Fix proxy headers handling (#60)

* Fix proxy headers handling

* Small refactor and moved proxy tests to new test-file.

src/WireMock.Net/Http/HttpClientHelper.cs

@@ -2,17 +2,24 @@
 using System.Linq;
 using System.Net.Http;
 using System.Threading.Tasks;
+using WireMock.Validation;
 
 namespace WireMock.Http
 {
     internal static class HttpClientHelper
     {
-        private static HttpClient CreateHttpClient(string clientX509Certificate2ThumbprintOrSubjectName = null)
+        public static HttpClient CreateHttpClient(string clientX509Certificate2ThumbprintOrSubjectName = null)
         {
-            if (!string.IsNullOrEmpty(clientX509Certificate2ThumbprintOrSubjectName))
+            HttpClientHandler handler;
+
+            if (string.IsNullOrEmpty(clientX509Certificate2ThumbprintOrSubjectName))
+            {
+                handler = new HttpClientHandler();
+            }
+            else
             {
 #if NETSTANDARD || NET46
-                var handler = new HttpClientHandler
+                handler = new HttpClientHandler
                 {
                     ClientCertificateOptions = ClientCertificateOption.Manual,
                     SslProtocols = System.Security.Authentication.SslProtocols.Tls12 | System.Security.Authentication.SslProtocols.Tls11 | System.Security.Authentication.SslProtocols.Tls,
@@ -22,7 +29,8 @@ namespace WireMock.Http
                 var x509Certificate2 = CertificateUtil.GetCertificate(clientX509Certificate2ThumbprintOrSubjectName);
                 handler.ClientCertificates.Add(x509Certificate2);
 #else
-                var handler = new WebRequestHandler
+
+                var webRequestHandler = new WebRequestHandler
                 {
                     ClientCertificateOptions = ClientCertificateOption.Manual,
                     ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true,
@@ -30,38 +38,51 @@ namespace WireMock.Http
                 };
 
                 var x509Certificate2 = CertificateUtil.GetCertificate(clientX509Certificate2ThumbprintOrSubjectName);
-                handler.ClientCertificates.Add(x509Certificate2);
-                return new HttpClient(handler);
+                webRequestHandler.ClientCertificates.Add(x509Certificate2);
+                handler = webRequestHandler;
 #endif
             }
 
-            return new HttpClient();
+            // For proxy we shouldn't follow auto redirects
+            handler.AllowAutoRedirect = false;
+
+            // If UseCookies enabled, httpClient ignores Cookie header
+            handler.UseCookies = false;
+
+            return new HttpClient(handler);
         }
 
-        public static async Task<ResponseMessage> SendAsync(RequestMessage requestMessage, string url, string clientX509Certificate2ThumbprintOrSubjectName = null)
+        public static async Task<ResponseMessage> SendAsync(HttpClient client, RequestMessage requestMessage, string url)
         {
-            var client = CreateHttpClient(clientX509Certificate2ThumbprintOrSubjectName);
+            Check.NotNull(client, nameof(client));
+
+            var originalUri = new Uri(requestMessage.Url);
+            var requiredUri = new Uri(url);
 
             var httpRequestMessage = new HttpRequestMessage(new HttpMethod(requestMessage.Method), url);
 
-            // Overwrite the host header
-            httpRequestMessage.Headers.Host = new Uri(url).Authority;
-
-            // Set headers if present
-            if (requestMessage.Headers != null)
-            {
-                foreach (var headerName in requestMessage.Headers.Keys.Where(k => k.ToUpper() != "HOST"))
-                {
-                    httpRequestMessage.Headers.TryAddWithoutValidation(headerName, requestMessage.Headers[headerName]);
-                }
-            }
-
             // Set Body if present
             if (requestMessage.BodyAsBytes != null && requestMessage.BodyAsBytes.Length > 0)
             {
                 httpRequestMessage.Content = new ByteArrayContent(requestMessage.BodyAsBytes);
             }
 
+            // Overwrite the host header
+            httpRequestMessage.Headers.Host = requiredUri.Authority;
+
+            // Set headers if present
+            if (requestMessage.Headers != null)
+            {
+                foreach (var header in requestMessage.Headers.Where(header => !string.Equals(header.Key, "HOST", StringComparison.OrdinalIgnoreCase)))
+                {
+                    // Try to add to request headers. If failed - try to add to content headers
+                    if (!httpRequestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value))
+                    {
+                        httpRequestMessage.Content?.Headers.TryAddWithoutValidation(header.Key, header.Value);
+                    }
+                }
+            }
+
             // Call the URL
             var httpResponseMessage = await client.SendAsync(httpRequestMessage, HttpCompletionOption.ResponseContentRead);
 
