rework dlna project

Emby.Dlna/Ssdp/Extensions.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+using System.Xml.Linq;
+
+namespace MediaBrowser.Dlna.Ssdp
+{
+    public static class Extensions
+    {
+        public static string GetValue(this XElement container, XName name)
+        {
+            var node = container.Element(name);
+
+            return node == null ? null : node.Value;
+        }
+
+        public static string GetAttributeValue(this XElement container, XName name)
+        {
+            var node = container.Attribute(name);
+
+            return node == null ? null : node.Value;
+        }
+
+        public static string GetDescendantValue(this XElement container, XName name)
+        {
+            var node = container.Descendants(name)
+                .FirstOrDefault();
+
+            return node == null ? null : node.Value;
+        }
+    }
+}