javascript “结束”来自 express/connect 中间件的请求的正确方法是什么？

What is the correct way to "end" a request from express/connect middleware?

提问by Isaac

Assuming I have middleware such as this;

假设我有这样的中间件；

var express = require('express');
var app = express();

app.use(function (req, res, next) {
    var host = "example.com";

    if (req.host !== host) {
        res.redirect(301, host + req.originalUrl);
        res.end();
    }
});

What sort of rules do I need to abide by here?

我在这里需要遵守什么样的规则？

1. Should I be calling res.end()? (or does res.redirect()do this for me?)
2. Should I be calling next()? (or does connect detect the request has ended and exit cleanly?)
3. Assuming that I shouldbe calling next(), I guess that means Ican potentially be receiving requests to my middleware which may have already been ended by other middleware higher in the chain; how do I protect myself against this?

1. 我应该打电话res.end()吗？（或者res.redirect()为我做这个？）
2. 我应该打电话next()吗？（或者连接是否检测到请求已经结束并干净地退出？）
3. 假设我应该调用next()，我想这意味着我可能会收到对我的中间件的请求，这些请求可能已经被链中更高的其他中间件终止了；我该如何保护自己免受这种伤害？

回答by robertklep

1. res.redirect()indeed calls res.end()itself;
2. You should call next()if your middleware isn't the end point; in the case of generating a redirect, it isan endpoint and next()shouldn't be called, but if req.host === host, you need to call next()to move the request up the chain to other middleware/routes;
3. A request doesn't get ended, a response does. And when it does, it will end the middleware chain so you don't have to worry about it.

1. res.redirect()确实res.end()自称；
2. next()如果您的中间件不是终点，您应该调用；在生成重定向的情况下，它是一个端点，next()不应调用，但如果req.host === host，则需要调用next()以将请求沿链向上移动到其他中间件/路由；
3. 请求不会结束，响应会结束。当它发生时，它将结束中间件链，因此您不必担心。