Memcached::get
(PECL memcached >= 0.1.0)
Memcached::get — Retrieve an item
Описание
Memcached::get() returns the item that was previously
stored under the key. If the item is found and
cas_token variable is provided, it will contain the
CAS token value for the item. See
Memcached::cas() for how to use CAS tokens. Read-through caching callback may be
specified via cache_cb parameter.
Список параметров
-
key -
The key of the item to retrieve.
-
cache_cb -
Read-through caching callback or
NULL. -
cas_token -
The variable to store the CAS token in.
Возвращаемые значения
Returns the value stored in the cache or FALSE otherwise.
The Memcached::getResultCode() will return
Memcached::RES_NOTFOUND if the key does not exist.
Примеры
Пример #1 Memcached::get() example #1
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$m->set('foo', 100);
var_dump($m->get('foo'));
?>
Результат выполнения данного примера:
int(100)
Пример #2 Memcached::get() example #2
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
if (!($ip = $m->get('ip_block'))) {
if ($m->getResultCode() == Memcached::RES_NOTFOUND) {
$ip = array();
$m->set('ip_block', $ip);
} else {
/* log error */
/* ... */
}
}
?>
Смотрите также
- Memcached::getByKey() - Retrieve an item from a specific server
- Memcached::getMulti() - Retrieve multiple items
- Memcached::getDelayed() - Request multiple items
- Функция Memcached::add() - Add an item under a new key
- Функция Memcached::addByKey() - Add an item under a new key on a specific server
- Функция Memcached::addServer() - Add a server to the server pool
- Функция Memcached::addServers() - Add multiple servers to the server pool
- Функция Memcached::append() - Append data to an existing item
- Функция Memcached::appendByKey() - Append data to an existing item on a specific server
- Функция Memcached::cas() - Compare and swap an item
- Функция Memcached::casByKey() - Compare and swap an item on a specific server
- Функция Memcached::__construct() - Create a Memcached instance
- Функция Memcached::decrement() - Decrement numeric item's value
- Функция Memcached::decrementByKey() - Decrement numeric item's value, stored on a specific server
- Функция Memcached::delete() - Delete an item
- Функция Memcached::deleteByKey() - Delete an item from a specific server
- Функция Memcached::deleteMulti() - Delete multiple items
- Функция Memcached::deleteMultiByKey() - Delete multiple items from a specific server
- Функция Memcached::fetch() - Fetch the next result
- Функция Memcached::fetchAll() - Fetch all the remaining results
- Функция Memcached::flush() - Invalidate all items in the cache
- Функция Memcached::get() - Retrieve an item
- Функция Memcached::getAllKeys() - Gets the keys stored on all the servers
- Функция Memcached::getByKey() - Retrieve an item from a specific server
- Функция Memcached::getDelayed() - Request multiple items
- Функция Memcached::getDelayedByKey() - Request multiple items from a specific server
- Функция Memcached::getMulti() - Retrieve multiple items
- Функция Memcached::getMultiByKey() - Retrieve multiple items from a specific server
- Функция Memcached::getOption() - Retrieve a Memcached option value
- Функция Memcached::getResultCode() - Return the result code of the last operation
- Функция Memcached::getResultMessage() - Return the message describing the result of the last operation
- Функция Memcached::getServerByKey() - Map a key to a server
- Функция Memcached::getServerList() - Get the list of the servers in the pool
- Функция Memcached::getStats() - Get server pool statistics
- Функция Memcached::getVersion() - Get server pool version info
- Функция Memcached::increment() - Increment numeric item's value
- Функция Memcached::incrementByKey() - Increment numeric item's value, stored on a specific server
- Функция Memcached::isPersistent() - Check if a persitent connection to memcache is being used
- Функция Memcached::isPristine() - Check if the instance was recently created
- Функция Memcached::prepend() - Prepend data to an existing item
- Функция Memcached::prependByKey() - Prepend data to an existing item on a specific server
- Функция Memcached::quit() - Close any open connections
- Функция Memcached::replace() - Replace the item under an existing key
- Функция Memcached::replaceByKey() - Replace the item under an existing key on a specific server
- Функция Memcached::resetServerList() - Clears all servers from the server list
- Функция Memcached::set() - Store an item
- Функция Memcached::setByKey() - Store an item on a specific server
- Функция Memcached::setMulti() - Store multiple items
- Функция Memcached::setMultiByKey() - Store multiple items on a specific server
- Функция Memcached::setOption() - Set a Memcached option
- Функция Memcached::setOptions() - Set Memcached options
- Функция Memcached::setSaslAuthData() - Set the credentials to use for authentication
- Функция Memcached::touch() - Set a new expiration on an item
- Функция Memcached::touchByKey() - Set a new expiration on an item on a specific server
Коментарии
This method also returns false in case you set the value to false, so in order to have a proper fault mechanism in place you need to check the result code to be certain that a key really does not exist in memcached.
<?php
$Memcached = new Memcached();
$Memcached->addServer('localhost', 11211);
$Memcached->set('key', false);
var_dump($Memcached->get('key')); // boolean false
var_dump($Memcached->getResultCode()); // int 0 which is Memcached::RES_SUCCESS
?>
Or just make sure the values are not false :)
Note that this function can return NULL as FALSE, so don't make checks with === FALSE as with the old Memcache class, because it won't work. :O
Use the not (!) operator and check the result code with getResultCode() as mentioned in the documentation :)
As of some version of php7 (i was not able to determine which exactly).
The $cas_token is no longer valid argument. It has been removed in favor of flags argument, as it appears to be causing issues when subclassing the Memcached class.
See https://github.com/php-memcached-dev/php-memcached/pull/214 for more details.
Basically you need to
<?php
function memcacheGet($key, $cb = null, &$cas = null) {
$m = memcacheGetObject();
if(empty($m))
return false;
if(defined('Memcached::GET_EXTENDED')) {
//Incompatible change in php7, took me 2 hours to figure this out, grrr
$_o = $m->get($key, $cb, Memcached::GET_EXTENDED);
$o = $_o['value'];
$cas = $_o['cas'];
} else {
$o = $m->get($key, $cb, $cas);
}
return $o;
}
?>