nodejs中处理回调函数的异常

假设是使用nodejs+express3这个经典的组合。那么有一种非常方面的处理回调函数异常的方法：

1. 安装模块：express-domain-middleware

2. 增加例如以下的代码：

app.use(require('express-domain-middleware'));
app.use(function errorHandler(err, req, res, next) {
  logger.error('error on request %d %s %s: %j', process.domain.id, req.method, req.url, err);
  res.send(500, "there is an error in callback function");
  if(err.domain) {
    //you should think about gracefully stopping & respawning your server
    //since an unhandled error might put your application into an unknown state
  }
});
app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));