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RSS Feed Aggregator and Blogging Smart Client

, 16 Aug 2005 CPOL
RSS Feed aggregator and blogging Smart Client which uses Enterprise Library, Updater Application Block, lots of XML hacks and desktop tricks. A comprehensive guide to real life hurdles of Smart Client development.
rssfeeder_src.zip
RSSFeeder
RSSBlogAPI
RSSBlogAPI.csproj.user
Web References
CommunityServer
blogservice.disco
blogservice.wsdl
Reference.map
DotText
Reference.map
simpleblogservice.disco
simpleblogservice.wsdl
RSSCommon
Helper
PropertyEditor
RSSCommon.csproj.user
RSSFeeder
Controls
docs
dropshadow.png
My Pic 7.jpg
WIndows98.jpg
Helpers
Resources
E-mail.ico
rss.ico
RSSFeeder.mdb
RSSFeeder.csproj.user
RSSStarter.exe
RSSFeederResources
PublicQueue.ico
RSSFeeder.mdb
RSSFeederResources.csproj.user
RSSFeederSetup
Messages.ico
RSSFeederSetup.vdproj
Test
RSSStarter
DummyForm.frm
DummyForm.frx
MainModule.bas
RSSStarter.exe
RSSStarter.vbp
RSSStarter.vbw
RSSTests
App.ico
RSSTests.csproj.user
Thirdparty
AxInterop.DHTMLEDLib.dll
AxInterop.SHDocVw.dll
Eyefinder.dll
GotDotNet.Exslt.dll
HttpDownloader.dll
Interop.DHTMLEDLib.dll
Interop.SHDocVw.dll
Interop.WindowsInstaller.dll
Microsoft.ApplicationBlocks.Updater.ActivationProcessors.dll
Microsoft.ApplicationBlocks.Updater.dll
Microsoft.ApplicationBlocks.Updater.Downloaders.dll
Microsoft.Practices.EnterpriseLibrary.Caching.dll
Microsoft.Practices.EnterpriseLibrary.Common.dll
Microsoft.Practices.EnterpriseLibrary.Configuration.dll
Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.dll
Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.dll
Microsoft.Practices.EnterpriseLibrary.Logging.dll
Microsoft.Practices.EnterpriseLibrary.Security.Cache.CachingStore.dll
Microsoft.Practices.EnterpriseLibrary.Security.Cryptography.dll
Microsoft.Practices.EnterpriseLibrary.Security.dll
NotifyIconBalloon.dll
SandBar.dll
SandDock.dll
SgmlReaderDll.dll
// 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.Globalization;
using System.IO;
using Sgml;
using System.Xml;
using System.Text;

namespace RSSBlogAPI
{
	public class DateHelper
	{
		public static string StoreDateTimeUtc(DateTime value) 
		{
			// e.g 2003-10-26T14:33:41.1234567Z
			return value.ToString("yyyy-MM-ddTHH:mm:ss.fffffffZ",
				CultureInfo.InvariantCulture);
		}

		public static DateTime ReadDateTimeUtc(String value) 
		{
			return DateTime.Parse(value, CultureInfo.InvariantCulture,
				DateTimeStyles.AdjustToUniversal);
		}


	}
	/// <summary>
	/// This class skips all nodes which has some kind of prefix. This trick does the job 
	/// to clean up MS Word/Outlook HTML markups.
	/// </summary>
	public class HtmlReader : Sgml.SgmlReader
	{
		public HtmlReader( TextReader reader ) : base( )
		{
			base.InputStream = reader;
			base.DocType = "HTML";
		}
		public HtmlReader( string content ) : base( )
		{
			base.InputStream = new StringReader( content );
			base.DocType = "HTML";
		}
		public override bool Read()
		{
			bool status = base.Read();
			if( status )
			{
				if( base.NodeType == XmlNodeType.Element )
				{
					// Got a node with prefix. This must be one of those "<o:p>" or something else.
					// Skip this node entirely. We want prefix less nodes so that the resultant XML 
					// requires not namespace.
					if( base.Name.IndexOf(':') > 0 )
						base.Skip();
				}
			}
			return status;
		}
	}

	/// <summary>
	/// Extends XmlTextWriter to provide Html writing feature which is not as strict as Xml
	/// writing. For example, Xml Writer encodes content passed to WriteString which encodes special markups like
	/// &nbsp to &amp;bsp. So, WriteString is bypassed by calling WriteRaw.
	/// </summary>
	public class HtmlWriter : XmlTextWriter
	{
		/// <summary>
		/// If set to true, it will filter the output by using tag and attribute filtering,
		/// space reduce etc
		/// </summary>
		public bool FilterOutput = false;

		/// <summary>
		/// If true, it will reduce consecutive &nbsp; with one instance
		/// </summary>
		public bool ReduceConsecutiveSpace = true;

		/// <summary>
		/// Set the tag names in lower case which are allowed to go to output
		/// </summary>
		public string [] AllowedTags = new string[] { "p", "b", "i", "u", "em", "big", "small", 
														"div", "img", "span", "blockquote", "code", "pre", "br", "hr", 
														"ul", "ol", "li", "del", "ins", "strong", "a", "font", "dd", "dt"};

