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[Cache] Handle arbitrary key length when the backend cant using hashing #20037

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Merged
merged 1 commit into from
Sep 24, 2016
Merged

[Cache] Handle arbitrary key length when the backend cant using hashing #20037

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20 changes: 18 additions & 2 deletions src/Symfony/Component/Cache/Adapter/AbstractAdapter.php
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
use Psr\Log\LoggerAwareTrait;
use Psr\Log\LoggerInterface;
use Symfony\Component\Cache\CacheItem;
use Symfony\Component\Cache\Exception\InvalidArgumentException;

/**
* @author Nicolas Grekas <p@tchwork.com>
Expand All @@ -32,9 +33,17 @@ abstract class AbstractAdapter implements AdapterInterface, LoggerAwareInterface
private $createCacheItem;
private $mergeByLifetime;

/**
* @var int|null The maximum length to enforce for identifiers or null when no limit applies
*/
protected $maxIdLength;

protected function __construct($namespace = '', $defaultLifetime = 0)
{
$this->namespace = '' === $namespace ? '' : $this->getId($namespace);
$this->namespace = '' === $namespace ? '' : $this->getId($namespace).':';
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: is a reserved char per psr6 so we use it internally to be free from any collision when concatenating keys and namespace later on

if (null !== $this->maxIdLength && strlen($namespace) > $this->maxIdLength - 24) {
throw new InvalidArgumentException(sprintf('Namespace must be %d chars max, %d given ("%s")', $this->maxIdLength - 24, strlen($namespace), $namespace));
}
$this->createCacheItem = \Closure::bind(
function ($key, $value, $isHit) use ($defaultLifetime) {
$item = new CacheItem();
Expand Down Expand Up @@ -401,7 +410,14 @@ private function getId($key)
{
CacheItem::validateKey($key);

return $this->namespace.$key;
if (null === $this->maxIdLength) {
return $this->namespace.$key;
}
if (strlen($id = $this->namespace.$key) > $this->maxIdLength) {
$id = $this->namespace.substr_replace(base64_encode(md5($key, true)), ':', -2);
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Namespace excluded, this is always 23 chars long, trailing padding = removed.

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The added trailing : is to prevent any collision between hashed keys and non-hasked keys.

}

return $id;
}

private function generateItems($items, &$keys)
Expand Down
4 changes: 2 additions & 2 deletions src/Symfony/Component/Cache/Adapter/ApcuAdapter.php
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Expand Up @@ -37,9 +37,9 @@ public function __construct($namespace = '', $defaultLifetime = 0, $version = nu
if (null !== $version) {
CacheItem::validateKey($version);

if (!apcu_exists($version.':'.$namespace)) {
if (!apcu_exists($version.'@'.$namespace)) {
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Just because : is a nice separator for namespace, thus had to change here. @ looks good also for version :)

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It's all about the looks ;)

$this->clear($namespace);
apcu_add($version.':'.$namespace, null);
apcu_add($version.'@'.$namespace, null);
}
}
}
Expand Down
56 changes: 56 additions & 0 deletions src/Symfony/Component/Cache/Tests/Adapter/MaxIdLengthAdapterTest.php
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@@ -0,0 +1,56 @@
<?php

/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/

namespace Symfony\Component\Cache\Tests\Adapter;

use Symfony\Component\Cache\Adapter\AbstractAdapter;

class MaxIdLengthAdapterTest extends \PHPUnit_Framework_TestCase
{
public function testLongKey()
{
$cache = $this->getMockBuilder(MaxIdLengthAdapter::class)
->setConstructorArgs(array(str_repeat('-', 10)))
->setMethods(array('doHave', 'doFetch', 'doDelete', 'doSave', 'doClear'))
->getMock();

$cache->expects($this->exactly(2))
->method('doHave')
->withConsecutive(
array($this->equalTo('----------:nWfzGiCgLczv3SSUzXL3kg:')),
array($this->equalTo('----------:---------------------------------------'))
);

$cache->hasItem(str_repeat('-', 40));
$cache->hasItem(str_repeat('-', 39));
}

/**
* @expectedException \Symfony\Component\Cache\Exception\InvalidArgumentException
* @expectedExceptionMessage Namespace must be 26 chars max, 40 given ("----------------------------------------")
*/
public function testTooLongNamespace()
{
$cache = $this->getMockBuilder(MaxIdLengthAdapter::class)
->setConstructorArgs(array(str_repeat('-', 40)))
->getMock();
}
}

abstract class MaxIdLengthAdapter extends AbstractAdapter
{
protected $maxIdLength = 50;

public function __construct($ns)
{
parent::__construct($ns);
}
}