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vendor/yiisoft/yii2-mongodb/src/Cache.php

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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\mongodb;
+
+use Yii;
+use yii\base\InvalidConfigException;
+use yii\di\Instance;
+
+/**
+ * Cache implements a cache application component by storing cached data in a MongoDB.
+ *
+ * By default, Cache stores session data in a MongoDB collection named 'cache' inside the default database.
+ * This collection is better to be pre-created with fields 'id' and 'expire' indexed.
+ * The collection name can be changed by setting [[cacheCollection]].
+ *
+ * Please refer to [[\yii\caching\Cache]] for common cache operations that are supported by Cache.
+ *
+ * The following example shows how you can configure the application to use Cache:
+ *
+ * ```php
+ * 'cache' => [
+ *     'class' => 'yii\mongodb\Cache',
+ *     // 'db' => 'mymongodb',
+ *     // 'cacheCollection' => 'my_cache',
+ * ]
+ * ```
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class Cache extends \yii\caching\Cache
+{
+    /**
+     * @var Connection|array|string the MongoDB connection object or the application component ID of the MongoDB connection.
+     * After the Cache object is created, if you want to change this property, you should only assign it
+     * with a MongoDB connection object.
+     * Starting from version 2.0.2, this can also be a configuration array for creating the object.
+     */
+    public $db = 'mongodb';
+    /**
+     * @var string|array the name of the MongoDB collection that stores the cache data.
+     * Please refer to [[Connection::getCollection()]] on how to specify this parameter.
+     * This collection is better to be pre-created with fields 'id' and 'expire' indexed.
+     */
+    public $cacheCollection = 'cache';
+    /**
+     * @var int 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 Cache component.
+     * This method will initialize the [[db]] property to make sure it refers to a valid MongoDB connection.
+     * @throws InvalidConfigException if [[db]] is invalid.
+     */
+    public function init()
+    {
+        parent::init();
+        $this->db = Instance::ensure($this->db, Connection::className());
+    }
+
+    /**
+     * Retrieves a value from cache with a specified key.
+     * This method should be implemented by child classes to retrieve the data
+     * from specific cache storage.
+     * @param string $key a unique key identifying the cached value
+     * @return string|bool the value stored in cache, false if the value is not in the cache or expired.
+     */
+    protected function getValue($key)
+    {
+        $query = new Query;
+        $row = $query->select(['data'])
+            ->from($this->cacheCollection)
+            ->where([
+                'id' => $key,
+                '$or' => [
+                    [
+                        'expire' => 0
+                    ],
+                    [
+                        'expire' => ['$gt' => time()]
+                    ],
+                ],
+            ])
+            ->one($this->db);
+
+        if (empty($row)) {
+            return false;
+        }
+        return $row['data'];
+    }
+
+    /**
+     * Stores a value identified by a key in cache.
+     * This method should be implemented by child classes to store the data
+     * in specific cache storage.
+     * @param string $key the key identifying the value to be cached
+     * @param string $value the value to be cached
+     * @param int $expire the number of seconds in which the cached value will expire. 0 means never expire.
+     * @return bool true if the value is successfully stored into cache, false otherwise
+     */
+    protected function setValue($key, $value, $expire)
+    {
+        $result = $this->db->getCollection($this->cacheCollection)
+            ->update(['id' => $key], [
+                'expire' => $expire > 0 ? $expire + time() : 0,
+                'data' => $value,
+            ]);
+
+        if ($result) {
+            $this->gc();
+            return true;
+        }
+        return $this->addValue($key, $value, $expire);
+    }
+
+    /**
+     * Stores a value identified by a key into cache if the cache does not contain this key.
+     * This method should be implemented by child classes to store the data
+     * in specific cache storage.
+     * @param string $key the key identifying the value to be cached
+     * @param string $value the value to be cached
+     * @param int $expire the number of seconds in which the cached value will expire. 0 means never expire.
+     * @return bool true if the value is successfully stored into cache, false otherwise
+     */
+    protected function addValue($key, $value, $expire)
+    {
+        $this->gc();
+
+        if ($expire > 0) {
+            $expire += time();
+        } else {
+            $expire = 0;
+        }
+
+        try {
+            $this->db->getCollection($this->cacheCollection)
+                ->insert([
+                    'id' => $key,
+                    'expire' => $expire,
+                    'data' => $value,
+                ]);
+
+            return true;
+        } catch (\Exception $e) {
+            return false;
+        }
+    }
+
+    /**
+     * Deletes a value with the specified key from cache
+     * This method should be implemented by child classes to delete the data from actual cache storage.
+     * @param string $key the key of the value to be deleted
+     * @return bool if no error happens during deletion
+     */
+    protected function deleteValue($key)
+    {
+        $this->db->getCollection($this->cacheCollection)->remove(['id' => $key]);
+        return true;
+    }
+
+    /**
+     * Deletes all values from cache.
+     * Child classes may implement this method to realize the flush operation.
+     * @return bool whether the flush operation was successful.
+     */
+    protected function flushValues()
+    {
+        $this->db->getCollection($this->cacheCollection)->remove();
+        return true;
+    }
+
+    /**
+     * Removes the expired data values.
+     * @param bool $force whether to enforce the garbage collection regardless of [[gcProbability]].
+     * Defaults to false, meaning the actual deletion happens with the probability as specified by [[gcProbability]].
+     */
+    public function gc($force = false)
+    {
+        if ($force || mt_rand(0, 1000000) < $this->gcProbability) {
+            $this->db->getCollection($this->cacheCollection)
+                ->remove([
+                    'expire' => [
+                        '$gt' => 0,
+                        '$lt' => time(),
+                    ]
+                ]);
+        }
+    }
+}