[1] | 1 | <?php |
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| 2 | /** |
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[362] | 3 | * The Strangecode Codebase - a general application development framework for PHP |
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| 4 | * For details visit the project site: <http://trac.strangecode.com/codebase/> |
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[396] | 5 | * Copyright 2001-2012 Strangecode, LLC |
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[468] | 6 | * |
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[362] | 7 | * This file is part of The Strangecode Codebase. |
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| 8 | * |
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| 9 | * The Strangecode Codebase is free software: you can redistribute it and/or |
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| 10 | * modify it under the terms of the GNU General Public License as published by the |
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| 11 | * Free Software Foundation, either version 3 of the License, or (at your option) |
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| 12 | * any later version. |
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[468] | 13 | * |
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[362] | 14 | * The Strangecode Codebase is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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| 16 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more |
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| 17 | * details. |
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[468] | 18 | * |
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[362] | 19 | * You should have received a copy of the GNU General Public License along with |
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| 20 | * The Strangecode Codebase. If not, see <http://www.gnu.org/licenses/>. |
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| 21 | */ |
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| 22 | |
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| 23 | /** |
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[136] | 24 | * Cache.inc.php |
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| 25 | * |
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[1] | 26 | * Provides an API for storing a limited amount of data |
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| 27 | * intended to have a short lifetime in a user's session. |
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| 28 | * |
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[534] | 29 | * Disable cache per-request by adding '_disable_cache=1' to a GET or POST parameter. |
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| 30 | * |
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[1] | 31 | * @author Quinn Comendant <quinn@strangecode.com> |
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[136] | 32 | * @version 2.1 |
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[1] | 33 | * @since 2001 |
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| 34 | */ |
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[136] | 35 | |
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[502] | 36 | class Cache |
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| 37 | { |
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[136] | 38 | |
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[468] | 39 | // A place to keep object instances for the singleton pattern. |
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[484] | 40 | protected static $instances = array(); |
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[468] | 41 | |
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[152] | 42 | // Namespace of this instance of Prefs. |
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[484] | 43 | protected $_ns; |
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[152] | 44 | |
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| 45 | // Configuration parameters for this object. |
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[484] | 46 | protected $_params = array( |
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[468] | 47 | |
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| 48 | // Type of cache. Currently only 'session' is supported. |
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| 49 | 'type' => 'session', |
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| 50 | |
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[334] | 51 | // If false nothing will be cached or retrieved. Useful for testing realtime data requests. |
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[21] | 52 | 'enabled' => true, |
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[152] | 53 | |
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| 54 | // The maximum size in bytes of any one variable. |
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| 55 | 'item_size_limit' => 4194304, // 4 MB |
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[468] | 56 | |
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[152] | 57 | // The maximum size in bytes before the cache will begin flushing out old items. |
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| 58 | 'stack_size_limit' => 4194304, // 4 MB |
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[468] | 59 | |
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[152] | 60 | // The minimum items to keep in the cache regardless of item or cache size. |
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| 61 | 'min_items' => 5, |
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[638] | 62 | |
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| 63 | // How long in seconds before items in the cache are considered expired. |
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| 64 | // When the cache expires, Cache->get() returns null. |
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| 65 | 'expires' => 3600, |
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[1] | 66 | ); |
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[468] | 67 | |
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[152] | 68 | /* |
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[537] | 69 | * Constructor. This is publicly accessible for compatibility with older implementations, |
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[468] | 70 | * but the preferred method of instantiation is by use of the singleton pattern: |
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| 71 | * $cache =& Cache::getInstance('namespace'); |
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| 72 | * $cache->setParam(array('enabled' => true)); |
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[152] | 73 | * |
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| 74 | * @access public |
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| 75 | * @param string $namespace This object will store data under this realm. |
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| 76 | * @author Quinn Comendant <quinn@strangecode.com> |
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| 77 | * @version 1.0 |
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| 78 | * @since 05 Jun 2006 23:14:21 |
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| 79 | */ |
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[468] | 80 | public function __construct($namespace='') |
