Rss Feeds in Asp.Net

This is a first part of two series article aimed at explaining; how to generate RSS Feeds and creating a RSS Feed Listener/Reader.

I have experienced that often clients will raise business requirement for enabling feeds on their news or events pages not just to popularise their site reach but also so that the target audiences who frequently visit the site can subscribe to and stay updated without visiting the site itself.

RSS (Really Simple Syndication) is a commonly adapted format for delivering frequently published changing any type of web content. In a nutshell, by subscribing to a feed, you save time to not visit the site and get the updates from your favourite site straight to you. For more information visit the following or Google as necessary.

http://msdn.microsoft.com/en-us/magazine/cc194384.aspx
http://www.rssboard.org/rss-profile

My absolute favourite thing about ASP.Net is that there are so many great improvisations you can do with it for constructing solutions for requirements you want. So here goes how you can generate a RSS Feed for any content on your website.

Using Microsoft’s PowerHouse Visual Studio create a new file from Generic Handler Template. Name it what you want and use the code below which I think is self explanatory.

<%@ WebHandler Language="VB" Class="Rss" %>

Imports System
Imports System.Web
Imports System.Xml
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration

Public Class Rss : Implements IHttpHandler    
    Dim writer As XmlTextWriter
    Dim rsslinks As DataTable = Nothing
        
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        context.Response.ContentType = "text/xml"
      
        writer = New XmlTextWriter(context.Response.OutputStream, Encoding.UTF8)
        writer.Formatting = Formatting.Indented
        writer.WriteStartDocument()
        
        ' RSS 2.0 Specification
        writer.WriteStartElement("rss")
        writer.WriteAttributeString("version", "2.0")
        
        ' Channel tag will contain Rss feed
        writer.WriteStartElement("channel")
        writer.WriteElementString("title", "Title of your Rss Feed")
        writer.WriteElementString("link", "URL.Of.Your.Website")
        writer.WriteElementString("description", "some text that you want to publish, " & _
                                     "on your rss feeds signature.")
        writer.WriteElementString("copyright", "blah blah. All rights reserved.")
               
        Dim links As DataTable = LinksTable()
        
        For Each row As DataRow In links.Rows                                   
            If Not IsDBNull(row("Title").ToString) Then
                writer.WriteStartElement("item")
                ' I am adding only title and description columns, you can use the ones you require
                writer.WriteElementString("title", row("Title").ToString)
                writer.WriteElementString("description", row("Description").ToString)
                ' Create or Get the links that you want rss feeds should be linking users to
                writer.WriteElementString("link", "http://sitename/testurl")
                writer.WriteEndElement()
            End If            
        Next
                
        writer.WriteEndElement()
        writer.WriteEndElement()
        writer.WriteEndDocument()
        writer.Flush()
        writer.Close()
    End Sub
 
    Public Function LinksTable() As DataTable        
        If IsNothing(rsslinks) Then
            Dim connStr As String = ConfigurationManager.ConnectionStrings("connection.string").ConnectionString
            Dim conn As SqlConnection = New SqlConnection(connStr)

            Dim cmd As New SqlCommand("stored.procedure.that.will.pull.back.rss.entries", conn)
            cmd.CommandType = CommandType.StoredProcedure

            Dim adapter As New SqlDataAdapter(cmd)
            
            rsslinks = New DataTable

            adapter.Fill(rsslinks)
        End If
        Return rsslinks
    End Function

    Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property

End Class

I have created a RSS Feed accessible from url/nameofyourrssfile which users can view on either mobile or website. Should you require to create a viewer of your RSS feed as a page then please follow this trail link.
http://net.tutsplus.com/tutorials/asp-net/how-to-build-an-rss-feed-with-asp-net/

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