secure-link/src/lib/generateNginxAccessToken.js

Functions to generate and validate resource access tokens.

const { createHash } = require('crypto');
const errors = require('../utils/errors');


/**
 * Generate token to validate access to a secure resource
 * @param {Object} options Configuration for token generation
 * @return {Object} Token and expiration params (if generated)
 */
const generateNginxAccessToken = (options = {}) => {
  const {
    secret,
    path,
    lifetime
  } = options;

  if (!secret) {
    throw new Error(errors.missingSecret);
  }

  if (!path) {
    throw new Error(errors.missingResourcePath);
  }

  // Expression based on ngx_http_secure_link_module
  const expires = lifetime ? lifetime : '';
  const data = `${path}${expires} ${secret}`;

  // Match secure_link_md5 directive
  const hash = createHash('md5').update(data).digest();

  return Buffer.from(hash)
    .toString('base64')
    .replace(/\//g, '_')
    .replace(/=/g, '')
    .replace(/\+/g, '-');
};


module.exports = generateNginxAccessToken;