mirror of
https://github.com/predis/predis.git
synced 2026-08-25 01:39:38 +00:00
Daniele Alessandri
b1761c55c5
This change is possible because, after a few changes in redis-cluster,
our default cluster strategy used for client side sharding and the one
used for redis-cluster turned out to be exactly the same, except for
the hashing function used to calculate distribution.
Actually some checks used to enforce correctness are redundant in the
context of redis-cluster (e.g. the one used to make sure that keys in
requests performing cross-keys operations will hash to the same slot,
which is performed by the server) so we could also add a more dumb and
permissive cluster strategy that relies on checks performed by Redis.
The only difference between the client-side sharding strategy and the
one used for redis-cluster, aside from the hash function, is in the
rules used for extracting hash tags from keys since empty tags {} are
considered valid by redis-cluster. In v1.0.0 the strategy used for our
client-side sharding cluster will reflect this change, but we will not
change it in v0.8 since it can be considered a breaking changes as it
can potentially affect existing cluster deployments.
399 lines
15 KiB
PHP
399 lines
15 KiB
PHP
<?php
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/*
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* This file is part of the Predis package.
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*
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* (c) Daniele Alessandri <suppakilla@gmail.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Predis\Cluster;
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use Predis\Cluster\Hash\HashGeneratorInterface;
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use Predis\Command\CommandInterface;
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use Predis\Command\ScriptedCommand;
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/**
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* Default class used by Predis for client-side sharding to calculate
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* hashes out of keys of supported commands.
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*
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* @author Daniele Alessandri <suppakilla@gmail.com>
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*/
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class PredisClusterHashStrategy implements CommandHashStrategyInterface
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{
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protected $commands;
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protected $hashGenerator;
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/**
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* @param HashGeneratorInterface $hashGenerator Hash generator instance.
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*/
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public function __construct(HashGeneratorInterface $hashGenerator)
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{
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$this->commands = $this->getDefaultCommands();
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$this->hashGenerator = $hashGenerator;
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}
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/**
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* Returns the default map of supported commands with their handlers.
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*
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* @return array
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*/
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protected function getDefaultCommands()
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{
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$getKeyFromFirstArgument = array($this, 'getKeyFromFirstArgument');
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$getKeyFromAllArguments = array($this, 'getKeyFromAllArguments');
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return array(
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/* commands operating on the key space */
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'EXISTS' => $getKeyFromFirstArgument,
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'DEL' => $getKeyFromAllArguments,
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'TYPE' => $getKeyFromFirstArgument,
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'EXPIRE' => $getKeyFromFirstArgument,
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'EXPIREAT' => $getKeyFromFirstArgument,
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'PERSIST' => $getKeyFromFirstArgument,
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'PEXPIRE' => $getKeyFromFirstArgument,
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'PEXPIREAT' => $getKeyFromFirstArgument,
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'TTL' => $getKeyFromFirstArgument,
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'PTTL' => $getKeyFromFirstArgument,
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'SORT' => $getKeyFromFirstArgument, // TODO
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'DUMP' => $getKeyFromFirstArgument,
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'RESTORE' => $getKeyFromFirstArgument,
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/* commands operating on string values */
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'APPEND' => $getKeyFromFirstArgument,
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'DECR' => $getKeyFromFirstArgument,
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'DECRBY' => $getKeyFromFirstArgument,
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'GET' => $getKeyFromFirstArgument,
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'GETBIT' => $getKeyFromFirstArgument,
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'MGET' => $getKeyFromAllArguments,
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'SET' => $getKeyFromFirstArgument,
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'GETRANGE' => $getKeyFromFirstArgument,
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'GETSET' => $getKeyFromFirstArgument,
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'INCR' => $getKeyFromFirstArgument,
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'INCRBY' => $getKeyFromFirstArgument,
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'INCRBYFLOAT' => $getKeyFromFirstArgument,
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'SETBIT' => $getKeyFromFirstArgument,
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'SETEX' => $getKeyFromFirstArgument,
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'MSET' => array($this, 'getKeyFromInterleavedArguments'),
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'MSETNX' => array($this, 'getKeyFromInterleavedArguments'),
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'SETNX' => $getKeyFromFirstArgument,
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'SETRANGE' => $getKeyFromFirstArgument,
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'STRLEN' => $getKeyFromFirstArgument,
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'SUBSTR' => $getKeyFromFirstArgument,
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'BITOP' => array($this, 'getKeyFromBitOp'),
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'BITCOUNT' => $getKeyFromFirstArgument,
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/* commands operating on lists */
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'LINSERT' => $getKeyFromFirstArgument,
