function getStorage (type, dir) {
type = type.toLowerCase();
if (type === 'local') {
return hasLocalStorage() ? localStorage : new LocalStorage(dir);
} else if (type === 'session') {
return hasLocalStorage() ? sessionStorage : new LocalStorage(dir);
} else {
throw new Error('unsupport storage type `' + type + '`');
}
}
(function (process){
/**
* Super-Cache
*
* @author Zongmin Lei <*****@*****.**>
*/
var hasLocalStorage = require('has-localstorage');
var LocalStorage = require('node-localstorage').LocalStorage;
var debug = require('../debug')('LocalStore');
debug('hasLocalStorage=%s', hasLocalStorage());
var DEFAULT_TYPE = 'local';
var DEFAULT_PREFIX = 'cache_';
var DEFAULT_PATH = './data';
var DEFAULT_MAX = 1000;
var DEFAULT_PROBABILITY = 0.01;
function getStorage (type, dir) {
type = type.toLowerCase();
if (type === 'local') {
return hasLocalStorage() ? localStorage : new LocalStorage(dir);
} else if (type === 'session') {
return hasLocalStorage() ? sessionStorage : new LocalStorage(dir);
} else {
throw new Error('unsupport storage type `' + type + '`');
}
}
/**
* LocalStore
*
* @param {Object} options
* - {Number} max
* - {Number} gcProbability
*/
function LocalStore (options) {
options = options || {};
options.max = Number(options.max);
if (isNaN(options.max)) options.max = DEFAULT_MAX;
this._max = options.max;
options.gcProbability = Number(options.gcProbability);
if (isNaN(options.gcProbability)) options.gcProbability = DEFAULT_PROBABILITY;
this._gcProbability = options.gcProbability;
options.path = options.path || DEFAULT_PATH;
this._path = options.path;
options.type = options.type || DEFAULT_TYPE;
this._type = options.type;
this._storage = getStorage(this._type, this._path);
options.prefix = options.prefix || DEFAULT_PREFIX;
this._prefix = options.prefix;
debug('init: type=%s, prefix=%s, path=%s, max=%s, gcProbability=%s', this._type, this._prefix, this._path, this._max, this._gcProbability);
this._setKeyTotal(this._itemLength());
debug('keyTotal=%s', this._getKeyTotal());
}
LocalStore.prototype._getItem = function (name) {
var json = this._storage.getItem(this._prefix + name);
if (!json) return;
try {
return JSON.parse(json);
} catch (err) {
debug('_getItem error: %s', err);
}
};
LocalStore.prototype._setItem = function (name, value) {
var json = JSON.stringify(value);
this._storage.setItem(this._prefix + name, json);
};
LocalStore.prototype._removeItem = function (name) {
this._storage.removeItem(this._prefix + name);
};
LocalStore.prototype._forEachItem = function (fn) {
var storage = this._storage;
var prefix = this._prefix;
var len = storage.length;
for (var i = 0; i < len; i++) {
var key = storage.key(i);
if (key.substr(0, prefix.length) === prefix) {
fn(this._getItem(key.slice(prefix.length)), key);
}
}
};
LocalStore.prototype._getKeyTotal = function () {
var n = Number(this._storage.getItem('$$' + this._prefix + '_key_total'));
if (isNaN(n)) n = 0;
return n;
};
LocalStore.prototype._setKeyTotal = function (n) {
this._storage.setItem('$$' + this._prefix + '_key_total', n);
};
LocalStore.prototype._itemLength = function () {
var storage = this._storage;
var prefix = this._prefix;
var len = storage.length;
var ret = 0;
for (var i = 0; i < len; i++) {
var key = storage.key(i);
if (key.substr(0, prefix.length) === prefix) {
ret++;
}
}
return ret;
};
LocalStore.prototype.get = function (name, callback) {
var me = this;
process.nextTick(function () {
var t = Date.now();
var info = me._getItem(name);
debug('get: name=%s, exists=%s', name, !!info);
if (info && info.expire < t) {
info = undefined;
me._removeItem(name);
}
callback(null, info && info.data);
});
if (this._isGCProbability()) this._gc();
};
LocalStore.prototype.set = function (name, data, ttl, callback) {
var me = this;
me._setItem(name, {
name: name,
data: data,
expire: Date.now() + ttl * 1000
});
debug('set: name=%s, ttl=%s, data=%j', name, ttl, data);
if (me._getKeyTotal() > me._max) {
me._gc();
}
process.nextTick(function () {
callback(null);
});
};
LocalStore.prototype.delete = function (name, callback) {
var me = this;
debug('delete: name=%s', name);
me._removeItem(name);
me._setKeyTotal(me._getKeyTotal() - 1);
process.nextTick(function () {
callback(null);
});
};
LocalStore.prototype._isGCProbability = function () {
return ((1 / this._gcProbability) * Math.random() <= 1);
};
LocalStore.prototype._gc = function () {
var me = this;
var prefix = me._prefix;
var keys = {};
var keyTotal = 0;
me._forEachItem(function (item, name) {
keys[name] = item;
keyTotal++;
});
debug('_gc: total=%s', keyTotal);
var t = Date.now();
for (var i in keys) {
if (keys[i].expire < t) {
debug('_gc delete: key=%s, expire=%s [expired]', i, keys[i].expire);
delete keys[i];
me._removeItem(i.slice(prefix.length));
keyTotal--;
}
}
if (keyTotal > me._max) {
var list = Object.keys(keys).map(function (k) {
return keys[k];
});
list.sort(function (a, b) {
return a.expire - b.expire;
});
var deleteList = list.slice(0, keyTotal - me._max);
deleteList.forEach(function (item) {
debug('_gc delete: key=%s, expire=%s [store full]', item.name, item.expire);
delete keys[item.name];
me._removeItem(item.name);
keyTotal--;
});
}
me._setKeyTotal(me._itemLength());
debug('keyTotal=%s', me._getKeyTotal());
};
module.exports = LocalStore;
}).call(this,require('_process'))
/**
* Super-Cache
*
* @author Zongmin Lei <*****@*****.**>
*/
var hasLocalStorage = require('has-localstorage');
var LocalStorage = require('node-localstorage').LocalStorage;
var debug = require('../debug')('LocalStore');
debug('hasLocalStorage=%s', hasLocalStorage());
var DEFAULT_TYPE = 'local';
var DEFAULT_PREFIX = 'cache_';
var DEFAULT_PATH = './data';
var DEFAULT_MAX = 1000;
var DEFAULT_PROBABILITY = 0.01;
function getStorage (type, dir) {
type = type.toLowerCase();
if (type === 'local') {
return hasLocalStorage() ? localStorage : new LocalStorage(dir);
} else if (type === 'session') {
return hasLocalStorage() ? sessionStorage : new LocalStorage(dir);
} else {
throw new Error('unsupport storage type `' + type + '`');
}
}