init & add agent & add job

predis/src/Connection/AbstractConnection.php

@@ -0,0 +1,226 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\CommunicationException;
+use Predis\Protocol\ProtocolException;
+
+/**
+ * Base class with the common logic used by connection classes to communicate
+ * with Redis.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+abstract class AbstractConnection implements NodeConnectionInterface
+{
+    private $resource;
+    private $cachedId;
+
+    protected $parameters;
+    protected $initCommands = array();
+
+    /**
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     */
+    public function __construct(ParametersInterface $parameters)
+    {
+        $this->parameters = $this->assertParameters($parameters);
+    }
+
+    /**
+     * Disconnects from the server and destroys the underlying resource when
+     * PHP's garbage collector kicks in.
+     */
+    public function __destruct()
+    {
+        $this->disconnect();
+    }
+
+    /**
+     * Checks some of the parameters used to initialize the connection.
+     *
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return ParametersInterface
+     */
+    abstract protected function assertParameters(ParametersInterface $parameters);
+
+    /**
+     * Creates the underlying resource used to communicate with Redis.
+     *
+     * @return mixed
+     */
+    abstract protected function createResource();
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        return isset($this->resource);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if (!$this->isConnected()) {
+            $this->resource = $this->createResource();
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        unset($this->resource);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function addConnectCommand(CommandInterface $command)
+    {
+        $this->initCommands[] = $command;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        $this->writeRequest($command);
+
+        return $this->readResponse($command);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        return $this->read();
+    }
+
+    /**
+     * Helper method that returns an exception message augmented with useful
+     * details from the connection parameters.
+     *
+     * @param string $message Error message.
+     *
+     * @return string
+     */
+    private function createExceptionMessage($message)
+    {
+        $parameters = $this->parameters;
+
+        if ($parameters->scheme === 'unix') {
+            return "$message [$parameters->scheme:$parameters->path]";
+        }
+
+        if (filter_var($parameters->host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
+            return "$message [$parameters->scheme://[$parameters->host]:$parameters->port]";
+        }
+
+        return "$message [$parameters->scheme://$parameters->host:$parameters->port]";
+    }
+
+    /**
+     * Helper method to handle connection errors.
+     *
+     * @param string $message Error message.
+     * @param int    $code    Error code.
+     */
+    protected function onConnectionError($message, $code = null)
+    {
+        CommunicationException::handle(
+            new ConnectionException($this, static::createExceptionMessage($message), $code)
+        );
+    }
+
+    /**
+     * Helper method to handle protocol errors.
+     *
+     * @param string $message Error message.
+     */
+    protected function onProtocolError($message)
+    {
+        CommunicationException::handle(
+            new ProtocolException($this, static::createExceptionMessage($message))
+        );
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getResource()
+    {
+        if (isset($this->resource)) {
+            return $this->resource;
+        }
+
+        $this->connect();
+
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getParameters()
+    {
+        return $this->parameters;
+    }
+
+    /**
+     * Gets an identifier for the connection.
+     *
+     * @return string
+     */
+    protected function getIdentifier()
+    {
+        if ($this->parameters->scheme === 'unix') {
+            return $this->parameters->path;
+        }
+
+        return "{$this->parameters->host}:{$this->parameters->port}";
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        if (!isset($this->cachedId)) {
+            $this->cachedId = $this->getIdentifier();
+        }
+
+        return $this->cachedId;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array('parameters', 'initCommands');
+    }
+}

predis/src/Connection/Aggregate/ClusterInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\Connection\AggregateConnectionInterface;
+
+/**
+ * Defines a cluster of Redis servers formed by aggregating multiple connection
+ * instances to single Redis nodes.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ClusterInterface extends AggregateConnectionInterface
+{
+}

predis/src/Connection/Aggregate/MasterSlaveReplication.php

@@ -0,0 +1,509 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\ClientException;
+use Predis\Command\CommandInterface;
+use Predis\Command\RawCommand;
+use Predis\Connection\ConnectionException;
+use Predis\Connection\FactoryInterface;
+use Predis\Connection\NodeConnectionInterface;
+use Predis\Replication\MissingMasterException;
+use Predis\Replication\ReplicationStrategy;
+use Predis\Response\ErrorInterface as ResponseErrorInterface;
+
+/**
+ * Aggregate connection handling replication of Redis nodes configured in a
+ * single master / multiple slaves setup.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class MasterSlaveReplication implements ReplicationInterface
+{
+    /**
+     * @var ReplicationStrategy
+     */
+    protected $strategy;
+
+    /**
+     * @var NodeConnectionInterface
+     */
+    protected $master;
+
+    /**
+     * @var NodeConnectionInterface[]
+     */
+    protected $slaves = array();
+
+    /**
+     * @var NodeConnectionInterface
+     */
+    protected $current;
+
+    /**
+     * @var bool
+     */
+    protected $autoDiscovery = false;
+
+    /**
+     * @var FactoryInterface
+     */
+    protected $connectionFactory;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __construct(ReplicationStrategy $strategy = null)
+    {
+        $this->strategy = $strategy ?: new ReplicationStrategy();
+    }
+
+    /**
+     * Configures the automatic discovery of the replication configuration on failure.
+     *
+     * @param bool $value Enable or disable auto discovery.
+     */
+    public function setAutoDiscovery($value)
+    {
+        if (!$this->connectionFactory) {
+            throw new ClientException('Automatic discovery requires a connection factory');
+        }
+
+        $this->autoDiscovery = (bool) $value;
+    }
+
+    /**
+     * Sets the connection factory used to create the connections by the auto
+     * discovery procedure.
+     *
+     * @param FactoryInterface $connectionFactory Connection factory instance.
+     */
+    public function setConnectionFactory(FactoryInterface $connectionFactory)
+    {
+        $this->connectionFactory = $connectionFactory;
+    }
+
+    /**
+     * Resets the connection state.
+     */
+    protected function reset()
+    {
+        $this->current = null;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function add(NodeConnectionInterface $connection)
+    {
+        $alias = $connection->getParameters()->alias;
+
+        if ($alias === 'master') {
+            $this->master = $connection;
+        } else {
+            $this->slaves[$alias ?: "slave-$connection"] = $connection;
+        }
+
+        $this->reset();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function remove(NodeConnectionInterface $connection)
+    {
+        if ($connection->getParameters()->alias === 'master') {
+            $this->master = null;
+            $this->reset();
+
+            return true;
+        } else {
+            if (($id = array_search($connection, $this->slaves, true)) !== false) {
+                unset($this->slaves[$id]);
+                $this->reset();
+
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnection(CommandInterface $command)
+    {
+        if (!$this->current) {
+            if ($this->strategy->isReadOperation($command) && $slave = $this->pickSlave()) {
+                $this->current = $slave;
+            } else {
+                $this->current = $this->getMasterOrDie();
+            }
+
+            return $this->current;
+        }
+
+        if ($this->current === $master = $this->getMasterOrDie()) {
+            return $master;
+        }
+
+        if (!$this->strategy->isReadOperation($command) || !$this->slaves) {
+            $this->current = $master;
+        }
+
+        return $this->current;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnectionById($connectionId)
+    {
+        if ($connectionId === 'master') {
+            return $this->master;
+        }
+
+        if (isset($this->slaves[$connectionId])) {
+            return $this->slaves[$connectionId];
+        }
+
+        return;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function switchTo($connection)
+    {
+        if (!$connection instanceof NodeConnectionInterface) {
+            $connection = $this->getConnectionById($connection);
+        }
+
+        if (!$connection) {
+            throw new \InvalidArgumentException('Invalid connection or connection not found.');
+        }
+
+        if ($connection !== $this->master && !in_array($connection, $this->slaves, true)) {
+            throw new \InvalidArgumentException('Invalid connection or connection not found.');
+        }
+
+        $this->current = $connection;
+    }
+
+    /**
+     * Switches to the master server.
+     */
+    public function switchToMaster()
+    {
+        $this->switchTo('master');
+    }
+
+    /**
+     * Switches to a random slave server.
+     */
+    public function switchToSlave()
+    {
+        $connection = $this->pickSlave();
+        $this->switchTo($connection);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getCurrent()
+    {
+        return $this->current;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getMaster()
+    {
+        return $this->master;
+    }
+
+    /**
+     * Returns the connection associated to the master server.
+     *
+     * @return NodeConnectionInterface
+     */
+    private function getMasterOrDie()
+    {
+        if (!$connection = $this->getMaster()) {
+            throw new MissingMasterException('No master server available for replication');
+        }
+
+        return $connection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getSlaves()
+    {
+        return array_values($this->slaves);
+    }
+
+    /**
+     * Returns the underlying replication strategy.
+     *
+     * @return ReplicationStrategy
+     */
+    public function getReplicationStrategy()
+    {
+        return $this->strategy;
+    }
+
+    /**
+     * Returns a random slave.
+     *
+     * @return NodeConnectionInterface
+     */
+    protected function pickSlave()
+    {
+        if ($this->slaves) {
+            return $this->slaves[array_rand($this->slaves)];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        return $this->current ? $this->current->isConnected() : false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if (!$this->current) {
+            if (!$this->current = $this->pickSlave()) {
+                if (!$this->current = $this->getMaster()) {
+                    throw new ClientException('No available connection for replication');
+                }
+            }
+        }
+
+        $this->current->connect();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        if ($this->master) {
+            $this->master->disconnect();
+        }
+
+        foreach ($this->slaves as $connection) {
+            $connection->disconnect();
+        }
+    }
+
+    /**
+     * Handles response from INFO.
+     *
+     * @param string $response
+     *
+     * @return array
+     */
+    private function handleInfoResponse($response)
+    {
+        $info = array();
+
+        foreach (preg_split('/\r?\n/', $response) as $row) {
+            if (strpos($row, ':') === false) {
+                continue;
+            }
+
+            list($k, $v) = explode(':', $row, 2);
+            $info[$k] = $v;
+        }
+
+        return $info;
+    }
+
+    /**
+     * Fetches the replication configuration from one of the servers.
+     */
+    public function discover()
+    {
+        if (!$this->connectionFactory) {
+            throw new ClientException('Discovery requires a connection factory');
+        }
+
+        RETRY_FETCH: {
+            try {
+                if ($connection = $this->getMaster()) {
+                    $this->discoverFromMaster($connection, $this->connectionFactory);
+                } elseif ($connection = $this->pickSlave()) {
+                    $this->discoverFromSlave($connection, $this->connectionFactory);
+                } else {
+                    throw new ClientException('No connection available for discovery');
+                }
+            } catch (ConnectionException $exception) {
+                $this->remove($connection);
+                goto RETRY_FETCH;
+            }
+        }
+    }
+
+    /**
+     * Discovers the replication configuration by contacting the master node.
+     *
+     * @param NodeConnectionInterface $connection        Connection to the master node.
+     * @param FactoryInterface        $connectionFactory Connection factory instance.
+     */
+    protected function discoverFromMaster(NodeConnectionInterface $connection, FactoryInterface $connectionFactory)
+    {
+        $response = $connection->executeCommand(RawCommand::create('INFO', 'REPLICATION'));
+        $replication = $this->handleInfoResponse($response);
+
+        if ($replication['role'] !== 'master') {
+            throw new ClientException("Role mismatch (expected master, got slave) [$connection]");
+        }
+
+        $this->slaves = array();
+
+        foreach ($replication as $k => $v) {
+            $parameters = null;
+
+            if (strpos($k, 'slave') === 0 && preg_match('/ip=(?P<host>.*),port=(?P<port>\d+)/', $v, $parameters)) {
+                $slaveConnection = $connectionFactory->create(array(
+                    'host' => $parameters['host'],
+                    'port' => $parameters['port'],
+                ));
+
+                $this->add($slaveConnection);
+            }
+        }
+    }
+
+    /**
+     * Discovers the replication configuration by contacting one of the slaves.
+     *
+     * @param NodeConnectionInterface $connection        Connection to one of the slaves.
+     * @param FactoryInterface        $connectionFactory Connection factory instance.
+     */
+    protected function discoverFromSlave(NodeConnectionInterface $connection, FactoryInterface $connectionFactory)
+    {
+        $response = $connection->executeCommand(RawCommand::create('INFO', 'REPLICATION'));
+        $replication = $this->handleInfoResponse($response);
+
+        if ($replication['role'] !== 'slave') {
+            throw new ClientException("Role mismatch (expected slave, got master) [$connection]");
+        }
+
+        $masterConnection = $connectionFactory->create(array(
+            'host' => $replication['master_host'],
+            'port' => $replication['master_port'],
+            'alias' => 'master',
+        ));
+
+        $this->add($masterConnection);
+
+        $this->discoverFromMaster($masterConnection, $connectionFactory);
+    }
+
+    /**
+     * Retries the execution of a command upon slave failure.
+     *
+     * @param CommandInterface $command Command instance.
+     * @param string           $method  Actual method.
+     *
+     * @return mixed
+     */
+    private function retryCommandOnFailure(CommandInterface $command, $method)
+    {
+        RETRY_COMMAND: {
+            try {
+                $connection = $this->getConnection($command);
+                $response = $connection->$method($command);
+
+                if ($response instanceof ResponseErrorInterface && $response->getErrorType() === 'LOADING') {
+                    throw new ConnectionException($connection, "Redis is loading the dataset in memory [$connection]");
+                }
+            } catch (ConnectionException $exception) {
+                $connection = $exception->getConnection();
+                $connection->disconnect();
+
+                if ($connection === $this->master && !$this->autoDiscovery) {
+                    // Throw immediately when master connection is failing, even
+                    // when the command represents a read-only operation, unless
+                    // automatic discovery has been enabled.
+                    throw $exception;
+                } else {
+                    // Otherwise remove the failing slave and attempt to execute
+                    // the command again on one of the remaining slaves...
+                    $this->remove($connection);
+                }
+
+                // ... that is, unless we have no more connections to use.
+                if (!$this->slaves && !$this->master) {
+                    throw $exception;
+                } elseif ($this->autoDiscovery) {
+                    $this->discover();
+                }
+
+                goto RETRY_COMMAND;
+            } catch (MissingMasterException $exception) {
+                if ($this->autoDiscovery) {
+                    $this->discover();
+                } else {
+                    throw $exception;
+                }
+
+                goto RETRY_COMMAND;
+            }
+        }
+
+        return $response;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        return $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        return $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array('master', 'slaves', 'strategy');
+    }
+}

