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/Option/ClientProfile.php

@@ -0,0 +1,61 @@
+<?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\Option;
+
+use Predis\Profile\ServerProfile;
+use Predis\Profile\ServerProfileInterface;
+
+/**
+ * Option class that handles server profiles to be used by a client.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class ClientProfile extends AbstractOption
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function filter(ClientOptionsInterface $options, $value)
+    {
+        if (is_string($value)) {
+            $value = ServerProfile::get($value);
+
+            if (isset($options->prefix)) {
+                $value->setProcessor($options->prefix);
+            }
+        }
+
+        if (is_callable($value)) {
+            $value = call_user_func($value, $options, $this);
+        }
+
+        if (!$value instanceof ServerProfileInterface) {
+            throw new \InvalidArgumentException('Invalid value for the profile option');
+        }
+
+        return $value;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getDefault(ClientOptionsInterface $options)
+    {
+        $profile = ServerProfile::getDefault();
+
+        if (isset($options->prefix)) {
+            $profile->setProcessor($options->prefix);
+        }
+
+        return $profile;
+    }
+}