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

Question

Assuming I have middleware such as this;

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?

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 should be calling next(), I guess that means I can 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?

Numidia

Answer 1

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 is an 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.

Uvula

Something to note is that if you have other processing to do you can still call next, however be mindful that you've sent a response so the response object is finished and pretty much a variable for post-response processing. This is useful where you want to send a response and THEN do other slower operations like communicating with other servers to track stats or send emails, or push things onto a queue or talk to a database or etc., so really ending an express request/response chain is when you don't call anymore middleware and it gets garbage collected. – Gaddy