使req.host /点播。当Express后台代理时，主机名有效必须满足两个条件:

App.set('信任代理'，'环回');在app.js x - forward - host头必须由你自己在webserver中指定。如。apache, nginx

nginx:

server {
    listen myhost:80;
    server_name  myhost;
    location / {
        root /path/to/myapp/public;
        proxy_set_header X-Forwarded-Host $host:$server_port;
        proxy_set_header X-Forwarded-Server $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://myapp:8080;
    }
}

apache:

<VirtualHost myhost:80>
    ServerName myhost
    DocumentRoot /path/to/myapp/public
    ProxyPass / http://myapp:8080/
    ProxyPassReverse / http://myapp:8080/
</VirtualHost>

你需要使用req.headers.host + req.url来构造它。当然，如果你是在不同的端口，你得到的想法;-)

我使用节点包'url' (npm install url)

它的作用是当你打电话的时候

url.parse(req.url, true, true)

它将给你检索url的全部或部分的可能性。更多信息请访问:https://github.com/defunctzombie/node-url

我以以下方式使用它来获取http://www.example.com/中/之后的任何内容作为变量并拉出特定的配置文件(有点像facebook: http://www.facebook.com/username)

    var url = require('url');
    var urlParts = url.parse(req.url, true, true);
    var pathname = urlParts.pathname;
    var username = pathname.slice(1);

不过，为了实现这一点，你必须在server.js文件中以这种方式创建路由:

self.routes['/:username'] = require('./routes/users');

这样设置你的路由文件:

router.get('/:username', function(req, res) {
 //here comes the url parsing code
}

The protocol is available as req.protocol. docs here Before express 3.0, the protocol you can assume to be http unless you see that req.get('X-Forwarded-Protocol') is set and has the value https, in which case you know that's your protocol The host comes from req.get('host') as Gopal has indicated Hopefully you don't need a non-standard port in your URLs, but if you did need to know it you'd have it in your application state because it's whatever you passed to app.listen at server startup time. However, in the case of local development on a non-standard port, Chrome seems to include the port in the host header so req.get('host') returns localhost:3000, for example. So at least for the cases of a production site on a standard port and browsing directly to your express app (without reverse proxy), the host header seems to do the right thing regarding the port in the URL. The path comes from req.originalUrl (thanks @pgrassant). Note this DOES include the query string. docs here on req.url and req.originalUrl. Depending on what you intend to do with the URL, originalUrl may or may not be the correct value as compared to req.url.

将这些组合在一起以重建绝对URL。

  var fullUrl = req.protocol + '://' + req.get('host') + req.originalUrl;

const fullUrl = `${protocol}://${host}:${port}${url}`
      
    const responseString = `Full URL is: ${fullUrl}`;                       
    res.send(responseString);  
})

我建议使用originalUrl而不是URL:

var url = req.protocol + '://' + req.get('host') + req.originalUrl;

查看originalUrl的描述: http://expressjs.com/api.html#req.originalUrl

在我们的系统中，我们这样做，所以originalUrl对我们很重要:

  foo = express();
  express().use('/foo', foo);
  foo.use(require('/foo/blah_controller'));

Blah_controller是这样的:

  controller = express();
  module.exports = controller;
  controller.get('/bar/:barparam', function(req, res) { /* handler code */ });

我们的url有这样的格式

www.example.com/foo/bar/:barparam

因此，我们需要req。originalUrl在bar控制器的获取处理程序。