Node.js: Generate XML sitemap

How to generate XML sitemap using Node.js#

Generating XML sitemaps for website can be done manually, through web apps, and by the website itself. If you are the technical kind, probably you want to use the last option and personally take control over the generation of XML sitemap of your website. Infact, if your website has hundred thousand pages and you want a dynamic way of generating the sitemap - programmatically generating it is the only option.

In reality your URLs might come from a database, but for this example, we'll assume it is coming from an array. Following is a function to generate dynamic XML sitemaps in Node.js.

function generate_xml_sitemap() {
  // this is the source of the URLs on your site, in this case we use a simple array, actually it could come from the database
  var urls = ['about.html', 'javascript.html', 'css.html', 'html5.html'];
  // the root of your website - the protocol and the domain name with a trailing slash
  var root_path = 'http://www.example.com/';
  // XML sitemap generation starts here
  var priority = 0.5;
  var freq = 'monthly';
  var xml = '<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
  for (var i in urls) {
    xml += '<url>';
    xml += '<loc>'+ root_path + urls[i] + '</loc>';
    xml += '<changefreq>'+ freq +'</changefreq>';
    xml += '<priority>'+ priority +'</priority>';
    xml += '</url>';
    i++;
  }
  xml += '</urlset>';
  return xml;
}

Now that we have the XML sitemap generator function, let's see how we might serve it. Let's assume we will make the sitemap available at http://www.example.com/sitemap.xml, here is how you would set up the route.

app.get('/sitemap.xml', function(req, res) {
  var sitemap = generate_xml_sitemap(); // get the dynamically generated XML sitemap
  res.header('Content-Type', 'text/xml');
  res.send(sitemap);     
});

Alright it's cool, we are abale to generate an XML sitemap using Node.js, but is there a way to send it as sitemap.xml.gz?

Heck yes, there is a way!

We will use Node.js' Zlib module to send a compressed XML sitemap. And here is the way to do it:

var zlib = require('zlib');
app.get('/sitemap.xml.gz', function(req, res) {
    // get the dynamically generated XML sitemap
    var sitemap = generate_xml_sitemap();
    // Set the appropriate HTTP headers to help old and new browsers equally to how to handle the output
    res.header('Content-Type: application/x-gzip');
    res.header('Content-Encoding: gzip');
    res.header('Content-Disposition: attachment; filename="sitemap.xml.gz"');
    zlib.gzip(new Buffer(sitemap, 'utf8'), function(error, data) {
      res.send(data);
    });
});

Depending on the size and nature of your sitemap, you could further optimize the gzipped XML sitemap generation process using the fs and Stream Node modules.