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'LINDEX' => $getKeyFromFirstArgument,
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'LLEN' => $getKeyFromFirstArgument,
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'LPOP' => $getKeyFromFirstArgument,
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'RPOP' => $getKeyFromFirstArgument,
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'RPOPLPUSH' => $getKeyFromAllArguments,
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'BLPOP' => array($this, 'getKeyFromBlockingListCommands'),
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'BRPOP' => array($this, 'getKeyFromBlockingListCommands'),
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'BRPOPLPUSH' => array($this, 'getKeyFromBlockingListCommands'),
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'LPUSH' => $getKeyFromFirstArgument,
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'LPUSHX' => $getKeyFromFirstArgument,
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'RPUSH' => $getKeyFromFirstArgument,
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'RPUSHX' => $getKeyFromFirstArgument,
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'LRANGE' => $getKeyFromFirstArgument,
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'LREM' => $getKeyFromFirstArgument,
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'LSET' => $getKeyFromFirstArgument,
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'LTRIM' => $getKeyFromFirstArgument,
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/* commands operating on sets */
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'SADD' => $getKeyFromFirstArgument,
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'SCARD' => $getKeyFromFirstArgument,
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'SDIFF' => $getKeyFromAllArguments,
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'SDIFFSTORE' => $getKeyFromAllArguments,
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'SINTER' => $getKeyFromAllArguments,
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'SINTERSTORE' => $getKeyFromAllArguments,
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'SUNION' => $getKeyFromAllArguments,
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'SUNIONSTORE' => $getKeyFromAllArguments,
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'SISMEMBER' => $getKeyFromFirstArgument,
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'SMEMBERS' => $getKeyFromFirstArgument,
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'SSCAN' => $getKeyFromFirstArgument,
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'SPOP' => $getKeyFromFirstArgument,
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'SRANDMEMBER' => $getKeyFromFirstArgument,
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'SREM' => $getKeyFromFirstArgument,
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/* commands operating on sorted sets */
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'ZADD' => $getKeyFromFirstArgument,
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'ZCARD' => $getKeyFromFirstArgument,
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'ZCOUNT' => $getKeyFromFirstArgument,
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'ZINCRBY' => $getKeyFromFirstArgument,
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'ZINTERSTORE' => array($this, 'getKeyFromZsetAggregationCommands'),
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'ZRANGE' => $getKeyFromFirstArgument,
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'ZRANGEBYSCORE' => $getKeyFromFirstArgument,
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'ZRANK' => $getKeyFromFirstArgument,
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'ZREM' => $getKeyFromFirstArgument,
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'ZREMRANGEBYRANK' => $getKeyFromFirstArgument,
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'ZREMRANGEBYSCORE' => $getKeyFromFirstArgument,
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'ZREVRANGE' => $getKeyFromFirstArgument,
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'ZREVRANGEBYSCORE' => $getKeyFromFirstArgument,
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'ZREVRANK' => $getKeyFromFirstArgument,
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'ZSCORE' => $getKeyFromFirstArgument,
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'ZUNIONSTORE' => array($this, 'getKeyFromZsetAggregationCommands'),
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'ZSCAN' => $getKeyFromFirstArgument,
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'ZLEXCOUNT' => $getKeyFromFirstArgument,
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'ZRANGEBYLEX' => $getKeyFromFirstArgument,
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'ZREMRANGEBYLEX' => $getKeyFromFirstArgument,
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/* commands operating on hashes */
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'HDEL' => $getKeyFromFirstArgument,
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'HEXISTS' => $getKeyFromFirstArgument,
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'HGET' => $getKeyFromFirstArgument,
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'HGETALL' => $getKeyFromFirstArgument,
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'HMGET' => $getKeyFromFirstArgument,
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'HMSET' => $getKeyFromFirstArgument,
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'HINCRBY' => $getKeyFromFirstArgument,
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'HINCRBYFLOAT' => $getKeyFromFirstArgument,
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'HKEYS' => $getKeyFromFirstArgument,
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'HLEN' => $getKeyFromFirstArgument,
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'HSET' => $getKeyFromFirstArgument,
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'HSETNX' => $getKeyFromFirstArgument,
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'HVALS' => $getKeyFromFirstArgument,
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'HSCAN' => $getKeyFromFirstArgument,
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/* commands operating on HyperLogLog */
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'PFADD' => $getKeyFromFirstArgument,
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'PFCOUNT' => $getKeyFromAllArguments,
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'PFMERGE' => $getKeyFromAllArguments,
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/* scripting */
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'EVAL' => array($this, 'getKeyFromScriptingCommands'),
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'EVALSHA' => array($this, 'getKeyFromScriptingCommands'),
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);
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}
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/**
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* Returns the list of IDs for the supported commands.
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*
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* @return array
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*/
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public function getSupportedCommands()
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{
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return array_keys($this->commands);
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}
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/**
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* Sets an handler for the specified command ID.
