text: /**
   * Copyright 2016, Google, Inc.
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  'use strict';
  
  const express = require('express');
  const memjs = require('memjs');
  
  const app = express();
  
  // [START gae_flex_redislabs_memcache]
  // Environment variables are defined in app.yaml.
  let MEMCACHE_URL = process.env.MEMCACHE_URL;
  
  const mc = memjs.Client.create(MEMCACHE_URL);
  // [END gae_flex_redislabs_memcache]
  
  app.get('/', (req, res, next) => {
    mc.get('foo', (err, value) => {
      if (err) {
        next(err);
        return;
      }
      if (value) {
        res.status(200).send(`Value: ${value.toString('utf-8')}`);
        return;
      }
  
      mc.set(
        'foo',
        `${Math.random()}`,
        err => {
          if (err) {
            next(err);
            return;
          }
          res.redirect('/');
        },
        60
      );
    });
  });
  
  const PORT = process.env.PORT || 8080;
  app.listen(PORT, () => {
    console.log(`App listening on port ${PORT}`);
    console.log('Press Ctrl+C to quit.');
  });
  