gistfile1.txt

/***************************************************
Refactor of Titanium Cache, by Guilherme Chapiewski - http://guilherme.it
Modified by Carlos Herrera [email protected] to follow NodeJS syntax and possible to use in Appcelerator Titanium

This is a simple Cache implementation for Titanium that uses local SQLite
database to cache strings and JavaScript objects.

More info at http://github.com/guilhermechapiewski/titanium-cache#readme
https://gist.github.com/caherrerapa/6425618

Usage:
  // the following call will return null
	var Cache = require('cache');
	Cache.get('my_data');

	// now we'll cache object under "my_data" key for 5 minutes
	// (if you do not specify, the default cache time is 5 minutes)
	var my_javascript_object = { property: 'value' };
	Cache.put('my_data', my_javascript_object);

	// returns cached object
	var cached_obj = Cache.get('my_data');

	// cache another object (a xml document) for 1 hour
	// (you can specify different cache expiration times then 5 minutes)
	Cache.put('another_data', xml_document, 3600);

	// the following call will delete an object from cache
	Cache.del('my_data');
***************************************************/

var CONFIG = {
		// Disables cache (useful during development).
		DISABLE: false,
		
		// Time to check for objects that will be expired.
		// Will check each CACHE_EXPIRATION_INTERVAL seconds.
		CACHE_EXPIRATION_INTERVAL: 60,
		
		// This will avoid the cache expiration task to be set up
		// and will expire objects from cache before get.
		EXPIRE_ON_GET: false
};
	

var init_cache, expire_cache, current_timestamp, get, put, del;

// Cache initialization
init_cache = function(cache_expiration_interval) {
	var db = Titanium.Database.open('cache');
	db.execute('CREATE TABLE IF NOT EXISTS cache (key TEXT UNIQUE, value TEXT, expiration INTEGER)');
	db.close();
	Ti.API.info('[CACHE] INITIALIZED');
	
	if (!CONFIG || (CONFIG && !CONFIG.EXPIRE_ON_GET)) {
		// set cache expiration task
		setInterval(expire_cache, cache_expiration_interval * 1000);
		Ti.API.info('[CACHE] Will expire objects each ' + cache_expiration_interval + ' seconds');
	}
};

expire_cache = function() {
	var db = Titanium.Database.open('cache');
	var timestamp = current_timestamp();

	// count how many objects will be deleted
	var count = 0;
    var rs = db.execute('SELECT COUNT(*) FROM cache WHERE expiration <= ?', timestamp);
    while (rs.isValidRow()) {
        count = rs.field(0);
        rs.next();
    }
    rs.close();

	// deletes everything older than timestamp
	db.execute('DELETE FROM cache WHERE expiration <= ?', timestamp);
	db.close();

	Ti.API.debug('[CACHE] EXPIRATION: [' + count + '] object(s) expired');
};

current_timestamp = function() {
	var value = Math.floor(new Date().getTime() / 1000);
	Ti.API.debug("[CACHE] current_timestamp=" + value);
	return value;
};

get = function(key) {
	var db = Titanium.Database.open('cache');
	
	if (CONFIG && CONFIG.EXPIRE_ON_GET) {
		Ti.API.debug('[CACHE] EXPIRE_ON_GET is set to "true"');
		expire_cache();
	}
	
	var rs = db.execute('SELECT value FROM cache WHERE key = ?', key);
	var result = null;
	if (rs.isValidRow()) {
		Ti.API.info('[CACHE] HIT, key[' + key + ']');
		result = JSON.parse(rs.fieldByName('value'));
	} else {
		Ti.API.info('[CACHE] MISS, key[' + key + ']');				
	}
	rs.close();
	db.close();
	
	return result;
};

put = function(key, value, expiration_seconds) {
	if (!expiration_seconds) {
		expiration_seconds = 300;
	}
	var expires_in = current_timestamp() + expiration_seconds;
	var db = Titanium.Database.open('cache');
	Ti.API.info('[CACHE] PUT: time=' + current_timestamp() + ', expires_in=' + expires_in);
	var query = 'INSERT OR REPLACE INTO cache (key, value, expiration) VALUES (?, ?, ?);';
	db.execute(query, key, JSON.stringify(value), expires_in);
	db.close();
};

del = function(key) {
	var db = Titanium.Database.open('cache');
	db.execute('DELETE FROM cache WHERE key = ?', key);
	db.close();
	Ti.API.info('[CACHE] DELETED key[' + key + ']');
};

		

// initialize everything
var cache_expiration_interval = 30;
if (CONFIG && CONFIG.CACHE_EXPIRATION_INTERVAL) {
	cache_expiration_interval = CONFIG.CACHE_EXPIRATION_INTERVAL;
}

init_cache(cache_expiration_interval);
exports.get = get;
exports.put = put;
exports.del = del;