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- <?php
- /**
- * @link http://www.yiiframework.com/
- * @copyright Copyright (c) 2008 Yii Software LLC
- * @license http://www.yiiframework.com/license/
- */
-
- namespace yii\caching;
-
- use Yii;
- use yii\base\InvalidConfigException;
- use yii\db\Connection;
- use yii\db\Query;
- use yii\di\Instance;
-
- /**
- * DbCache implements a cache application component by storing cached data in a database.
- *
- * By default, DbCache stores session data in a DB table named 'cache'. This table
- * must be pre-created. The table name can be changed by setting [[cacheTable]].
- *
- * Please refer to [[Cache]] for common cache operations that are supported by DbCache.
- *
- * The following example shows how you can configure the application to use DbCache:
- *
- * ```php
- * 'cache' => [
- * 'class' => 'yii\caching\DbCache',
- * // 'db' => 'mydb',
- * // 'cacheTable' => 'my_cache',
- * ]
- * ```
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @since 2.0
- */
- class DbCache extends Cache
- {
- /**
- * @var Connection|array|string the DB connection object or the application component ID of the DB connection.
- * After the DbCache object is created, if you want to change this property, you should only assign it
- * with a DB connection object.
- * Starting from version 2.0.2, this can also be a configuration array for creating the object.
- */
- public $db = 'db';
- /**
- * @var string name of the DB table to store cache content.
- * The table should be pre-created as follows:
- *
- * ```php
- * CREATE TABLE cache (
- * id char(128) NOT NULL PRIMARY KEY,
- * expire int(11),
- * data BLOB
- * );
- * ```
- *
- * where 'BLOB' refers to the BLOB-type of your preferred DBMS. Below are the BLOB type
- * that can be used for some popular DBMS:
- *
- * - MySQL: LONGBLOB
- * - PostgreSQL: BYTEA
- * - MSSQL: BLOB
- *
- * When using DbCache in a production server, we recommend you create a DB index for the 'expire'
- * column in the cache table to improve the performance.
- */
- public $cacheTable = '{{%cache}}';
- /**
- * @var integer the probability (parts per million) that garbage collection (GC) should be performed
- * when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
- * This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.
- */
- public $gcProbability = 100;
-
-
- /**
- * Initializes the DbCache component.
- * This method will initialize the [[db]] property to make sure it refers to a valid DB connection.
- * @throws InvalidConfigException if [[db]] is invalid.
- */
- public function init()
- {
- parent::init();
- $this->db = Instance::ensure($this->db, Connection::className());
- }
-
- /**
- * Checks whether a specified key exists in the cache.
- * This can be faster than getting the value from the cache if the data is big.
- * Note that this method does not check whether the dependency associated
- * with the cached data, if there is any, has changed. So a call to [[get]]
- * may return false while exists returns true.
- * @param mixed $key a key identifying the cached value. This can be a simple string or
- * a complex data structure consisting of factors representing the key.
- * @return boolean true if a value exists in cache, false if the value is not in the cache or expired.
- */
- public function exists($key)
- {
- $key = $this->buildKey($key);
-
- $query = new Query;
- $query->select(['COUNT(*)'])
- ->from($this->cacheTable)
- ->where('[[id]] = :id AND ([[expire]] = 0 OR [[expire]] >' . time() . ')', [':id' => $key]);
- if ($this->db->enableQueryCache) {
- // temporarily disable and re-enable query caching
- $this->db->enableQueryCache = false;
- $result = $query->createCommand($this->db)->queryScalar();
- $this->db->enableQueryCache = true;
- } else {
- $result = $query->createCommand($this->db)->queryScalar();
- }
-
- return $result > 0;
- }
-
- /**
- * Retrieves a value from cache with a specified key.
- * This is the implementation of the method declared in the parent class.
- * @param string $key a unique key identifying the cached value
- * @return string|boolean the value stored in cache, false if the value is not in the cache or expired.