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*
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* The signature of the callback must have a single parameter
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* of type Predis\Command\CommandInterface.
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*
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* When the callback argument is omitted or NULL, the previously
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* associated handler for the specified command ID is removed.
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*
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* @param string $commandId The ID of the command to be handled.
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* @param mixed $callback A valid callable object or NULL.
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*/
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public function setCommandHandler($commandId, $callback = null)
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{
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$commandId = strtoupper($commandId);
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if (!isset($callback)) {
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unset($this->commands[$commandId]);
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return;
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}
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if (!is_callable($callback)) {
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throw new \InvalidArgumentException("Callback must be a valid callable object or NULL");
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}
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$this->commands[$commandId] = $callback;
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}
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/**
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* Extracts the key from the first argument of a command instance.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromFirstArgument(CommandInterface $command)
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{
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return $command->getArgument(0);
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}
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/**
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* Extracts the key from a command with multiple keys only when all keys
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* in the arguments array produce the same hash.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromAllArguments(CommandInterface $command)
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{
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$arguments = $command->getArguments();
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if ($this->checkSameHashForKeys($arguments)) {
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return $arguments[0];
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}
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}
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/**
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* Extracts the key from a command with multiple keys only when all keys
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* in the arguments array produce the same hash.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromInterleavedArguments(CommandInterface $command)
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{
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$arguments = $command->getArguments();
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$keys = array();
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for ($i = 0; $i < count($arguments); $i += 2) {
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$keys[] = $arguments[$i];
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}
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if ($this->checkSameHashForKeys($keys)) {
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return $arguments[0];
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}
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}
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/**
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* Extracts the key from BLPOP and BRPOP commands.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromBlockingListCommands(CommandInterface $command)
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{
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$arguments = $command->getArguments();
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if ($this->checkSameHashForKeys(array_slice($arguments, 0, count($arguments) - 1))) {
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return $arguments[0];
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}
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}
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/**
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* Extracts the key from BITOP command.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromBitOp(CommandInterface $command)
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{
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$arguments = $command->getArguments();
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if ($this->checkSameHashForKeys(array_slice($arguments, 1, count($arguments)))) {
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return $arguments[1];
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}
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}
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/**
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* Extracts the key from ZINTERSTORE and ZUNIONSTORE commands.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromZsetAggregationCommands(CommandInterface $command)
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{
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$arguments = $command->getArguments();
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$keys = array_merge(array($arguments[0]), array_slice($arguments, 2, $arguments[1]));
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if ($this->checkSameHashForKeys($keys)) {
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return $arguments[0];
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}
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}
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/**
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* Extracts the key from EVAL and EVALSHA commands.
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*
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* @param CommandInterface $command Command instance.
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* @return string
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*/
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protected function getKeyFromScriptingCommands(CommandInterface $command)
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{
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if ($command instanceof ScriptedCommand) {
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$keys = $command->getKeys();
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} else {
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$keys = array_slice($args = $command->getArguments(), 2, $args[1]);
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}
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if ($keys && $this->checkSameHashForKeys($keys)) {
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return $keys[0];
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}
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}
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/**
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* {@inheritdoc}
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*/
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public function getHash(CommandInterface $command)
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{
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$hash = $command->getHash();
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if (!isset($hash) && isset($this->commands[$cmdID = $command->getId()])) {
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$key = call_user_func($this->commands[$cmdID], $command);
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if (isset($key)) {
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$hash = $this->getKeyHash($key);
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$command->setHash($hash);
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}
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}
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return $hash;
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}
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/**
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* {@inheritdoc}
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*/
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public function getKeyHash($key)
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{
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$key = $this->extractKeyTag($key);
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$hash = $this->hashGenerator->hash($key);
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return $hash;
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}
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/**
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* Checks if the specified array of keys will generate the same hash.
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*
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* @param array $keys Array of keys.
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* @return bool
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*/
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protected function checkSameHashForKeys(Array $keys)
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{
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if (!$count = count($keys)) {
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return false;
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}
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$currentKey = $this->extractKeyTag($keys[0]);
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for ($i = 1; $i < $count; $i++) {
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$nextKey = $this->extractKeyTag($keys[$i]);
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if ($currentKey !== $nextKey) {
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return false;
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}
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$currentKey = $nextKey;
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}
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return true;
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}
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/**
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* Returns only the hashable part of a key (delimited by "{...}"), or the
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* whole key if a key tag is not found in the string.
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*
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* @param string $key A key.
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* @return string
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*/
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protected function extractKeyTag($key)
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{
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if (false !== $start = strpos($key, '{')) {
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if (false !== $end = strpos($key, '}', $start)) {
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$key = substr($key, ++$start, $end - $start);
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}
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}
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return $key;
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}
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}
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