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[152] | 81 | { |
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[172] | 82 | $app =& App::getInstance(); |
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[468] | 83 | |
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[154] | 84 | $this->_ns = $namespace; |
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[172] | 85 | |
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| 86 | if (true !== $app->getParam('enable_session')) { |
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[523] | 87 | // Force disable the cache because there is no session to save to. |
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[534] | 88 | $app->logMsg('Cache disabled, enable_session != true.', LOG_DEBUG, __FILE__, __LINE__); |
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[172] | 89 | $this->setParam(array('enabled' => false)); |
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[523] | 90 | } else if (!isset($_SESSION['_cache'][$this->_ns])) { |
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| 91 | // Otherwise, clear to initialize the session variable. |
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[152] | 92 | $this->clear(); |
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| 93 | } |
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| 94 | } |
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[1] | 95 | |
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| 96 | /** |
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| 97 | * This method enforces the singleton pattern for this class. |
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| 98 | * |
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[136] | 99 | * @return object Reference to the global Cache object. |
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[1] | 100 | * @access public |
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| 101 | * @static |
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| 102 | */ |
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[468] | 103 | public static function &getInstance($namespace='') |
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[136] | 104 | { |
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[468] | 105 | if (!array_key_exists($namespace, self::$instances)) { |
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| 106 | self::$instances[$namespace] = new self($namespace); |
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[1] | 107 | } |
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[468] | 108 | return self::$instances[$namespace]; |
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[1] | 109 | } |
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| 110 | |
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| 111 | /** |
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| 112 | * Set (or overwrite existing) parameters by passing an array of new parameters. |
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| 113 | * |
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| 114 | * @access public |
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| 115 | * @param array $params Array of parameters (key => val pairs). |
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| 116 | */ |
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[468] | 117 | public function setParam($params) |
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[1] | 118 | { |
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[479] | 119 | $app =& App::getInstance(); |
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[21] | 120 | |
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[1] | 121 | if (isset($params) && is_array($params)) { |
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| 122 | // Merge new parameters with old overriding only those passed. |
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[136] | 123 | $this->_params = array_merge($this->_params, $params); |
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[1] | 124 | } else { |
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[136] | 125 | $app->logMsg(sprintf('Parameters are not an array: %s', $params), LOG_ERR, __FILE__, __LINE__); |
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[1] | 126 | } |
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| 127 | } |
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| 128 | |
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| 129 | /** |
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| 130 | * Return the value of a parameter, if it exists. |
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| 131 | * |
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| 132 | * @access public |
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| 133 | * @param string $param Which parameter to return. |
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| 134 | * @return mixed Configured parameter value. |
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| 135 | */ |
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[468] | 136 | public function getParam($param) |
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[1] | 137 | { |
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[479] | 138 | $app =& App::getInstance(); |
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[468] | 139 | |
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[478] | 140 | if (array_key_exists($param, $this->_params)) { |
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[136] | 141 | return $this->_params[$param]; |
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[1] | 142 | } else { |
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[146] | 143 | $app->logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 144 | return null; |
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| 145 | } |
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| 146 | } |
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| 147 | |
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| 148 | /** |
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[334] | 149 | * Stores a new variable in the session cache. The $key should not be numeric |
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[468] | 150 | * because the array_shift function will reset the key to the next largest |
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[174] | 151 | * int key. Weird behavior I can't understand. For example $cache["123"] will become $cache[0] |
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[1] | 152 | * |
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[468] | 153 | * @param str $key An identifier for the cached object. |
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| 154 | * @param mixed $var The data to store in the session cache. |
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| 155 | * @param bool $allow_oversized If we have something really big that we still want to cache, setting this to true allows this. |
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| 156 | * @return bool True on success, false otherwise. |
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[1] | 157 | */ |
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[468] | 158 | public function set($key, $var, $allow_oversized=false) |
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[1] | 159 | { |
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[479] | 160 | $app =& App::getInstance(); |
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[1] | 161 | |
