smt
10/31/2014 - 9:08 PM
Stache
Stache
<!doctype html>
<html>
<head>
<title>Stache Example</title>
<script src="https://gist.githack.com/smt/f3e86363de4ab89fc5ec/raw/e722954f8442c71e1c14bead3d2d45992035d323/stache.js"></script>
</head>
<body>
<script>
var stache = new Stache({ttl:2000, longTtl:4000, debug:true})
setTimeout(function () {
console.log('--- Getting SESSION STORAGE initial poop')
stache.get('poop') }, 1000)
setTimeout(function () {
console.log('--- Setting SESSION STORAGE poop to fart')
stache.set('poop', 'fart') }, 1100)
setTimeout(function () {
console.log('--- Getting SESSION STORAGE poop within cache expire time')
stache.get('poop') }, 2000)
setTimeout(function () {
console.log('--- Getting SESSION STORAGE poop after cache expire time')
stache.get('poop') }, 3200)
setTimeout(function () {
console.log('--- Setting SESSION STORAGE poop to null')
stache.set('poop', null) }, 3900)
setTimeout(function () {
console.log('--- Getting SESSION STORAGE poop within cache expire time')
stache.get('poop') }, 4000)
setTimeout(function () {
console.log('--- Getting SESSION STORAGE poop after cache expire time')
stache.get('poop') }, 6000)
setTimeout(function () {
console.log('--- Getting LOCAL STORAGE initial foo')
stache.get('foo') }, 7000)
setTimeout(function () {
console.log('--- Setting LOCAL STORAGE foo to bar')
stache.set('foo', 'bar', true) }, 7100)
setTimeout(function () {
console.log('--- Getting LOCAL STORAGE foo within cache expire time')
stache.get('foo') }, 8000)
setTimeout(function () {
console.log('--- Getting LOCAL STORAGE foo after cache expire time')
stache.get('foo') }, 11200)
setTimeout(function () {
console.log('--- Setting LOCAL STORAGE foo to null')
stache.set('foo', null, true) }, 11900)
setTimeout(function () {
console.log('--- Getting LOCAL STORAGE foo within cache expire time')
stache.get('foo') }, 13000)
setTimeout(function () {
console.log('--- Getting LOCAL STORAGE foo after cache expire time')
stache.get('foo') }, 16000)
</script>
</body>
</html>(function (window, document, undefined) {
"use strict";
var _cache;
var _local = window.localStorage;
var _session = window.sessionStorage;
/**
* Validate a well-formed cache/storage object (used internally).
* @function
* @param {Object} item
* @returns {Boolean}
*/
var validateItem = function validateItem(item) {
return (item &&
item.hasOwnProperty('id') &&
item.hasOwnProperty('value') &&
item.hasOwnProperty('expires') &&
item.hasOwnProperty('isLongTerm') &&
typeof item.id !== 'undefined' &&
typeof item.value !== 'undefined' &&
typeof item.expires !== 'undefined' &&
typeof item.isLongTerm !== 'undefined')
};
/**
* Creates a new Stache object
* @class Stache
* @param {Object} [options]
*/
var Stache = function Stache(options) {
var _options = options;
if (!_options) {
_options = {};
}
// Ensure this was called with the 'new' keyword
if (!(this instanceof Stache)) {
return new Stache(options);
}
if (_cache) {
console.warn('There can only be one Stache cache');
return this;
}
_cache = {};
/** @member {Number} */
this.ttl = _options.ttl || 1000*60*60*24;
/** @member {Number} */
this.longTtl = _options.longTtl || 1000*60*60*24*30;
/** @member {String} */
this.ns = _options.ns || 'Stache';
if (_options.debug) {
console.log('Cleaning localStorage and sessionStorage (for testing only)');
_local.removeItem(this.ns);
_session.removeItem(this.ns);
}
};
/**
* Add a TTL value to a date and return a new date to use as expiry value.
* @private
* @param {Number} [ttl]
* @param {Date} [now]
* @returns {Date}
*/
Stache.prototype._calculateExpiresDate = function _getNewExpiresDate(ttl, now) {
var _now = (typeof now === 'object' && now.toDateString) ? now : new Date();
var _ttl = ttl || this.ttl;
return new Date(_now.valueOf() + _ttl);
};
/**
* Create a new well-formed cache/storage object (used internally).