		/// <summary>
		/// If any tag found which is not allowed, it is replaced by this tag.
		/// Specify a tag which has least impact on output
		/// </summary>
		public string ReplacementTag = "dd";

		/// <summary>
		/// New lines \r\n are replaced with space which saves space and makes the
		/// output compact
		/// </summary>
		public bool RemoveNewlines = true;
		/// <summary>
		/// Specify which attributes are allowed. Any other attribute will be discarded
		/// </summary>
		public string [] AllowedAttributes = new string[] { "class", "href", "target", 
															  "border", "src", "align", "width", "height", "color", "size" };

		public HtmlWriter( TextWriter writer ) : base( writer ) 
		{
		}
		public HtmlWriter( StringBuilder builder ) : base( new StringWriter(builder) )
		{
		}
		public HtmlWriter( Stream stream, Encoding enc ) : base( stream, enc )
		{
		}

		/// <summary>
		/// The reason why we are overriding this method is, we do not want the output to be
		/// encoded for texts inside attribute and inside node elements. For example, all the &nbsp;
		/// gets converted to &amp;nbsp in output. But this does not 
		/// apply to HTML. In HTML, we need to have &nbsp; as it is.
		/// </summary>
		/// <param name="text"></param>
		public override void WriteString(string text)
		{	
			// Change all non-breaking space to normal space
			text = text.Replace( "�", "&nbsp;" );
			/// When you are reading RSS feed and writing Html, this line helps remove
			/// those CDATA tags
			text = text.Replace("<![CDATA[","");
			text = text.Replace("]]>", "");

			/*
			// Do some encoding of our own because we are going to use WriteRaw which won't
			// do any of the necessary encoding
			text = text.Replace( "<", "&lt;" );
			text = text.Replace( ">", "&gt;" );
			text = text.Replace( "'", "&apos;" );
			text = text.Replace( "\"", "&quote;" );
			*/

			if( this.FilterOutput )
			{
				//text = text.Trim();
			
				// We want to replace consecutive spaces to one space in order to save horizontal
				// width
				if( this.ReduceConsecutiveSpace ) text = text.Replace("&nbsp;&nbsp;&nbsp;", "&nbsp;");

				if( this.RemoveNewlines ) text = text.Replace(Environment.NewLine, " ");

				base.WriteRaw( text );
			}
			else
			{
				base.WriteRaw( text );
			}
		}

		public override void WriteWhitespace(string ws)
		{
			if( !this.FilterOutput ) base.WriteWhitespace(ws);	
		}

		public override void WriteComment(string text)
		{
			if( !this.FilterOutput ) base.WriteComment(text);
		}

		/// <summary>
		/// This method is overriden to filter out tags which are not allowed
		/// </summary>
		public override void WriteStartElement(string prefix, string localName, string ns)
		{
			if( this.FilterOutput ) 
			{
				bool canWrite = false;						
				string tagLocalName = localName.ToLower();				
				foreach( string name in this.AllowedTags )
				{
					if( name == tagLocalName )
					{
						canWrite = true;
						break;
					}
				}

				if( !canWrite ) 
					localName = "dd";
			}

			base.WriteStartElement(prefix, localName, ns);
		}

		/// <summary>
		/// This method is overriden to filter out attributes which are not allowed
		/// </summary>
		public override void WriteAttributes(XmlReader reader, bool defattr)
		{
			if( this.FilterOutput )
			{
				// The following code is copied from implementation of XmlWriter's
				// WriteAttributes method. 
				if (reader == null)
				{
					throw new ArgumentNullException("reader");
				}
				if ((reader.NodeType == XmlNodeType.Element) || (reader.NodeType == XmlNodeType.XmlDeclaration))
				{
					if (reader.MoveToFirstAttribute())
					{
						this.WriteAttributes(reader, defattr);
						reader.MoveToElement();
					}
				}
				else
				{
					if (reader.NodeType != XmlNodeType.Attribute)
					{
						throw new XmlException("Xml_InvalidPosition");
					}
					do
					{
						if (defattr || !reader.IsDefault)
						{
							// Check if the attribute is allowed 
							bool canWrite = false;						
							string attributeLocalName = reader.LocalName.ToLower();						
							foreach( string name in this.AllowedAttributes )
							{
								if( name == attributeLocalName )
								{
									canWrite = true;
									break;
								}
							}

							// If allowed, write the attribute
							if( canWrite ) 
								this.WriteStartAttribute(reader.Prefix, attributeLocalName, 
									reader.NamespaceURI);

							while (reader.ReadAttributeValue())
							{
								if (reader.NodeType == XmlNodeType.EntityReference)
								{
									if( canWrite ) this.WriteEntityRef(reader.Name);
									continue;
								}
								if( canWrite )this.WriteString(reader.Value);
							}
							if( canWrite ) this.WriteEndAttribute();
						}
					} while (reader.MoveToNextAttribute());
				}
			}
			else
			{
				base.WriteAttributes( reader, defattr );
			}
		}
	}

}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Omar Al Zabir
Architect BT, UK (ex British Telecom)
United Kingdom United Kingdom

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Web04 | 2.8.141216.1 | Last Updated 16 Aug 2005
Article Copyright 2005 by Omar Al Zabir
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