Refactor error handling. Add test for checking for bad username / password scenario

1 files changed, 57 insertions, 0 deletions

diff --git a/SendGrid/SendGridMail/Transport/ErrorChecker.cs b/SendGrid/SendGridMail/Transport/ErrorChecker.cs
new file mode 100644
index 0000000..035d2b8
--- /dev/null
+++ b/SendGrid/SendGridMail/Transport/ErrorChecker.cs
@@ -0,0 +1,57 @@
+namespace SendGrid
+{
+    using System;
+    using System.IO;
+    using System.Net;
+    using System.Net.Http;
+    using System.Threading.Tasks;
+    using System.Xml;
+
+    using Exceptions;
+
+    public static class ErrorChecker
+    {
+        public static void CheckForErrors(HttpResponseMessage response)
+        {
+            CheckForErrors(response, response.Content.ReadAsStreamAsync().Result);
+        }
+
+        public static async Task CheckForErrorsAsync(HttpResponseMessage response)
+        {
+            CheckForErrors(response, await response.Content.ReadAsStreamAsync());
+        }
+
+        private static void CheckForErrors(HttpResponseMessage response, Stream stream)
+        {
+            if (response.StatusCode != HttpStatusCode.OK)
+            {
+                using (var reader = XmlReader.Create(stream))
+                {
+                    while (reader.Read())
+                    {
+                        if (!reader.IsStartElement())
+                        {
+                            continue;
+                        }
+
+                        switch (reader.Name)
+                        {
+                            case "result":
+                                continue;
+                            case "message":
+                                continue;
+                            case "errors":
+                                reader.ReadToFollowing("error");
+                                var message = reader.ReadElementContentAsString("error", reader.NamespaceURI);
+                                throw new InvalidApiRequestException(response.StatusCode, new[] { message }, response.ReasonPhrase);
+                            case "error":
+                                throw new ProtocolViolationException();
+                            default:
+                                throw new ArgumentException("Unknown element: " + reader.Name);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
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