predis/src/Connection/Aggregate/PredisCluster.php

@@ -0,0 +1,235 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\Cluster\PredisStrategy;
+use Predis\Cluster\StrategyInterface;
+use Predis\Command\CommandInterface;
+use Predis\Connection\NodeConnectionInterface;
+use Predis\NotSupportedException;
+
+/**
+ * Abstraction for a cluster of aggregate connections to various Redis servers
+ * implementing client-side sharding based on pluggable distribution strategies.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * @todo Add the ability to remove connections from pool.
+ */
+class PredisCluster implements ClusterInterface, \IteratorAggregate, \Countable
+{
+    private $pool;
+    private $strategy;
+    private $distributor;
+
+    /**
+     * @param StrategyInterface $strategy Optional cluster strategy.
+     */
+    public function __construct(StrategyInterface $strategy = null)
+    {
+        $this->pool = array();
+        $this->strategy = $strategy ?: new PredisStrategy();
+        $this->distributor = $this->strategy->getDistributor();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        foreach ($this->pool as $connection) {
+            if ($connection->isConnected()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        foreach ($this->pool as $connection) {
+            $connection->connect();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        foreach ($this->pool as $connection) {
+            $connection->disconnect();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function add(NodeConnectionInterface $connection)
+    {
+        $parameters = $connection->getParameters();
+
+        if (isset($parameters->alias)) {
+            $this->pool[$parameters->alias] = $connection;
+        } else {
+            $this->pool[] = $connection;
+        }
+
+        $weight = isset($parameters->weight) ? $parameters->weight : null;
+        $this->distributor->add($connection, $weight);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function remove(NodeConnectionInterface $connection)
+    {
+        if (($id = array_search($connection, $this->pool, true)) !== false) {
+            unset($this->pool[$id]);
+            $this->distributor->remove($connection);
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Removes a connection instance using its alias or index.
+     *
+     * @param string $connectionID Alias or index of a connection.
+     *
+     * @return bool Returns true if the connection was in the pool.
+     */
+    public function removeById($connectionID)
+    {
+        if ($connection = $this->getConnectionById($connectionID)) {
+            return $this->remove($connection);
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnection(CommandInterface $command)
+    {
+        $slot = $this->strategy->getSlot($command);
+
+        if (!isset($slot)) {
+            throw new NotSupportedException(
+                "Cannot use '{$command->getId()}' over clusters of connections."
+            );
+        }
+
+        $node = $this->distributor->getBySlot($slot);
+
+        return $node;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnectionById($connectionID)
+    {
+        return isset($this->pool[$connectionID]) ? $this->pool[$connectionID] : null;
+    }
+
+    /**
+     * Retrieves a connection instance from the cluster using a key.
+     *
+     * @param string $key Key string.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getConnectionByKey($key)
+    {
+        $hash = $this->strategy->getSlotByKey($key);
+        $node = $this->distributor->getBySlot($hash);
+
+        return $node;
+    }
+
+    /**
+     * Returns the underlying command hash strategy used to hash commands by
+     * using keys found in their arguments.
+     *
+     * @return StrategyInterface
+     */
+    public function getClusterStrategy()
+    {
+        return $this->strategy;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function count()
+    {
+        return count($this->pool);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getIterator()
+    {
+        return new \ArrayIterator($this->pool);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->getConnection($command)->writeRequest($command);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        return $this->getConnection($command)->readResponse($command);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        return $this->getConnection($command)->executeCommand($command);
+    }
+
+    /**
+     * Executes the specified Redis command on all the nodes of a cluster.
+     *
+     * @param CommandInterface $command A Redis command.
+     *
+     * @return array
+     */
+    public function executeCommandOnNodes(CommandInterface $command)
+    {
+        $responses = array();
+
+        foreach ($this->pool as $connection) {
+            $responses[] = $connection->executeCommand($command);
+        }
+
+        return $responses;
+    }
+}

