Viewing file:  ReplicationStrategy.php (8.12 KB) -rw-r--r--
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<?php
/*
* This file is part of the Predis package.
*
* (c) 2009-2020 Daniele Alessandri
* (c) 2021-2025 Till Krüss
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Predis\Replication;
use Predis\Command\CommandInterface;
use Predis\NotSupportedException;
/**
* Defines a strategy for master/slave replication.
*/
class ReplicationStrategy
{
protected $disallowed;
protected $readonly;
protected $readonlySHA1;
protected $loadBalancing = true;
public function __construct()
{
$this->disallowed = $this->getDisallowedOperations();
$this->readonly = $this->getReadOnlyOperations();
$this->readonlySHA1 = [];
}
/**
* Returns if the specified command will perform a read-only operation
* on Redis or not.
*
* @param CommandInterface $command Command instance.
*
* @return bool
* @throws NotSupportedException
*/
public function isReadOperation(CommandInterface $command)
{
if (!$this->loadBalancing) {
return false;
}
if (isset($this->disallowed[$id = $command->getId()])) {
throw new NotSupportedException(
"The command '$id' is not allowed in replication mode."
);
}
if (isset($this->readonly[$id])) {
if (true === $readonly = $this->readonly[$id]) {
return true;
}
return call_user_func($readonly, $command);
}
if (($eval = $id === 'EVAL') || $id === 'EVALSHA') {
$argument = $command->getArgument(0);
$sha1 = $eval ? sha1(strval($argument)) : $argument;
if (isset($this->readonlySHA1[$sha1])) {
if (true === $readonly = $this->readonlySHA1[$sha1]) {
return true;
}
return call_user_func($readonly, $command);
}
}
return false;
}
/**
* Returns if the specified command is not allowed for execution in a master
* / slave replication context.
*
* @param CommandInterface $command Command instance.
*
* @return bool
*/
public function isDisallowedOperation(CommandInterface $command)
{
return isset($this->disallowed[$command->getId()]);
}
/**
* Checks if BITFIELD performs a read-only operation by looking for certain
* SET and INCRYBY modifiers in the arguments array of the command.
*
* @param CommandInterface $command Command instance.
*
* @return bool
*/
protected function isBitfieldReadOnly(CommandInterface $command)
{
$arguments = $command->getArguments();
$argc = count($arguments);
if ($argc >= 2) {
for ($i = 1; $i < $argc; ++$i) {
$argument = strtoupper($arguments[$i]);
if ($argument === 'SET' || $argument === 'INCRBY') {
return false;
}
}
}
return true;
}
/**
* Checks if a GEORADIUS command is a readable operation by parsing the
* arguments array of the specified command instance.
*
* @param CommandInterface $command Command instance.
*
* @return bool
*/
protected function isGeoradiusReadOnly(CommandInterface $command)
{
$arguments = $command->getArguments();
$argc = count($arguments);
$startIndex = $command->getId() === 'GEORADIUS' ? 5 : 4;
if ($argc > $startIndex) {
for ($i = $startIndex; $i < $argc; ++$i) {
$argument = strtoupper($arguments[$i]);
if ($argument === 'STORE' || $argument === 'STOREDIST') {
return false;
}
}
}
return true;
}
/**
* Marks a command as a read-only operation.
*
* When the behavior of a command can be decided only at runtime depending
* on its arguments, a callable object can be provided to dynamically check
* if the specified command performs a read or a write operation.
*
* @param string $commandID Command ID.
* @param mixed $readonly A boolean value or a callable object.
*/
public function setCommandReadOnly($commandID, $readonly = true)
{
$commandID = strtoupper($commandID);
if ($readonly) {
$this->readonly[$commandID] = $readonly;
} else {
unset($this->readonly[$commandID]);
}
}
/**
* Marks a Lua script for EVAL and EVALSHA as a read-only operation. When
* the behaviour of a script can be decided only at runtime depending on
* its arguments, a callable object can be provided to dynamically check
* if the passed instance of EVAL or EVALSHA performs write operations or
* not.
*
* @param string $script Body of the Lua script.
* @param mixed $readonly A boolean value or a callable object.
*/
public function setScriptReadOnly($script, $readonly = true)
{
$sha1 = sha1($script);
if ($readonly) {
$this->readonlySHA1[$sha1] = $readonly;
} else {
unset($this->readonlySHA1[$sha1]);
}
}
/**
* Returns the default list of disallowed commands.
*
* @return array
*/
protected function getDisallowedOperations()
{
return [
'SHUTDOWN' => true,
'INFO' => true,
'DBSIZE' => true,
'LASTSAVE' => true,
'CONFIG' => true,
'MONITOR' => true,
'SLAVEOF' => true,
'SAVE' => true,
'BGSAVE' => true,
'BGREWRITEAOF' => true,
'SLOWLOG' => true,
];
}
/**
* Returns the default list of commands performing read-only operations.
*
* @return array
*/
protected function getReadOnlyOperations()
{
return [
'EXISTS' => true,
'TYPE' => true,
'KEYS' => true,
'SCAN' => true,
'RANDOMKEY' => true,
'TTL' => true,
'GET' => true,
'MGET' => true,
'SUBSTR' => true,
'STRLEN' => true,
'GETRANGE' => true,
'GETBIT' => true,
'LLEN' => true,
'LRANGE' => true,
'LINDEX' => true,
'SCARD' => true,
'SISMEMBER' => true,
'SINTER' => true,
'SUNION' => true,
'SDIFF' => true,
'SMEMBERS' => true,
'SSCAN' => true,
'SRANDMEMBER' => true,
'ZRANGE' => true,
'ZREVRANGE' => true,
'ZRANGEBYSCORE' => true,
'ZREVRANGEBYSCORE' => true,
'ZCARD' => true,
'ZSCORE' => true,
'ZCOUNT' => true,
'ZRANK' => true,
'ZREVRANK' => true,
'ZSCAN' => true,
'ZLEXCOUNT' => true,
'ZRANGEBYLEX' => true,
'ZREVRANGEBYLEX' => true,
'HGET' => true,
'HMGET' => true,
'HEXISTS' => true,
'HLEN' => true,
'HKEYS' => true,
'HVALS' => true,
'HGETALL' => true,
'HSCAN' => true,
'HSTRLEN' => true,
'PING' => true,
'AUTH' => true,
'SELECT' => true,
'ECHO' => true,
'QUIT' => true,
'OBJECT' => true,
'BITCOUNT' => true,
'BITPOS' => true,
'TIME' => true,
'PFCOUNT' => true,
'BITFIELD' => [$this, 'isBitfieldReadOnly'],
'GEOHASH' => true,
'GEOPOS' => true,
'GEODIST' => true,
'GEORADIUS' => [$this, 'isGeoradiusReadOnly'],
'GEORADIUSBYMEMBER' => [$this, 'isGeoradiusReadOnly'],
'GEOSEARCH' => true,
];
}
/**
* Disables reads to slaves when using
* a replication topology.
*
* @return self
*/
public function disableLoadBalancing(): self
{
$this->loadBalancing = false;
return $this;
}
}
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