@leisurelink/trusted-endpoint/lib/cache.js

'use strict';

var Promise = require('bluebird');
var NodeCache = require('node-cache');
var AuthContext = require('@leisurelink/auth-context').AuthContext;

var cache = new NodeCache({
  useClones: false,
  checkperiod: 0 /* disable active reaping of cache, items are only reaped when the item is looked up next */
});
var _cache = cache;
Promise.promisifyAll(cache);

function _key(ns, key){
  return (ns ? ns + ':' : '') + key;
}

module.exports = {
  get: function(ns, key, ttl, getter) {
    var k = _key(ns, key);
    return cache.getAsync(k).then(function(result){
      if (result !== undefined) {
        if (!(result instanceof AuthContext) || !result.isExpired) {
          return result;
        }
      }
      return Promise.resolve(getter())
        .then(function(result){
          if (result !== undefined) {
            return cache.setAsync(k, result, ttl / 1000).then(function(){
              return result;
            });
          }
          return result;
        });
    });
  },
  enable: function(){
    cache = _cache;
  },
  disable: function(){
    cache = {
      getAsync: function(){ return Promise.resolve(undefined); },
      setAsync: function(){ return Promise.resolve(); },
      flushAll: function(){ }
    };
  },
  clear: function(){
    cache.flushAll();
  },
  key: _key,
  _cache: cache
};