Refactor HttpClientHttpRequester Cache HttpClient

src/Ocelot/DependencyInjection/ServiceCollectionExtensions.cs

@@ -135,6 +135,7 @@ namespace Ocelot.DependencyInjection
             services.AddSingleton<IAuthenticationHandlerFactory, AuthenticationHandlerFactory>();
             services.AddSingleton<IAuthenticationHandlerCreator, AuthenticationHandlerCreator>();
             services.AddSingleton<IRateLimitCounterHandler, MemoryCacheRateLimitCounterHandler>();
+            services.AddSingleton<IHttpClientMessageCacheHandler, MemoryHttpClientMessageCacheHandler>();
 
             // see this for why we register this as singleton http://stackoverflow.com/questions/37371264/invalidoperationexception-unable-to-resolve-service-for-type-microsoft-aspnetc
             // could maybe use a scoped data repository

src/Ocelot/Requester/HttpClientBuilder.cs

@@ -1,46 +1,110 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net;
 using System.Net.Http;
+using System.Threading.Tasks;
 using Ocelot.Logging;
 using Ocelot.Requester.QoS;
 
 namespace Ocelot.Requester
 {
-    internal class HttpClientBuilder
+    internal class HttpClientBuilder : IHttpClientBuilder
     {
-        private readonly Dictionary<int, Func<DelegatingHandler>> _handlers = new Dictionary<int, Func<DelegatingHandler>>();
+        private TimeSpan? _timeout;
+        private readonly List<DelegatingHandler> _handlers = new List<DelegatingHandler>();
+        private Dictionary<string, string> _defaultHeaders;
+        private CookieContainer _cookieContainer;
+        private IQoSProvider _qoSProvider;
 
-        public HttpClientBuilder WithQoS(IQoSProvider qoSProvider, IOcelotLogger logger, HttpMessageHandler innerHandler)
+        public IHttpClientBuilder WithCookieContainer(CookieContainer cookieContainer)
         {
-            _handlers.Add(5000, () => new PollyCircuitBreakingDelegatingHandler(qoSProvider, logger, innerHandler));
+            _cookieContainer = cookieContainer;
             return this;
         }
 
-        internal HttpClient Build(HttpMessageHandler innerHandler)
+        public IHttpClientBuilder WithTimeout(TimeSpan timeout)
         {
-            return _handlers.Any() ? 
-                new HttpClient(CreateHttpMessageHandler()) : 
-                new HttpClient(innerHandler);
+            _timeout = timeout;
+            return this;
         }
 
-        private HttpMessageHandler CreateHttpMessageHandler()
+        public IHttpClientBuilder WithHandler(DelegatingHandler handler)
         {
-            HttpMessageHandler httpMessageHandler = new HttpClientHandler();
+            _handlers.Add(handler);
+            return this;
+        }
 
-            _handlers
-                .OrderByDescending(handler => handler.Key)
-                .Select(handler => handler.Value)
-                .Reverse()
-                .ToList()
-                .ForEach(handler =>
+        public IHttpClientBuilder WithDefaultRequestHeaders(Dictionary<string, string> headers)
         {
-                var delegatingHandler = handler();
-                delegatingHandler.InnerHandler = httpMessageHandler;
-                httpMessageHandler = delegatingHandler;
-            });
+            _defaultHeaders = headers;
+            return this;
+        }
 
+
+        public IHttpClient Create()
+        {
+            HttpClientHandler httpclientHandler = null;
+            if (_cookieContainer != null)
+            {
+                httpclientHandler = new HttpClientHandler() { CookieContainer = _cookieContainer };
+            }
+            else
+            {
+                httpclientHandler = new HttpClientHandler();
+            }
+
+            if (httpclientHandler.SupportsAutomaticDecompression)
+            {
+                httpclientHandler.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
+            }
+
+            var client = new HttpClient(CreateHttpMessageHandler(httpclientHandler));                
+
+            if (_timeout.HasValue)
+            {
+                client.Timeout = _timeout.Value;
+            }
+           
+            if (_defaultHeaders == null)
+            {
+                return new HttpClientWrapper(client);
+            }
+
+            foreach (var header in _defaultHeaders)
+            {
+                client.DefaultRequestHeaders.Add(header.Key, header.Value);
+            }
+
+            return new HttpClientWrapper(client);
+        }
+
+        private HttpMessageHandler CreateHttpMessageHandler(HttpMessageHandler httpMessageHandler)
+        {            
+            foreach (var handler in _handlers)
+            {
+                handler.InnerHandler = httpMessageHandler;
+                httpMessageHandler = handler;
+            }       
             return httpMessageHandler;
         }
     }
+
+    /// <summary>
+    /// This class was made to make unit testing easier when HttpClient is used.
+    /// </summary>
+    internal class HttpClientWrapper : IHttpClient
+    {
+        public HttpClient Client { get; }
+
+        public HttpClientWrapper(HttpClient client)
+        {
+            Client = client;
+        }
+
+        public Task<HttpResponseMessage> SendAsync(HttpRequestMessage request)
+        {
+            return Client.SendAsync(request);
+        }
+    }
 }

src/Ocelot/Requester/HttpClientHttpRequester.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Net.Http;
 using System.Threading.Tasks;
 using Ocelot.Logging;
@@ -10,26 +11,36 @@ namespace Ocelot.Requester
 {
     public class HttpClientHttpRequester : IHttpRequester
     {
+        private IHttpClientMessageCacheHandler _cacheHandlers;
         private readonly IOcelotLogger _logger;
 
