Memcached::get

(PECL memcached >= 0.1.0)

Memcached::get — Retrieve an item

Descrizione

public Memcached::get(string $key, ?callable $cache_cb = null, int $get_flags = 0): mixed

Memcached::get() returns the item that was previously stored under the key. If the item is found and the get_flags is given Memcached::GET_EXTENDED, it will also return 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.

Elenco dei parametri

key: The key of the item to retrieve.
cache_cb: Read-through caching callback or null.
get_flags: Flags to control the returned result. When Memcached::GET_EXTENDED is given, the function will also return the CAS token.

Valori restituiti

Returns the value stored in the cache or false otherwise. If the get_flags is set to Memcached::GET_EXTENDED, an array containing the value and the CAS token is returned instead of only the value. The Memcached::getResultCode() will return Memcached::RES_NOTFOUND if the key does not exist.

Log delle modifiche

Versione	Descrizione
PECL memcached 3.0.0	The `&cas_token` parameter was removed. Instead `get_flags` was added and when it is given the value of `Memcached::GET_EXTENDED` it will ensure the CAS token to be fetched.

Esempi

Example #1 Memcached::get() example #1

<?php
$m = new Memcached();
$m->addServer('localhost', 11211);

$m->set('foo', 100);
var_dump($m->get('foo'));
?>

Il precedente esempio visualizzerà:

int(100)

Example #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 */
        /* ...       */
    }
}
?>

Vedere anche:

Memcached::getByKey() - Retrieve an item from a specific server
Memcached::getMulti() - Retrieve multiple items
Memcached::getDelayed() - Request multiple items

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User Contributed Notes 3 notes

down

letynsoft at gmail dot com ¶

7 years ago

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The $cas_token is no longer valid argument.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;
}
?>

down

miha at hribar dot info ¶

15 years ago

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 :)

down

-2

denis_truffaut[A-T]hotmail[D-O-T]com ¶

13 years ago

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 :)

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