* @private
* @param {String} key
* @param {*} value
* @param {Boolean} [isLongTerm]
* @returns {Object}
*/
Stache.prototype._createNewItem = function _createNewItem(key, value, isLongTerm) {
var _value = (typeof value === 'undefined') ? null : value;
var _isLongTerm = !!isLongTerm;
return {
id: key,
value: _value,
expires: this._calculateExpiresDate((isLongTerm ? this.ttl : this.longTtl)),
isLongTerm: _isLongTerm
};
};
/**
* @private
* @param {String} key
* @returns {Object}
*/
Stache.prototype._getCacheItem = function _getCacheItem(key) {
if (!key) {
console.warn('Please provide a key');
return;
}
var item = _cache[key];
return validateItem(item) ? item : null;
};
/**
* @private
* @param {Object} item
*/
Stache.prototype._setCacheItem = function _setCacheItem(item) {
if (!validateItem(item)) {
console.warn('Item was not set or properly formed: ', item);
return;
}
_cache[item.id] = item;
};
/**
* @private
* @param {String} key
*/
Stache.prototype._deleteCacheItem = function _deleteCacheItem(key) {
if (!key) {
console.warn('Please provide a key');
return;
}
if (typeof _cache[key] !== 'undefined') {
_cache[key] = null;
delete _cache[key];
}
};
/**
* @private
* @param {String} key
* @returns {Object}
*/
Stache.prototype._getStoreItem = function _getStoreItem(key) {
if (!key) {
console.warn('Please provide a key');
return;
}
var item = _cache[key];
// default to session storage
var storeMechanism = (validateItem(item) && item.isLongTerm) ? _local : _session;
var storeObj = JSON.parse(storeMechanism.getItem(this.ns));
if (!storeObj) {
return null;
}
item = (typeof storeObj[key] === 'undefined') ? null : storeObj[key];
return item;
};
/**
* @private
* @param {Object} item
*/
Stache.prototype._setStoreItem = function _setStoreItem(item) {
if (!validateItem(item)) {
console.warn('Item was not set or properly formed: ', item);
return;
}
var storeMechanism = item.isLongTerm ? _local : _session;
var storeObj = JSON.parse(storeMechanism.getItem(this.ns));
if (!storeObj) {
storeObj = {};
}
storeObj[item.id] = item;
storeMechanism.setItem(this.ns, JSON.stringify(storeObj));
};
/**
* @private
* @param {String} key
*/
Stache.prototype._deleteStoreItem = function _deleteStoreItem(key) {
if (!key) {
console.warn('Please provide a key');
return;
}
var item = _cache[key];
if (!validateItem(item)) {
console.warn('Item was not set or properly formed: ', item);
return;
}
var storeMechanism = item.isLongTerm ? _local : _session;
var storeObj = JSON.parse(storeMechanism.getItem(this.ns));
storeObj[item.id] = null;
delete storeObj[item.id];
storeMechanism.setItem(this.ns, JSON.stringify(storeObj));
};
/**
* @private
* @param {Object} item
* @returns {Boolean}
*/
Stache.prototype._isExpired = function _isExpired(item) {
if (!item) {
console.warn('Please provide an item');
return;
}
var now = new Date();
return new Date(item.expires.valueOf()) < now;
};
/**
* @method
* @param {String} key
* @returns {*}
*/
Stache.prototype.get = function get(key) {
var now = new Date();
var storeObj;
var item = this._getCacheItem(key);
if (!item) {
// prime cache
storeObj = this._getStoreItem(key);
if (!storeObj) {
storeObj = this._createNewItem(key, null);
}
this._setCacheItem(storeObj);
item = this._getCacheItem(key);
console.log('Initialized new cache item because blank "' + key + '"');
console.table(_cache);
} else if (this._isExpired(item)) {
// refresh expired cached item from storage
storeObj = this._getStoreItem(key);
if (validateItem(storeObj)) {
item.value = storeObj.value;
}
item.expires = this._calculateExpiresDate((item.isLongTerm ? this.ttl : this.longTtl));
this._setStoreItem(item);
this._setCacheItem(item);
console.log('Updated cache item because expired "' + key + '" (' + item.value + ')');
console.table(_cache);
} else {
console.log('No cache init or update required, our data is still fresh.');
console.table(_cache);
}
console.log('It is now ' + now.toString() + ' and _cache[' + key + '] expires at ', item.expires.toString());
return item.value;
};
/**
* @method
* @param {String} key
* @param {*} value
* @param {Boolean} [isLongTerm]
*/
Stache.prototype.set = function set(key, value, isLongTerm) {
var now = new Date();
var item = this._getCacheItem(key);
if (!item) {
item = this._createNewItem(key, value, isLongTerm);
console.log('Initialized new cache item because blank "' + key + '"');
console.table(_cache);
} else {
item.value = value;
item.expires = this._calculateExpiresDate((isLongTerm ? this.ttl : this.longTtl));
console.log('Updated existing cache item "' + key + '" (' + value + ') : ' + now.toString());
console.table(_cache);
}
// Ensure we never save the same key to two different types of storage.
// If a different isLongTerm option is passed, delete the existing storage item.
if (item.isLongTerm !== !!isLongTerm) {
this._deleteStoreItem(key);
item.isLongTerm = isLongTerm;
}
this._setStoreItem(item);
this._setCacheItem(item);
};
/**
* @method
* @param {String} key
* @param {Boolean} [confirmDeleteAll]
*/
Stache.prototype.del = function del(key, confirmDeleteAll) {
// Provide the means to wipe the whole slate clean if desired.
if (!key && confirmDeleteAll) {
_session.removeItem(this.ns);
_local.removeItem(this.ns);
_cache = null;
_cache = {};
console.log('Nuked the Stache, kaboom!');
return;
}
// Important to delete store item first so that the storage mechanism, if any, can be determined
this._deleteStoreItem(key)
this._deleteCacheItem(key)
};
return window.Stache = Stache;
}(this, this.document));