Zombie / SEO middleware

gistfile1.js

var app               = requireBase('libs/app'),
    Zombie            = require('zombie');

var botRegex = /bot|crawler|baiduspider|80legs|mediapartners-google|adsbot-google/i;

module.exports = function(req, res, next) {
  // Zombie not necessary for homepage since it's boostrapped
  // Exclude non-get calls and API calls
  if (req.url === '/' || req.method !== 'GET' || /^\/api\//.test(req.url)) return next();

  // Check if the requester is a bot
  if (!botRegex.test(req.headers['user-agent'] || '')) return next();

  // Check redis for html
  var cacheId = 'htmlCache' + app.config.seoVersion + ':' + req.url;

  app.redis.get(cacheId, function(err, cachedHtml) {
    if (!err && cachedHtml) return res.send(cachedHtml);

    // Generate HTML and cache it to redis
    Zombie.visit(app.config.siteUrl + req.url, { 
      debug: app.config.isDev,
      runScripts: true,
      loadCSS: true,
      silent: true,
      headers: { bot: true }
    }, function (e, browser, status) {
      var html = browser.html();
      res.send(html);

      // Save to redis
      app.redis.setex(cacheId, (5 * 24 * 60 * 60), html);
    });
  });
};