Windows-classic-samples/Samples/Win7Samples/winui/rssscreensaver/rss/RssItem.cs

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) 2006 Microsoft Corporation. All rights reserved.

using System;
using System.Xml;
using System.IO;
using System.Text.RegularExpressions;
using Microsoft.Feeds.Interop;

namespace Microsoft.Samples.RssPlatform.ScreenSaver.Rss
{
    /// <summary>
    /// Representation of an Item element in an RSS 2.0 XML document.
    /// Zero or more RssItems are contained in an RssChannel.
    /// </summary>
    public class RssItem : UI.IItem
	{
		private readonly string title;
		private readonly string description;
		private readonly string link;
		private readonly FileInfo enclosure;

		public string Title { get { return title; } }
		public string Description { get { return description; } }
		public string Link { get { return link; } }
		public FileInfo Enclosure { get { return enclosure; } }

		/// <summary>
		/// Build an RSSItem from an XmlNode representing an Item element inside an RSS 2.0 XML document.
		/// </summary>
		/// <param name="itemNode"></param>
		internal RssItem(XmlNode itemNode)
		{
			XmlNode selected;
			selected = itemNode.SelectSingleNode("title");
			if (selected != null)
			{
				title = selected.InnerText;
			}

			selected = itemNode.SelectSingleNode("description");
			if (selected != null)
				description = selected.InnerText;

			selected = itemNode.SelectSingleNode("link");
			if (selected != null)
				link = selected.InnerText;

			selected = itemNode.SelectSingleNode("enclosure/@url");
			if (selected != null)
			{
				string filename = selected.InnerText;
				if (ScreenSaverForm.IsResourcePictureUrl(filename))
				{
					enclosure = new FileInfo("@" + filename.Substring(4));
				}
				else if (File.Exists(filename))
				{
					enclosure = new FileInfo(filename);
				}
			}
		}

		internal RssItem(IFeedItem item)
        {
			title = StripHTMLTags(item.Title);
            link = item.Link;

            try
            {
                description = StripHTMLTags(item.Description);
            }
            catch (ArgumentException)
            {
                description = "<<<Item text too long.>>>";
            }

            IFeedEnclosure enclosure = (IFeedEnclosure)item.Enclosure;
            if (enclosure != null)
            {
                string filename = GetLocalPath(enclosure);

                try
                {
                    // Let's make sure we only add pictures
                    string extension = "*" + Path.GetExtension(filename);
                    extension = extension.ToUpperInvariant();
                    if (FeedList.imageExtensions.Contains(extension))
                    {
                        // Set enclosure without checking for existence, since enclosure might
                        // not be on disk yet (BITS still getting it)
                        this.enclosure = new FileInfo(filename);
                    }
                }
                catch (ArgumentException)
                {
                    System.Diagnostics.Debug.Print("Illegal character in filename."); 
                    // 'Illegal character in filename' is one possible exception.
                    // Ignore exception; since we'll skip rssItems with this.enclosure == null
                    // higher up in the call chain.
                }
                catch (NotSupportedException)
                {
                    System.Diagnostics.Debug.Print("The given path's format is not supported.");
                    // 'Message="The given path's format is not supported."' is another possible exception.
                    // Ignore exception; since we'll skip rssItems with this.enclosure == null
                    // higher up in the call chain.
                }
            }
        }

        //private IFeedEnclosure GetEnclosure(IFeedItem item)
        //{
        //    try
        //    {
        //        System.Diagnostics.Debug.Print("Enclosure is null={0}",item.Enclosure == null);

        //        return (IFeedEnclosure)item.Enclosure;
        //    }
        //    catch (System.Runtime.InteropServices.COMException ex)
        //    {
        //        if (ex.ErrorCode == -2147023728)    
        //        {
        //            // "Element not found. (Exception from HRESULT: 0x80070490)"
        //            // ignore exception
        //            System.Diagnostics.Debug.Print("Enclosure element not found exception.");
        //            return null;
        //        }
        //        else
        //            throw;
        //    }
        //}

		private static string GetLocalPath(IFeedEnclosure encl)
		{
			try
			{
                return encl.LocalPath;
			}
			catch (System.Runtime.InteropServices.COMException ex)
			{
				if (ex.ErrorCode == -2147024735)
				{
                    System.Diagnostics.Debug.Print("Enclosure localPath is invalid.");
                    // "The specified path is invalid. (Exception from HRESULT: 0x800700A1)"
					// ignore exception
				}
				else
					throw;
			}
			catch (FileNotFoundException)
			{
                System.Diagnostics.Debug.Print("Enclosure localPath element not found exception.");
                // ignore
			}
			return null;
		}

        private static string StripHTMLTags(string input)
        {
            if (null != input)
            {
                Regex rgx = new Regex("<[^>]*>", RegexOptions.Multiline);
                return rgx.Replace(input, "");
            }

            return null;
        }
	}
}