predis/src/Connection/Aggregate/RedisCluster.php

@@ -0,0 +1,673 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\ClientException;
+use Predis\Cluster\RedisStrategy as RedisClusterStrategy;
+use Predis\Cluster\StrategyInterface;
+use Predis\Command\CommandInterface;
+use Predis\Command\RawCommand;
+use Predis\Connection\ConnectionException;
+use Predis\Connection\FactoryInterface;
+use Predis\Connection\NodeConnectionInterface;
+use Predis\NotSupportedException;
+use Predis\Response\ErrorInterface as ErrorResponseInterface;
+
+/**
+ * Abstraction for a Redis-backed cluster of nodes (Redis >= 3.0.0).
+ *
+ * This connection backend offers smart support for redis-cluster by handling
+ * automatic slots map (re)generation upon -MOVED or -ASK responses returned by
+ * Redis when redirecting a client to a different node.
+ *
+ * The cluster can be pre-initialized using only a subset of the actual nodes in
+ * the cluster, Predis will do the rest by adjusting the slots map and creating
+ * the missing underlying connection instances on the fly.
+ *
+ * It is possible to pre-associate connections to a slots range with the "slots"
+ * parameter in the form "$first-$last". This can greatly reduce runtime node
+ * guessing and redirections.
+ *
+ * It is also possible to ask for the full and updated slots map directly to one
+ * of the nodes and optionally enable such a behaviour upon -MOVED redirections.
+ * Asking for the cluster configuration to Redis is actually done by issuing a
+ * CLUSTER SLOTS command to a random node in the pool.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class RedisCluster implements ClusterInterface, \IteratorAggregate, \Countable
+{
+    private $useClusterSlots = true;
+    private $pool = array();
+    private $slots = array();
+    private $slotsMap;
+    private $strategy;
+    private $connections;
+    private $retryLimit = 5;
+
+    /**
+     * @param FactoryInterface  $connections Optional connection factory.
+     * @param StrategyInterface $strategy    Optional cluster strategy.
+     */
+    public function __construct(
+        FactoryInterface $connections,
+        StrategyInterface $strategy = null
+    ) {
+        $this->connections = $connections;
+        $this->strategy = $strategy ?: new RedisClusterStrategy();
+    }
+
+    /**
+     * Sets the maximum number of retries for commands upon server failure.
+     *
+     * -1 = unlimited retry attempts
+     *  0 = no retry attempts (fails immediatly)
+     *  n = fail only after n retry attempts
+     *
+     * @param int $retry Number of retry attempts.
+     */
+    public function setRetryLimit($retry)
+    {
+        $this->retryLimit = (int) $retry;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        foreach ($this->pool as $connection) {
+            if ($connection->isConnected()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if ($connection = $this->getRandomConnection()) {
+            $connection->connect();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        foreach ($this->pool as $connection) {
+            $connection->disconnect();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function add(NodeConnectionInterface $connection)
+    {
+        $this->pool[(string) $connection] = $connection;
+        unset($this->slotsMap);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function remove(NodeConnectionInterface $connection)
+    {
+        if (false !== $id = array_search($connection, $this->pool, true)) {
+            unset(
+                $this->pool[$id],
+                $this->slotsMap
+            );
+
+            $this->slots = array_diff($this->slots, array($connection));
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Removes a connection instance by using its identifier.
+     *
+     * @param string $connectionID Connection identifier.
+     *
+     * @return bool True if the connection was in the pool.
+     */
+    public function removeById($connectionID)
+    {
+        if (isset($this->pool[$connectionID])) {
+            unset(
+                $this->pool[$connectionID],
+                $this->slotsMap
+            );
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Generates the current slots map by guessing the cluster configuration out
+     * of the connection parameters of the connections in the pool.
+     *
+     * Generation is based on the same algorithm used by Redis to generate the
+     * cluster, so it is most effective when all of the connections supplied on
+     * initialization have the "slots" parameter properly set accordingly to the
+     * current cluster configuration.
+     *
+     * @return array
+     */
+    public function buildSlotsMap()
+    {
+        $this->slotsMap = array();
+
+        foreach ($this->pool as $connectionID => $connection) {
+            $parameters = $connection->getParameters();
+
+            if (!isset($parameters->slots)) {
+                continue;
+            }
+
+            foreach (explode(',', $parameters->slots) as $slotRange) {
+                $slots = explode('-', $slotRange, 2);
+
+                if (!isset($slots[1])) {
+                    $slots[1] = $slots[0];
+                }
+
+                $this->setSlots($slots[0], $slots[1], $connectionID);
+            }
+        }
+
+        return $this->slotsMap;
+    }
+
+    /**
+     * Queries the specified node of the cluster to fetch the updated slots map.
+     *
+     * When the connection fails, this method tries to execute the same command
+     * on a different connection picked at random from the pool of known nodes,
+     * up until the retry limit is reached.
+     *
+     * @param NodeConnectionInterface $connection Connection to a node of the cluster.
+     *
+     * @return mixed
+     */
+    private function queryClusterNodeForSlotsMap(NodeConnectionInterface $connection)
+    {
+        $retries = 0;
+        $command = RawCommand::create('CLUSTER', 'SLOTS');
+
+        RETRY_COMMAND: {
+            try {
+                $response = $connection->executeCommand($command);
+            } catch (ConnectionException $exception) {
+                $connection = $exception->getConnection();
+                $connection->disconnect();
+
+                $this->remove($connection);
+
+                if ($retries === $this->retryLimit) {
+                    throw $exception;
+                }
+
+                if (!$connection = $this->getRandomConnection()) {
+                    throw new ClientException('No connections left in the pool for `CLUSTER SLOTS`');
+                }
+
+                ++$retries;
+                goto RETRY_COMMAND;
+            }
+        }
+
+        return $response;
+    }
+
+    /**
+     * Generates an updated slots map fetching the cluster configuration using
+     * the CLUSTER SLOTS command against the specified node or a random one from
+     * the pool.
+     *
+     * @param NodeConnectionInterface $connection Optional connection instance.
+     *
+     * @return array
+     */
+    public function askSlotsMap(NodeConnectionInterface $connection = null)
+    {
+        if (!$connection && !$connection = $this->getRandomConnection()) {
+            return array();
+        }
+
+        $this->resetSlotsMap();
+
+        $response = $this->queryClusterNodeForSlotsMap($connection);
+
+        foreach ($response as $slots) {
+            // We only support master servers for now, so we ignore subsequent
+            // elements in the $slots array identifying slaves.
+            list($start, $end, $master) = $slots;
+
+            if ($master[0] === '') {
+                $this->setSlots($start, $end, (string) $connection);
+            } else {
+                $this->setSlots($start, $end, "{$master[0]}:{$master[1]}");
+            }
+        }
+
+        return $this->slotsMap;
+    }
+
+    /**
+     * Resets the slots map cache.
+     */
+    public function resetSlotsMap()
+    {
+        $this->slotsMap = array();
+    }
+
+    /**
+     * Returns the current slots map for the cluster.
+     *
+     * The order of the returned $slot => $server dictionary is not guaranteed.
+     *
+     * @return array
+     */
+    public function getSlotsMap()
+    {
+        if (!isset($this->slotsMap)) {
+            $this->slotsMap = array();
+        }
+
+        return $this->slotsMap;
+    }
+
+    /**
+     * Pre-associates a connection to a slots range to avoid runtime guessing.
+     *
+     * @param int                            $first      Initial slot of the range.
+     * @param int                            $last       Last slot of the range.
+     * @param NodeConnectionInterface|string $connection ID or connection instance.
+     *
+     * @throws \OutOfBoundsException
+     */
+    public function setSlots($first, $last, $connection)
+    {
+        if ($first < 0x0000 || $first > 0x3FFF ||
+            $last < 0x0000 || $last > 0x3FFF ||
+            $last < $first
+        ) {
+            throw new \OutOfBoundsException(
+                "Invalid slot range for $connection: [$first-$last]."
+            );
+        }
+
+        $slots = array_fill($first, $last - $first + 1, (string) $connection);
+        $this->slotsMap = $this->getSlotsMap() + $slots;
+    }
+
+    /**
+     * Guesses the correct node associated to a given slot using a precalculated
+     * slots map, falling back to the same logic used by Redis to initialize a
+     * cluster (best-effort).
+     *
+     * @param int $slot Slot index.
+     *
+     * @return string Connection ID.
+     */
+    protected function guessNode($slot)
+    {
+        if (!$this->pool) {
+            throw new ClientException('No connections available in the pool');
+        }
+
+        if (!isset($this->slotsMap)) {
+            $this->buildSlotsMap();
+        }
+
+        if (isset($this->slotsMap[$slot])) {
+            return $this->slotsMap[$slot];
+        }
+
+        $count = count($this->pool);
+        $index = min((int) ($slot / (int) (16384 / $count)), $count - 1);
+        $nodes = array_keys($this->pool);
+
+        return $nodes[$index];
+    }
+
+    /**
+     * Creates a new connection instance from the given connection ID.
+     *
+     * @param string $connectionID Identifier for the connection.
+     *
+     * @return NodeConnectionInterface
+     */
+    protected function createConnection($connectionID)
+    {
+        $separator = strrpos($connectionID, ':');
+
+        return $this->connections->create(array(
+            'host' => substr($connectionID, 0, $separator),
+            'port' => substr($connectionID, $separator + 1),
+        ));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnection(CommandInterface $command)
+    {
+        $slot = $this->strategy->getSlot($command);
+
+        if (!isset($slot)) {
+            throw new NotSupportedException(
+                "Cannot use '{$command->getId()}' with redis-cluster."
+            );
+        }
+
+        if (isset($this->slots[$slot])) {
+            return $this->slots[$slot];
+        } else {
+            return $this->getConnectionBySlot($slot);
+        }
+    }
+
+    /**
+     * Returns the connection currently associated to a given slot.
+     *
+     * @param int $slot Slot index.
+     *
+     * @throws \OutOfBoundsException
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getConnectionBySlot($slot)
+    {
+        if ($slot < 0x0000 || $slot > 0x3FFF) {
+            throw new \OutOfBoundsException("Invalid slot [$slot].");
+        }
+
+        if (isset($this->slots[$slot])) {
+            return $this->slots[$slot];
+        }
+
+        $connectionID = $this->guessNode($slot);
+
+        if (!$connection = $this->getConnectionById($connectionID)) {
+            $connection = $this->createConnection($connectionID);
+            $this->pool[$connectionID] = $connection;
+        }
+
+        return $this->slots[$slot] = $connection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnectionById($connectionID)
+    {
+        if (isset($this->pool[$connectionID])) {
+            return $this->pool[$connectionID];
+        }
+    }
+
+    /**
+     * Returns a random connection from the pool.
+     *
+     * @return NodeConnectionInterface|null
+     */
+    protected function getRandomConnection()
+    {
+        if ($this->pool) {
+            return $this->pool[array_rand($this->pool)];
+        }
+    }
+
+    /**
+     * Permanently associates the connection instance to a new slot.
+     * The connection is added to the connections pool if not yet included.
+     *
+     * @param NodeConnectionInterface $connection Connection instance.
+     * @param int                     $slot       Target slot index.
+     */
+    protected function move(NodeConnectionInterface $connection, $slot)
+    {
+        $this->pool[(string) $connection] = $connection;
+        $this->slots[(int) $slot] = $connection;
+    }
+
+    /**
+     * Handles -ERR responses returned by Redis.
+     *
+     * @param CommandInterface       $command Command that generated the -ERR response.
+     * @param ErrorResponseInterface $error   Redis error response object.
+     *
+     * @return mixed
+     */
+    protected function onErrorResponse(CommandInterface $command, ErrorResponseInterface $error)
+    {
+        $details = explode(' ', $error->getMessage(), 2);
+
+        switch ($details[0]) {
+            case 'MOVED':
+                return $this->onMovedResponse($command, $details[1]);
+
+            case 'ASK':
+                return $this->onAskResponse($command, $details[1]);
+
+            default:
+                return $error;
+        }
+    }
+
+    /**
+     * Handles -MOVED responses by executing again the command against the node
+     * indicated by the Redis response.
+     *
+     * @param CommandInterface $command Command that generated the -MOVED response.
+     * @param string           $details Parameters of the -MOVED response.
+     *
+     * @return mixed
+     */
+    protected function onMovedResponse(CommandInterface $command, $details)
+    {
+        list($slot, $connectionID) = explode(' ', $details, 2);
+
+        if (!$connection = $this->getConnectionById($connectionID)) {
+            $connection = $this->createConnection($connectionID);
+        }
+
+        if ($this->useClusterSlots) {
+            $this->askSlotsMap($connection);
+        }
+
+        $this->move($connection, $slot);
+        $response = $this->executeCommand($command);
+
+        return $response;
+    }
+
+    /**
+     * Handles -ASK responses by executing again the command against the node
+     * indicated by the Redis response.
+     *
+     * @param CommandInterface $command Command that generated the -ASK response.
+     * @param string           $details Parameters of the -ASK response.
+     *
+     * @return mixed
+     */
+    protected function onAskResponse(CommandInterface $command, $details)
+    {
+        list($slot, $connectionID) = explode(' ', $details, 2);
+
+        if (!$connection = $this->getConnectionById($connectionID)) {
+            $connection = $this->createConnection($connectionID);
+        }
+
+        $connection->executeCommand(RawCommand::create('ASKING'));
+        $response = $connection->executeCommand($command);
+
+        return $response;
+    }
+
+    /**
+     * Ensures that a command is executed one more time on connection failure.
+     *
+     * The connection to the node that generated the error is evicted from the
+     * pool before trying to fetch an updated slots map from another node. If
+     * the new slots map points to an unreachable server the client gives up and
+     * throws the exception as the nodes participating in the cluster may still
+     * have to agree that something changed in the configuration of the cluster.
+     *
+     * @param CommandInterface $command Command instance.
+     * @param string           $method  Actual method.
+     *
+     * @return mixed
+     */
+    private function retryCommandOnFailure(CommandInterface $command, $method)
+    {
+        $failure = false;
+
+        RETRY_COMMAND: {
+            try {
+                $response = $this->getConnection($command)->$method($command);
+            } catch (ConnectionException $exception) {
+                $connection = $exception->getConnection();
+                $connection->disconnect();
+
+                $this->remove($connection);
+
+                if ($failure) {
+                    throw $exception;
+                } elseif ($this->useClusterSlots) {
+                    $this->askSlotsMap();
+                }
+
+                $failure = true;
+
+                goto RETRY_COMMAND;
+            }
+        }
+
+        return $response;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        return $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        $response = $this->retryCommandOnFailure($command, __FUNCTION__);
+
+        if ($response instanceof ErrorResponseInterface) {
+            return $this->onErrorResponse($command, $response);
+        }
+
+        return $response;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function count()
+    {
+        return count($this->pool);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getIterator()
+    {
+        if ($this->useClusterSlots) {
+            $slotsmap = $this->getSlotsMap() ?: $this->askSlotsMap();
+        } else {
+            $slotsmap = $this->getSlotsMap() ?: $this->buildSlotsMap();
+        }
+
+        $connections = array();
+
+        foreach (array_unique($slotsmap) as $node) {
+            if (!$connection = $this->getConnectionById($node)) {
+                $this->add($connection = $this->createConnection($node));
+            }
+
+            $connections[] = $connection;
+        }
+
+        return new \ArrayIterator($connections);
+    }
+
+    /**
+     * Returns the underlying command hash strategy used to hash commands by
+     * using keys found in their arguments.
+     *
+     * @return StrategyInterface
+     */
+    public function getClusterStrategy()
+    {
+        return $this->strategy;
+    }
+
+    /**
+     * Returns the underlying connection factory used to create new connection
+     * instances to Redis nodes indicated by redis-cluster.
+     *
+     * @return FactoryInterface
+     */
+    public function getConnectionFactory()
+    {
+        return $this->connections;
+    }
+
+    /**
+     * Enables automatic fetching of the current slots map from one of the nodes
+     * using the CLUSTER SLOTS command. This option is enabled by default as
+     * asking the current slots map to Redis upon -MOVED responses may reduce
+     * overhead by eliminating the trial-and-error nature of the node guessing
+     * procedure, mostly when targeting many keys that would end up in a lot of
+     * redirections.
+     *
+     * The slots map can still be manually fetched using the askSlotsMap()
+     * method whether or not this option is enabled.
+     *
+     * @param bool $value Enable or disable the use of CLUSTER SLOTS.
+     */
+    public function useClusterSlots($value)
+    {
+        $this->useClusterSlots = (bool) $value;
+    }
+}

predis/src/Connection/Aggregate/ReplicationInterface.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\Connection\AggregateConnectionInterface;
+use Predis\Connection\NodeConnectionInterface;
+
+/**
+ * Defines a group of Redis nodes in a master / slave replication setup.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ReplicationInterface extends AggregateConnectionInterface
+{
+    /**
+     * Switches the internal connection instance in use.
+     *
+     * @param string $connection Alias of a connection
+     */
+    public function switchTo($connection);
+
+    /**
+     * Returns the connection instance currently in use by the aggregate
+     * connection.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getCurrent();
+
+    /**
+     * Returns the connection instance for the master Redis node.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getMaster();
+
+    /**
+     * Returns a list of connection instances to slave nodes.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getSlaves();
+}

