node Node { get; set; }
 		public AuditEvent OnFailureAuditEvent => MadeItToResponse ? AuditEvent.BadResponse : AuditEvent.BadRequest;
@@ -111,11 +119,12 @@ private string CreatePathWithQueryStrings(string path, IConnectionConfigurationV
 		{
 			path = path ?? string.Empty;
 			if (path.Contains("?"))
-				throw new ArgumentException($"{nameof(path)} can not contain querystring parmeters and needs to be already escaped");
+				throw new ArgumentException($"{nameof(path)} can not contain querystring parameters and needs to be already escaped");
 
 			var g = global.QueryStringParameters;
 			var l = request?.QueryString;
-			if (g?.Count == 0 && l?.Count == 0) return path;
+
+			if ((g == null || g.Count == 0) && (l == null || l.Count == 0)) return path;
 
 			//create a copy of the global query string collection if needed.
 			var nv = g == null ? new NameValueCollection() : new NameValueCollection(g);
@@ -138,15 +147,22 @@ internal static class NameValueCollectionExtensions
 	{
 		internal static string ToQueryString(this NameValueCollection nv)
 		{
-			if (nv == null) return string.Empty;
-			if (nv.AllKeys.Length == 0) return string.Empty;
+			if (nv == null || nv.AllKeys.Length == 0) return string.Empty;
 
-			string E(string v)
+			// initialize with capacity for number of key/values with length 5 each
+			var builder = new StringBuilder("?", nv.AllKeys.Length * 2 * 5);
+			for (int i = 0; i < nv.AllKeys.Length; i++)
 			{
-				return Uri.EscapeDataString(v);
+				if (i != 0)
+					builder.Append("&");
+
+				var key = nv.AllKeys[i];
+				builder.Append(Uri.EscapeDataString(key));
+				builder.Append("=");
+				builder.Append(Uri.EscapeDataString(nv[key]));
 			}
 
-			return "?" + string.Join("&", nv.AllKeys.Select(key => $"{E(key)}={E(nv[key])}"));
+			return builder.ToString();
 		}
 
 		internal static void UpdateFromDictionary(this NameValueCollection queryString, Dictionary<string, object> queryStringUpdates,

src/Elasticsearch.Net/Transport/Pipeline/ResponseBuilder.cs

@@ -90,7 +90,7 @@ private static TResponse SetBody<TResponse>(ApiCallDetails details, RequestData
 
 			using (responseStream)
 			{
-				if (SetSpecialTypes<TResponse>(bytes, out var r))
+				if (SetSpecialTypes<TResponse>(requestData, bytes, out var r))
 					return r;
 
 				if (details.HttpStatusCode.HasValue && requestData.SkipDeserializationForStatusCodes.Contains(details.HttpStatusCode.Value))
@@ -121,7 +121,7 @@ private static async Task<TResponse> SetBodyAsync<TResponse>(
 
 			using (responseStream)
 			{
-				if (SetSpecialTypes<TResponse>(bytes, out var r)) return r;
+				if (SetSpecialTypes<TResponse>(requestData, bytes, out var r)) return r;
 
 				if (details.HttpStatusCode.HasValue && requestData.SkipDeserializationForStatusCodes.Contains(details.HttpStatusCode.Value))
 					return null;
@@ -136,7 +136,7 @@ private static async Task<TResponse> SetBodyAsync<TResponse>(
 			}
 		}
 
-		private static bool SetSpecialTypes<TResponse>(byte[] bytes, out TResponse cs)
+		private static bool SetSpecialTypes<TResponse>(RequestData requestData, byte[] bytes, out TResponse cs)
 			where TResponse : class, IElasticsearchResponse, new()
 		{
 			cs = null;
@@ -151,7 +151,7 @@ private static bool SetSpecialTypes<TResponse>(byte[] bytes, out TResponse cs)
 				cs = new VoidResponse() as TResponse;
 			else if (responseType == typeof(DynamicResponse))
 			{
-				using (var ms = new MemoryStream(bytes))
+				using (var ms = requestData.MemoryStreamFactory.Create(bytes))
 				{
 					var body = LowLevelRequestResponseSerializer.Instance.Deserialize<DynamicBody>(ms);
 					cs = new DynamicResponse(body) as TResponse;

src/Tests/Tests/ClientConcepts/Connection/HttpConnectionTests.cs

@@ -127,9 +127,9 @@ public override Task<TResponse> RequestAsync<TResponse>(RequestData requestData,
 				return base.RequestAsync<TResponse>(requestData, cancellationToken);
 			}
 
-			protected override HttpClientHandler CreateHttpClientHandler(RequestData requestData)
+			protected override HttpMessageHandler CreateHttpClientHandler(RequestData requestData)
 			{
-				LastUsedHttpClientHandler = base.CreateHttpClientHandler(requestData);
+				LastUsedHttpClientHandler = (HttpClientHandler)base.CreateHttpClientHandler(requestData);
 				return LastUsedHttpClientHandler;
 			}
 		}