auth.js

// Verify and decode the Approov token and respond with 403 if the JWT
// could not be decoded, has expired, or has an invalid signature
const checkApproovTokenJWT = jwt({
  secret: new Buffer(config.approovTokenSecret, 'base64'),
  getToken: function fromApproovTokenHeader(req) {
    // Retrieve the Approov token used to authenticate the mobile app from the request header
    var approovToken = req.get('Approov-Token')
    if (!approovToken) {
      console.log('\tApproov token not specified or in the wrong format')
    }
    return approovToken
  },
  algorithms: ['HS256']
})
router.use(checkApproovTokenJWT)