swoole_event_add实现异步

swoole提供了swoole_event_add函数，可以实现异步。此函数可以用在Server或Client模式下。

swoole_event_add属于AsyncIO，必须运行在CLI 模式。

异步tcp客户端

stream_socket_client实现tcp同步客户端

示例：

<?php

$start_time = microtime(TRUE);

$fp = stream_socket_client("tcp://www.52fhy.com:80", $errno, $errstr, 30);
fwrite($fp,"GET /test.json HTTP/1.1
Host: www.52fhy.com

");

echo $resp = fread($fp, 8192);
fclose($fp);
echo "Finish
";  

$end_time = microtime(TRUE);
echo sprintf("use time:%.3f s
", $end_time - $start_time);

上述代码是同步执行的。如何变成异步呢？

stream_socket_client实现tcp异步客户端

由于fread读取响应数据是同步堵塞的，我们将$fp加入到事件监听后，底层会自动将该socket设置为非阻塞模式。修改fread那一行：

swoole_event_add($fp, function($fp) {
    echo $resp = fread($fp, 8192);
    swoole_event_del($fp);//socket处理完成后，从epoll事件中移除socket
    fclose($fp);
});
echo "Finish
";  //swoole_event_add不会阻塞进程，这行代码会顺序执行

执行后输出：

Finish
use time:0.087 s
HTTP/1.1 200 OK
Server: AliyunOSS
Date: Sat, 21 Apr 2018 08:36:40 GMT
Content-Type: application/json
Content-Length: 26
Connection: keep-alive
x-oss-request-id: 5ADAF81884D23C965A5D2614
Accept-Ranges: bytes
ETag: "3B3B50D9C802324BB72A74FCD9060004"
Last-Modified: Sat, 21 Apr 2018 04:43:33 GMT
x-oss-object-type: Normal
x-oss-hash-crc64ecma: 9917578698767912878
x-oss-storage-class: Standard
Content-MD5: OztQ2cgCMku3KnT82QYABA==
x-oss-server-time: 5

{"url":"http://52fhy.com"}

swoole_event_add函数原型：

bool swoole_event_add(mixed $sock, mixed $read_callback, mixed $write_callback = null,
    int $flags = null);

$sock可以为以下四种类型：

• int，就是文件描述符，包括swoole_client->$sock、swoole_process->$pipe或者其他fd
• stream资源，就是stream_socket_client/fsockopen创建的资源
• sockets资源，就是sockets扩展中socket_create创建的资源，需要在编译时加入 ./configure --enable-sockets
• object，swoole_process或swoole_client，底层自动转换为管道或客户端连接的socket

多个tcp客户端实时交互

上面的例子，已经实现了异步tcp客户端。接下来的例子会复杂些：可以在客户端A输入，客户端B能实时收到，反之也可以。

首先，我们得创建个tcp_server:

swoole_tcp_server.php

<?php 

$serv = new swoole_server('0.0.0.0', 9001);

$serv->on('Start', function(){
    echo "Tcp server start. Waiting client... 
";
});

$serv->on('Connect', function($serv, $fd){
    echo "New client fd:{$fd}. 
";
});

$serv->on('Receive', function($serv, $fd, $from_id, $data){
    echo "Recv msg from fd:{$fd}:{$data}
";
    foreach ($serv->connections as $client) {
        if($fd != $client){
            $serv->send($client, $data);
        }
    }
});

$serv->on('Close', function($serv, $fd){
    echo "Client fd:{$fd} closed. 
";
});

$serv->start();

