php wrapper實現

【背景】

做一個thrift client的wrapper，用以實現對於伺服器的重試邏輯。

【關鍵點】

1. wrapper要求跟用client一樣方便。

2. 當某個伺服器掛掉之後可以隨機選另一台重試。

3. 用到的php幾個關鍵特性： __call()（magic function，當訪問的對象函數不存在時會調用這個）, ReflectionClass 反射類及其其成員函數newInstanceArgs ,   call_user_func_array回呼函數。

直接看代碼吧(某位牛人寫的，not me)：

#!/usr/bin/env php<?phpnamespace wrapper;error_reporting(E_ALL);require_once '/usr/local/Cellar/thrift/0.9.1/Thrift/ClassLoader/ThriftClassLoader.php';use Thrift\ClassLoader\ThriftClassLoader;$GEN_DIR = realpath(dirname(__FILE__).'/..').'/gen-php';$loader = new ThriftClassLoader();$loader->registerNamespace('Thrift', '/usr/local/Cellar/thrift/0.9.1/');$loader->registerDefinition('xiaoju', $GEN_DIR);$loader->register();use Thrift\Protocol\TBinaryProtocol;use Thrift\Transport\TSocket;use Thrift\Transport\THttpClient;use Thrift\Transport\TBufferedTransport;use Thrift\Exception\TException;class RetryWrapper {    public function __construct($classname, $hosts) {        $this->clazz = new \ReflectionClass($classname);        $this->hosts = $hosts;    }    public function __call($method, $args) {        shuffle($this->hosts);        foreach ($this->hosts as $key => $host) {            try {                return $this->inner_call($host, $method, $args);            } catch (TException $ex) {                $msg = $ex->getMessage();                if (!strstr($msg, 'TSocket')) {                    throw $ex;                }            }        }        throw new TException("all server down!");    }    public function inner_call($host, $method, $args) {        $tmp = explode(":", $host);        $socket = new TSocket($tmp[0], (int)$tmp[1]);        $transport = new TBufferedTransport($socket, 1024, 1024);        $protocol = new TBinaryProtocol($transport);        $client = $this->clazz->newInstanceArgs(array($protocol));        $transport->open();        $result = call_user_func_array(array($client, $method), $args);        $transport->close();        return $result;    }}$hosts = array('localhost:9090', 'localhost:9091');$wrapper = new RetryWrapper("\xxx\xx\MessageServiceClient", $hosts, 3);$data = array('businessId' => 300100001, 'phones' => array('2','2','3'), 'message' => 'asdfqer') ;$message = new \xxx\xx\Message($data);print $wrapper->sendMessage($message);print "\n";?>

還是挺巧妙的，先記錄下來