这里有一个添加函数的好方法，你可以调用req对象来获取url

  app.use(function(req, res, next) {
    req.getUrl = function() {
      return req.protocol + "://" + req.get('host') + req.originalUrl;
    }
    return next();
  });

现在，您有了一个可以在需要时按需调用的函数。

async function (request, response, next) {
  const url = request.rawHeaders[9] + request.originalUrl;
  //or
  const url = request.headers.host + request.originalUrl;
}

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。

使用url.format:

var url = require('url');

这支持所有协议，包括端口号。如果你的originalUrl中没有查询字符串，你可以使用这个更干净的解决方案:

var requrl = url.format({
    protocol: req.protocol,
    host: req.get('host'),
    pathname: req.originalUrl,
});

如果你有一个查询字符串:

var urlobj = url.parse(req.originalUrl);
urlobj.protocol = req.protocol;
urlobj.host = req.get('host');
var requrl = url.format(urlobj);

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;

用这个,

var url = req.headers.host + '/' + req.url;