Retwis ported to modern Redis data types.

The example (and related documentation at redis.io) was not updated for
5 years. Redis had no sorted sets and hashes when the original code was
written (!). An update was really needed.

We also use a modern PHP client now: Predis. A copy is shipped within
this repository to make life easier to newcomers trying Redis for the
first time via this example.

Predis/Connection/PhpiredisStreamConnection.php

@@ -0,0 +1,196 @@
+<?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\NotSupportedException;
+use Predis\ResponseError;
+use Predis\ResponseQueued;
+use Predis\Command\CommandInterface;
+
+/**
+ * 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. Everything
+ * is highly experimental (even the very same phpiredis since it is quite new),
+ * so use it at your own risk.
+ *
+ * This class is mainly intended to provide an optional low-overhead alternative
+ * for processing replies from Redis compared to the standard pure-PHP classes.
+ * Differences in speed when dealing with short inline replies are practically
+ * nonexistent, the actual speed boost is for long multibulk replies when this
+ * protocol processor can parse and return replies 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 '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(ConnectionParametersInterface $parameters)
+    {
+        $this->checkExtensions();
+        $this->initializeReader();
+
+        parent::__construct($parameters);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __destruct()
+    {
+        phpiredis_reader_destroy($this->reader);
+
+        parent::__destruct();
+    }
+
+    /**
+     * Checks if the phpiredis extension is loaded in PHP.
+     */
+    protected function checkExtensions()
+    {
+        if (!function_exists('phpiredis_reader_create')) {
+            throw new NotSupportedException(
+                'The phpiredis extension must be loaded in order to be able to use this connection class'
+            );
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function checkParameters(ConnectionParametersInterface $parameters)
+    {
+        if (isset($parameters->iterable_multibulk)) {
+            $this->onInvalidOption('iterable_multibulk', $parameters);
+        }
+
+        return parent::checkParameters($parameters);
+    }
+
+    /**
+     * Initializes the protocol reader resource.
+     */
+    protected function initializeReader()
+    {
+        $reader = phpiredis_reader_create();
+
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler());
+
+        $this->reader = $reader;
+    }
+
+    /**
+     * Gets the handler used by the protocol reader to handle status replies.
+     *
+     * @return \Closure
+     */
+    protected function getStatusHandler()
+    {
+        return function ($payload) {
+            switch ($payload) {
+                case 'OK':
+                    return true;
+
+                case 'QUEUED':
+                    return new ResponseQueued();
+
+                default:
+                    return $payload;
+            }
+        };
+    }
+
+    /**
+     * Gets the handler used by the protocol reader to handle Redis errors.
+     *
+     * @return \Closure
+     */
+    protected function getErrorHandler()
+    {
+        return function ($errorMessage) {
+            return new ResponseError($errorMessage);
+        };
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function read()
+    {
+        $socket = $this->getResource();
+        $reader = $this->reader;
+
+        while (PHPIREDIS_READER_STATE_INCOMPLETE === $state = phpiredis_reader_get_state($reader)) {
+            $buffer = fread($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));
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeCommand(CommandInterface $command)
+    {
+        $cmdargs = $command->getArguments();
+        array_unshift($cmdargs, $command->getId());
+        $this->writeBytes(phpiredis_format_command($cmdargs));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __sleep()
+    {
+        return array_diff(parent::__sleep(), array('mbiterable'));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __wakeup()
+    {
+        $this->checkExtensions();
+        $this->initializeReader();
+    }
+}