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/ConnectionFactory.php

@@ -0,0 +1,180 @@
+<?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\Profile\ServerProfileInterface;
+
+/**
+ * Provides a default factory for Redis connections that maps URI schemes
+ * to connection classes implementing Predis\Connection\SingleConnectionInterface.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class ConnectionFactory implements ConnectionFactoryInterface
+{
+    protected $schemes;
+    protected $profile;
+
+    /**
+     * Initializes a new instance of the default connection factory class used by Predis.
+     *
+     * @param ServerProfileInterface $profile Server profile used to initialize new connections.
+     */
+    public function __construct(ServerProfileInterface $profile = null)
+    {
+        $this->schemes = $this->getDefaultSchemes();
+        $this->profile = $profile;
+    }
+
+    /**
+     * Returns a named array that maps URI schemes to connection classes.
+     *
+     * @return array Map of URI schemes and connection classes.
+     */
+    protected function getDefaultSchemes()
+    {
+        return array(
+            'tcp'  => 'Predis\Connection\StreamConnection',
+            'unix' => 'Predis\Connection\StreamConnection',
+            'http' => 'Predis\Connection\WebdisConnection',
+        );
+    }
+
+    /**
+     * Checks if the provided argument represents a valid connection class
+     * implementing Predis\Connection\SingleConnectionInterface. Optionally,
+     * callable objects are used for lazy initialization of connection objects.
+     *
+     * @param  mixed $initializer FQN of a connection class or a callable for lazy initialization.
+     * @return mixed
+     */
+    protected function checkInitializer($initializer)
+    {
+        if (is_callable($initializer)) {
+            return $initializer;
+        }
+
+        $initializerReflection = new \ReflectionClass($initializer);
+
+        if (!$initializerReflection->isSubclassOf('Predis\Connection\SingleConnectionInterface')) {
+            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 ConnectionParametersInterface) {
+            $parameters = new ConnectionParameters($parameters ?: array());
+        }
+
+        $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 SingleConnectionInterface) {
+            throw new \InvalidArgumentException(
+                'Objects returned by connection initializers must implement ' .
+                'Predis\Connection\SingleConnectionInterface'
+            );
+        }
+
+        return $connection;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function createAggregated(AggregatedConnectionInterface $connection, Array $parameters)
+    {
+        foreach ($parameters as $node) {
+            $connection->add($node instanceof SingleConnectionInterface ? $node : $this->create($node));
+        }
+
+        return $connection;
+    }
+
+    /**
+     * Prepares a connection object after its initialization.
+     *
+     * @param SingleConnectionInterface $connection Instance of a connection object.
+     */
+    protected function prepareConnection(SingleConnectionInterface $connection)
+    {
+        if (isset($this->profile)) {
+            $parameters = $connection->getParameters();
+
+            if (isset($parameters->password)) {
+                $command = $this->profile->createCommand('auth', array($parameters->password));
+                $connection->pushInitCommand($command);
+            }
+
+            if (isset($parameters->database)) {
+                $command = $this->profile->createCommand('select', array($parameters->database));
+                $connection->pushInitCommand($command);
+            }
+        }
+    }
+
+    /**
+     * Sets the server profile used to create initialization commands for connections.
+     *
+     * @param ServerProfileInterface $profile Server profile instance.
+     */
+    public function setProfile(ServerProfileInterface $profile)
+    {
+        $this->profile = $profile;
+    }
+
+    /**
+     * Returns the server profile used to create initialization commands for connections.
+     *
+     * @return ServerProfileInterface
+     */
+    public function getProfile()
+    {
+        return $this->profile;
+    }
+}