@@ -74,9 +95,24 @@ namespace WireMock.Http
                 Body = await httpResponseMessage.Content.ReadAsStringAsync()
             };
 
-            foreach (var header in httpResponseMessage.Headers)
+            // Set both content and response headers, replacing URLs in values
+            var headers = httpResponseMessage.Content?.Headers.Union(httpResponseMessage.Headers);
+
+            foreach (var header in headers)
             {
-                responseMessage.AddHeader(header.Key, header.Value.FirstOrDefault());
+                // if Location header contains absolute redirect URL, and base URL is one that we proxy to,
+                // we need to replace it to original one.
+                if (string.Equals(header.Key, "Location", StringComparison.OrdinalIgnoreCase)
+                    && Uri.TryCreate(header.Value.First(), UriKind.Absolute, out Uri absoluteLocationUri)
+                    && string.Equals(absoluteLocationUri.Host, requiredUri.Host, StringComparison.OrdinalIgnoreCase))
+                {
+                    var replacedLocationUri = new Uri(originalUri, absoluteLocationUri.PathAndQuery);
+                    responseMessage.AddHeader(header.Key, replacedLocationUri.ToString());
+                }
+                else
+                {
+                    responseMessage.AddHeader(header.Key, header.Value.ToArray());
+                }
             }
 
             return responseMessage;

src/WireMock.Net/ResponseBuilders/Response.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
+using System.Net.Http;
 using System.Text;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -19,6 +20,8 @@ namespace WireMock.ResponseBuilders
     /// </summary>
     public class Response : IResponseBuilder
     {
+        private HttpClient httpClientForProxy;
+
         /// <summary>
         /// The delay
         /// </summary>
@@ -317,6 +320,7 @@ namespace WireMock.ResponseBuilders
 
             ProxyUrl = proxyUrl;
             X509Certificate2ThumbprintOrSubjectName = clientX509Certificate2ThumbprintOrSubjectName;
+            httpClientForProxy = HttpClientHelper.CreateHttpClient(clientX509Certificate2ThumbprintOrSubjectName);
             return this;
         }
 
@@ -332,12 +336,12 @@ namespace WireMock.ResponseBuilders
             if (Delay != null)
                 await Task.Delay(Delay.Value);
 
-            if (ProxyUrl != null)
+            if (ProxyUrl != null && httpClientForProxy != null)
             {
                 var requestUri = new Uri(requestMessage.Url);
                 var proxyUri = new Uri(ProxyUrl);
                 var proxyUriWithRequestPathAndQuery = new Uri(proxyUri, requestUri.PathAndQuery);
-                return await HttpClientHelper.SendAsync(requestMessage, proxyUriWithRequestPathAndQuery.AbsoluteUri, X509Certificate2ThumbprintOrSubjectName);
+                return await HttpClientHelper.SendAsync(httpClientForProxy, requestMessage, proxyUriWithRequestPathAndQuery.AbsoluteUri);
             }
 
             if (UseTransformer)

src/WireMock.Net/Server/FluentMockServer.Admin.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Net.Http;
 using System.Text;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -129,8 +130,11 @@ namespace WireMock.Server
         }
 
         #region Proxy and Record
+        private HttpClient httpClientForProxy;
+
         private void InitProxyAndRecord(ProxyAndRecordSettings settings)
         {
+            httpClientForProxy = HttpClientHelper.CreateHttpClient(settings.X509Certificate2ThumbprintOrSubjectName);
             Given(Request.Create().WithPath("/*").UsingAnyVerb()).RespondWith(new ProxyAsyncResponseProvider(ProxyAndRecordAsync, settings));
         }
 
@@ -140,7 +144,7 @@ namespace WireMock.Server
             var proxyUri = new Uri(settings.Url);
             var proxyUriWithRequestPathAndQuery = new Uri(proxyUri, requestUri.PathAndQuery);
 
-            var responseMessage = await HttpClientHelper.SendAsync(requestMessage, proxyUriWithRequestPathAndQuery.AbsoluteUri, settings.X509Certificate2ThumbprintOrSubjectName);
+            var responseMessage = await HttpClientHelper.SendAsync(httpClientForProxy, requestMessage, proxyUriWithRequestPathAndQuery.AbsoluteUri);
 
             if (settings.SaveMapping)
             {