RSS Feed Aggregator and Blogging Smart Client

// Copyright � 2005 by Omar Al Zabir. All rights are reserved.
// 
// If you like this code then feel free to go ahead and use it.
// The only thing I ask is that you don't remove or alter my copyright notice.
//
// Your use of this software is entirely at your own risk. I make no claims or
// warrantees about the reliability or fitness of this code for any particular purpose.
// If you make changes or additions to this code please mark your code as being yours.
// 
// website http://www.oazabir.com, email OmarAlZabir@gmail.com, msn oazabir@hotmail.com

using System;
using System.Text;
using System.Xml;
using System.Xml.XPath;
using System.Xml.Xsl;
using System.Collections;
using System.IO;	
using GotDotNet.Exslt;
using RSSBlogAPI;

namespace RSSFeeder.Helpers
{
	/// <summary>
	/// Helper class for XML related activities
	/// </summary>
	public class XMLHelper
	{
		public static ExsltTransform GetTransformer( string path )
		{
			ExsltTransform transform = (ExsltTransform) EntLibHelper.GetCachedObject( path );
			if( null != transform )
			{				
				return transform;
			}
			else
			{
				transform = new ExsltTransform();
				transform.SupportedFunctions = ExsltFunctionNamespace.All;
				transform.MultiOutput = false;

				transform.Load(path);

				EntLibHelper.StoreInCache( path, transform );

				return transform;
			}
		}

		/// <summary>
		/// Transforms specified XML using the specified XSL file to the output stream
		/// </summary>
		/// <param name="xsltFile">Full path to an XSL file</param>
		/// <param name="xml">A complete XML which can be loaded in a document</param>
		/// <param name="outputStream">A stream where output will be written</param>
		public static void TransformXml (string xsltFile, string xml, Stream outputStream)
		{			
			ExsltTransform transformer = GetTransformer( xsltFile );
		
			//ExsltTransform transformer = new ExsltTransform();
			//transformer.Load(xsltFile);

			try
			{
				using( StringReader stringReader = new StringReader( xml ) )
				{
					XmlTextReader xmlReader = new XmlTextReader( stringReader );
					xmlReader.Namespaces = false;
					XPathDocument document = new XPathDocument( xmlReader );
					
					HtmlWriter writer = new HtmlWriter( outputStream, System.Text.Encoding.ASCII );
					transformer.Transform( document, null, writer );
				}
			}
			catch( Exception x )
			{
				ErrorReportForm.QueueErrorReport( new ErrorReportItem( x.Message, x.ToString() ) );
			}
			
		}

		/// <summary>
		/// Generates an XML file which contains a referene to the XSLT file which browsers
		/// use to transform the XML automatically
		/// </summary>
		/// <param name="xsltFileName"></param>
		/// <param name="xml"></param>
		/// <param name="outputStream"></param>
		public static void GenerateXMLForChannel( string xsltFileName, string xml, Stream outputStream )
		{
			// Prepare a header which includes reference to the XSLT file
			string header = "<?xml version=\"1.0\" encoding=\"utf-8\"?><?xml-stylesheet type=\"text/xsl\" href=\"{0}\"?>";

			StreamWriter writer = new StreamWriter( outputStream );

			writer.WriteLine( string.Format( header, xsltFileName ) );

			writer.WriteLine( xml );

			writer.Flush();
		}
		
	}


}