3 * StatusNet, the distributed open-source microblogging tool
5 * Cache interface plus default in-memory cache implementation
9 * LICENCE: This program is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU Affero General Public License as published by
11 * the Free Software Foundation, either version 3 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU Affero General Public License for more details.
19 * You should have received a copy of the GNU Affero General Public License
20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 * @author Evan Prodromou <evan@status.net>
25 * @copyright 2009 StatusNet, Inc.
26 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
27 * @link http://status.net/
31 * Interface for caching
33 * An abstract interface for caching. Because we originally used the
34 * Memcache plugin directly, the interface uses a small subset of the
39 * @author Evan Prodromou <evan@status.net>
40 * @copyright 2009 StatusNet, Inc.
41 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
42 * @link http://status.net/
47 var $_items = array();
51 * Singleton constructor
53 * Use this to get the singleton instance of Cache.
55 * @return Cache cache object
58 static function instance()
60 if (is_null(self::$_inst)) {
61 self::$_inst = new Cache();
68 * Create a cache key from input text
70 * Builds a cache key from input text. Helps to namespace
71 * the cache area (if shared with other applications or sites)
72 * and prevent conflicts.
74 * @param string $extra the real part of the key
76 * @return string full key
79 static function key($extra)
81 $base_key = common_config('cache', 'base');
83 if (empty($base_key)) {
84 $base_key = common_keyize(common_config('site', 'name'));
87 return 'statusnet:' . $base_key . ':' . $extra;
91 * Make a string suitable for use as a key
93 * Useful for turning primary keys of tables into cache keys.
95 * @param string $str string to turn into a key
97 * @return string keyized string
100 static function keyize($str)
102 $str = strtolower($str);
103 $str = preg_replace('/\s/', '_', $str);
108 * Get a value associated with a key
110 * The value should have been set previously.
112 * @param string $key Lookup key
114 * @return string retrieved value or null if unfound
121 if (Event::handle('StartCacheGet', array(&$key, &$value))) {
122 if (array_key_exists($key, $this->_items)) {
123 $value = unserialize($this->_items[$key]);
125 Event::handle('EndCacheGet', array($key, &$value));
132 * Set the value associated with a key
134 * @param string $key The key to use for lookups
135 * @param string $value The value to store
136 * @param integer $flag Flags to use, mostly ignored
137 * @param integer $expiry Expiry value, mostly ignored
139 * @return boolean success flag
142 function set($key, $value, $flag=null, $expiry=null)
146 if (Event::handle('StartCacheSet', array(&$key, &$value, &$flag,
147 &$expiry, &$success))) {
149 $this->_items[$key] = serialize($value);
153 Event::handle('EndCacheSet', array($key, $value, $flag,
161 * Delete the value associated with a key
163 * @param string $key Key to delete
165 * @return boolean success flag
168 function delete($key)
172 if (Event::handle('StartCacheDelete', array(&$key, &$success))) {
173 if (array_key_exists($key, $this->_items)) {
174 unset($this->_items[$key]);
177 Event::handle('EndCacheDelete', array($key));