predis/src/Connection/Aggregate/SentinelReplication.php

@@ -0,0 +1,720 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection\Aggregate;
+
+use Predis\Command\CommandInterface;
+use Predis\Command\RawCommand;
+use Predis\CommunicationException;
+use Predis\Connection\ConnectionException;
+use Predis\Connection\FactoryInterface as ConnectionFactoryInterface;
+use Predis\Connection\NodeConnectionInterface;
+use Predis\Connection\Parameters;
+use Predis\Replication\ReplicationStrategy;
+use Predis\Replication\RoleException;
+use Predis\Response\ErrorInterface as ErrorResponseInterface;
+use Predis\Response\ServerException;
+
+/**
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ * @author Ville Mattila <ville@eventio.fi>
+ */
+class SentinelReplication implements ReplicationInterface
+{
+    /**
+     * @var NodeConnectionInterface
+     */
+    protected $master;
+
+    /**
+     * @var NodeConnectionInterface[]
+     */
+    protected $slaves = array();
+
+    /**
+     * @var NodeConnectionInterface
+     */
+    protected $current;
+
+    /**
+     * @var string
+     */
+    protected $service;
+
+    /**
+     * @var ConnectionFactoryInterface
+     */
+    protected $connectionFactory;
+
+    /**
+     * @var ReplicationStrategy
+     */
+    protected $strategy;
+
+    /**
+     * @var NodeConnectionInterface[]
+     */
+    protected $sentinels = array();
+
+    /**
+     * @var NodeConnectionInterface
+     */
+    protected $sentinelConnection;
+
+    /**
+     * @var float
+     */
+    protected $sentinelTimeout = 0.100;
+
+    /**
+     * Max number of automatic retries of commands upon server failure.
+     *
+     * -1 = unlimited retry attempts
+     *  0 = no retry attempts (fails immediatly)
+     *  n = fail only after n retry attempts
+     *
+     * @var int
+     */
+    protected $retryLimit = 20;
+
+    /**
+     * Time to wait in milliseconds before fetching a new configuration from one
+     * of the sentinel servers.
+     *
+     * @var int
+     */
+    protected $retryWait = 1000;
+
+    /**
+     * Flag for automatic fetching of available sentinels.
+     *
+     * @var bool
+     */
+    protected $updateSentinels = false;
+
+    /**
+     * @param string                     $service           Name of the service for autodiscovery.
+     * @param array                      $sentinels         Sentinel servers connection parameters.
+     * @param ConnectionFactoryInterface $connectionFactory Connection factory instance.
+     * @param ReplicationStrategy        $strategy          Replication strategy instance.
+     */
+    public function __construct(
+        $service,
+        array $sentinels,
+        ConnectionFactoryInterface $connectionFactory,
+        ReplicationStrategy $strategy = null
+    ) {
+        $this->sentinels = $sentinels;
+        $this->service = $service;
+        $this->connectionFactory = $connectionFactory;
+        $this->strategy = $strategy ?: new ReplicationStrategy();
+    }
+
+    /**
+     * Sets a default timeout for connections to sentinels.
+     *
+     * When "timeout" is present in the connection parameters of sentinels, its
+     * value overrides the default sentinel timeout.
+     *
+     * @param float $timeout Timeout value.
+     */
+    public function setSentinelTimeout($timeout)
+    {
+        $this->sentinelTimeout = (float) $timeout;
+    }
+
+    /**
+     * Sets the maximum number of retries for commands upon server failure.
+     *
+     * -1 = unlimited retry attempts
+     *  0 = no retry attempts (fails immediatly)
+     *  n = fail only after n retry attempts
+     *
+     * @param int $retry Number of retry attempts.
+     */
+    public function setRetryLimit($retry)
+    {
+        $this->retryLimit = (int) $retry;
+    }
+
+    /**
+     * Sets the time to wait (in seconds) before fetching a new configuration
+     * from one of the sentinels.
+     *
+     * @param float $seconds Time to wait before the next attempt.
+     */
+    public function setRetryWait($seconds)
+    {
+        $this->retryWait = (float) $seconds;
+    }
+
+    /**
+     * Set automatic fetching of available sentinels.
+     *
+     * @param bool $update Enable or disable automatic updates.
+     */
+    public function setUpdateSentinels($update)
+    {
+        $this->updateSentinels = (bool) $update;
+    }
+
+    /**
+     * Resets the current connection.
+     */
+    protected function reset()
+    {
+        $this->current = null;
+    }
+
+    /**
+     * Wipes the current list of master and slaves nodes.
+     */
+    protected function wipeServerList()
+    {
+        $this->reset();
+
+        $this->master = null;
+        $this->slaves = array();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function add(NodeConnectionInterface $connection)
+    {
+        $alias = $connection->getParameters()->alias;
+
+        if ($alias === 'master') {
+            $this->master = $connection;
+        } else {
+            $this->slaves[$alias ?: count($this->slaves)] = $connection;
+        }
+
+        $this->reset();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function remove(NodeConnectionInterface $connection)
+    {
+        if ($connection === $this->master) {
+            $this->master = null;
+            $this->reset();
+
+            return true;
+        }
+
+        if (false !== $id = array_search($connection, $this->slaves, true)) {
+            unset($this->slaves[$id]);
+            $this->reset();
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Creates a new connection to a sentinel server.
+     *
+     * @return NodeConnectionInterface
+     */
+    protected function createSentinelConnection($parameters)
+    {
+        if ($parameters instanceof NodeConnectionInterface) {
+            return $parameters;
+        }
+
+        if (is_string($parameters)) {
+            $parameters = Parameters::parse($parameters);
+        }
+
+        if (is_array($parameters)) {
+            // We explicitly set "database" and "password" to null,
+            // so that no AUTH and SELECT command is send to the sentinels.
+            $parameters['database'] = null;
+            $parameters['password'] = null;
+
+            if (!isset($parameters['timeout'])) {
+                $parameters['timeout'] = $this->sentinelTimeout;
+            }
+        }
+
+        $connection = $this->connectionFactory->create($parameters);
+
+        return $connection;
+    }
+
+    /**
+     * Returns the current sentinel connection.
+     *
+     * If there is no active sentinel connection, a new connection is created.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getSentinelConnection()
+    {
+        if (!$this->sentinelConnection) {
+            if (!$this->sentinels) {
+                throw new \Predis\ClientException('No sentinel server available for autodiscovery.');
+            }
+
+            $sentinel = array_shift($this->sentinels);
+            $this->sentinelConnection = $this->createSentinelConnection($sentinel);
+        }
+
+        return $this->sentinelConnection;
+    }
+
+    /**
+     * Fetches an updated list of sentinels from a sentinel.
+     */
+    public function updateSentinels()
+    {
+        SENTINEL_QUERY: {
+            $sentinel = $this->getSentinelConnection();
+
+            try {
+                $payload = $sentinel->executeCommand(
+                    RawCommand::create('SENTINEL', 'sentinels', $this->service)
+                );
+
+                $this->sentinels = array();
+                // NOTE: sentinel server does not return itself, so we add it back.
+                $this->sentinels[] = $sentinel->getParameters()->toArray();
+
+                foreach ($payload as $sentinel) {
+                    $this->sentinels[] = array(
+                        'host' => $sentinel[3],
+                        'port' => $sentinel[5],
+                    );
+                }
+            } catch (ConnectionException $exception) {
+                $this->sentinelConnection = null;
+
+                goto SENTINEL_QUERY;
+            }
+        }
+    }
+
+    /**
+     * Fetches the details for the master and slave servers from a sentinel.
+     */
+    public function querySentinel()
+    {
+        $this->wipeServerList();
+
+        $this->updateSentinels();
+        $this->getMaster();
+        $this->getSlaves();
+    }
+
+    /**
+     * Handles error responses returned by redis-sentinel.
+     *
+     * @param NodeConnectionInterface $sentinel Connection to a sentinel server.
+     * @param ErrorResponseInterface  $error    Error response.
+     */
+    private function handleSentinelErrorResponse(NodeConnectionInterface $sentinel, ErrorResponseInterface $error)
+    {
+        if ($error->getErrorType() === 'IDONTKNOW') {
+            throw new ConnectionException($sentinel, $error->getMessage());
+        } else {
+            throw new ServerException($error->getMessage());
+        }
+    }
+
+    /**
+     * Fetches the details for the master server from a sentinel.
+     *
+     * @param NodeConnectionInterface $sentinel Connection to a sentinel server.
+     * @param string                  $service  Name of the service.
+     *
+     * @return array
+     */
+    protected function querySentinelForMaster(NodeConnectionInterface $sentinel, $service)
+    {
+        $payload = $sentinel->executeCommand(
+            RawCommand::create('SENTINEL', 'get-master-addr-by-name', $service)
+        );
+
+        if ($payload === null) {
+            throw new ServerException('ERR No such master with that name');
+        }
+
+        if ($payload instanceof ErrorResponseInterface) {
+            $this->handleSentinelErrorResponse($sentinel, $payload);
+        }
+
+        return array(
+            'host' => $payload[0],
+            'port' => $payload[1],
+            'alias' => 'master',
+        );
+    }
+
+    /**
+     * Fetches the details for the slave servers from a sentinel.
+     *
+     * @param NodeConnectionInterface $sentinel Connection to a sentinel server.
+     * @param string                  $service  Name of the service.
+     *
+     * @return array
+     */
+    protected function querySentinelForSlaves(NodeConnectionInterface $sentinel, $service)
+    {
+        $slaves = array();
+
+        $payload = $sentinel->executeCommand(
+            RawCommand::create('SENTINEL', 'slaves', $service)
+        );
+
+        if ($payload instanceof ErrorResponseInterface) {
+            $this->handleSentinelErrorResponse($sentinel, $payload);
+        }
+
+        foreach ($payload as $slave) {
+            $flags = explode(',', $slave[9]);
+
+            if (array_intersect($flags, array('s_down', 'o_down', 'disconnected'))) {
+                continue;
+            }
+
+            $slaves[] = array(
+                'host' => $slave[3],
+                'port' => $slave[5],
+                'alias' => "slave-$slave[1]",
+            );
+        }
+
+        return $slaves;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getCurrent()
+    {
+        return $this->current;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getMaster()
+    {
+        if ($this->master) {
+            return $this->master;
+        }
+
+        if ($this->updateSentinels) {
+            $this->updateSentinels();
+        }
+
+        SENTINEL_QUERY: {
+            $sentinel = $this->getSentinelConnection();
+
+            try {
+                $masterParameters = $this->querySentinelForMaster($sentinel, $this->service);
+                $masterConnection = $this->connectionFactory->create($masterParameters);
+
+                $this->add($masterConnection);
+            } catch (ConnectionException $exception) {
+                $this->sentinelConnection = null;
+
+                goto SENTINEL_QUERY;
+            }
+        }
+
+        return $masterConnection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getSlaves()
+    {
+        if ($this->slaves) {
+            return array_values($this->slaves);
+        }
+
+        if ($this->updateSentinels) {
+            $this->updateSentinels();
+        }
+
+        SENTINEL_QUERY: {
+            $sentinel = $this->getSentinelConnection();
+
+            try {
+                $slavesParameters = $this->querySentinelForSlaves($sentinel, $this->service);
+
+                foreach ($slavesParameters as $slaveParameters) {
+                    $this->add($this->connectionFactory->create($slaveParameters));
+                }
+            } catch (ConnectionException $exception) {
+                $this->sentinelConnection = null;
+
+                goto SENTINEL_QUERY;
+            }
+        }
+
+        return array_values($this->slaves ?: array());
+    }
+
+    /**
+     * Returns a random slave.
+     *
+     * @return NodeConnectionInterface
+     */
+    protected function pickSlave()
+    {
+        if ($slaves = $this->getSlaves()) {
+            return $slaves[rand(1, count($slaves)) - 1];
+        }
+    }
+
+    /**
+     * Returns the connection instance in charge for the given command.
+     *
+     * @param CommandInterface $command Command instance.
+     *
+     * @return NodeConnectionInterface
+     */
+    private function getConnectionInternal(CommandInterface $command)
+    {
+        if (!$this->current) {
+            if ($this->strategy->isReadOperation($command) && $slave = $this->pickSlave()) {
+                $this->current = $slave;
+            } else {
+                $this->current = $this->getMaster();
+            }
+
+            return $this->current;
+        }
+
+        if ($this->current === $this->master) {
+            return $this->current;
+        }
+
+        if (!$this->strategy->isReadOperation($command)) {
+            $this->current = $this->getMaster();
+        }
+
+        return $this->current;
+    }
+
+    /**
+     * Asserts that the specified connection matches an expected role.
+     *
+     * @param NodeConnectionInterface $sentinel Connection to a redis server.
+     * @param string                  $role     Expected role of the server ("master", "slave" or "sentinel").
+     */
+    protected function assertConnectionRole(NodeConnectionInterface $connection, $role)
+    {
+        $role = strtolower($role);
+        $actualRole = $connection->executeCommand(RawCommand::create('ROLE'));
+
+        if ($role !== $actualRole[0]) {
+            throw new RoleException($connection, "Expected $role but got $actualRole[0] [$connection]");
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnection(CommandInterface $command)
+    {
+        $connection = $this->getConnectionInternal($command);
+
+        if (!$connection->isConnected()) {
+            // When we do not have any available slave in the pool we can expect
+            // read-only operations to hit the master server.
+            $expectedRole = $this->strategy->isReadOperation($command) && $this->slaves ? 'slave' : 'master';
+            $this->assertConnectionRole($connection, $expectedRole);
+        }
+
+        return $connection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConnectionById($connectionId)
+    {
+        if ($connectionId === 'master') {
+            return $this->getMaster();
+        }
+
+        $this->getSlaves();
+
+        if (isset($this->slaves[$connectionId])) {
+            return $this->slaves[$connectionId];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function switchTo($connection)
+    {
+        if (!$connection instanceof NodeConnectionInterface) {
+            $connection = $this->getConnectionById($connection);
+        }
+
+        if ($connection && $connection === $this->current) {
+            return;
+        }
+
+        if ($connection !== $this->master && !in_array($connection, $this->slaves, true)) {
+            throw new \InvalidArgumentException('Invalid connection or connection not found.');
+        }
+
+        $connection->connect();
+
+        if ($this->current) {
+            $this->current->disconnect();
+        }
+
+        $this->current = $connection;
+    }
+
+    /**
+     * Switches to the master server.
+     */
+    public function switchToMaster()
+    {
+        $this->switchTo('master');
+    }
+
+    /**
+     * Switches to a random slave server.
+     */
+    public function switchToSlave()
+    {
+        $connection = $this->pickSlave();
+        $this->switchTo($connection);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        return $this->current ? $this->current->isConnected() : false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if (!$this->current) {
+            if (!$this->current = $this->pickSlave()) {
+                $this->current = $this->getMaster();
+            }
+        }
+
+        $this->current->connect();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        if ($this->master) {
+            $this->master->disconnect();
+        }
+
+        foreach ($this->slaves as $connection) {
+            $connection->disconnect();
+        }
+    }
+
+    /**
+     * Retries the execution of a command upon server failure after asking a new
+     * configuration to one of the sentinels.
+     *
+     * @param CommandInterface $command Command instance.
+     * @param string           $method  Actual method.
+     *
+     * @return mixed
+     */
+    private function retryCommandOnFailure(CommandInterface $command, $method)
+    {
+        $retries = 0;
+
+        SENTINEL_RETRY: {
+            try {
+                $response = $this->getConnection($command)->$method($command);
+            } catch (CommunicationException $exception) {
+                $this->wipeServerList();
+                $exception->getConnection()->disconnect();
+
+                if ($retries == $this->retryLimit) {
+                    throw $exception;
+                }
+
+                usleep($this->retryWait * 1000);
+
+                ++$retries;
+                goto SENTINEL_RETRY;
+            }
+        }
+
+        return $response;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        return $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        return $this->retryCommandOnFailure($command, __FUNCTION__);
+    }
+
+    /**
+     * Returns the underlying replication strategy.
+     *
+     * @return ReplicationStrategy
+     */
+    public function getReplicationStrategy()
+    {
+        return $this->strategy;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array(
+            'master', 'slaves', 'service', 'sentinels', 'connectionFactory', 'strategy',
+        );
+    }
+}

