Absolute URL from req

absolute.js

import url from 'url'

const defaultValidHostRegex = /www\.example\.com/

export function getProtocol(req) {
  let proto = req.connection.encrypted ? 'https' : 'http'
  // only do this if you trust the proxy
  proto = req.headers['x-forwarded-proto'] || proto
  return proto.split(/\s*,\s*/)[0]
}

export function getAbsoluteUrl(req, { fallbackHost = 'www.example.com', validHostRegex = defaultValidHostRegex } = {}) {
  let host = req.headers.host || ''
  if (!validHostRegex.test(host)) {
    host = fallbackHost
  }

  return url.format({
    protocol: getProtocol(req),
    host,
    pathname: req.url
  })
}