然后实现客户端：

event_add_tcp_client.php

<?php

$socket = @stream_socket_client("tcp://127.0.0.1:9001", $errno, $errstr, 30);
if(!$socket) exit("connect server err!");

function onRead($socket){
    $msg = stream_socket_recvfrom($socket, 1024);
    if(!$msg){
        swoole_event_del($socket);
    }
    echo "Recv: {$msg}
";
    fwrite(STDOUT, "ENTER MSG:");
}

function onWrite($socket){
    echo "onWrite
";
}

function onStdin(){
    global $socket;
    $msg = trim(fgets(STDIN));
    if($msg == 'exit'){ //必须trim此处才会相等
        swoole_event_exit();
        // exit();
    }
    fwrite($socket, $msg);//数据量大的时候用swoole_event_write
    fwrite(STDOUT, "ENTER MSG:");
}

swoole_event_add($socket, 'onRead', 'onWrite');
swoole_event_add(STDIN, 'onStdin');

fwrite(STDOUT, "ENTER MSG:");  //swoole_event_add不会阻塞进程，这行代码会顺序执行

先运行服务端：

$ php swoole_tcp_server.php
Tcp server start. Waiting client...

打开两个终端，运行客户端：

$ php event_add_tcp_client.php
ENTER MSG:

效果图：

swoole_client

其实swoole已经提供了异步的swoole_client，无需使用stream_socket_*系列函数：

<?php 

$client = new swoole_client(SWOOLE_SOCK_TCP, SWOOLE_SOCK_ASYNC);
$client->on("connect", function(swoole_client $cli) {
    
});
$client->on("receive", function(swoole_client $cli, $data){
    echo "Receive: $data";
    $cli->send(str_repeat('A', 100)."
");
    sleep(1);
});
$client->on("error", function(swoole_client $cli){
    echo "error
";
});
$client->on("close", function(swoole_client $cli){
    echo "Connection close
";
});
$client->connect('127.0.0.1', 9001);

还有swoole实现的tcp/udp同步阻塞客户端：

$client = new swoole_client(SWOOLE_SOCK_TCP);
if (!$client->connect('127.0.0.1', 9001, -1))
{
    exit("connect failed. Error: {$client->errCode}
");
}
$client->send("hello world
");
echo $client->recv();
$client->close();

swoole_client 函数原型：

swoole_client->__construct(int $sock_type, int $is_sync = SWOOLE_SOCK_SYNC, string $key);

可以使用swoole提供的宏来之指定类型，请参考 swoole常量定义

• $sock_type表示socket的类型，如TCP/UDP
• 使用$sock_type | SWOOLE_SSL可以启用SSL加密
  $is_sync表示同步阻塞还是异步非阻塞，默认为同步阻塞
• $key用于长连接的Key，默认使用IP:PORT作为key。相同key的连接会被复用

php-fpm/apache环境下只能使用同步客户端。异步客户端只能使用在cli命令行环境。

异步http客户端

curl或者file_get_contents发送http请求是同步阻塞的。基于swoole_event_add封装可以实现异步。

swoole_event_add实现异步http客户端

event_add_http_client.php

<?php

class HttpClient{

    private $callback = null;

    public function __construct($url, $method = 'GET', $postfields = NULL, $headers = array()){
        
        //子进程发起请求
        $process = new swoole_process(function(swoole_process $worker) use($url, $method, $postfields, $headers){
            $response = $this->http($url, $method, $postfields, $headers);
            $worker->write($response);
        }, true);
        $process->start();

        //异步读取
        swoole_event_add($process->pipe, function($pipe) use ($process){
            $response = $process->read();
            // print_r($response);
            if(is_callable($this->callback)){
                call_user_func($this->callback, $response); //回调
            }
            swoole_event_del($pipe);
        });
    }

    public function setCallback($callback){
        $this->callback = $callback;
    }

