global object

tokenFromGlobal

function(user, context, callback) {
  // Modules
  const request = require('request');


  // Options
  const requestTokenOptions = {
    method: 'POST',
    uri: 'https://' + auth0.domain + '/oauth/token',
    headers: {
      'content-type': 'application/json'
    },
    json: {
      grant_type: 'client_credentials',
      client_id: configuration.clientId,
      client_secret: configuration.clientSecret,
      audience: '<<Your backend API>>'
    }
  };

  var updateProfile = {
    uri: configuration.userEndpoint,
    method: 'POST',
    headers: {
      'content-type': 'application/json'
    },
    json: { /// Sample data to POST to your API
      'auth0_id': user.user_id,
      'email': user.email,
      'email_verified': user.email_verified,
      'account_created_at': user.created_at,
      'last_login_at': user.updated_at,
      'last_login_ip': context.request.ip
    }
  };

  function callbackWithData(error, response, data) {
    if (error !== null) {
      callback(new Error('HTTP request error.'));
    } else if (response.statusCode === 403) {
      callback(new UnauthorizedError(`Access denied - [403 - ${data.code} - ${data.msg}]`));
    } else if (response.statusCode === 200) {
      const namespace = 'https://sample.com/';
      context.idToken[namespace + 'user_id'] = data.user_id;
      context.idToken[namespace + 'email'] = user.email;

      callback(null, user, context);
    } else {
      callback(new Error(`Generic Error - [${response.statusCode} - ${data.code} - ${data.msg}]`));
    }
  }

  function postProfile(data) {


    // Set access token in header
    updateProfile.headers.authorization = `Bearer ${data.access_token}`;

    // Request for user profile and callback
    request(updateProfile, callbackWithData);

  }

  if (global.tokenData) {
    if (global.tokenData.expire_time > new Date().getTime()) {
      postProfile(global.tokenData);
      return;
    }
  }

  // Request access token
  request(requestTokenOptions, function prepareToken(error, response, data) {
    if (error) {
      callback(new Error('HTTP request error.'));
      return;
    } else {
      data.expire_time = new Date().getTime() + (data.expires_in * 1000);
      global.tokenData = data;
      postProfile(data);
    }
  });
}