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[534] | 162 | if (true !== $this->getParam('enabled') || getFormData('_disable_cache')) { |
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[316] | 163 | $app->logMsg(sprintf('Cache disabled, not saving data.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 164 | return false; |
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| 165 | } |
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| 166 | |
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[468] | 167 | if (is_numeric($key)) { |
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| 168 | $app->logMsg(sprintf('Cache::set key value should not be numeric (%s given)', $key), LOG_WARNING, __FILE__, __LINE__); |
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| 169 | } |
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| 170 | |
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[152] | 171 | $var = serialize($var); |
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[247] | 172 | $var_len = mb_strlen($var); |
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[42] | 173 | |
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[152] | 174 | if ($var_len >= $this->getParam('item_size_limit')) { |
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| 175 | $app->logMsg(sprintf('Serialized variable (%s bytes) more than item_size_limit (%s bytes).', $var_len, $this->getParam('item_size_limit')), LOG_NOTICE, __FILE__, __LINE__); |
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[1] | 176 | return false; |
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| 177 | } |
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[42] | 178 | |
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[468] | 179 | if ($allow_oversized && $var_len >= $this->getParam('stack_size_limit')) { |
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[152] | 180 | $app->logMsg(sprintf('Serialized variable (%s bytes) more than stack_size_limit (%s bytes).', $var_len, $this->getParam('stack_size_limit')), LOG_NOTICE, __FILE__, __LINE__); |
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[1] | 181 | return false; |
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[468] | 182 | } |
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[1] | 183 | |
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[152] | 184 | // Remove any value already stored under this key. |
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[174] | 185 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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[152] | 186 | |
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| 187 | // Continue to prune the cache if its size is greater than stack_size_limit, but keep at least min_items. |
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[247] | 188 | while (mb_strlen(serialize($_SESSION['_cache'][$this->_ns])) + $var_len >= $this->getParam('stack_size_limit') && sizeof($_SESSION['_cache'][$this->_ns]) >= $this->getParam('min_items')) { |
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[154] | 189 | array_shift($_SESSION['_cache'][$this->_ns]); |
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[1] | 190 | } |
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[42] | 191 | |
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[152] | 192 | // Save this value under the specified key. |
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[638] | 193 | $_SESSION['_cache'][$this->_ns][$key] = array( |
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| 194 | 'var' => $var, |
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| 195 | 'time' => time(), |
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| 196 | ); |
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[152] | 197 | |
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[558] | 198 | $app->logMsg(sprintf('Set cache item â%sâ', $key), LOG_DEBUG, __FILE__, __LINE__); |
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| 199 | |
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[152] | 200 | if ($var_len >= 1024000) { |
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| 201 | $app->logMsg(sprintf('Successfully cached oversized variable (%s bytes).', $var_len), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 202 | } |
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[42] | 203 | |
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[136] | 204 | return true; |
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[1] | 205 | } |
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[42] | 206 | |
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[1] | 207 | /** |
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[334] | 208 | * Retrieves an object from the session cache and returns it unserialized. |
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[1] | 209 | * It also moves it to the top of the stack, which makes it such that the |
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| 210 | * cache flushing mechanism of putCache deletes the oldest referenced items |
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| 211 | * first. |
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| 212 | * |
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[136] | 213 | * @param string $key The key for the datum to retrieve. |
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[1] | 214 | * @return mixed The requested datum, or false on failure. |
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| 215 | */ |
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[468] | 216 | public function get($key) |
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[1] | 217 | { |
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[153] | 218 | $app =& App::getInstance(); |
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[162] | 219 | |
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[534] | 220 | if (true !== $this->getParam('enabled') || getFormData('_disable_cache')) { |
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[316] | 221 | $app->logMsg(sprintf('Cache disabled, not getting data.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 222 | return false; |
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| 223 | } |
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[42] | 224 | |
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[480] | 225 | if (isset($_SESSION['_cache'][$this->_ns]) && array_key_exists($key, $_SESSION['_cache'][$this->_ns])) { |
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[638] | 226 | if (isset($_SESSION['_cache'][$this->_ns][$key]['time']) && $_SESSION['_cache'][$this->_ns][$key]['time'] > (time() - $this->getParam('expires'))) { |
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| 227 | $app->logMsg(sprintf('Retrieving %s from cache.', $key), LOG_DEBUG, __FILE__, __LINE__); |
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| 228 | // Move the accessed cached datum to the top of the stack. Maybe somebody knows a better way to do this? |
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| 229 | $tmp =& $_SESSION['_cache'][$this->_ns][$key]; |
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| 230 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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| 231 | $_SESSION['_cache'][$this->_ns][$key] =& $tmp; |
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| 232 | // Return the unserialized datum. |
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| 233 | return unserialize($_SESSION['_cache'][$this->_ns][$key]['var']); |
