expressjs node.js serve different data to google/etc bot and human traffic

Question

I want to determine if incoming requests are from a bot (eg google, bing), or a human, and serve different data to each, for example, json data for client javascript to construct the site or preprocessed html.

Using expressjs, is there an easy way to do this? Thanks.

Answer 1

You can check the req.header('User-Agent') for 'Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html'. If it's that you know it's Google and can send it different data.

http://www.google.com/support/webmasters/bin/answer.py?answer=1061943

How to get headers http://expressjs.com/4x/api.html#req.get

Answer 2

I recommend you to response according to the requested MIME type (which is present in the "Accept" header). You can do this with Express this way:

app.get('/route', function (req, res) {
    if (req.is('json')) res.json(data);
    else if (req.is('html')) res.render('view', {});
    else ...
});