passport-ethereum-fork/lib/utils.js

exports.originalOrigin = function(req, options) {
  options = options || {};
  var app = req.app;
  if (app && app.get && app.get('trust proxy')) {
    options.proxy = true;
  }
  var trustProxy = options.proxy;
  
  var proto = (req.headers['x-forwarded-proto'] || '').toLowerCase()
    , tls = req.connection.encrypted || (trustProxy && 'https' == proto.split(/\s*,\s*/)[0])
    , host = (trustProxy && req.headers['x-forwarded-host']) || req.headers.host
    , protocol = tls ? 'https' : 'http';
  return protocol + '://' + host;
};