proxy-auth.js

'use strict'

module.exports = auth
module.exports.parse = parse

/**
 * RegExp for basic auth credentials
 *
 * credentials = auth-scheme 1*SP token68
 * auth-scheme = "Basic" ; case insensitive
 * token68     = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" ) *"="
 * @private
 */

var CREDENTIALS_REGEXP = /^ *(?:[Bb][Aa][Ss][Ii][Cc]) +([A-Za-z0-9._~+/-]+=*) *$/

/**
 * RegExp for basic auth user/pass
 *
 * user-pass   = userid ":" password
 * userid      = *<TEXT excluding ":">
 * password    = *TEXT
 * @private
 */

var USER_PASS_REGEXP = /^([^:]*):(.*)$/

/**
 * Parse the Proxy Authorization header field of a request.
 *
 * @param {object} req
 * @return {object} with .name and .pass
 * @public
 */

function auth (req) {
  if (!req) {
    throw new TypeError('argument req is required')
  }

  if (typeof req !== 'object') {
    throw new TypeError('argument req is required to be an object')
  }

  // get header
  var header = getProxyAuthorization(req.req || req)

  // parse header
  return parse(header)
}

/**
 * Decode base64 string.
 * @private
 */

function decodeBase64 (str) {
  var escapedCredentials = decodeURIComponent(escape(str))
  return new Buffer(escapedCredentials, 'base64').toString()
}

/**
 * Get the Proxy Authorization header from request object.
 * @private
 */

function getProxyAuthorization (req) {
  if (!req.headers || typeof req.headers !== 'object') {
    throw new TypeError('argument req is required to have headers property')
  }

  return req.headers['x-proxy-authorization']
}

/**
 * Parse basic auth to object.
 *
 * @param {string} string
 * @return {object}
 * @public
 */

function parse (string) {
  if (typeof string !== 'string') {
    return undefined
  }

  // parse header
  var match = CREDENTIALS_REGEXP.exec(string)

  if (!match) {
    return undefined
  }

  // decode user pass
  var userPass = USER_PASS_REGEXP.exec(decodeBase64(match[1]))

  if (!userPass) {
    return undefined
  }

  // return credentials object
  return new Credentials(userPass[1], userPass[2])
}

/**
 * Object to represent user credentials.
 * @private
 */

function Credentials (name, pass) {
  this.name = name
  this.pass = pass
}