Express middleware for refreshing an access token with a refresh token

refreshTokenMiddleware.js

import { TokenSet } from 'openid-client'
import error from 'http-errors'
import debugFactory from 'debug'

const debug = debugFactory('ac:refresh')
/**
 * Refreshes an expired token set.
 * Requires middleware `oidc` to be called first.
 *
 * @param {Request} req The express request object
 * @param {Response} res The express response object
 * @param {Function} next The express next callback
 */
const refreshToken = async (req, res, next) => {
  const tokenSet = new TokenSet(req.session.tokenSet)

  if (tokenSet.expired()) {
    const { client } = req.oidc

    debug(`Trying to refresh token set using refresh_token ${tokenSet.refresh_token}`)

    try {
      const refreshedTokenSet = await client.refresh(tokenSet.refresh_token)

      debug('Token set refreshed')
      debug(`New refresh_token ${refreshedTokenSet.refresh_token}`)
      // Available session stores: https://www.npmjs.com/package/express-session#user-content-compatible-session-stores
      req.session.tokenSet = refreshedTokenSet
    } catch (err) {
      debug(`Unable to refresh token: ${err.message}`)

      return res.status(401).json(new error.Unauthorized())
    }
  }

  next()
}

export { refreshToken }