add proxy support, make httpClient instance variable [#15]

Author: dnl-blkv

BunqSdk/Context/ApiContext.cs

@@ -63,6 +63,9 @@ public class ApiContext
         [JsonProperty(PropertyName = "session_context")]
         public SessionContext SessionContext { get; private set; }
 
+        [JsonProperty(PropertyName = "proxy")]
+        public string Proxy { get; private set; }
+
         [JsonConstructor]
         private ApiContext()
         {
@@ -71,21 +74,23 @@ private ApiContext()
         /// <summary>
         /// Create and initialize an API Context with current IP as permitted.
         /// </summary>
-        public static ApiContext Create(ApiEnvironmentType environmentType, string apiKey, string deviceDescription)
+        public static ApiContext Create(ApiEnvironmentType environmentType, string apiKey, string deviceDescription,
+            string proxy=null)
         {
-            return Create(environmentType, apiKey, deviceDescription, new List<string>());
+            return Create(environmentType, apiKey, deviceDescription, new List<string>(), proxy);
         }
 
         /// <summary>
         /// Create and initialize an API Context.
         /// </summary>
         public static ApiContext Create(ApiEnvironmentType environmentType, string apiKey, string deviceDescription,
-            IList<string> permittedIps)
+            IList<string> permittedIps, string proxy=null)
         {
             var apiContext = new ApiContext
             {
                 ApiKey = apiKey,
                 EnvironmentType = environmentType,
+                Proxy = proxy,
             };
             apiContext.Initialize(deviceDescription, permittedIps);
 

BunqSdk/Http/ApiClient.cs

@@ -49,15 +49,42 @@ public class ApiClient
         /// </summary>
         private const string DELIMITER_HEADER_VALUE = ",";
 
-        private static HttpClient client;
+        private readonly HttpClient client;
 
         private readonly ApiContext apiContext;
 
         public ApiClient(ApiContext apiContext)
         {
             this.apiContext = apiContext;
+            client = CreateHttpClient();
         }
 
+        private HttpClient CreateHttpClient()
+        {
+            return new HttpClient(CreateHttpClientHandler())
+            {
+                BaseAddress = new Uri(apiContext.GetBaseUri())
+            };
+        }
+
+        private HttpClientHandler CreateHttpClientHandler()
+        {
+            // TODO: Add HTTP Public Key Pinning. It is needed to prevent possible man-in-the-middle attacks using
+            // the fake (or mis-issued) certificates.
+            // More info: https://timtaubert.de/blog/2014/10/http-public-key-pinning-explained/
+            // Simply put, we reduce the amount of certificates which are accepted in bunq API responses.
+            var handler = new HttpClientHandler();
+
+            if (apiContext.Proxy != null)
+            {
+                handler.Proxy = new BunqProxy(apiContext.Proxy);
+                handler.UseProxy = true;
+            }
+
+            return handler;
+        }
+
+
         /// <summary>
         /// Executes a POST request and returns the resulting HTTP response message.
         /// </summary>
@@ -90,7 +117,6 @@ private BunqResponseRaw SendRequest(HttpRequestMessage requestMessage,
             SetDefaultHeaders(requestMessage);
             SetHeaders(requestMessage, customHeaders);
             SetSessionHeaders(requestMessage);
-            InitializeHttpClientIfNeeded(apiContext);
             var responseMessage = client.SendAsync(requestMessage).Result;
             AssertResponseSuccess(responseMessage);
             ValidateResponse(responseMessage);
@@ -194,21 +220,6 @@ private string GenerateSignature(HttpRequestMessage requestMessage)
             return SecurityUtils.GenerateSignature(requestMessage, apiContext.InstallationContext.KeyPairClient);
         }
 
-        private static void InitializeHttpClientIfNeeded(ApiContext apiContext)
-        {
-            if (client == null)
-            {
-                // TODO: Add HTTP Public Key Pinning. It is needed to prevent possible man-in-the-middle attacks using
-                // the fake (or mis-issued) certificates.
-                // More info: https://timtaubert.de/blog/2014/10/http-public-key-pinning-explained/
-                // Simply put, we reduce the amount of certificates which are accepted in bunq API responses.
-                client = new HttpClient
-                {
-                    BaseAddress = new Uri(apiContext.GetBaseUri())
-                };
-            }
-        }
-
         private static void AssertResponseSuccess(HttpResponseMessage responseMessage)
         {
             if (responseMessage.IsSuccessStatusCode) return;

BunqSdk/Http/BunqProxy.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Net;
+
+namespace Bunq.Sdk.Http
+{
+    public class BunqProxy : IWebProxy
+    {
+        public BunqProxy(string proxyUri)
+            : this(new Uri(proxyUri))
+        {
+        }
+
+        public BunqProxy(Uri proxyUri)
+        {
+            ProxyUri = proxyUri;
+        }
+
+        public Uri ProxyUri { get; set; }
+
+        public ICredentials Credentials { get; set; }
+
+        public Uri GetProxy(Uri destination)
+        {
+            return ProxyUri;
+        }
+
+        public bool IsBypassed(Uri host)
+        {
+            return false; /* Proxy all requests */
+        }
+    }
+}