express.js auto route，遍历controllers目录里的所有js文件，对里面每个module的每个属性都当做一个/:controller/:action，作自动路由（就跟ASP.NET MVC差不多啦！）

app.js

// app.js
for (var controller in routes){
    var mod = routes[controller];
    app.all('/' + controller + ':action', function(req, res){
        var action = req.params.action;
        if (action in mod){
            mod[action](req, res);
        }else{
            res.statusCode = 404;
            res.send('404 not found');
        }
    });
}

routes.js

// routes.js
var controllerPath = path.join(__dirname, 'controllers');
fs.readdirSync(controllerPath).forEach(function(filename){
    var extname = path.extname(filename);
    if (extname !== '.js') return;
    var fullname = path.join(controllerPath, filename);
    var stats = fs.statSync(fullname)
    if (stats.isFile()){
        try{
            var moduleName = path.basename(filename, extname);
            exports[moduleName] = require('./controllers/' + moduleName);
        }catch(ex){
            console.log('route error', ex);
        }
    }
});