-        public HttpClientHttpRequester(IOcelotLoggerFactory loggerFactory)
+        public HttpClientHttpRequester(IOcelotLoggerFactory loggerFactory, IHttpClientMessageCacheHandler cacheHandlers)
         {
             _logger = loggerFactory.CreateLogger<HttpClientHttpRequester>();
+            _cacheHandlers = cacheHandlers;
         }
 
         public async Task<Response<HttpResponseMessage>> GetResponse(Request.Request request)
         {
             var builder = new HttpClientBuilder();
 
-            using (var handler = new HttpClientHandler { CookieContainer = request.CookieContainer })
-            {
+            builder.WithCookieContainer(request.CookieContainer);
+
+            string baseUrl = $"{request.HttpRequestMessage.RequestUri.Scheme}://{request.HttpRequestMessage.RequestUri.Authority}";
+
             if (request.IsQos)
             {
-                    builder.WithQoS(request.QosProvider, _logger, handler);
+                builder.WithHandler(new PollyCircuitBreakingDelegatingHandler(request.QosProvider, _logger));
+                baseUrl = $"{baseUrl}{request.QosProvider.CircuitBreaker.CircuitBreakerPolicy.PolicyKey}";
             }
 
-                using (var httpClient = builder.Build(handler))
+            IHttpClient httpClient = _cacheHandlers.Get(baseUrl);
+            if (httpClient == null)
             {
+                httpClient = builder.Create();
+                _cacheHandlers.Set(baseUrl, httpClient, TimeSpan.FromMinutes(30));
+            } 
+   
             try
             {
                 var response = await httpClient.SendAsync(request.HttpRequestMessage);
@@ -49,8 +60,7 @@ namespace Ocelot.Requester
             {
                 return new ErrorResponse<HttpResponseMessage>(new UnableToCompleteRequestError(exception));
             }
-                }
-            }
+
         }
     }
 }

src/Ocelot/Requester/IHttpClient.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Ocelot.Requester
+{
+    public interface IHttpClient
+    {
+        HttpClient Client { get; }
+
+        Task<HttpResponseMessage> SendAsync(HttpRequestMessage request);
+    }
+}

src/Ocelot/Requester/IHttpClientBuilder.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Ocelot.Logging;
+using Ocelot.Requester.QoS;
+using System.Net;
+
+namespace Ocelot.Requester
+{
+    public interface IHttpClientBuilder
+    {
+        /// <summary>
+        /// Sets the cookie container used to store server cookies by the handler
+        /// </summary>
+        /// <param name="cookieContainer"></param>
+        /// <returns></returns>
+        IHttpClientBuilder WithCookieContainer(CookieContainer cookieContainer);
+
+        /// <summary>
+        /// Sets the number of milliseconds to wait before the request times out.
+        /// </summary>
+        IHttpClientBuilder WithTimeout(TimeSpan timeout);
+
+        /// <summary>
+        /// Sets a DelegatingHandler.
+        /// Can be reused to set several different Handlers in a pipeline.
+        /// </summary>
+        IHttpClientBuilder WithHandler(DelegatingHandler handler);     
+
+        /// <summary>
+        /// Sets Default HttpRequestHeaders
+        /// </summary>
+        IHttpClientBuilder WithDefaultRequestHeaders(Dictionary<string, string> headers);
+
+        /// <summary>
+        /// Creates the <see cref="HttpClient"/>
+        /// </summary>
+        IHttpClient Create();
+    }
+}

src/Ocelot/Requester/IHttpClientMessageCacheHandler.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Ocelot.Requester
+{
+    public interface IHttpClientMessageCacheHandler
+    {
+        bool Exists(string id);
+        IHttpClient Get(string id);
+        void Remove(string id);
+        void Set(string id, IHttpClient handler, TimeSpan expirationTime);
+    }
+}

src/Ocelot/Requester/MemoryHttpClientMessageCacheHandler.cs

@@ -0,0 +1,46 @@
+using Microsoft.Extensions.Caching.Memory;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Ocelot.Requester
+{
+    public class MemoryHttpClientMessageCacheHandler : IHttpClientMessageCacheHandler
+    {
+        private readonly IMemoryCache _memoryCache;
+
+        public MemoryHttpClientMessageCacheHandler(IMemoryCache memoryCache)
+        {
+            _memoryCache = memoryCache;
+        }
+
+        public void Set(string id, IHttpClient counter, TimeSpan expirationTime)
+        {
+            _memoryCache.Set(id, counter, new MemoryCacheEntryOptions().SetAbsoluteExpiration(expirationTime));
+        }
+
+        public bool Exists(string id)
+        {
+            IHttpClient counter;
+            return _memoryCache.TryGetValue(id, out counter);
+        }
+
+        public IHttpClient Get(string id)
+        {
+            IHttpClient counter;
+            if (_memoryCache.TryGetValue(id, out counter))
+            {
+                return counter;
+            }
+
+            return null;
+        }
+
+        public void Remove(string id)
+        {
+            _memoryCache.Remove(id);
+        }
+    }
+}

src/Ocelot/Requester/PollyCircuitBreakingDelegatingHandler.cs

@@ -16,9 +16,7 @@ namespace Ocelot.Requester
 
         public PollyCircuitBreakingDelegatingHandler(
             IQoSProvider qoSProvider,
-            IOcelotLogger logger, 
-            HttpMessageHandler innerHandler)
-            : base(innerHandler)
+            IOcelotLogger logger)
         {
             _qoSProvider = qoSProvider;
             _logger = logger;