predis/src/Connection/AggregateConnectionInterface.php

@@ -0,0 +1,57 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+
+/**
+ * Defines a virtual connection composed of multiple connection instances to
+ * single Redis nodes.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface AggregateConnectionInterface extends ConnectionInterface
+{
+    /**
+     * Adds a connection instance to the aggregate connection.
+     *
+     * @param NodeConnectionInterface $connection Connection instance.
+     */
+    public function add(NodeConnectionInterface $connection);
+
+    /**
+     * Removes the specified connection instance from the aggregate connection.
+     *
+     * @param NodeConnectionInterface $connection Connection instance.
+     *
+     * @return bool Returns true if the connection was in the pool.
+     */
+    public function remove(NodeConnectionInterface $connection);
+
+    /**
+     * Returns the connection instance in charge for the given command.
+     *
+     * @param CommandInterface $command Command instance.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function getConnection(CommandInterface $command);
+
+    /**
+     * Returns a connection instance from the aggregate connection by its alias.
+     *
+     * @param string $connectionID Connection alias.
+     *
+     * @return NodeConnectionInterface|null
+     */
+    public function getConnectionById($connectionID);
+}

predis/src/Connection/CompositeConnectionInterface.php

@@ -0,0 +1,49 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+/**
+ * Defines a connection to communicate with a single Redis server that leverages
+ * an external protocol processor to handle pluggable protocol handlers.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface CompositeConnectionInterface extends NodeConnectionInterface
+{
+    /**
+     * Returns the protocol processor used by the connection.
+     */
+    public function getProtocol();
+
+    /**
+     * Writes the buffer containing over the connection.
+     *
+     * @param string $buffer String buffer to be sent over the connection.
+     */
+    public function writeBuffer($buffer);
+
+    /**
+     * Reads the given number of bytes from the connection.
+     *
+     * @param int $length Number of bytes to read from the connection.
+     *
+     * @return string
+     */
+    public function readBuffer($length);
+
+    /**
+     * Reads a line from the connection.
+     *
+     * @param string
+     */
+    public function readLine();
+}

predis/src/Connection/CompositeStreamConnection.php

@@ -0,0 +1,125 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\Protocol\ProtocolProcessorInterface;
+use Predis\Protocol\Text\ProtocolProcessor as TextProtocolProcessor;
+
+/**
+ * Connection abstraction to Redis servers based on PHP's stream that uses an
+ * external protocol processor defining the protocol used for the communication.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class CompositeStreamConnection extends StreamConnection implements CompositeConnectionInterface
+{
+    protected $protocol;
+
+    /**
+     * @param ParametersInterface        $parameters Initialization parameters for the connection.
+     * @param ProtocolProcessorInterface $protocol   Protocol processor.
+     */
+    public function __construct(
+        ParametersInterface $parameters,
+        ProtocolProcessorInterface $protocol = null
+    ) {
+        $this->parameters = $this->assertParameters($parameters);
+        $this->protocol = $protocol ?: new TextProtocolProcessor();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getProtocol()
+    {
+        return $this->protocol;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeBuffer($buffer)
+    {
+        $this->write($buffer);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readBuffer($length)
+    {
+        if ($length <= 0) {
+            throw new \InvalidArgumentException('Length parameter must be greater than 0.');
+        }
+
+        $value = '';
+        $socket = $this->getResource();
+
+        do {
+            $chunk = fread($socket, $length);
+
+            if ($chunk === false || $chunk === '') {
+                $this->onConnectionError('Error while reading bytes from the server.');
+            }
+
+            $value .= $chunk;
+        } while (($length -= strlen($chunk)) > 0);
+
+        return $value;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readLine()
+    {
+        $value = '';
+        $socket = $this->getResource();
+
+        do {
+            $chunk = fgets($socket);
+
+            if ($chunk === false || $chunk === '') {
+                $this->onConnectionError('Error while reading line from the server.');
+            }
+
+            $value .= $chunk;
+        } while (substr($value, -2) !== "\r\n");
+
+        return substr($value, 0, -2);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->protocol->write($this, $command);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        return $this->protocol->read($this);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array_merge(parent::__sleep(), array('protocol'));
+    }
+}

predis/src/Connection/ConnectionException.php

@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\CommunicationException;
+
+/**
+ * Exception class that identifies connection-related errors.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class ConnectionException extends CommunicationException
+{
+}

predis/src/Connection/ConnectionInterface.php

@@ -0,0 +1,66 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+
+/**
+ * Defines a connection object used to communicate with one or multiple
+ * Redis servers.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ConnectionInterface
+{
+    /**
+     * Opens the connection to Redis.
+     */
+    public function connect();
+
+    /**
+     * Closes the connection to Redis.
+     */
+    public function disconnect();
+
+    /**
+     * Checks if the connection to Redis is considered open.
+     *
+     * @return bool
+     */
+    public function isConnected();
+
+    /**
+     * Writes the request for the given command over the connection.
+     *
+     * @param CommandInterface $command Command instance.
+     */
+    public function writeRequest(CommandInterface $command);
+
+    /**
+     * Reads the response to the given command from the connection.
+     *
+     * @param CommandInterface $command Command instance.
+     *
+     * @return mixed
+     */
+    public function readResponse(CommandInterface $command);
+
+    /**
+     * Writes a request for the given command over the connection and reads back
+     * the response returned by Redis.
+     *
+     * @param CommandInterface $command Command instance.
+     *
+     * @return mixed
+     */
+    public function executeCommand(CommandInterface $command);
+}

predis/src/Connection/Factory.php

@@ -0,0 +1,188 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\RawCommand;
+
+/**
+ * Standard connection factory for creating connections to Redis nodes.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class Factory implements FactoryInterface
+{
+    private $defaults = array();
+
+    protected $schemes = array(
+        'tcp' => 'Predis\Connection\StreamConnection',
+        'unix' => 'Predis\Connection\StreamConnection',
+        'tls' => 'Predis\Connection\StreamConnection',
+        'redis' => 'Predis\Connection\StreamConnection',
+        'rediss' => 'Predis\Connection\StreamConnection',
+        'http' => 'Predis\Connection\WebdisConnection',
+    );
+
+    /**
+     * Checks if the provided argument represents a valid connection class
+     * implementing Predis\Connection\NodeConnectionInterface. Optionally,
+     * callable objects are used for lazy initialization of connection objects.
+     *
+     * @param mixed $initializer FQN of a connection class or a callable for lazy initialization.
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return mixed
+     */
+    protected function checkInitializer($initializer)
+    {
+        if (is_callable($initializer)) {
+            return $initializer;
+        }
+
+        $class = new \ReflectionClass($initializer);
+
+        if (!$class->isSubclassOf('Predis\Connection\NodeConnectionInterface')) {
+            throw new \InvalidArgumentException(
+                'A connection initializer must be a valid connection class or a callable object.'
+            );
+        }
+
+        return $initializer;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function define($scheme, $initializer)
+    {
+        $this->schemes[$scheme] = $this->checkInitializer($initializer);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function undefine($scheme)
+    {
+        unset($this->schemes[$scheme]);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function create($parameters)
+    {
+        if (!$parameters instanceof ParametersInterface) {
+            $parameters = $this->createParameters($parameters);
+        }
+
+        $scheme = $parameters->scheme;
+
+        if (!isset($this->schemes[$scheme])) {
+            throw new \InvalidArgumentException("Unknown connection scheme: '$scheme'.");
+        }
+
+        $initializer = $this->schemes[$scheme];
+
+        if (is_callable($initializer)) {
+            $connection = call_user_func($initializer, $parameters, $this);
+        } else {
+            $connection = new $initializer($parameters);
+            $this->prepareConnection($connection);
+        }
+
+        if (!$connection instanceof NodeConnectionInterface) {
+            throw new \UnexpectedValueException(
+                'Objects returned by connection initializers must implement '.
+                "'Predis\Connection\NodeConnectionInterface'."
+            );
+        }
+
+        return $connection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function aggregate(AggregateConnectionInterface $connection, array $parameters)
+    {
+        foreach ($parameters as $node) {
+            $connection->add($node instanceof NodeConnectionInterface ? $node : $this->create($node));
+        }
+    }
+
+    /**
+     * Assigns a default set of parameters applied to new connections.
+     *
+     * The set of parameters passed to create a new connection have precedence
+     * over the default values set for the connection factory.
+     *
+     * @param array $parameters Set of connection parameters.
+     */
+    public function setDefaultParameters(array $parameters)
+    {
+        $this->defaults = $parameters;
+    }
+
+    /**
+     * Returns the default set of parameters applied to new connections.
+     *
+     * @return array
+     */
+    public function getDefaultParameters()
+    {
+        return $this->defaults;
+    }
+
+    /**
+     * Creates a connection parameters instance from the supplied argument.
+     *
+     * @param mixed $parameters Original connection parameters.
+     *
+     * @return ParametersInterface
+     */
+    protected function createParameters($parameters)
+    {
+        if (is_string($parameters)) {
+            $parameters = Parameters::parse($parameters);
+        } else {
+            $parameters = $parameters ?: array();
+        }
+
+        if ($this->defaults) {
+            $parameters += $this->defaults;
+        }
+
+        return new Parameters($parameters);
+    }
+
+    /**
+     * Prepares a connection instance after its initialization.
+     *
+     * @param NodeConnectionInterface $connection Connection instance.
+     */
+    protected function prepareConnection(NodeConnectionInterface $connection)
+    {
+        $parameters = $connection->getParameters();
+
+        if (isset($parameters->password)) {
+            $connection->addConnectCommand(
+                new RawCommand(array('AUTH', $parameters->password))
+            );
+        }
+
+        if (isset($parameters->database)) {
+            $connection->addConnectCommand(
+                new RawCommand(array('SELECT', $parameters->database))
+            );
+        }
+    }
+}

predis/src/Connection/FactoryInterface.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+/**
+ * Interface for classes providing a factory of connections to Redis nodes.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface FactoryInterface
+{
+    /**
+     * Defines or overrides the connection class identified by a scheme prefix.
+     *
+     * @param string $scheme      Target connection scheme.
+     * @param mixed  $initializer Fully-qualified name of a class or a callable for lazy initialization.
+     */
+    public function define($scheme, $initializer);
+
+    /**
+     * Undefines the connection identified by a scheme prefix.
+     *
+     * @param string $scheme Target connection scheme.
+     */
+    public function undefine($scheme);
+
+    /**
+     * Creates a new connection object.
+     *
+     * @param mixed $parameters Initialization parameters for the connection.
+     *
+     * @return NodeConnectionInterface
+     */
+    public function create($parameters);
+
+    /**
+     * Aggregates single connections into an aggregate connection instance.
+     *
+     * @param AggregateConnectionInterface $aggregate  Aggregate connection instance.
+     * @param array                        $parameters List of parameters for each connection.
+     */
+    public function aggregate(AggregateConnectionInterface $aggregate, array $parameters);
+}

predis/src/Connection/NodeConnectionInterface.php

@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+
+/**
+ * Defines a connection used to communicate with a single Redis node.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface NodeConnectionInterface extends ConnectionInterface
+{
+    /**
+     * Returns a string representation of the connection.
+     *
+     * @return string
+     */
+    public function __toString();
+
+    /**
+     * Returns the underlying resource used to communicate with Redis.
+     *
+     * @return mixed
+     */
+    public function getResource();
+
+    /**
+     * Returns the parameters used to initialize the connection.
+     *
+     * @return ParametersInterface
+     */
+    public function getParameters();
+
+    /**
+     * Pushes the given command into a queue of commands executed when
+     * establishing the actual connection to Redis.
+     *
+     * @param CommandInterface $command Instance of a Redis command.
+     */
+    public function addConnectCommand(CommandInterface $command);
+
+    /**
+     * Reads a response from the server.
+     *
+     * @return mixed
+     */
+    public function read();
+}

