swoole之协程实现并发

主要使用 swoole的子协程 和 协程channel 的两个特征 实现任务并发。
直接上代码说明：

$server = new SwooleHttpServer("0.0.0.0",20000,SWOOLE_PROCESS,SWOOLE_SOCK_TCP);
$server->on("request",function(SwooleHttpRequest $request,SwooleHttpResponse $response){
    $fd = $request->fd;
    if($request->server["request_uri"] == "/favicon.ico"){
        $this->server->close($fd);
        return false;
    }
    $urls = [
        "http://www.estb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25885.html",
        "http://www.sweb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_23660.html",
        "http://www.daiinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25596.html",
        "http://www.us764.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_16724.html",
        "http://www.vieinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25571.html",
        "http://www.estb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25885.html",
        "http://www.sweb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_23660.html",
        "http://www.daiinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25596.html",
        "http://www.us764.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_16724.html",
        "http://www.vieinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25571.html",
        "http://www.estb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25885.html",
        "http://www.sweb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_23660.html",
        "http://www.daiinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25596.html",
        "http://www.us764.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_16724.html",
        "http://www.vieinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25571.html",
        "http://www.estb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25885.html",
        "http://www.sweb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_23660.html",
        "http://www.daiinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25596.html",
        "http://www.us764.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_16724.html",
        "http://www.vieinfo.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25571.html",
        "http://www.estb2b.com/product-detail/BPA-free-80--120-80mm-cash-register-paper-80--120-70mm-thermal-paper-rolls_25885.html",
        ......
    ];
    $taskCount = count($urls);
    $channel = new SwooleCoroutineChannel($taskCount); // 用于子协程与 主进程之间的通信
    $start = time();
    foreach ($urls as $url){
        go(function()use($channel,$url){
            // 在swoole协程中 http 客户端强烈推荐使用composer包 swlib/saber , 该包库功能强大，缺点是只能在 协程环境中使用
            // 该包库是由 swoole 核心开发组开发，用于代替swoole原生协程 客户端
            // 使用详情参考  https://github.com/swlib/saber
             try{
                  $saberRespOnse= SwlibSaberGM::get($url); // 返回 SwlibSaberResponse 对象
                  $code = $saberResponse->getStatusCode();
                  $r = $code . " => " . strlen($saberResponse->getBody());
                  $channel->push($r);
             }catch(Exception $e){
                  $channel->push("Exception : ".$e->getMessage());
             }
        });
    }
    for ($i = 1; $i <= $taskCount; $i++){
        // 阻塞 等待处理结果
        $r= $channel->pop();
        var_dump($r);
    }
    $diff = time() - $start;
    echo "全部完成需要时间差 diff={$diff}s n";
    $response->end("返回响应数据到客户端");
}); 
$server->start();

经本人实测，在同时请求 任务多的情况下，性能尤为明显。以本案例爬取海外站点源码为例，性能比多进程process模型更高，所用时间只需要process模块1/3的时间。
重点掌握 #协程运行生命周期， #协程通信Channel， #协程Http客户端swlib/saber 的使用。

重点说明：协程模式环境下(也是使用协程的缺点)，编写的代码与传统同步串行代码存在部分差异，某些pecl扩展和阻塞代码不能在协程环境下使用。
例如： curl扩展，sleep睡眠函数等不能在协程环境模式下使用（详细参考swoole文档）但是swoole官方开发组为之提供了对应的解决方案。使用swoole官方提供的函数或者库能很好解决对用的问题。(例如 mysql/redis客户端等在协程模式下必须使用协程客户端(最好使用基于协程连接池的pool)，否则并不能体现很好的性能)