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/WebdisConnection.php

@@ -0,0 +1,335 @@
+<?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\Command\CommandInterface;
+use Predis\Connection\ConnectionException;
+use Predis\Protocol\ProtocolException;
+
+/**
+ * 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 of the replies 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.
+ *  - 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 SingleConnectionInterface
+{
+    const ERR_MSG_EXTENSION = 'The %s extension must be loaded in order to be able to use this connection class';
+
+    private $parameters;
+    private $resource;
+    private $reader;
+
+    /**
+     * @param ConnectionParametersInterface $parameters Parameters used to initialize the connection.
+     */
+    public function __construct(ConnectionParametersInterface $parameters)
+    {
+        $this->checkExtensions();
+
+        if ($parameters->scheme !== 'http') {
+            throw new \InvalidArgumentException("Invalid scheme: {$parameters->scheme}");
+        }
+
+        $this->parameters = $parameters;
+        $this->resource = $this->initializeCurl($parameters);
+        $this->reader = $this->initializeReader($parameters);
+    }
+
+    /**
+     * Frees the underlying cURL and protocol reader resources when PHP's
+     * garbage collector kicks in.
+     */
+    public function __destruct()
+    {
+        curl_close($this->resource);
+        phpiredis_reader_destroy($this->reader);
+    }
+
+    /**
+     * Helper method used to throw on unsupported methods.
+     */
+    private function throwNotSupportedException($function)
+    {
+        $class = __CLASS__;
+        throw new NotSupportedException("The method $class::$function() is not supported");
+    }
+
+    /**
+     * Checks if the cURL and phpiredis extensions are loaded in PHP.
+     */
+    private function checkExtensions()
+    {
+        if (!function_exists('curl_init')) {
+            throw new NotSupportedException(sprintf(self::ERR_MSG_EXTENSION, 'curl'));
+        }
+
+        if (!function_exists('phpiredis_reader_create')) {
+            throw new NotSupportedException(sprintf(self::ERR_MSG_EXTENSION, 'phpiredis'));
+        }
+    }
+
+    /**
+     * Initializes cURL.
+     *
+     * @param  ConnectionParametersInterface $parameters Parameters used to initialize the connection.
+     * @return resource
+     */
+    private function initializeCurl(ConnectionParametersInterface $parameters)
+    {
+        $options = array(
+            CURLOPT_FAILONERROR => true,
+            CURLOPT_CONNECTTIMEOUT_MS => $parameters->timeout * 1000,
+            CURLOPT_URL => "{$parameters->scheme}://{$parameters->host}:{$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 phpiredis' protocol reader.
+     *
+     * @param  ConnectionParametersInterface $parameters Parameters used to initialize the connection.
+     * @return resource
+     */
+    private function initializeReader(ConnectionParametersInterface $parameters)
+    {
+        $reader = phpiredis_reader_create();
+
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler());
+
+        return $reader;
+    }
+
+    /**
+     * Gets the handler used by the protocol reader to handle status replies.
+     *
+     * @return \Closure
+     */
+    protected function getStatusHandler()
+    {
+        return function ($payload) {
+            return $payload === 'OK' ? true : $payload;
+        };
+    }
+
+    /**
+     * Gets the handler used by the protocol reader to handle Redis errors.
+     *
+     * @return \Closure
+     */
+    protected function getErrorHandler()
+    {
+        return function ($errorMessage) {
+            return new ResponseError($errorMessage);
+        };
+    }
+
+    /**
+     * Feeds phpredis' reader resource with the data read from the network.
+     *
+     * @param  resource $resource Reader resource.
+     * @param  string   $buffer   Buffer with the reply read from the network.
+     * @return int
+     */
+    protected function feedReader($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 The instance of a Redis command.
+     * @return string
+     */
+    protected function getCommandId(CommandInterface $command)
+    {
+        switch (($commandId = $command->getId())) {
+            case 'AUTH':
+            case 'SELECT':
+            case 'MULTI':
+            case 'EXEC':
+            case 'WATCH':
+            case 'UNWATCH':
+            case 'DISCARD':
+            case 'MONITOR':
+                throw new NotSupportedException("Disabled command: {$command->getId()}");
+
+            default:
+                return $commandId;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function writeCommand(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 pushInitCommand(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->checkExtensions();
+        $parameters = $this->getParameters();
+
+        $this->resource = $this->initializeCurl($parameters);
+        $this->reader = $this->initializeReader($parameters);
+    }
+}