predis/src/Connection/Parameters.php

@@ -0,0 +1,176 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+/**
+ * Container for connection parameters used to initialize connections to Redis.
+ *
+ * {@inheritdoc}
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class Parameters implements ParametersInterface
+{
+    private $parameters;
+
+    private static $defaults = array(
+        'scheme' => 'tcp',
+        'host' => '127.0.0.1',
+        'port' => 6379,
+    );
+
+    /**
+     * @param array $parameters Named array of connection parameters.
+     */
+    public function __construct(array $parameters = array())
+    {
+        $this->parameters = $this->filter($parameters) + $this->getDefaults();
+    }
+
+    /**
+     * Returns some default parameters with their values.
+     *
+     * @return array
+     */
+    protected function getDefaults()
+    {
+        return self::$defaults;
+    }
+
+    /**
+     * Creates a new instance by supplying the initial parameters either in the
+     * form of an URI string or a named array.
+     *
+     * @param array|string $parameters Set of connection parameters.
+     *
+     * @return Parameters
+     */
+    public static function create($parameters)
+    {
+        if (is_string($parameters)) {
+            $parameters = static::parse($parameters);
+        }
+
+        return new static($parameters ?: array());
+    }
+
+    /**
+     * Parses an URI string returning an array of connection parameters.
+     *
+     * When using the "redis" and "rediss" schemes the URI is parsed according
+     * to the rules defined by the provisional registration documents approved
+     * by IANA. If the URI has a password in its "user-information" part or a
+     * database number in the "path" part these values override the values of
+     * "password" and "database" if they are present in the "query" part.
+     *
+     * @link http://www.iana.org/assignments/uri-schemes/prov/redis
+     * @link http://www.iana.org/assignments/uri-schemes/prov/rediss
+     *
+     * @param string $uri URI string.
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return array
+     */
+    public static function parse($uri)
+    {
+        if (stripos($uri, 'unix://') === 0) {
+            // parse_url() can parse unix:/path/to/sock so we do not need the
+            // unix:///path/to/sock hack, we will support it anyway until 2.0.
+            $uri = str_ireplace('unix://', 'unix:', $uri);
+        }
+
+        if (!$parsed = parse_url($uri)) {
+            throw new \InvalidArgumentException("Invalid parameters URI: $uri");
+        }
+
+        if (
+            isset($parsed['host'])
+            && false !== strpos($parsed['host'], '[')
+            && false !== strpos($parsed['host'], ']')
+        ) {
+            $parsed['host'] = substr($parsed['host'], 1, -1);
+        }
+
+        if (isset($parsed['query'])) {
+            parse_str($parsed['query'], $queryarray);
+            unset($parsed['query']);
+
+            $parsed = array_merge($parsed, $queryarray);
+        }
+
+        if (stripos($uri, 'redis') === 0) {
+            if (isset($parsed['pass'])) {
+                $parsed['password'] = $parsed['pass'];
+                unset($parsed['pass']);
+            }
+
+            if (isset($parsed['path']) && preg_match('/^\/(\d+)(\/.*)?/', $parsed['path'], $path)) {
+                $parsed['database'] = $path[1];
+
+                if (isset($path[2])) {
+                    $parsed['path'] = $path[2];
+                } else {
+                    unset($parsed['path']);
+                }
+            }
+        }
+
+        return $parsed;
+    }
+
+    /**
+     * Validates and converts each value of the connection parameters array.
+     *
+     * @param array $parameters Connection parameters.
+     *
+     * @return array
+     */
+    protected function filter(array $parameters)
+    {
+        return $parameters ?: array();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __get($parameter)
+    {
+        if (isset($this->parameters[$parameter])) {
+            return $this->parameters[$parameter];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __isset($parameter)
+    {
+        return isset($this->parameters[$parameter]);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function toArray()
+    {
+        return $this->parameters;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array('parameters');
+    }
+}

predis/src/Connection/ParametersInterface.php

@@ -0,0 +1,62 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+/**
+ * Interface defining a container for connection parameters.
+ *
+ * The actual list of connection parameters depends on the features supported by
+ * each connection backend class (please refer to their specific documentation),
+ * but the most common parameters used through the library are:
+ *
+ * @property-read string scheme             Connection scheme, such as 'tcp' or 'unix'.
+ * @property-read string host               IP address or hostname of Redis.
+ * @property-read int    port               TCP port on which Redis is listening to.
+ * @property-read string path               Path of a UNIX domain socket file.
+ * @property-read string alias              Alias for the connection.
+ * @property-read float  timeout            Timeout for the connect() operation.
+ * @property-read float  read_write_timeout Timeout for read() and write() operations.
+ * @property-read bool   async_connect      Performs the connect() operation asynchronously.
+ * @property-read bool   tcp_nodelay        Toggles the Nagle's algorithm for coalescing.
+ * @property-read bool   persistent         Leaves the connection open after a GC collection.
+ * @property-read string password           Password to access Redis (see the AUTH command).
+ * @property-read string database           Database index (see the SELECT command).
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ParametersInterface
+{
+    /**
+     * Checks if the specified parameters is set.
+     *
+     * @param string $parameter Name of the parameter.
+     *
+     * @return bool
+     */
+    public function __isset($parameter);
+
+    /**
+     * Returns the value of the specified parameter.
+     *
+     * @param string $parameter Name of the parameter.
+     *
+     * @return mixed|null
+     */
+    public function __get($parameter);
+
+    /**
+     * Returns an array representation of the connection parameters.
+     *
+     * @return array
+     */
+    public function toArray();
+}

predis/src/Connection/PhpiredisSocketConnection.php

@@ -0,0 +1,418 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\NotSupportedException;
+use Predis\Response\Error as ErrorResponse;
+use Predis\Response\ErrorInterface as ErrorResponseInterface;
+use Predis\Response\Status as StatusResponse;
+
+/**
+ * This class provides the implementation of a Predis connection that uses the
+ * PHP socket extension for network communication and wraps the phpiredis C
+ * extension (PHP bindings for hiredis) to parse the Redis protocol.
+ *
+ * This class is intended to provide an optional low-overhead alternative for
+ * processing responses from Redis compared to the standard pure-PHP classes.
+ * Differences in speed when dealing with short inline responses are practically
+ * nonexistent, the actual speed boost is for big multibulk responses when this
+ * protocol processor can parse and return responses very fast.
+ *
+ * For instructions on how to build and install the phpiredis extension, please
+ * consult the repository of the project.
+ *
+ * The connection parameters supported by this class are:
+ *
+ *  - scheme: it can be either 'redis', 'tcp' or 'unix'.
+ *  - host: hostname or IP address of the server.
+ *  - port: TCP port of the server.
+ *  - path: path of a UNIX domain socket when scheme is 'unix'.
+ *  - timeout: timeout to perform the connection (default is 5 seconds).
+ *  - read_write_timeout: timeout of read / write operations.
+ *
+ * @link http://github.com/nrk/phpiredis
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class PhpiredisSocketConnection extends AbstractConnection
+{
+    private $reader;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __construct(ParametersInterface $parameters)
+    {
+        $this->assertExtensions();
+
+        parent::__construct($parameters);
+
+        $this->reader = $this->createReader();
+    }
+
+    /**
+     * Disconnects from the server and destroys the underlying resource and the
+     * protocol reader resource when PHP's garbage collector kicks in.
+     */
+    public function __destruct()
+    {
+        phpiredis_reader_destroy($this->reader);
+
+        parent::__destruct();
+    }
+
+    /**
+     * Checks if the socket and phpiredis extensions are loaded in PHP.
+     */
+    protected function assertExtensions()
+    {
+        if (!extension_loaded('sockets')) {
+            throw new NotSupportedException(
+                'The "sockets" extension is required by this connection backend.'
+            );
+        }
+
+        if (!extension_loaded('phpiredis')) {
+            throw new NotSupportedException(
+                'The "phpiredis" extension is required by this connection backend.'
+            );
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function assertParameters(ParametersInterface $parameters)
+    {
+        switch ($parameters->scheme) {
+            case 'tcp':
+            case 'redis':
+            case 'unix':
+                break;
+
+            default:
+                throw new \InvalidArgumentException("Invalid scheme: '$parameters->scheme'.");
+        }
+
+        if (isset($parameters->persistent)) {
+            throw new NotSupportedException(
+                'Persistent connections are not supported by this connection backend.'
+            );
+        }
+
+        return $parameters;
+    }
+
+    /**
+     * Creates a new instance of the protocol reader resource.
+     *
+     * @return resource
+     */
+    private function createReader()
+    {
+        $reader = phpiredis_reader_create();
+
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler());
+
+        return $reader;
+    }
+
+    /**
+     * Returns the underlying protocol reader resource.
+     *
+     * @return resource
+     */
+    protected function getReader()
+    {
+        return $this->reader;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for inline responses.
+     *
+     * @return \Closure
+     */
+    protected function getStatusHandler()
+    {
+        static $statusHandler;
+
+        if (!$statusHandler) {
+            $statusHandler = function ($payload) {
+                return StatusResponse::get($payload);
+            };
+        }
+
+        return $statusHandler;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for error responses.
+     *
+     * @return \Closure
+     */
+    protected function getErrorHandler()
+    {
+        static $errorHandler;
+
+        if (!$errorHandler) {
+            $errorHandler = function ($errorMessage) {
+                return new ErrorResponse($errorMessage);
+            };
+        }
+
+        return $errorHandler;
+    }
+
+    /**
+     * Helper method used to throw exceptions on socket errors.
+     */
+    private function emitSocketError()
+    {
+        $errno = socket_last_error();
+        $errstr = socket_strerror($errno);
+
+        $this->disconnect();
+
+        $this->onConnectionError(trim($errstr), $errno);
+    }
+
+    /**
+     * Gets the address of an host from connection parameters.
+     *
+     * @param ParametersInterface $parameters Parameters used to initialize the connection.
+     *
+     * @return string
+     */
+    protected static function getAddress(ParametersInterface $parameters)
+    {
+        if (filter_var($host = $parameters->host, FILTER_VALIDATE_IP)) {
+            return $host;
+        }
+
+        if ($host === $address = gethostbyname($host)) {
+            return false;
+        }
+
+        return $address;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function createResource()
+    {
+        $parameters = $this->parameters;
+
+        if ($parameters->scheme === 'unix') {
+            $address = $parameters->path;
+            $domain = AF_UNIX;
+            $protocol = 0;
+        } else {
+            if (false === $address = self::getAddress($parameters)) {
+                $this->onConnectionError("Cannot resolve the address of '$parameters->host'.");
+            }
+
+            $domain = filter_var($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) ? AF_INET6 : AF_INET;
+            $protocol = SOL_TCP;
+        }
+
+        $socket = @socket_create($domain, SOCK_STREAM, $protocol);
+
+        if (!is_resource($socket)) {
+            $this->emitSocketError();
+        }
+
+        $this->setSocketOptions($socket, $parameters);
+        $this->connectWithTimeout($socket, $address, $parameters);
+
+        return $socket;
+    }
+
+    /**
+     * Sets options on the socket resource from the connection parameters.
+     *
+     * @param resource            $socket     Socket resource.
+     * @param ParametersInterface $parameters Parameters used to initialize the connection.
+     */
+    private function setSocketOptions($socket, ParametersInterface $parameters)
+    {
+        if ($parameters->scheme !== 'unix') {
+            if (!socket_set_option($socket, SOL_TCP, TCP_NODELAY, 1)) {
+                $this->emitSocketError();
+            }
+
+            if (!socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1)) {
+                $this->emitSocketError();
+            }
+        }
+
+        if (isset($parameters->read_write_timeout)) {
+            $rwtimeout = (float) $parameters->read_write_timeout;
+            $timeoutSec = floor($rwtimeout);
+            $timeoutUsec = ($rwtimeout - $timeoutSec) * 1000000;
+
+            $timeout = array(
+                'sec' => $timeoutSec,
+                'usec' => $timeoutUsec,
+            );
+
+            if (!socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, $timeout)) {
+                $this->emitSocketError();
+            }
+
+            if (!socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, $timeout)) {
+                $this->emitSocketError();
+            }
+        }
+    }
+
+    /**
+     * Opens the actual connection to the server with a timeout.
+     *
+     * @param resource            $socket     Socket resource.
+     * @param string              $address    IP address (DNS-resolved from hostname)
+     * @param ParametersInterface $parameters Parameters used to initialize the connection.
+     *
+     * @return string
+     */
+    private function connectWithTimeout($socket, $address, ParametersInterface $parameters)
+    {
+        socket_set_nonblock($socket);
+
+        if (@socket_connect($socket, $address, (int) $parameters->port) === false) {
+            $error = socket_last_error();
+
+            if ($error != SOCKET_EINPROGRESS && $error != SOCKET_EALREADY) {
+                $this->emitSocketError();
+            }
+        }
+
+        socket_set_block($socket);
+
+        $null = null;
+        $selectable = array($socket);
+
+        $timeout = (isset($parameters->timeout) ? (float) $parameters->timeout : 5.0);
+        $timeoutSecs = floor($timeout);
+        $timeoutUSecs = ($timeout - $timeoutSecs) * 1000000;
+
+        $selected = socket_select($selectable, $selectable, $null, $timeoutSecs, $timeoutUSecs);
+
+        if ($selected === 2) {
+            $this->onConnectionError('Connection refused.', SOCKET_ECONNREFUSED);
+        }
+
+        if ($selected === 0) {
+            $this->onConnectionError('Connection timed out.', SOCKET_ETIMEDOUT);
+        }
+
+        if ($selected === false) {
+            $this->emitSocketError();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if (parent::connect() && $this->initCommands) {
+            foreach ($this->initCommands as $command) {
+                $response = $this->executeCommand($command);
+
+                if ($response instanceof ErrorResponseInterface) {
+                    $this->onConnectionError("`{$command->getId()}` failed: $response", 0);
+                }
+            }
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        if ($this->isConnected()) {
+            socket_close($this->getResource());
+            parent::disconnect();
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function write($buffer)
+    {
+        $socket = $this->getResource();
+
+        while (($length = strlen($buffer)) > 0) {
+            $written = socket_write($socket, $buffer, $length);
+
+            if ($length === $written) {
+                return;
+            }
+
+            if ($written === false) {
+                $this->onConnectionError('Error while writing bytes to the server.');
+            }
+
+            $buffer = substr($buffer, $written);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        $socket = $this->getResource();
+        $reader = $this->reader;
+
+        while (PHPIREDIS_READER_STATE_INCOMPLETE === $state = phpiredis_reader_get_state($reader)) {
+            if (@socket_recv($socket, $buffer, 4096, 0) === false || $buffer === '' || $buffer === null) {
+                $this->emitSocketError();
+            }
+
+            phpiredis_reader_feed($reader, $buffer);
+        }
+
+        if ($state === PHPIREDIS_READER_STATE_COMPLETE) {
+            return phpiredis_reader_get_reply($reader);
+        } else {
+            $this->onProtocolError(phpiredis_reader_get_error($reader));
+
+            return;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $arguments = $command->getArguments();
+        array_unshift($arguments, $command->getId());
+
+        $this->write(phpiredis_format_command($arguments));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __wakeup()
+    {
+        $this->assertExtensions();
+        $this->reader = $this->createReader();
+    }
+}

