Return error status if invalid request is received.

DPE/DPEWebServer.cs

@@ -28,14 +28,15 @@ namespace pEp.DPE
             if (context.Request.HttpMethod != "POST")
             {
                 Log.Warning("Process request: Ignoring request of type " + context.Request.HttpMethod);
+                return;
             }
 
             string request = null;
 
             try
             {
-                using (var stream = context.Request.InputStream)
-                using (var sr = new StreamReader(stream))
+                using (Stream stream = context.Request.InputStream)
+                using (StreamReader sr = new StreamReader(stream))
                 {
                     request = sr.ReadToEnd();
                 }
@@ -43,6 +44,8 @@ namespace pEp.DPE
             catch (Exception ex)
             {
                 Log.Error("ProcessRequest: Error getting request. " + ex.ToString());
+                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
+                context.Response.Close();
                 return;
             }