APCu might not be available.
/dev/shm might be.
- Don't have APCu, but /dev/shm is writable
I wrote some code, which I am sharing now (https://gist.github.com/LionsAd/31043834e54ac53d8af168d32a2a238f):
<?php
namespace Drupal\Core\Cache;
use Drupal\Component\Assertion\Inspector;
/**
* Stores cache items in /dev/shm.
*/
class ShmBackend implements CacheBackendInterface {
/**
* The name of the cache bin to use.
*
* @var string
*/
protected $bin;
/**
* Prefix for all keys in the storage that belong to this site.
*
* @var string
*/
protected $sitePrefix;
/**
* Prefix for all keys in this cache bin.
*
* Includes the site-specific prefix in $sitePrefix.
*
* @var string
*/
protected $binPrefix;
/**
* The cache tags checksum provider.
*
* @var \Drupal\Core\Cache\CacheTagsChecksumInterface
*/
protected $checksumProvider;
/**
* Constructs a new ApcuBackend instance.
*
* @param string $bin
* The name of the cache bin.
* @param string $site_prefix
* The prefix to use for all keys in the storage that belong to this site.
* @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
* The cache tags checksum provider.
*/
public function __construct($bin, $site_prefix, CacheTagsChecksumInterface $checksum_provider) {
$this->bin = $bin;
$this->sitePrefix = $site_prefix;
$this->checksumProvider = $checksum_provider;
$this->binPrefix = '/dev/shm/' . $this->sitePrefix . '/' . $this->bin . '/';
@mkdir('/dev/shm/' . $this->sitePrefix);
@mkdir($this->binPrefix);
}
/**
* Prepends the APCu user variable prefix for this bin to a cache item ID.
*
* @param string $cid
* The cache item ID to prefix.
*
* @return string
* The APCu key for the cache item ID.
*/
public function getApcuKey($cid) {
return $this->binPrefix . str_replace('%3A', ':', rawurlencode($cid));
}
/**
* {@inheritdoc}
*/
public function get($cid, $allow_invalid = FALSE) {
$cids = [$cid];
$data = $this->getMultiple($cids, $allow_invalid);
return !empty($data[$cid]) ? $data[$cid] : FALSE;
}
/**
* {@inheritdoc}
*/
public function getMultiple(&$cids, $allow_invalid = FALSE) {
$start = microtime(TRUE);
$cids_copy = $cids;
$memory = memory_get_usage();
// Translate the requested cache item IDs to APCu keys.
$map = [];
foreach ($cids as $cid) {
$map[$this->getApcuKey($cid)] = $cid;
}
$result = $this->fetch(array_keys($map));
$cache = [];
if ($result) {
foreach ($result as $key => $item) {
$item = $this->prepareItem($item, $allow_invalid);
if ($item) {
$cache[$map[$key]] = $item;
}
}
}
unset($result);
$cids = array_diff($cids, array_keys($cache));
return $cache;
}
/**
* Prepares a cached item.
*
* Checks that the item is either permanent or did not expire.
*
* @param \stdClass $cache
* An item loaded from cache_get() or cache_get_multiple().
* @param bool $allow_invalid
* If TRUE, a cache item may be returned even if it is expired or has been
* invalidated. See ::get().
*
* @return mixed
* The cache item or FALSE if the item expired.
*/
protected function prepareItem($cache, $allow_invalid) {
if (!isset($cache->data)) {
return FALSE;
}
$cache->tags = $cache->tags ? explode(' ', $cache->tags) : [];
// Check expire time.
$cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
// Check if invalidateTags() has been called with any of the entry's tags.
if (!$this->checksumProvider->isValid($cache->checksum, $cache->tags)) {
$cache->valid = FALSE;
}
if (!$allow_invalid && !$cache->valid) {
return FALSE;
}
return $cache;
}
/**
* {@inheritdoc}
*/
public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = []) {
assert(Inspector::assertAllStrings($tags), 'Cache tags must be strings.');
$tags = array_unique($tags);
$cache = new \stdClass();
$cache->cid = $cid;
$cache->expire = $expire;
$cache->tags = implode(' ', $tags);
$cache->checksum = $this->checksumProvider->getCurrentChecksum($tags);
// APCu serializes/unserializes any structure itself.
$cache->serialized = 0;
$cache->data = $data;
$filename = $this->getApcuKey($cid);
$mtime_filename = $filename . '_mtime';
$old_data = file_get_contents($filename);
$data = serialize($cache);
if ($data !== $old_data) {
file_put_contents($filename, serialize($cache));
}
file_put_contents($mtime_filename, round(microtime(TRUE), 3));
}
/**
* {@inheritdoc}
*/
public function setMultiple(array $items = []) {
foreach ($items as $cid => $item) {
$this->set($cid, $item['data'], isset($item['expire']) ? $item['expire'] : CacheBackendInterface::CACHE_PERMANENT, isset($item['tags']) ? $item['tags'] : []);
}
}
/**
* {@inheritdoc}
*/
public function delete($cid) {
unlink($this->getApcuKey($cid));
}
/**
* {@inheritdoc}
*/
public function deleteMultiple(array $cids) {
foreach ($cids as $cid) {
$this->delete($cid);
}
}
/**
* {@inheritdoc}
*/
public function deleteAll() {
throw new \Exception('Unsupported');
// @todo Implement?
}
/**
* {@inheritdoc}
*/
public function garbageCollection() {
// APCu performs garbage collection automatically.
// @todo Add by removing files from directory.
}
/**
* {@inheritdoc}
*/
public function removeBin() {
throw new \Exception('Unsupported');
}
/**
* {@inheritdoc}
*/
public function invalidate($cid) {
$this->invalidateMultiple([$cid]);
}
/**
* {@inheritdoc}
*/
public function invalidateMultiple(array $cids) {
foreach ($this->getMultiple($cids) as $cache) {
$this->set($cache->cid, $cache, REQUEST_TIME - 1);
}
}
/**
* {@inheritdoc}
*/
public function invalidateAll() {
// Clear whole bin.
throw new \Exception('Unsupported');
}
protected function fetch($cids) {
$data = [];
foreach ($cids as $cid) {
$mtime_file = $cid . '_mtime';
if (file_exists($cid) && file_exists($mtime_file)) {
$data[$cid] = unserialize(file_get_contents($cid));
$data[$cid]->created = file_get_contents($mtime_file);
}
}
return $data;
}
}
- Make into a patch
- Discuss if we want to add this to core
- Add test coverage (?) - if GITLAB CI supports this
- Fix todos
- Remove all APCu related things
Active
11.0 🔥
Last updated