predis/src/Connection/PhpiredisStreamConnection.php

@@ -0,0 +1,238 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\NotSupportedException;
+use Predis\Response\Error as ErrorResponse;
+use Predis\Response\Status as StatusResponse;
+
+/**
+ * This class provides the implementation of a Predis connection that uses PHP's
+ * streams for network communication and wraps the phpiredis C extension (PHP
+ * bindings for hiredis) to parse and serialize the Redis protocol.
+ *
+ * This class is intended to provide an optional low-overhead alternative for
+ * processing responses from Redis compared to the standard pure-PHP classes.
+ * Differences in speed when dealing with short inline responses are practically
+ * nonexistent, the actual speed boost is for big multibulk responses when this
+ * protocol processor can parse and return responses very fast.
+ *
+ * For instructions on how to build and install the phpiredis extension, please
+ * consult the repository of the project.
+ *
+ * The connection parameters supported by this class are:
+ *
+ *  - scheme: it can be either 'redis', 'tcp' or 'unix'.
+ *  - host: hostname or IP address of the server.
+ *  - port: TCP port of the server.
+ *  - path: path of a UNIX domain socket when scheme is 'unix'.
+ *  - timeout: timeout to perform the connection.
+ *  - read_write_timeout: timeout of read / write operations.
+ *  - async_connect: performs the connection asynchronously.
+ *  - tcp_nodelay: enables or disables Nagle's algorithm for coalescing.
+ *  - persistent: the connection is left intact after a GC collection.
+ *
+ * @link https://github.com/nrk/phpiredis
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class PhpiredisStreamConnection extends StreamConnection
+{
+    private $reader;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __construct(ParametersInterface $parameters)
+    {
+        $this->assertExtensions();
+
+        parent::__construct($parameters);
+
+        $this->reader = $this->createReader();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __destruct()
+    {
+        phpiredis_reader_destroy($this->reader);
+
+        parent::__destruct();
+    }
+
+    /**
+     * Checks if the phpiredis extension is loaded in PHP.
+     */
+    private function assertExtensions()
+    {
+        if (!extension_loaded('phpiredis')) {
+            throw new NotSupportedException(
+                'The "phpiredis" extension is required by this connection backend.'
+            );
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function assertSslSupport(ParametersInterface $parameters)
+    {
+        throw new \InvalidArgumentException('SSL encryption is not supported by this connection backend.');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function createStreamSocket(ParametersInterface $parameters, $address, $flags, $context = null)
+    {
+        $socket = null;
+        $timeout = (isset($parameters->timeout) ? (float) $parameters->timeout : 5.0);
+
+        $resource = @stream_socket_client($address, $errno, $errstr, $timeout, $flags);
+
+        if (!$resource) {
+            $this->onConnectionError(trim($errstr), $errno);
+        }
+
+        if (isset($parameters->read_write_timeout) && function_exists('socket_import_stream')) {
+            $rwtimeout = (float) $parameters->read_write_timeout;
+            $rwtimeout = $rwtimeout > 0 ? $rwtimeout : -1;
+
+            $timeout = array(
+                'sec' => $timeoutSeconds = floor($rwtimeout),
+                'usec' => ($rwtimeout - $timeoutSeconds) * 1000000,
+            );
+
+            $socket = $socket ?: socket_import_stream($resource);
+            @socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, $timeout);
+            @socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, $timeout);
+        }
+
+        if (isset($parameters->tcp_nodelay) && function_exists('socket_import_stream')) {
+            $socket = $socket ?: socket_import_stream($resource);
+            socket_set_option($socket, SOL_TCP, TCP_NODELAY, (int) $parameters->tcp_nodelay);
+        }
+
+        return $resource;
+    }
+
+    /**
+     * Creates a new instance of the protocol reader resource.
+     *
+     * @return resource
+     */
+    private function createReader()
+    {
+        $reader = phpiredis_reader_create();
+
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler());
+
+        return $reader;
+    }
+
+    /**
+     * Returns the underlying protocol reader resource.
+     *
+     * @return resource
+     */
+    protected function getReader()
+    {
+        return $this->reader;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for inline responses.
+     *
+     * @return \Closure
+     */
+    protected function getStatusHandler()
+    {
+        static $statusHandler;
+
+        if (!$statusHandler) {
+            $statusHandler = function ($payload) {
+                return StatusResponse::get($payload);
+            };
+        }
+
+        return $statusHandler;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for error responses.
+     *
+     * @return \Closure
+     */
+    protected function getErrorHandler()
+    {
+        static $errorHandler;
+
+        if (!$errorHandler) {
+            $errorHandler = function ($errorMessage) {
+                return new ErrorResponse($errorMessage);
+            };
+        }
+
+        return $errorHandler;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        $socket = $this->getResource();
+        $reader = $this->reader;
+
+        while (PHPIREDIS_READER_STATE_INCOMPLETE === $state = phpiredis_reader_get_state($reader)) {
+            $buffer = stream_socket_recvfrom($socket, 4096);
+
+            if ($buffer === false || $buffer === '') {
+                $this->onConnectionError('Error while reading bytes from the server.');
+            }
+
+            phpiredis_reader_feed($reader, $buffer);
+        }
+
+        if ($state === PHPIREDIS_READER_STATE_COMPLETE) {
+            return phpiredis_reader_get_reply($reader);
+        } else {
+            $this->onProtocolError(phpiredis_reader_get_error($reader));
+
+            return;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $arguments = $command->getArguments();
+        array_unshift($arguments, $command->getId());
+
+        $this->write(phpiredis_format_command($arguments));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __wakeup()
+    {
+        $this->assertExtensions();
+        $this->reader = $this->createReader();
+    }
+}

predis/src/Connection/StreamConnection.php

@@ -0,0 +1,396 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\Response\Error as ErrorResponse;
+use Predis\Response\ErrorInterface as ErrorResponseInterface;
+use Predis\Response\Status as StatusResponse;
+
+/**
+ * Standard connection to Redis servers implemented on top of PHP's streams.
+ * The connection parameters supported by this class are:.
+ *
+ *  - scheme: it can be either 'redis', 'tcp', 'rediss', 'tls' or 'unix'.
+ *  - host: hostname or IP address of the server.
+ *  - port: TCP port of the server.
+ *  - path: path of a UNIX domain socket when scheme is 'unix'.
+ *  - timeout: timeout to perform the connection (default is 5 seconds).
+ *  - read_write_timeout: timeout of read / write operations.
+ *  - async_connect: performs the connection asynchronously.
+ *  - tcp_nodelay: enables or disables Nagle's algorithm for coalescing.
+ *  - persistent: the connection is left intact after a GC collection.
+ *  - ssl: context options array (see http://php.net/manual/en/context.ssl.php)
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class StreamConnection extends AbstractConnection
+{
+    /**
+     * Disconnects from the server and destroys the underlying resource when the
+     * garbage collector kicks in only if the connection has not been marked as
+     * persistent.
+     */
+    public function __destruct()
+    {
+        if (isset($this->parameters->persistent) && $this->parameters->persistent) {
+            return;
+        }
+
+        $this->disconnect();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function assertParameters(ParametersInterface $parameters)
+    {
+        switch ($parameters->scheme) {
+            case 'tcp':
+            case 'redis':
+            case 'unix':
+                break;
+
+            case 'tls':
+            case 'rediss':
+                $this->assertSslSupport($parameters);
+                break;
+
+            default:
+                throw new \InvalidArgumentException("Invalid scheme: '$parameters->scheme'.");
+        }
+
+        return $parameters;
+    }
+
+    /**
+     * Checks needed conditions for SSL-encrypted connections.
+     *
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @throws \InvalidArgumentException
+     */
+    protected function assertSslSupport(ParametersInterface $parameters)
+    {
+        if (
+            filter_var($parameters->persistent, FILTER_VALIDATE_BOOLEAN) &&
+            version_compare(PHP_VERSION, '7.0.0beta') < 0
+        ) {
+            throw new \InvalidArgumentException('Persistent SSL connections require PHP >= 7.0.0.');
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function createResource()
+    {
+        switch ($this->parameters->scheme) {
+            case 'tcp':
+            case 'redis':
+                return $this->tcpStreamInitializer($this->parameters);
+
+            case 'unix':
+                return $this->unixStreamInitializer($this->parameters);
+
+            case 'tls':
+            case 'rediss':
+                return $this->tlsStreamInitializer($this->parameters);
+
+            default:
+                throw new \InvalidArgumentException("Invalid scheme: '{$this->parameters->scheme}'.");
+        }
+    }
+
+    /**
+     * Creates a connected stream socket resource.
+     *
+     * @param ParametersInterface $parameters Connection parameters.
+     * @param string              $address    Address for stream_socket_client().
+     * @param int                 $flags      Flags for stream_socket_client().
+     *
+     * @return resource
+     */
+    protected function createStreamSocket(ParametersInterface $parameters, $address, $flags)
+    {
+        $timeout = (isset($parameters->timeout) ? (float) $parameters->timeout : 5.0);
+
+        if (!$resource = @stream_socket_client($address, $errno, $errstr, $timeout, $flags)) {
+            $this->onConnectionError(trim($errstr), $errno);
+        }
+
+        if (isset($parameters->read_write_timeout)) {
+            $rwtimeout = (float) $parameters->read_write_timeout;
+            $rwtimeout = $rwtimeout > 0 ? $rwtimeout : -1;
+            $timeoutSeconds = floor($rwtimeout);
+            $timeoutUSeconds = ($rwtimeout - $timeoutSeconds) * 1000000;
+            stream_set_timeout($resource, $timeoutSeconds, $timeoutUSeconds);
+        }
+
+        if (isset($parameters->tcp_nodelay) && function_exists('socket_import_stream')) {
+            $socket = socket_import_stream($resource);
+            socket_set_option($socket, SOL_TCP, TCP_NODELAY, (int) $parameters->tcp_nodelay);
+        }
+
+        return $resource;
+    }
+
+    /**
+     * Initializes a TCP stream resource.
+     *
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @return resource
+     */
+    protected function tcpStreamInitializer(ParametersInterface $parameters)
+    {
+        if (!filter_var($parameters->host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
+            $address = "tcp://$parameters->host:$parameters->port";
+        } else {
+            $address = "tcp://[$parameters->host]:$parameters->port";
+        }
+
+        $flags = STREAM_CLIENT_CONNECT;
+
+        if (isset($parameters->async_connect) && $parameters->async_connect) {
+            $flags |= STREAM_CLIENT_ASYNC_CONNECT;
+        }
+
+        if (isset($parameters->persistent)) {
+            if (false !== $persistent = filter_var($parameters->persistent, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)) {
+                $flags |= STREAM_CLIENT_PERSISTENT;
+
+                if ($persistent === null) {
+                    $address = "{$address}/{$parameters->persistent}";
+                }
+            }
+        }
+
+        $resource = $this->createStreamSocket($parameters, $address, $flags);
+
+        return $resource;
+    }
+
+    /**
+     * Initializes a UNIX stream resource.
+     *
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @return resource
+     */
+    protected function unixStreamInitializer(ParametersInterface $parameters)
+    {
+        if (!isset($parameters->path)) {
+            throw new \InvalidArgumentException('Missing UNIX domain socket path.');
+        }
+
+        $flags = STREAM_CLIENT_CONNECT;
+
+        if (isset($parameters->persistent)) {
+            if (false !== $persistent = filter_var($parameters->persistent, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)) {
+                $flags |= STREAM_CLIENT_PERSISTENT;
+
+                if ($persistent === null) {
+                    throw new \InvalidArgumentException(
+                        'Persistent connection IDs are not supported when using UNIX domain sockets.'
+                    );
+                }
+            }
+        }
+
+        $resource = $this->createStreamSocket($parameters, "unix://{$parameters->path}", $flags);
+
+        return $resource;
+    }
+
+    /**
+     * Initializes a SSL-encrypted TCP stream resource.
+     *
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @return resource
+     */
+    protected function tlsStreamInitializer(ParametersInterface $parameters)
+    {
+        $resource = $this->tcpStreamInitializer($parameters);
+        $metadata = stream_get_meta_data($resource);
+
+        // Detect if crypto mode is already enabled for this stream (PHP >= 7.0.0).
+        if (isset($metadata['crypto'])) {
+            return $resource;
+        }
+
+        if (is_array($parameters->ssl)) {
+            $options = $parameters->ssl;
+        } else {
+            $options = array();
+        }
+
+        if (!isset($options['crypto_type'])) {
+            $options['crypto_type'] = STREAM_CRYPTO_METHOD_TLS_CLIENT;
+        }
+
+        if (!stream_context_set_option($resource, array('ssl' => $options))) {
+            $this->onConnectionError('Error while setting SSL context options');
+        }
+
+        if (!stream_socket_enable_crypto($resource, true, $options['crypto_type'])) {
+            $this->onConnectionError('Error while switching to encrypted communication');
+        }
+
+        return $resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        if (parent::connect() && $this->initCommands) {
+            foreach ($this->initCommands as $command) {
+                $response = $this->executeCommand($command);
+
+                if ($response instanceof ErrorResponseInterface) {
+                    $this->onConnectionError("`{$command->getId()}` failed: $response", 0);
+                }
+            }
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        if ($this->isConnected()) {
+            fclose($this->getResource());
+            parent::disconnect();
+        }
+    }
+
+    /**
+     * Performs a write operation over the stream of the buffer containing a
+     * command serialized with the Redis wire protocol.
+     *
+     * @param string $buffer Representation of a command in the Redis wire protocol.
+     */
+    protected function write($buffer)
+    {
+        $socket = $this->getResource();
+
+        while (($length = strlen($buffer)) > 0) {
+            $written = @fwrite($socket, $buffer);
+
+            if ($length === $written) {
+                return;
+            }
+
+            if ($written === false || $written === 0) {
+                $this->onConnectionError('Error while writing bytes to the server.');
+            }
+
+            $buffer = substr($buffer, $written);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        $socket = $this->getResource();
+        $chunk = fgets($socket);
+
+        if ($chunk === false || $chunk === '') {
+            $this->onConnectionError('Error while reading line from the server.');
+        }
+
+        $prefix = $chunk[0];
+        $payload = substr($chunk, 1, -2);
+
+        switch ($prefix) {
+            case '+':
+                return StatusResponse::get($payload);
+
+            case '$':
+                $size = (int) $payload;
+
+                if ($size === -1) {
+                    return;
+                }
+
+                $bulkData = '';
+                $bytesLeft = ($size += 2);
+
+                do {
+                    $chunk = fread($socket, min($bytesLeft, 4096));
+
+                    if ($chunk === false || $chunk === '') {
+                        $this->onConnectionError('Error while reading bytes from the server.');
+                    }
+
+                    $bulkData .= $chunk;
+                    $bytesLeft = $size - strlen($bulkData);
+                } while ($bytesLeft > 0);
+
+                return substr($bulkData, 0, -2);
+
+            case '*':
+                $count = (int) $payload;
+
+                if ($count === -1) {
+                    return;
+                }
+
+                $multibulk = array();
+
+                for ($i = 0; $i < $count; ++$i) {
+                    $multibulk[$i] = $this->read();
+                }
+
+                return $multibulk;
+
+            case ':':
+                $integer = (int) $payload;
+                return $integer == $payload ? $integer : $payload;
+
+            case '-':
+                return new ErrorResponse($payload);
+
+            default:
+                $this->onProtocolError("Unknown response prefix: '$prefix'.");
+
+                return;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $commandID = $command->getId();
+        $arguments = $command->getArguments();
+
+        $cmdlen = strlen($commandID);
+        $reqlen = count($arguments) + 1;
+
+        $buffer = "*{$reqlen}\r\n\${$cmdlen}\r\n{$commandID}\r\n";
+
+        foreach ($arguments as $argument) {
+            $arglen = strlen($argument);
+            $buffer .= "\${$arglen}\r\n{$argument}\r\n";
+        }
+
+        $this->write($buffer);
+    }
+}

