cache_get

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• Drupal 4.7
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Definition

cache_get($key, $table = 'cache')
includes/cache.inc, line 12

Description

Return data from the persistent cache.

Parameters

$key 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.

Code

<?php
function cache_get($key, $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) <= 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_query("DELETE FROM {". $table ."} WHERE expire != %d AND expire <= %d", CACHE_PERMANENT, $cache_flush);
  }

  $cache = db_fetch_object(db_query("SELECT data, created, headers, expire FROM {". $table ."} WHERE cid = '%s'", $key));
  if (isset($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)) {
      $cache->data = db_decode_blob($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 0;
      }
      else {
        $cache->data = db_decode_blob($cache->data);
      }
    }
    return $cache;
  }
  return 0;
}
?>