Umbraco: Converting and namespacing the JSON data to XML (for use with XSLT/XPath)

01-umbraco-xml-cache-json-namespaced.xml

<root id="-1">
	<HomePage id="1234" parentID="-1" level="1" creatorID="1" sortOrder="0" createDate="2014-12-16T00:00:00" updateDate="2014-12-16T00:00:00" nodeName="Home" urlName="home" path="-1,1156" isDoc="" nodeType="1111" creatorName="admin" writerName="admin" writerID="1" template="0" nodeTypeAlias="HomePage">
		<archetypeLinks><![CDATA[{"fieldsets":[{"properties":[{"alias":"linkUrl","value":"http://www.example.com/"},{"alias":"linkLabel","value":"Website"}],"alias":"externalLink","disabled":false},{"properties":[{"alias":"linkUrl","value":"http://www.example2.com/"},{"alias":"linkLabel","value":"Webshop"}],"alias":"externalLink","disabled":false}]}]]></archetypeLinks>
		<json:archetypeLinks xmlns:json="http://pimpmyxslt.com/json">
			<fieldsets>
				<properties>
					<alias>linkUrl</alias>
					<value>http://www.example.com/</value>
				</properties>
				<properties>
					<alias>linkLabel</alias>
					<value>Website</value>
				</properties>
				<alias>externalLink</alias>
				<disabled>false</disabled>
			</fieldsets>
			<fieldsets>
				<properties>
					<alias>linkUrl</alias>
					<value>http://www.example2.com/</value>
				</properties>
				<properties>
					<alias>linkLabel</alias>
					<value>Webshop</value>
				</properties>
				<alias>externalLink</alias>
				<disabled>false</disabled>
			</fieldsets>
		</json:archetypeLinks>
	</HomePage>
</root>

02-JsonXmlXsltEventHandler.cs

// Dumping this on GitHub gist, for reference. (Else I'll probably lose it) [LK]
public class JsonXmlXsltEventHandler : ApplicationEventHandler
{
	protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
	{
		umbraco.content.AfterContentCacheLoadNodeFromDatabase += (sender, e) =>
		{
			if (!sender.HasChildNodes)
				return;

			foreach (System.Xml.XmlNode item in sender.ChildNodes)
			{
				if (item.NodeType == System.Xml.XmlNodeType.Element)
				{
					if (item.HasChildNodes)
					{
						var inner = item.FirstChild;
						if (inner.NodeType == System.Xml.XmlNodeType.CDATA)
						{
							var text = inner.InnerText;
							if (text.DetectIsJson())
							{
								if (text.StartsWith("["))
								{
									text = "{\"arrayitem\":" + text + "}";
								}

								try
								{
									var jsonXml = Newtonsoft.Json.JsonConvert.DeserializeXmlNode(text, item.Name, true);

									var newElement = item.OwnerDocument.CreateElement("json", item.Name, "http://pimpmyxslt.com/json");
									newElement.InnerXml = jsonXml.DocumentElement.InnerXml;

									var newChild = item.OwnerDocument.ImportNode(newElement, true);
									item.ParentNode.InsertAfter(newChild, item);
								}
								catch { /* do nothing */ }
							}
						}
					}
				}
			}
		};
	}
}

The work around the JsonConvert.DeserializeXmlNode call is a rough prototype... it needs further research and development. For example, it would need to handle nested JSON structures; (e.g. Nested Archetypes are escaped).

Would this work from the App_Code folder if one were to add the necessary @using statements?

@greystate - in answer to your question, (over a year later), yes it would work from App_Code 👍