Dynamically Create Google Sitemap with ASP.NET

This article will cover dynamically generating your sitemap to submit to Google Sitemaps using ASP.NET and as usual the code will be available in C# and VB.NET. Whenever you develop a site with the intention of putting it on the internet, it’s necessary to do everything you can to index your site with the various search engines using all the tools at your disposal. Google allows you to submit a sitemap of your site to their search engine to help optimize your searching. You can see more details here

Google Sitemaps

We’re going to use HTTP handlers which are files that work similar to ISAPI modules but with no need to install on the server, ASP.NET handles everything for you.

First step is to create a .sitemap file and populate it.

Now that we have the sitemap file, we can use a handler to process the request. The handler will do the following

1. Prepare all the XML header information for the file
2. Read in the sitemap file
3. Create root node, then nodes for each page in the sitemap file

Pretty straight forward really. Now to the code!

C# <%@ WebHandler Language="C#" Class="OurSiteMap" %> using System; using System.Web; using System.Xml; using System.Text; using System.IO; public class OurSiteMap : IHttpHandler { private XmlWriter xmlWriter; public void ProcessRequest(HttpContext context) { context.Response.ContentType = “text/xml"; XmlWriterSettings settings = new XmlWriterSettings(); settings.Encoding = Encoding.UTF8; settings.Indent = true; xmlWriter = XmlWriter.Create(context.Response.OutputStream, settings); xmlWriter.WriteStartDocument(); xmlWriter.WriteStartElement("urlset", “http://www.sitemaps.org/schemas/sitemap/0.9″); // Add root node AddUrl(SiteMap.RootNode); // Add all other nodes SiteMapNodeCollection nodes = SiteMap.RootNode.GetAllNodes(); foreach (SiteMapNode node in nodes) { AddUrl(node); } xmlWriter.WriteEndElement(); xmlWriter.WriteEndDocument(); xmlWriter.Flush(); } private void AddUrl(SiteMapNode node) { // ignore any nodes that are empty if (string.IsNullOrEmpty(node.Url)) { return; } // ignore any nodes that are not part of the site if (node.Url.StartsWith("http", true, null)) { return; } // Open url tag xmlWriter.WriteStartElement("url"); // Write location xmlWriter.WriteStartElement("loc"); xmlWriter.WriteString(GetFullUrl(node.Url)); xmlWriter.WriteEndElement(); // Write last modified xmlWriter.WriteStartElement("lastmod"); xmlWriter.WriteString(GetLastModifiedDate(node.Url)); xmlWriter.WriteEndElement(); // Close url tag xmlWriter.WriteEndElement(); } private string GetFullUrl(string url) { HttpContext currentContext = HttpContext.Current; string server = currentContext.Request.Url.GetComponents(UriComponents.SchemeAndServer, UriFormat.UriEscaped); return CombineURL(server, url); } private string CombineURL(string urlBase, string url) { urlBase = urlBase.TrimEnd(new char[] { '/' }); url = url.TrimStart(new char[] { '/' }); return urlBase + “/" + url; } private string GetLastModifiedDate(string url) { HttpContext currentContext = HttpContext.Current; string path = currentContext.Server.MapPath(url); return File.GetLastWriteTimeUtc(path).ToString("s"); } public bool IsReusable { get { return true; } } }

VB.NET <%@ WebHandler Language="VB" Class="OurSiteMap" %> Imports System Imports System.Web Imports System.Xml Imports System.Text Imports System.IO Public Class OurSiteMap Implements IHttpHandler Private xmlWriter As XmlWriter Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest context.Response.ContentType = “text/xml" Dim settings As New XmlWriterSettings() settings.Encoding = Encoding.UTF8 settings.Indent = True xmlWriter = XmlWriter.Create(context.Response.OutputStream, settings) xmlWriter.WriteStartDocument() xmlWriter.WriteStartElement("urlset", “http://www.sitemaps.org/schemas/sitemap/0.9″) ' Add root node AddUrl(SiteMap.RootNode) ' Add all other nodes Dim nodes As SiteMapNodeCollection = SiteMap.RootNode.GetAllNodes() For Each node As SiteMapNode In nodes AddUrl(node) Next xmlWriter.WriteEndElement() xmlWriter.WriteEndDocument() xmlWriter.Flush() End Sub Private Sub AddUrl(ByVal node As SiteMapNode) ' ignore any nodes that are empty If String.IsNullOrEmpty(node.Url) Then Return End If ' ignore any nodes that are not part of the site If node.Url.StartsWith("http",True,Nothing) Then Return End If ' Open url tag xmlWriter.WriteStartElement("url") ' Write location xmlWriter.WriteStartElement("loc") xmlWriter.WriteString(GetFullUrl(node.Url)) xmlWriter.WriteEndElement() ' Write last modified xmlWriter.WriteStartElement("lastmod") xmlWriter.WriteString(GetLastModifiedDate(node.Url)) xmlWriter.WriteEndElement() ' Close url tag xmlWriter.WriteEndElement() End Sub Private Function GetFullUrl(ByVal url As String) As String Dim currentContext As HttpContext = HttpContext.Current Dim server As String = currentContext.Request.Url.GetComponents(UriComponents.SchemeAndServer, UriFormat.UriEscaped) Return CombineURL(server,url) End Function Private Function CombineURL(ByVal urlBase As String, ByVal url As String) As String urlBase = urlBase.TrimEnd(New Char() {"/"c}) url = url.TrimStart(New Char() {"/"c}) Return urlBase + “/" + url End Function Private Function GetLastModifiedDate(ByVal url As String) As String Dim currentContext As HttpContext = HttpContext.Current Dim path As String = currentContext.Server.MapPath(url) Return File.GetLastWriteTimeUtc(path).ToString("s") End Function Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable Get Return True End Get End Property End Class

That’s it! Now you can submit your .ashx file as the XML to Google Sitemaps and you are done!