Class yii\mongodb\Cache
Inheritance | yii\mongodb\Cache » yii\caching\Cache |
---|---|
Available since extension's version | 2.0 |
Source Code | https://github.com/yiisoft/yii2-mongodb/blob/master/src/Cache.php |
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:
'cache' => [
'class' => 'yii\mongodb\Cache',
// 'db' => 'mymongodb',
// 'cacheCollection' => 'my_cache',
]
Public Properties
Property | Type | Description | Defined By |
---|---|---|---|
$cacheCollection | string|array | The name of the MongoDB collection that stores the cache data. | yii\mongodb\Cache |
$db | yii\mongodb\Connection|array|string | The MongoDB connection object or the application component ID of the MongoDB connection. | yii\mongodb\Cache |
$gcProbability | integer | The probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. | yii\mongodb\Cache |
Public Methods
Method | Description | Defined By |
---|---|---|
gc() | Removes the expired data values. | yii\mongodb\Cache |
init() | Initializes the Cache component. | yii\mongodb\Cache |
Protected Methods
Method | Description | Defined By |
---|---|---|
addValue() | Stores a value identified by a key into cache if the cache does not contain this key. | yii\mongodb\Cache |
deleteValue() | 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. | yii\mongodb\Cache |
flushValues() | Deletes all values from cache. | yii\mongodb\Cache |
getValue() | Retrieves a value from cache with a specified key. | yii\mongodb\Cache |
setValue() | Stores a value identified by a key in cache. | yii\mongodb\Cache |
Property Details
The name of the MongoDB collection that stores the cache data. Please refer to yii\mongodb\Connection::getCollection() on how to specify this parameter. This collection is better to be pre-created with fields 'id' and 'expire' indexed.
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.
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.
Method Details
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.
protected boolean addValue ( $key, $value, $expire ) | ||
$key | string |
The key identifying the value to be cached |
$value | string |
The value to be cached |
$expire | integer |
The number of seconds in which the cached value will expire. 0 means never expire. |
return | boolean |
True if the value is successfully stored into cache, false otherwise |
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protected function addValue($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.
protected boolean deleteValue ( $key ) | ||
$key | string |
The key of the value to be deleted |
return | boolean |
If no error happens during deletion |
---|
protected function deleteValue($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.
protected boolean flushValues ( ) | ||
return | boolean |
Whether the flush operation was successful. |
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protected function flushValues()
{
$this->db->getCollection($this->cacheCollection)->remove();
return true;
}
Removes the expired data values.
public void gc ( $force = false ) | ||
$force | boolean |
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 || random_int(0, 1000000) < $this->gcProbability) {
$this->db->getCollection($this->cacheCollection)
->remove([
'expire' => [
'$gt' => 0,
'$lt' => time(),
]
]);
}
}
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.
protected string|boolean getValue ( $key ) | ||
$key | string |
A unique key identifying the cached value |
return | string|boolean |
The value stored in cache, false if the value is not in the cache or expired. |
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protected function getValue($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'];
}
Initializes the Cache component.
This method will initialize the $db property to make sure it refers to a valid MongoDB connection.
public void init ( ) | ||
throws | \yii\base\InvalidConfigException |
if $db is invalid. |
---|
public function init()
{
parent::init();
$this->db = Instance::ensure($this->db, Connection::className());
}
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.
protected boolean setValue ( $key, $value, $expire ) | ||
$key | string |
The key identifying the value to be cached |
$value | string |
The value to be cached |
$expire | integer |
The number of seconds in which the cached value will expire. 0 means never expire. |
return | boolean |
True if the value is successfully stored into cache, false otherwise |
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protected function setValue($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);
}