Reimport Predis\Network\WebdisConnection with updates.

I could have rebased the previous branch with master, but since it was only a
single file and its history was basically meaningless I preferred to start
from scratch.

lib/Predis/Network/WebdisConnection.php

@@ -0,0 +1,143 @@
+<?php
+/*
+This class implements a Predis connection that actually talks with Webdis
+(http://github.com/nicolasff/webdis) instead of connecting directly to Redis.
+It relies on the http PECL extension to communicate with the web server and the
+phpiredis extension to parse the protocol of the replies returned in the http
+response bodies.
+
+Since this connection class is highly experimental, some features have not been
+implemented yet (or they simply cannot be implemented at all). Here is a list:
+
+  - Pipelining commands.
+  - Publish / Subscribe.
+  - MULTI / EXEC transactions (not yet supported by Webdis).
+*/
+
+namespace Predis\Network;
+
+use HttpRequest;
+use Predis\IConnectionParameters;
+use Predis\ResponseError;
+use Predis\ClientException;
+use Predis\ServerException;
+use Predis\CommunicationException;
+use Predis\Commands\ICommand;
+
+const ERR_MSG_EXTENSION = 'The %s extension must be loaded in order to be able to use this connection class';
+
+class WebdisConnection implements IConnectionSingle {
+    private $_parameters;
+    private $_webdisUrl;
+    private $_reader;
+
+    private static function throwNotImplementedException($class, $function) {
+        throw new \RuntimeException("The method $class::$function() is not implemented");
+    }
+
+    public function __construct(IConnectionParameters $parameters) {
+        $this->checkExtensions();
+        if ($parameters->scheme !== 'http') {
+            throw new \InvalidArgumentException("Invalid scheme: {$parameters->scheme}");
+        }
+        $this->_parameters = $parameters;
+        $this->_webdisUrl = "{$parameters->scheme}://{$parameters->host}:{$parameters->port}";
+        $this->_reader = $this->initializeReader($parameters);
+    }
+
+    public function __destruct() {
+        phpiredis_reader_destroy($this->_reader);
+    }
+
+    private function checkExtensions() {
+        if (!class_exists("HttpRequest")) {
+            throw new ClientException(sprintf(ERR_MSG_EXTENSION, 'http'));
+        }
+        if (!function_exists('phpiredis_reader_create')) {
+            throw new ClientException(sprintf(ERR_MSG_EXTENSION, 'phpiredis'));
+        }
+    }
+
+    private function initializeReader(IConnectionParameters $parameters) {
+        $throwErrors = $parameters->throw_errors;
+        $reader = phpiredis_reader_create();
+        phpiredis_reader_set_status_handler($reader, $this->getStatusHandler());
+        phpiredis_reader_set_error_handler($reader, $this->getErrorHandler($throwErrors));
+        return $reader;
+    }
+
+    private function getStatusHandler() {
+        return function($payload) {
+            return $payload === 'OK' ? true : $payload;
+        };
+    }
+
+    private function getErrorHandler($throwErrors) {
+        if ($throwErrors) {
+            return function($errorMessage) {
+                throw new ServerException($errorMessage);
+            };
+        }
+        return function($errorMessage) {
+            return new ResponseError($errorMessage);
+        };
+    }
+
+    private static function argumentsSerializer($str, $arg) {
+        $str .= '/' . urlencode($arg);
+        return $str;
+    }
+
+    public function connect() {
+        // NOOP
+    }
+
+    public function disconnect() {
+        // NOOP
+    }
+
+    public function isConnected() {
+        return true;
+    }
+
+    public function writeCommand(ICommand $command) {
+        self::throwNotImplementedException(__CLASS__, __FUNCTION__);
+    }
+
+    public function readResponse(ICommand $command) {
+        self::throwNotImplementedException(__CLASS__, __FUNCTION__);
+    }
+
+    public function executeCommand(ICommand $command) {
+        $params = $this->_parameters;
+        $arguments = array_reduce($command->getArguments(), 'self::argumentsSerializer');
+
+        $request = new HttpRequest($this->_webdisUrl, HttpRequest::METH_POST);
+        $request->setBody(sprintf('%s%s.raw', $command->getId(), $arguments));
+        $request->send();
+
+        phpiredis_reader_feed($this->_reader, $request->getResponseBody());
+        $reply = phpiredis_reader_get_reply($this->_reader);
+        return isset($reply->skipParse) ? $reply : $command->parseResponse($reply);
+    }
+
+    public function getResource() {
+        self::throwNotImplementedException(__CLASS__, __FUNCTION__);
+    }
+
+    public function getParameters() {
+        return $this->_parameters;
+    }
+
+    public function pushInitCommand(ICommand $command) {
+        self::throwNotImplementedException(__CLASS__, __FUNCTION__);
+    }
+
+    public function read() {
+        self::throwNotImplementedException(__CLASS__, __FUNCTION__);
+    }
+
+    public function __toString() {
+        return "{$this->_parameters->host}:{$this->_parameters->port}";
+    }
+}