OPMLHelper.cs :  » RSS-RDF » RSS-Feeder » RSSFeeder » Helpers » C# / CSharp Open Source

using System;
using System.Collections;
using System.Xml;
using RSSCommon;

namespace RSSFeeder.Helpers{
  /// <summary>
  /// Helper class to read/write OPML documents
  /// </summary>
  public class OPMLHelper
  {
    public static IList ImportOPML( string fileName )
    {
      XmlDocument doc = new XmlDocument();
      doc.Load( fileName );

      ArrayList importedChannels = new ArrayList();

      foreach( XmlElement outlineNode in doc.DocumentElement.SelectNodes(".//outline") )
      {
        string title = outlineNode.GetAttribute("title");
        string outlookFolderPath = outlineNode.GetAttribute("ng:folderName");
        string feedUrl = outlineNode.GetAttribute("xmlUrl");
        
        // xmlurl is for Newsgator. When the whole world is using xmlUrl with 'U' capital,
        // newsgator is using small 'u'
        if( null == feedUrl || 0 == feedUrl.Length ) feedUrl = outlineNode.GetAttribute("xmlurl");
        
        string htmlUrl = outlineNode.GetAttribute("htmlUrl");

        // Same newsgator hack
        if( null == htmlUrl || 0 == htmlUrl.Length ) htmlUrl = outlineNode.GetAttribute("htmlurl");

        string folderType = outlineNode.GetAttribute("ng:folderType");

        // Onlt newsgator provides outlook folder path
        if( null == outlookFolderPath ) outlookFolderPath = string.Empty;

        if( null != feedUrl && feedUrl.Length > 0 )
        {
          Channel newChannel = new Channel( 0, title, new Uri(feedUrl),
            TimeSpan.FromMinutes(30), DateTime.MinValue, DateTime.Now, DateTime.MinValue,
            outlookFolderPath, string.Empty, true, 0, 0, Channel.FolderCreationTypeEnum.Automatic_under_Base_Folder,
            string.Empty, string.Empty, 
            string.Empty, string.Empty );

          // Newsgator will give us a folder type
          if( null != folderType )
          {
            Channel.FolderCreationTypeEnum type;
            if( folderType == "auto" )
            {
              type = Channel.FolderCreationTypeEnum.Automatic_under_Base_Folder;
            }
            else
            {
              type = Channel.FolderCreationTypeEnum.Specific_Folder;
            }

            newChannel.FolderType = type;
          }

          DatabaseHelper.AddNewChannel( ref newChannel );

          importedChannels.Add( newChannel );
        }
      }

      return importedChannels;
    }

    public static void ExportOPML( IList channels, string fileName )
    {
      XmlTextWriter writer = new XmlTextWriter( fileName, RSSCommon.Constants.DefaultEncoding );

      writer.IndentChar = '\t';
      writer.Formatting = Formatting.Indented;
      writer.WriteStartElement("opml");
      writer.WriteAttributeString("xmlns:ng", "http://newsgator.com/schema/opml");
      writer.WriteStartElement("body");

      foreach( Channel channel in channels )
      {
        writer.WriteStartElement("outline");

        writer.WriteAttributeString("title", channel.Title );
        writer.WriteAttributeString("ng:folderName", channel.FolderPath );
        writer.WriteAttributeString("xmlUrl", channel.FeedURL.ToString() );
        writer.WriteAttributeString("htmlUrl", channel.FeedURL.ToString() );
        writer.WriteAttributeString("ng:folderType", 
          ( channel.FolderType == Channel.FolderCreationTypeEnum.Automatic_under_Base_Folder ?
          "auto" : "manual" ) );

        writer.WriteEndElement();
      }

      writer.WriteEndElement();
      writer.WriteEndElement();

      writer.Close();
    }
  }
}