cache_get
Definition
cache_get($cid, $table = 'cache')
drupal/includes/cache.inc, line 16
Description
Return data from the persistent cache. Data may be stored as either plain text or as serialized data. cache_get will automatically return unserialized objects and arrays.
Parameters
$cid The cache ID of the data to retrieve.
$table The table $table to store the data in. Valid core values are 'cache_filter', 'cache_menu', 'cache_page', or 'cache' for the default cache.
Return value
The cache or FALSE on failure.
Code
function cache_get($cid, $table = 'cache') {
global $user;
// Garbage collection necessary when enforcing a minimum cache lifetime
$cache_flush = variable_get('cache_flush', 0);
if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= REQUEST_TIME)) {
// Reset the variable immediately to prevent a meltdown in heavy load situations.
variable_set('cache_flush', 0);
// Time to flush old cache data
db_delete($table)
->condition('expire', CACHE_PERMANENT, '<>')
->condition('expire', $cache_flush, '<=')
->execute();
}
$cache = db_query("SELECT data, created, headers, expire, serialized FROM {" . $table . "} WHERE cid = :cid", array(':cid' => $cid))->fetchObject();
if (isset($cache->data)) {
// If the data is permanent or we're not enforcing a minimum cache lifetime
// always return the cached data.
if ($cache->expire == CACHE_PERMANENT || !variable_get('cache_lifetime', 0)) {
if ($cache->serialized) {
$cache->data = unserialize($cache->data);
}
}
// If enforcing a minimum cache lifetime, validate that the data is
// currently valid for this user before we return it by making sure the
// cache entry was created before the timestamp in the current session's
// cache timer. The cache variable is loaded into the $user object by
// _sess_read() in session.inc.
else {
if ($user->cache > $cache->created) {
// This cache data is too old and thus not valid for us, ignore it.
return FALSE;
}
else {
if ($cache->serialized) {
$cache->data = unserialize($cache->data);
}
}
}
return $cache;
}
return FALSE;
}