Added isSessionActive method and fixed client #33.

Author: Kevin Hellemun

BunqSdk/Context/ApiContext.cs

@@ -176,19 +176,27 @@ private void DeleteSession()
         /// </summary>
         public void EnsureSessionActive()
         {
-            if (SessionContext == null) return;
+            if (!IsSessionActive())
+            {
+                ResetSession();
+            }
+        }
 
+        public bool IsSessionActive()
+        {
+            if (SessionContext == null)
+            {
+                return false;
+            }
+            
             var timeToExpiry = SessionContext.ExpiryTime.Subtract(DateTime.Now);
             var timeToExpiryMinimum = new TimeSpan(
                 TIME_UNIT_COUNT_NONE,
                 TIME_UNIT_COUNT_NONE,
                 TIME_TO_SESSION_EXPIRY_MINIMUM_SECONDS
             );
 
-            if (timeToExpiry < timeToExpiryMinimum)
-            {
-                ResetSession();
-            }
+            return timeToExpiry > timeToExpiryMinimum;
         }
 
         /// <summary>

BunqSdk/Http/ApiClient.cs

@@ -16,6 +16,18 @@ namespace Bunq.Sdk.Http
 {
     public class ApiClient
     {
+
+        private const string DEVICE_SERVER_URL = "device-server";
+        private const string INSTALLATION_URL = "installation";
+        private const string SESSION_SERVER_URL = "session-server";
+
+        private static readonly string[] URIS_NOT_REQUIRING_ACTIVE_SESSION = new string[]
+        {
+            DEVICE_SERVER_URL,
+            INSTALLATION_URL,
+            SESSION_SERVER_URL
+        };
+
         /// <summary>
         /// Header constants.
         /// </summary>
@@ -115,21 +127,25 @@ private BunqResponseRaw SendRequest(HttpMethod method, string uriRelative, byte[
         {
             var requestMessage = CreateHttpRequestMessage(method, uriRelative, uriParams, requestBodyBytes);
 
-            return SendRequest(requestMessage, customHeaders);
+            return SendRequest(requestMessage, customHeaders, uriRelative);
         }
 
         private BunqResponseRaw SendRequest(HttpMethod method, string uriRelative,
             IDictionary<string, string> uriParams, IDictionary<string, string> customHeaders)
         {
             var requestMessage = CreateHttpRequestMessage(method, uriRelative, uriParams);
 
-            return SendRequest(requestMessage, customHeaders);
+            return SendRequest(requestMessage, customHeaders, uriRelative);
         }
 
         private BunqResponseRaw SendRequest(HttpRequestMessage requestMessage,
-            IDictionary<string, string> customHeaders)
+            IDictionary<string, string> customHeaders, string uriRelative)
         {
-            apiContext.EnsureSessionActive();
+            if (!URIS_NOT_REQUIRING_ACTIVE_SESSION.Contains(uriRelative))
+            {
+                apiContext.EnsureSessionActive();
+            }
+            
             SetDefaultHeaders(requestMessage);
             SetHeaders(requestMessage, customHeaders);
             SetSessionHeaders(requestMessage);