ExpressJS 应用中的中间件使用 next() 调用自身

Question

我有一个基本的 ExpressJS 服务器，它只是用来记录连接的 IP，并提供静态网页。当我自己连接到它时会发生什么，记录请求 IP 的中间件会重复多次。如果我删除对 next() 的调用，这将停止，但它也会阻止管理静态页面的中间件从运行.

服务器代码是这样的：

var express = require('express');

    app = express();

app.use(function(req, res, next) {
    console.log('Received a connection from: ' + req.ip)
    next();
})

app.use('/', express.static(__dirname + '/public'));

var port = 55671;
app.listen(port, function() { 
    console.log('Listening on: ' + port);
});

如果我只连接一次，这是标准输出：

Listening on: 55671
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1
Received a connection from: ::ffff:127.0.0.1

我尝试过中间件的不同排序，我以前认为这是可行的，但我可能记错了。为什么 next() 调用在移动到另一个中间件然后停止之前多次调用一个中间件？

Answer 1

不是 next() 多次调用 thing。它只允许您继续前进，否则您的应用程序会在第一个日志语句之后卡住。

但是，中间件的顺序很重要，这里将为访问的所有静态文件调用您的日志记录中间件。

如果不想跟踪静态中间件，最好将静态中间件放在日志中间件之前。

ExpressJS 应用中的中间件使用 next() 调用自身

Middleware in ExpressJS app uses next() to call itself

middleware

node.js

express