Umbraco Xml Sitemap using Razor

web.config

  <system.webServer>
    <rewrite>
      <rules>
        <rule name="Xml Sitemap">
          <match url="sitemap.xml"/>
          <action type="Rewrite" url="xmlsitemap"/>
        </rule>
      </rules>
    </rewrite>
  </system.webServer>

XmlSitemap.cshtml

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@{
    Layout = null;
    var root = Umbraco.TypedContentSingleAtXPath("//homePage");
    umbraco.library.ChangeContentType("text/xml");
}
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    @renderUrl(root)
</urlset>
@helper renderUrl(IPublishedContent node)
{
    var changeFreq = (node.HasValue("changeFrequency")) ? node.GetPropertyValue<string>("changeFrequency").ToLower() : "monthly";
    var priority = node.GetPropertyValue<double>("crawlPriority");

    <url>
        <loc>@node.UrlAbsolute()</loc>
        <lastmod>@node.UpdateDate.ToString("yyyy-MM-dd")</lastmod>
        <changefreq>@changeFreq</changefreq>
        <priority>@((priority == 0) ? 0.5 : priority)</priority>
    </url>
    if (node.Children.Any())
    {
        foreach (var child in node.Children)
        {
            @renderUrl(child)
        }
    }
}