Parsing Amazon s3 bucket listing with C# XmlDocument (Unity3d)

Question

Disclaimer: This issue is happening within a Unity application, but AFAIK, this is more of a C# issue than a Unity issue...

I am trying to use System.Xml.XmlDocument to parse an Amazon S3 bucket listing. Here is my bucket xml. I am using an example that I found in a C# Xml tutorial.

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load("http://rss.cnn.com/rss/edition_world.rss");
XmlNode titleNode = xmlDoc.SelectSingleNode("//rss/channel/title");
if(titleNode != null)
    Debug.Log(titleNode.InnerText); 

This works fine for that particular XML file, but when I put my stuff in there:

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load("https://s3.amazonaws.com/themall/");
Debug.Log ( xmlDoc.InnerXml );
XmlNode nameNode = xmlDoc.SelectSingleNode("//Name");
if(nameNode != null)
    Debug.Log(nameNode.InnerText); 

I get the raw XML in the console, so I know it is being downloaded successfully, but even the simplest XPath produces no results!

My only theory is that perhaps it has something to do with the default namespace in my XML? Do I need to tell XmlDocument about that somehow? Here is my root tag:

<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">

I have tried creating an XmlNamespaceManager and using it with all of my calls to "SelectSingleNode", but that doesn't seem to work either.

XPathNavigator nav = xmlDoc.CreateNavigator();
XmlNamespaceManager ns = new XmlNamespaceManager(nav.NameTable);
ns.AddNamespace(System.String.Empty, "http://s3.amazonaws.com/doc/2006-03-01/");

What am I doing wrong?

Thanks!

Answer 1

When you add the namespace to the namespace manager you need to give it a non-empty prefix. According to MSDN:

If the XmlNamespaceManager will be used for resolving namespaces in an XML Path Language (XPath) expression, a prefix must be specified. Blockquote

The prefix must then be used in your XPath select statement. Here is the code I used and the output was "themall" as expected:

        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load("http://s3.amazonaws.com/themall/");

        XmlNamespaceManager namespaceManager =
            new XmlNamespaceManager(xmlDoc.NameTable);
        namespaceManager.AddNamespace("ns",
            "http://s3.amazonaws.com/doc/2006-03-01/");

        XmlNode titleNode =
            xmlDoc.SelectSingleNode("//ns:Name", namespaceManager);
        if (titleNode != null)
            Console.WriteLine(titleNode.InnerText);