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MemcachedBagOStuff.php
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MemcachedBagOStuff.php
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<?php
/**
* @license GPL-2.0-or-later
* @file
*/
namespace Wikimedia\ObjectCache;
use Exception;
use InvalidArgumentException;
use RuntimeException;
/**
* Store data in a memcached server or memcached cluster.
*
* This is a base class for MemcachedPhpBagOStuff and MemcachedPeclBagOStuff.
*
* @ingroup Cache
*/
abstract class MemcachedBagOStuff extends MediumSpecificBagOStuff {
/** @var string Routing prefix appended to keys during operations */
protected $routingPrefix;
/**
* @param array $params Additional parameters include:
* - routingPrefix: a routing prefix of the form "<datacenter>/<cluster>/" used to convey
* the location/strategy to use for handling keys accessed from this instance. The prefix
* is prepended to keys during cache operations. The memcached proxy must preserve these
* prefixes in any responses that include requested keys (e.g. get/gets). The proxy is
* also assumed to strip the routing prefix from the stored key name, which allows for
* unprefixed access. This can be used with mcrouter. [optional]
*/
public function __construct( array $params ) {
$params['segmentationSize'] ??= 917_504; // < 1MiB
parent::__construct( $params );
$this->routingPrefix = $params['routingPrefix'] ?? '';
// ...and does not use special disk-cache plugins
$this->attrMap[self::ATTR_DURABILITY] = self::QOS_DURABILITY_SERVICE;
}
/**
* Format a cache key.
*
* @since 1.27
* @see BagOStuff::makeKeyInternal
*
* @param string $keyspace
* @param string[]|int[]|null $components
*
* @return string
*/
protected function makeKeyInternal( $keyspace, $components ) {
$key = $keyspace;
foreach ( $components as $component ) {
$component = strtr( $component ?? '', ' ', '_' );
// Make sure %, #, and non-ASCII chars are escaped
$component = preg_replace_callback(
'/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
static function ( $m ) {
return rawurlencode( $m[0] );
},
$component
);
$key .= ':' . $component;
}
// Memcached keys have a maximum length of 250 characters.
// * Reserve 45 chars for prefixes used by wrappers like WANObjectCache.
return $this->makeFallbackKey( $key, 205 );
}
protected function requireConvertGenericKey(): bool {
return true;
}
/**
* Ensure that a key is safe to use (contains no control characters and no
* characters above the ASCII range.)
*
* @param string $key
*
* @return string
* @throws Exception
*/
public function validateKeyEncoding( $key ) {
if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
throw new InvalidArgumentException( "Key contains invalid characters: $key" );
}
return $key;
}
/**
* @param string $key
*
* @return string
*/
protected function validateKeyAndPrependRoute( $key ) {
$this->validateKeyEncoding( $key );
if ( $this->routingPrefix === '' ) {
return $key;
}
if ( $key[0] === '/' ) {
throw new RuntimeException( "Key '$key' already contains a route." );
}
return $this->routingPrefix . $key;
}
/**
* @param string $key
*
* @return string
*/
protected function stripRouteFromKey( $key ) {
if ( $this->routingPrefix === '' ) {
return $key;
}
if ( str_starts_with( $key, $this->routingPrefix ) ) {
return substr( $key, strlen( $this->routingPrefix ) );
}
return $key;
}
/**
* @param int|float $exptime
*
* @return int
*/
protected function fixExpiry( $exptime ) {
if ( $exptime < 0 ) {
// The PECL driver does not seem to like negative relative values
$expiresAt = $this->getCurrentTime() + $exptime;
} elseif ( $this->isRelativeExpiration( $exptime ) ) {
// TTLs higher than 30 days will be detected as absolute TTLs
// (UNIX timestamps), and will result in the cache entry being
// discarded immediately because the expiry is in the past.
// Clamp expires >30d at 30d, unless they're >=1e9 in which
// case they are likely to really be absolute (1e9 = 2011-09-09)
$expiresAt = min( $exptime, self::TTL_MONTH );
} else {
$expiresAt = $exptime;
}
return (int)$expiresAt;
}
/** @inheritDoc */
protected function doIncrWithInit( $key, $exptime, $step, $init, $flags ) {
if ( $flags & self::WRITE_BACKGROUND ) {
return $this->doIncrWithInitAsync( $key, $exptime, $step, $init );
} else {
return $this->doIncrWithInitSync( $key, $exptime, $step, $init );
}
}
/**
* @param string $key
* @param int $exptime
* @param int $step
* @param int $init
*
* @return bool True on success, false on failure
*/
abstract protected function doIncrWithInitAsync( $key, $exptime, $step, $init );
/**
* @param string $key
* @param int $exptime
* @param int $step
* @param int $init
*
* @return int|bool New value or false on failure
*/
abstract protected function doIncrWithInitSync( $key, $exptime, $step, $init );
}
/** @deprecated class alias since 1.43 */
class_alias( MemcachedBagOStuff::class, 'MemcachedBagOStuff' );

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text/x-php
Expires
Wed, Aug 19, 02:25 (2 w, 2 d ago)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
54/e5/0a2ca0ceda65eec9913627681007
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MemcachedBagOStuff.php (4 KB)

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