- */
- protected function getValue($key)
- {
- $query = new Query;
- $query->select(['data'])
- ->from($this->cacheTable)
- ->where('[[id]] = :id AND ([[expire]] = 0 OR [[expire]] >' . time() . ')', [':id' => $key]);
- if ($this->db->enableQueryCache) {
- // temporarily disable and re-enable query caching
- $this->db->enableQueryCache = false;
- $result = $query->createCommand($this->db)->queryScalar();
- $this->db->enableQueryCache = true;
-
- return $result;
- } else {
- return $query->createCommand($this->db)->queryScalar();
- }
- }
-
- /**
- * Retrieves multiple values from cache with the specified keys.
- * @param array $keys a list of keys identifying the cached values
- * @return array a list of cached values indexed by the keys
- */
- protected function getValues($keys)
- {
- if (empty($keys)) {
- return [];
- }
- $query = new Query;
- $query->select(['id', 'data'])
- ->from($this->cacheTable)
- ->where(['id' => $keys])
- ->andWhere('([[expire]] = 0 OR [[expire]] > ' . time() . ')');
-
- if ($this->db->enableQueryCache) {
- $this->db->enableQueryCache = false;
- $rows = $query->createCommand($this->db)->queryAll();
- $this->db->enableQueryCache = true;
- } else {
- $rows = $query->createCommand($this->db)->queryAll();
- }
-
- $results = [];
- foreach ($keys as $key) {
- $results[$key] = false;
- }
- foreach ($rows as $row) {
- $results[$row['id']] = $row['data'];
- }
-
- return $results;
- }
-
- /**
- * Stores a value identified by a key in cache.
- * This is the implementation of the method declared in the parent class.
- *
- * @param string $key the key identifying the value to be cached
- * @param string $value the value to be cached
- * @param integer $duration the number of seconds in which the cached value will expire. 0 means never expire.
- * @return boolean true if the value is successfully stored into cache, false otherwise
- */
- protected function setValue($key, $value, $duration)
- {
- $command = $this->db->createCommand()
- ->update($this->cacheTable, [
- 'expire' => $duration > 0 ? $duration + time() : 0,
- 'data' => [$value, \PDO::PARAM_LOB],
- ], ['id' => $key]);
-
- if ($command->execute()) {
- $this->gc();
-
- return true;
- } else {
- return $this->addValue($key, $value, $duration);
- }
- }
-
- /**
- * Stores a value identified by a key into cache if the cache does not contain this key.
- * This is the implementation of the method declared in the parent class.
- *
- * @param string $key the key identifying the value to be cached
- * @param string $value the value to be cached
- * @param integer $duration the number of seconds in which the cached value will expire. 0 means never expire.
- * @return boolean true if the value is successfully stored into cache, false otherwise
- */
- protected function addValue($key, $value, $duration)
- {
- $this->gc();
-
- try {
- $this->db->createCommand()
- ->insert($this->cacheTable, [
- 'id' => $key,
- 'expire' => $duration > 0 ? $duration + time() : 0,
- 'data' => [$value, \PDO::PARAM_LOB],
- ])->execute();
-
- return true;
- } catch (\Exception $e) {
- return false;
- }
- }
-
- /**
- * Deletes a value with the specified key from cache
- * This is the implementation of the method declared in the parent class.
- * @param string $key the key of the value to be deleted
- * @return boolean if no error happens during deletion
- */
- protected function deleteValue($key)
- {
- $this->db->createCommand()
- ->delete($this->cacheTable, ['id' => $key])
- ->execute();
-
- return true;
- }
-
- /**
- * Removes the expired data values.
- * @param boolean $force whether to enforce the garbage collection regardless of [[gcProbability]].
- * Defaults to false, meaning the actual deletion happens with the probability as specified by [[gcProbability]].
- */
- public function gc($force = false)
- {
- if ($force || mt_rand(0, 1000000) < $this->gcProbability) {
- $this->db->createCommand()
- ->delete($this->cacheTable, '[[expire]] > 0 AND [[expire]] < ' . time())
- ->execute();
- }
- }
-
- /**
- * Deletes all values from cache.
- * This is the implementation of the method declared in the parent class.
- * @return boolean whether the flush operation was successful.
- */
- protected function flushValues()
- {
- $this->db->createCommand()
- ->delete($this->cacheTable)
- ->execute();
-
- return true;
- }
- }
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