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/Command/RawCommand.php

@@ -0,0 +1,157 @@
+<?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\Command;
+
+use InvalidArgumentException;
+
+/**
+ * Class for generic "anonymous" Redis commands.
+ *
+ * This command class does not filter input arguments or parse responses, but
+ * can be used to leverage the standard Predis API to execute any command simply
+ * by providing the needed arguments following the command signature as defined
+ * by Redis in its documentation.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class RawCommand implements CommandInterface
+{
+    private $hash;
+    private $commandID;
+    private $arguments;
+
+    public function __construct(array $arguments)
+    {
+        if (!$arguments) {
+            throw new InvalidArgumentException("Arguments array is missing the command ID");
+        }
+
+        $this->commandID = strtoupper(array_shift($arguments));
+        $this->arguments = $arguments;
+    }
+
+    /**
+     * Creates a new raw command using a variadic method.
+     *
+     * @param string $commandID Redis command ID.
+     * @param string ... Arguments list for the command.
+     * @return CommandInterface
+     */
+    public static function create($commandID /* [ $arg, ... */)
+    {
+        $arguments = func_get_args();
+        $command = new self($arguments);
+
+        return $command;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getId()
+    {
+        return $this->commandID;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setArguments(array $arguments)
+    {
+        $this->arguments = $arguments;
+        unset($this->hash);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setRawArguments(array $arguments)
+    {
+        $this->setArguments($arguments);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getArguments()
+    {
+        return $this->arguments;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getArgument($index)
+    {
+        if (isset($this->arguments[$index])) {
+            return $this->arguments[$index];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setHash($hash)
+    {
+        $this->hash = $hash;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getHash()
+    {
+        if (isset($this->hash)) {
+            return $this->hash;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function parseResponse($data)
+    {
+        return $data;
+    }
+
+    /**
+     * Helper function used to reduce a list of arguments to a string.
+     *
+     * @param  string $accumulator Temporary string.
+     * @param  string $argument    Current argument.
+     * @return string
+     */
+    protected function toStringArgumentReducer($accumulator, $argument)
+    {
+        if (strlen($argument) > 32) {
+            $argument = substr($argument, 0, 32) . '[...]';
+        }
+
+        $accumulator .= " $argument";
+
+        return $accumulator;
+    }
+
+    /**
+     * Returns a partial string representation of the command with its arguments.
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        return array_reduce(
+            $this->getArguments(),
+            array($this, 'toStringArgumentReducer'),
+            $this->getId()
+        );
+    }
+}