joola.io.engine/lib/shared/cache.js

/**
 *  joola.io
 *
 *  Copyright Joola Smart Solutions, Ltd. <info@joo.la>
 *
 *  Licensed under GNU General Public License 3.0 or later.
 *  Some rights reserved. See LICENSE, AUTHORS.
 *
 *  @license GPL-3.0+ <http://spdx.org/licenses/GPL-3.0+>
 */
var cache = function (joola, next) {
  joola.cache = {};
  joola.cache.sweeperTimer = null;
  joola.cache.sweeperTimeout = 10 * 1000;
  joola.cache.redisCacheKey = "joola:cache";

  joola.cache._start = function (joola, callback) {
    joola.cache.runSweeper();
    return callback();
  };

  joola.cache._teardown = function (joola, next) {
    joola.cache.stopTimers(joola);
    return next();
  };

  joola.cache.stopTimers = function (joola) {
    clearTimeout(joola.cache.sweeperTimer);
  };

  joola.cache.prepareDomain = function () {
    // until the redis module handles domains, we need to force the callback to be bound properly
    // https://github.com/mranney/node_redis/pull/310/files
    return {
      bind: function (callback) {
        return callback
      }
    }
  };

  joola.cache.size = function (next) {
    var domain = joola.cache.prepareDomain();
    joola.redis.client.hlen(joola.cache.redisCacheKey, domain.bind(function (err, count) {
      next(null, count);
    }));
  };

  joola.cache.load = function (store, key, options, next) {
    if (typeof options == "function") {
      next = options;
      options = {}
    }
    var domain = joola.cache.prepareDomain();
    joola.redis.client.hget(joola.cache.redisCacheKey + ':' + store, key, domain.bind(function (err, cacheObj) {
      if (err != null) {
        //joola.error(err);
        return next(new Error("Failed to get value from redis"), null, null, null, null);
      }
      try {
        cacheObj = JSON.parse(cacheObj);
      } catch (e) {
      }
      if (cacheObj == null) {
        if (typeof next == "function") {
          process.nextTick(function () {
            return  next(new Error("Object not found"), null, null, null, null);
          });
        }
      } else if (cacheObj.expireTimestamp >= new Date().getTime() || cacheObj.expireTimestamp == null) {
        cacheObj.readAt = new Date().getTime();
        if (cacheObj.expireTimestamp != null && options.expireTimeMS)
          cacheObj.expireTimestamp = new Date().getTime() + options.expireTimeMS;
        joola.redis.client.hset(joola.cache.redisCacheKey, key, JSON.stringify(cacheObj), domain.bind(function () {
          if (typeof next == "function") {
            process.nextTick(function () {
              return  next(null, cacheObj.value, cacheObj.expireTimestamp, cacheObj.createdAt, cacheObj.readAt);
            });
          }
        }));
      } else {
        if (typeof next == "function") {
          process.nextTick(function () {
            return next(new Error("Object expired"), null, null, null, null);
          });
        }
      }
    }));
  };

  joola.cache.destroy = function (key, next) {
    var domain = joola.cache.prepareDomain();
    joola.redis.client.hdel(joola.cache.redisCacheKey, key, domain.bind(function (err, count) {
      //joola.stats.increment("cache:cachedObjects", -1 );
      if (err != null) {
        joola.logger.error(err);
      }
      var resp = true;
      if (count != 1) {
        resp = false;
      }
      if (typeof next == "function") {
        process.nextTick(function () {
          next(null, resp);
        });
      }
    }));
  };

  joola.cache.sweeper = function (next) {
    var domain = joola.cache.prepareDomain();
    joola.redis.client.hkeys(joola.cache.redisCacheKey, domain.bind(function (err, keys) {
      var started = 0;
      var sweepedKeys = [];
      keys.forEach(function (key) {
        started++;
        joola.redis.client.hget(joola.cache.redisCacheKey, key, domain.bind(function (err, cacheObj) {
          if (err != null) {
            joola.logger.error(err);
          }
          try {
            JSON.parse(cacheObj);
          } catch (e) {
          }
          if (cacheObj != null) {
            if (cacheObj.expireTimestamp != null && cacheObj.expireTimestamp < new Date().getTime()) {
              joola.redis.client.hdel(joola.cache.redisCacheKey, key, domain.bind(function (err) {
                sweepedKeys.push(key);
                started--;
                if (started == 0 && typeof next == "function") {
                  next(err, sweepedKeys);
                }
              }));
            } else {
              started--;
              if (started == 0 && typeof next == "function") {
                next(err, sweepedKeys);
              }
            }
          } else {
            started--;
            if (started == 0 && typeof next == "function") {
              next(err, sweepedKeys);
            }
          }
        }));
      });
      if (keys.length == 0 && typeof next == "function") {
        next(err, sweepedKeys);
      }
    }));
  };

  joola.cache.save = function (store, key, value, expireTimeMS, next) {
    var domain = joola.cache.prepareDomain();
    if (typeof expireTimeMS == "function" && typeof next == "undefined") {
      next = expireTimeMS;
      expireTimeMS = null;
    }
    if (expireTimeMS != null) {
      var expireTimestamp = new Date().getTime() + expireTimeMS;
    } else {
      expireTimestamp = null;
    }
    var cacheObj = {
      value: value,
      expireTimestamp: expireTimestamp,
      createdAt: new Date().getTime(),
      readAt: null
    };
    joola.redis.client.hset(joola.cache.redisCacheKey + ':' + store, key, JSON.stringify(cacheObj), domain.bind(function () {
      if (typeof next == "function") {
        process.nextTick(function () {
          next(null, true);
        });
      }
    }));
  };

  joola.cache.runSweeper = function () {
    clearTimeout(joola.cache.sweeperTimer);
    joola.cache.sweeper(function (err, sweepedKeys) {
      if (sweepedKeys.length > 0) {
        joola.logger.info("cleaned " + sweepedKeys.length + " expired cache keys", "debug");
      }
      if (joola.running) {
        joola.cache.sweeperTimer = setTimeout(joola.cache.runSweeper, joola.cache.sweeperTimeout, joola);
      }
    });
  };

  next();
};

/////////////////////////////////////////////////////////////////////
// exports
exports.cache = cache;