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| 234 | } else { |
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| 235 | // Cached item has expired. |
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| 236 | $app->logMsg(sprintf('Cached %s expired %s ago', $key, humanTime(time() - $_SESSION['_cache'][$this->_ns][$key]['time'])), LOG_DEBUG, __FILE__, __LINE__); |
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| 237 | return null; |
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| 238 | } |
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[1] | 239 | } else { |
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[172] | 240 | $app->logMsg(sprintf('Missing %s from cache.', $key), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 241 | return false; |
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| 242 | } |
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| 243 | } |
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[42] | 244 | |
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[1] | 245 | /** |
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| 246 | * Tells you if the object is cached. |
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| 247 | * |
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[136] | 248 | * @param string $key The key of the object to check. |
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[218] | 249 | * @return bool True if a value exists for the given key. |
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[1] | 250 | */ |
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[468] | 251 | public function exists($key) |
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[1] | 252 | { |
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[405] | 253 | $app =& App::getInstance(); |
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| 254 | |
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[534] | 255 | if (true !== $this->getParam('enabled') || getFormData('_disable_cache')) { |
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[405] | 256 | $app->logMsg(sprintf('Cache disabled on exist assertion.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 257 | return false; |
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| 258 | } |
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| 259 | |
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[638] | 260 | if (isset($_SESSION['_cache'][$this->_ns]) |
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| 261 | && array_key_exists($key, $_SESSION['_cache'][$this->_ns]) |
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| 262 | && isset($_SESSION['_cache'][$this->_ns][$key]['time']) |
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| 263 | && $_SESSION['_cache'][$this->_ns][$key]['time'] > (time() - $this->getParam('expires'))) { |
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| 264 | $app->logMsg(sprintf('Cache item â%sâ exists', $key), LOG_DEBUG, __FILE__, __LINE__); |
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| 265 | return true; |
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| 266 | } else { |
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| 267 | $app->logMsg(sprintf('Cache item â%sâ missing or expired', $key), LOG_DEBUG, __FILE__, __LINE__); |
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| 268 | return false; |
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| 269 | } |
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[1] | 270 | } |
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[42] | 271 | |
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[1] | 272 | /** |
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[188] | 273 | * Removes a cached object. |
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[1] | 274 | * |
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[136] | 275 | * @param string $key The key of the object to check. |
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[218] | 276 | * @return bool True if the value existed before being unset. |
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[1] | 277 | */ |
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[468] | 278 | public function delete($key) |
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[1] | 279 | { |
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[523] | 280 | $app =& App::getInstance(); |
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| 281 | |
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[534] | 282 | if (true !== $this->getParam('enabled') || getFormData('_disable_cache')) { |
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[523] | 283 | $app->logMsg(sprintf('Cache disabled, skipping delete of %s', $key), LOG_DEBUG, __FILE__, __LINE__); |
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| 284 | return false; |
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| 285 | } |
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| 286 | |
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[480] | 287 | if (isset($_SESSION['_cache'][$this->_ns]) && array_key_exists($key, $_SESSION['_cache'][$this->_ns])) { |
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[558] | 288 | $app->logMsg(sprintf('Deleting cache item â%sâ', $key), LOG_DEBUG, __FILE__, __LINE__); |
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[218] | 289 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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| 290 | return true; |
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| 291 | } else { |
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| 292 | return false; |
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| 293 | } |
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[1] | 294 | } |
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[468] | 295 | |
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[152] | 296 | /* |
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| 297 | * Delete all existing items from the cache. |
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| 298 | * |
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| 299 | * @access public |
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| 300 | * @author Quinn Comendant <quinn@strangecode.com> |
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| 301 | * @version 1.0 |
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| 302 | * @since 05 Jun 2006 23:51:34 |
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| 303 | */ |
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[468] | 304 | public function clear() |
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[152] | 305 | { |
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[611] | 306 | $app =& App::getInstance(); |
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| 307 | |
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[154] | 308 | $_SESSION['_cache'][$this->_ns] = array(); |
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[611] | 309 | $app->logMsg(sprintf('Cleared %s cache', $this->_ns), LOG_DEBUG, __FILE__, __LINE__); |
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[152] | 310 | } |
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[1] | 311 | |
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[136] | 312 | // END Cache |
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[1] | 313 | } |
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| 314 | |
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