Question

我有以下代码。有错误处理中间件，当我在浏览器上打开localhost：3000时会调用该中间件，但是响应永远不会是“系统暂时不可用”。相反，我收到错误消息“我的自定义错误”以及完整的堆栈跟踪。

我的理解是错误的，一旦出现未处理的错误，就会通过express调用错误中间件？/

CODE

let express = require('express');
let app =  express(); 
let pug = require('pug');
let session = require('express-session');
let passport = require('passport');
require('dotenv').config();


app.listen(3000,"",()=>{
    console.log('server started');
}); 

// set express properties. these properties can be had anywhere in the code
app.set('title','Sample application using Express, Expression session, Pug, Socktet and Passport');

// for pug
app.set('view engine','pug');
app.set('views','./pages'); 

console.log(process.env.ExpressSecret);
console.log(process.env.Port);

// use the express session to se the cookie, 
// use function can take a series of middlewares 
app.use( session({
      secret: process.env.ExpressSecret,
      saveUninitialized:true,
      resave:true
  }),passport.initialize(),passport.session())

app.use((err, req, res,next) => {
    console.error(err.stack);
    res.status(500).json({ error: 'system is unavailable for the moment' });
  });

app.get('/',(request, response)=>{     
    throw new Error('my custom error');               
});

Answer 1

您需要在其他app.use（）之后定义错误处理中间件并路由调用。

app.use( session({
      secret: process.env.ExpressSecret,
      saveUninitialized:true,
      resave:true
  }),passport.initialize(),passport.session())



app.get('/',(request, response)=>{     
    throw new Error('my custom error');               
});

app.use((err, req, res,next) => {
    console.error(err.stack);
    res.status(500).json({ error: 'system is unavailable for the moment' });
  });

https://expressjs.com/en/guide/error-handling.html

在Express.js的错误处理中间件中返回自定义消息时出现问题

1 个答案: