original-url

Reconstruct the original URL used in an HTTP request based on the HTTP request headers.

The module takes into account potential URL rewrites made by proxies, load balancers, etc along the way (as long as these append special HTTP headers to the request).

Supported HTTP headers:

• Host
• Forwarded
• X-Forwarded-Proto
• X-Forwarded-Protocol
• X-Url-Scheme
• Front-End-Https
• X-Forwarded-Ssl
• X-Forwarded-Host
• X-Forwarded-Port

If the protocol (http vs https) cannot be determined based on the above headers, the encrypted flag on the TLS connection is used.

Installation

npm install original-url --save

Usage

Server example:

const http = require('http')
const originalUrl = require('original-url')

const server = http.createServer(function (req, res) {
  const url = originalUrl(req)
  if (url.full) {
    res.end(`Original URL: ${url.full}\n`)
  } else {
    res.end('Original URL could not be determined\n')
  }
})

server.listen(1337)

Request examples:

$ curl localhost:1337
Original URL: http://localhost:1337/

$ curl -H 'Host: example.com' localhost:1337
Original URL: http://example.com/

$ curl -H 'Host: example.com:1234' localhost:1337
Original URL: http://example.com:1234/

$ curl -H 'Forwarded: proto=https; host=example.com; for="10.0.0.1:1234"' localhost:1337/sub/path?key=value
Original URL: https://example.com:1234/sub/path?key=value

$ curl -H 'X-Forwarded-Host: example.com' -H 'X-Forwarded-Host: proxy.local' localhost:1337
Original URL: http://example.com/

API

result = originalUrl(req)

This module exposes a single function which takes an HTTP request object in the form of http.IncomingMessage.

When called, the function returns a result object with a full property containing the fully resolved URL. The result object will also contain any other property normally returned by the Node.js core url.parse function.

If the hostname for some reason cannot be determined, result.full will not be present.

License

MIT