<?php
/**
+-----------------------------------------------------------------------+
| This file is part of the Roundcube Webmail client |
| |
| Copyright (C) The Roundcube Dev Team |
| Copyright (C) Kolab Systems AG |
| |
| Licensed under the GNU General Public License version 3 or |
| any later version with exceptions for skins & plugins. |
| See the README file for a full license statement. |
| |
| PURPOSE: |
| Caching engine - SQL DB |
+-----------------------------------------------------------------------+
| Author: Thomas Bruederli <roundcube@gmail.com> |
| Author: Aleksander Machniak <alec@alec.pl> |
+-----------------------------------------------------------------------+
*/
/**
* Interface class for accessing SQL Database cache
*
* @package Framework
* @subpackage Cache
*/
class rcube_cache_db extends rcube_cache
{
/**
* Instance of database handler
*
* @var rcube_db
*/
protected $db;
/**
* (Escaped) Cache table name (cache or cache_shared)
*
* @var string
*/
protected $table;
/**
* Object constructor.
*
* @param int $userid User identifier
* @param string $prefix Key name prefix
* @param string $ttl Expiration time of memcache/apc items
* @param bool $packed Enables/disabled data serialization.
* It's possible to disable data serialization if you're sure
* stored data will be always a safe string
*/
public function __construct($userid, $prefix = '', $ttl = 0, $packed = true)
{
parent::__construct($userid, $prefix, $ttl, $packed);
$rcube = rcube::get_instance();
$this->type = 'db';
$this->db = $rcube->get_dbh();
$this->table = $this->db->table_name($userid ? 'cache' : 'cache_shared', true);
}
/**
* Remove cache records older than ttl
*/
public function expunge()
{
if ($this->db && $this->ttl) {
$this->db->query(
"DELETE FROM {$this->table} WHERE "
. ($this->userid ? "`user_id` = {$this->userid} AND " : "")
. "`cache_key` LIKE ?"
. " AND `expires` < " . $this->db->now(),
$this->prefix . '.%');
}
}
/**
* Remove expired records of all caches
*/
public static function gc()
{
$rcube = rcube::get_instance();
$db = $rcube->get_dbh();
$db->query("DELETE FROM " . $db->table_name('cache', true) . " WHERE `expires` < " . $db->now());
$db->query("DELETE FROM " . $db->table_name('cache_shared', true) . " WHERE `expires` < " . $db->now());
}
/**
* Reads cache entry.
*
* @param string $key Cache key name
* @param boolean $nostore Enable to skip in-memory store
*
* @return mixed Cached value
*/
protected function read_record($key, $nostore=false)
{
if (!$this->db) {
return;
}
$sql_result = $this->db->query(
"SELECT `data`, `cache_key` FROM {$this->table} WHERE "
. ($this->userid ? "`user_id` = {$this->userid} AND " : "")
."`cache_key` = ?",
$this->prefix . '.' . $key);
if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
if (strlen($sql_arr['data']) > 0) {
$md5sum = md5($sql_arr['data']);
$data = $this->unserialize($sql_arr['data']);
}
$this->db->reset();
if ($nostore) {
return $data;
}
$this->cache[$key] = $data;
$this->cache_sums[$key] = $md5sum;
}
else {
$this->cache[$key] = null;
}
return $this->cache[$key];
}
/**
* Writes single cache record into DB.
*
* @param string $key Cache key name
* @param mixed $data Serialized cache data
*
* @param boolean True on success, False on failure
*/
protected function write_record($key, $data)
{
if (!$this->db) {
return false;
}
// don't attempt to write too big data sets
if (strlen($data) > $this->max_packet_size()) {
trigger_error("rcube_cache: max_packet_size ($this->max_packet) exceeded for key $key. Tried to write " . strlen($data) . " bytes", E_USER_WARNING);
return false;
}
$db_key = $this->prefix . '.' . $key;
// Remove NULL rows (here we don't need to check if the record exist)
if ($data == 'N;') {
$result = $this->db->query(
"DELETE FROM {$this->table} WHERE "
. ($this->userid ? "`user_id` = {$this->userid} AND " : "")
."`cache_key` = ?",
$db_key);
return !$this->db->is_error($result);
}
$key_exists = array_key_exists($key, $this->cache_sums);
$expires = $this->ttl ? $this->db->now($this->ttl) : 'NULL';
if (!$key_exists) {
// Try INSERT temporarily ignoring "duplicate key" errors
$this->db->set_option('ignore_key_errors', true);
if ($this->userid) {
$result = $this->db->query(
"INSERT INTO {$this->table} (`expires`, `user_id`, `cache_key`, `data`)"
. " VALUES ($expires, ?, ?, ?)",
$this->userid, $db_key, $data);
}
else {
$result = $this->db->query(
"INSERT INTO {$this->table} (`expires`, `cache_key`, `data`)"
. " VALUES ($expires, ?, ?)",
$db_key, $data);
}
$this->db->set_option('ignore_key_errors', false);
}
// otherwise try UPDATE
if (!isset($result) || !($count = $this->db->affected_rows($result))) {
$result = $this->db->query(
"UPDATE {$this->table} SET `expires` = $expires, `data` = ? WHERE "
. ($this->userid ? "`user_id` = {$this->userid} AND " : "")
. "`cache_key` = ?",
$data, $db_key);
$count = $this->db->affected_rows($result);
}
return $count > 0;
}
/**
* Deletes the cache record(s).
*
* @param string $key Cache key name or pattern
* @param boolean $prefix_mode Enable it to clear all keys starting
* with prefix specified in $key
*/
protected function remove_record($key = null, $prefix_mode = false)
{
if (!$this->db) {
return;
}
// Remove all keys (in specified cache)
if ($key === null) {
$where = "`cache_key` LIKE " . $this->db->quote($this->prefix . '.%');
}
// Remove keys by name prefix
else if ($prefix_mode) {
$where = "`cache_key` LIKE " . $this->db->quote($this->prefix . '.' . $key . '%');
}
// Remove one key by name
else {
$where = "`cache_key` = " . $this->db->quote($this->prefix . '.' . $key);
}
$this->db->query(
"DELETE FROM {$this->table} WHERE "
. ($this->userid ? "`user_id` = {$this->userid} AND " : "") . $where
);
}
/**
* Serializes data for storing
*/
protected function serialize($data)
{
return $this->db ? $this->db->encode($data, $this->packed) : false;
}
/**
* Unserializes serialized data
*/
protected function unserialize($data)
{
return $this->db ? $this->db->decode($data, $this->packed) : false;
}
/**
* Determine the maximum size for cache data to be written
*/
protected function max_packet_size()
{
if ($this->max_packet < 0) {
$this->max_packet = 2097152; // default/max is 2 MB
if ($value = $this->db->get_variable('max_allowed_packet', $this->max_packet)) {
$this->max_packet = $value;
}
$this->max_packet -= 2000;
}
return $this->max_packet;
}
}
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