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

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 开发者_高级运维for client javascript to construct the site or preprocessed html.

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

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

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 ...
});