补充：安装socket.io@0.9版本，1.0版本中去掉了get和set方法，外加一个：nodejs + socket.io + redis 新手上路：http://www.cnblogs.com/aibo/p/3366925.html

自问自答吧，找到答案了，在官方文档里，被《nodejs高级编程》这本书坑了啊，都过时了。。：

The old io.set() and io.get() methods are deprecated and only supported for backwards compatibility. Here is a translation of an old authorization example into middleware-style.

io.set(‘authorization’, function (handshakeData, callback) { // make sure the handshake data looks good callback(null, true); // error first, ‘authorized’ boolean second }); vs.

io.use(function(socket, next) { var handshakeData = socket.request; // make sure the handshake data looks good as before // if error do this: // next(new Error(‘not authorized’); // else just call next next(); });

socket.io官方文档