predis/src/Connection/WebdisConnection.php

@@ -0,0 +1,366 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Connection;
+
+use Predis\Command\CommandInterface;
+use Predis\NotSupportedException;
+use Predis\Protocol\ProtocolException;
+use Predis\Response\Error as ErrorResponse;
+use Predis\Response\Status as StatusResponse;
+
+/**
+ * This class implements a Predis connection that actually talks with Webdis
+ * instead of connecting directly to Redis. It relies on the cURL extension to
+ * communicate with the web server and the phpiredis extension to parse the
+ * protocol for responses returned in the http response bodies.
+ *
+ * Some features are not yet available or they simply cannot be implemented:
+ *   - Pipelining commands.
+ *   - Publish / Subscribe.
+ *   - MULTI / EXEC transactions (not yet supported by Webdis).
+ *
+ * The connection parameters supported by this class are:
+ *
+ *  - scheme: must be 'http'.
+ *  - host: hostname or IP address of the server.
+ *  - port: TCP port of the server.
+ *  - timeout: timeout to perform the connection (default is 5 seconds).
+ *  - user: username for authentication.
+ *  - pass: password for authentication.
+ *
+ * @link http://webd.is
+ * @link http://github.com/nicolasff/webdis
+ * @link http://github.com/seppo0010/phpiredis
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class WebdisConnection implements NodeConnectionInterface
+{
+    private $parameters;
+    private $resource;
+    private $reader;
+
+    /**
+     * @param ParametersInterface $parameters Initialization parameters for the connection.
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct(ParametersInterface $parameters)
+    {
+        $this->assertExtensions();
+
+        if ($parameters->scheme !== 'http') {
+            throw new \InvalidArgumentException("Invalid scheme: '{$parameters->scheme}'.");
+        }
+
+        $this->parameters = $parameters;
+
+        $this->resource = $this->createCurl();
+        $this->reader = $this->createReader();
+    }
+
+    /**
+     * Frees the underlying cURL and protocol reader resources when the garbage
+     * collector kicks in.
+     */
+    public function __destruct()
+    {
+        curl_close($this->resource);
+        phpiredis_reader_destroy($this->reader);
+    }
+
+    /**
+     * Helper method used to throw on unsupported methods.
+     *
+     * @param string $method Name of the unsupported method.
+     *
+     * @throws NotSupportedException
+     */
+    private function throwNotSupportedException($method)
+    {
+        $class = __CLASS__;
+        throw new NotSupportedException("The method $class::$method() is not supported.");
+    }
+
+    /**
+     * Checks if the cURL and phpiredis extensions are loaded in PHP.
+     */
+    private function assertExtensions()
+    {
+        if (!extension_loaded('curl')) {
+            throw new NotSupportedException(
+                'The "curl" extension is required by this connection backend.'
+            );
+        }
+
+        if (!extension_loaded('phpiredis')) {
+            throw new NotSupportedException(
+                'The "phpiredis" extension is required by this connection backend.'
+            );
+        }
+    }
+
+    /**
+     * Initializes cURL.
+     *
+     * @return resource
+     */
+    private function createCurl()
+    {
+        $parameters = $this->getParameters();
+        $timeout = (isset($parameters->timeout) ? (float) $parameters->timeout : 5.0) * 1000;
+
+        if (filter_var($host = $parameters->host, FILTER_VALIDATE_IP)) {
+            $host = "[$host]";
+        }
+
+        $options = array(
+            CURLOPT_FAILONERROR => true,
+            CURLOPT_CONNECTTIMEOUT_MS => $timeout,
+            CURLOPT_URL => "$parameters->scheme://$host:$parameters->port",
+            CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
+            CURLOPT_POST => true,
+            CURLOPT_WRITEFUNCTION => array($this, 'feedReader'),
+        );
+
+        if (isset($parameters->user, $parameters->pass)) {
+            $options[CURLOPT_USERPWD] = "{$parameters->user}:{$parameters->pass}";
+        }
+
+        curl_setopt_array($resource = curl_init(), $options);
+
+        return $resource;
+    }
+
+    /**
+     * Initializes the phpiredis protocol reader.
+     *
+     * @return resource
+     */
+    private function createReader()
+    {
+        $reader = phpiredis_reader_create();
+
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler());
+
+        return $reader;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for inline responses.
+     *
+     * @return \Closure
+     */
+    protected function getStatusHandler()
+    {
+        static $statusHandler;
+
+        if (!$statusHandler) {
+            $statusHandler = function ($payload) {
+                return StatusResponse::get($payload);
+            };
+        }
+
+        return $statusHandler;
+    }
+
+    /**
+     * Returns the handler used by the protocol reader for error responses.
+     *
+     * @return \Closure
+     */
+    protected function getErrorHandler()
+    {
+        static $errorHandler;
+
+        if (!$errorHandler) {
+            $errorHandler = function ($errorMessage) {
+                return new ErrorResponse($errorMessage);
+            };
+        }
+
+        return $errorHandler;
+    }
+
+    /**
+     * Feeds the phpredis reader resource with the data read from the network.
+     *
+     * @param resource $resource Reader resource.
+     * @param string   $buffer   Buffer of data read from a connection.
+     *
+     * @return int
+     */
+    protected function feedReader($resource, $buffer)
+    {
+        phpiredis_reader_feed($this->reader, $buffer);
+
+        return strlen($buffer);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function connect()
+    {
+        // NOOP
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function disconnect()
+    {
+        // NOOP
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isConnected()
+    {
+        return true;
+    }
+
+    /**
+     * Checks if the specified command is supported by this connection class.
+     *
+     * @param CommandInterface $command Command instance.
+     *
+     * @throws NotSupportedException
+     *
+     * @return string
+     */
+    protected function getCommandId(CommandInterface $command)
+    {
+        switch ($commandID = $command->getId()) {
+            case 'AUTH':
+            case 'SELECT':
+            case 'MULTI':
+            case 'EXEC':
+            case 'WATCH':
+            case 'UNWATCH':
+            case 'DISCARD':
+            case 'MONITOR':
+                throw new NotSupportedException("Command '$commandID' is not allowed by Webdis.");
+
+            default:
+                return $commandID;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeRequest(CommandInterface $command)
+    {
+        $this->throwNotSupportedException(__FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function readResponse(CommandInterface $command)
+    {
+        $this->throwNotSupportedException(__FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function executeCommand(CommandInterface $command)
+    {
+        $resource = $this->resource;
+        $commandId = $this->getCommandId($command);
+
+        if ($arguments = $command->getArguments()) {
+            $arguments = implode('/', array_map('urlencode', $arguments));
+            $serializedCommand = "$commandId/$arguments.raw";
+        } else {
+            $serializedCommand = "$commandId.raw";
+        }
+
+        curl_setopt($resource, CURLOPT_POSTFIELDS, $serializedCommand);
+
+        if (curl_exec($resource) === false) {
+            $error = curl_error($resource);
+            $errno = curl_errno($resource);
+
+            throw new ConnectionException($this, trim($error), $errno);
+        }
+
+        if (phpiredis_reader_get_state($this->reader) !== PHPIREDIS_READER_STATE_COMPLETE) {
+            throw new ProtocolException($this, phpiredis_reader_get_error($this->reader));
+        }
+
+        return phpiredis_reader_get_reply($this->reader);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getParameters()
+    {
+        return $this->parameters;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function addConnectCommand(CommandInterface $command)
+    {
+        $this->throwNotSupportedException(__FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        $this->throwNotSupportedException(__FUNCTION__);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return "{$this->parameters->host}:{$this->parameters->port}";
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array('parameters');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __wakeup()
+    {
+        $this->assertExtensions();
+
+        $this->resource = $this->createCurl();
+        $this->reader = $this->createReader();
+    }
+}