    /**
     * http请求
     */
    private function http($url, $method, $postfields = NULL, $headers = array()) {
        try{
            $ssl = stripos($url,'https://') === 0 ? true : false;
            $ci = curl_init();
            /* Curl settings */
            curl_setopt($ci, CURLOPT_USERAGENT, @$_SERVER['HTTP_USER_AGENT']); //在HTTP请求中包含一个"User-Agent: "头的字符串。    
            curl_setopt($ci, CURLOPT_CONNECTTIMEOUT, 30);
            curl_setopt($ci, CURLOPT_TIMEOUT, 30);
            curl_setopt($ci, CURLOPT_RETURNTRANSFER, TRUE);
            curl_setopt($ci, CURLOPT_ENCODING, "");
            if ($ssl) {
                curl_setopt($ci, CURLOPT_SSL_VERIFYPEER, 0); // 对认证证书来源的检查 
                curl_setopt($ci, CURLOPT_SSL_VERIFYHOST, 2); // 从证书中检查SSL加密算法是否存在
            }
            curl_setopt($ci, CURLOPT_HEADER, FALSE);
    
            switch ($method) {
                case 'POST':
                    curl_setopt($ci, CURLOPT_POST, TRUE);
                    if (!empty($postfields)) {
                        curl_setopt($ci, CURLOPT_POSTFIELDS, $postfields);
                    }
                    break;
            }
    
            curl_setopt($ci, CURLOPT_URL, $url );
            curl_setopt($ci, CURLOPT_HTTPHEADER, $headers );
            curl_setopt($ci, CURLINFO_HEADER_OUT, TRUE );
    
            $response = curl_exec($ci);
            $httpCode = curl_getinfo($ci, CURLINFO_HTTP_CODE);
            $httpInfo = curl_getinfo($ci);
            
            if (FALSE === $response)
                throw new Exception(curl_error($ci), curl_errno($ci));
        
        } catch(Exception $e) {
            throw $e;
        }
        
        //echo '<pre>';
        //var_dump($response);
        //var_dump($httpInfo);

        curl_close ($ci);
        return $response;
    }
}

$client = new HttpClient('http://www.52fhy.com/test.json');
$client->setCallback(function($response){
    print_r($response);
});
echo "OK
";

运行：

$ php event_add_http_client.php
OK
{"url":"http://52fhy.com"}[

由返回结果可以看出，客户端请求是异步执行的。

swoole_http_client

Swoole也内置了http异步客户端（swoole>=1.8.0）。

相比curl和file_get_contents这样PHP提供的Http客户端，swoole_http_client最大的优势是支持大量并发。
file_get_contents只能同时请求一个URL，并发只能通过开启多进程实现。curl提供了curl_multi功能实现并发基于select和多线程。并发能力都很差。而swoole_http_client是基于epoll实现的异步客户端，没有并发限制，可在一个进程内同时并发上万请求。更多介绍详见swoole文档。

示例：

get:

$cli = new swoole_http_client('www.52fhy.com', 80);
$cli->setHeaders(['User-Agent' => "swoole"]);

$cli->get('/test.json', function ($cli) {
    echo $cli->body;
});

echo "ok
";

输出：

ok
{"url":"http://52fhy.com"}

post:

$cli = new swoole_http_client('127.0.0.1', 81); 
$cli->post('/post_demo.php', array("a" => '1234', 'b' => '456'), function ($cli) {
    echo "Length: " . strlen($cli->body) . "
";
    echo $cli->body;
});

echo "ok
";

websocket:

<?php 
$cli = new swoole_http_client('118.25.40.163', 8088);

$cli->on('message', function ($_cli, $frame) {
    // var_dump($frame);
    echo $frame->data;
});

$cli->upgrade('/', function ($cli) {
    $cli->push("hello world");
});

echo "ok
";

发送完客户端会立即close。

参考

1、swoole_event_add
https://wiki.swoole.com/wiki/page/119.html
2、Client
https://wiki.swoole.com/wiki/page/p-client.html
3、利用swoole_process和eventloop实现php异步编程
https://segmentfault.com/a/1190000008034626
4、关于swoole_process的一些使用疑惑
https://group.swoole.com/question/106198
5、swoole多进程操作
https://blog.csdn.net/koastal/article/details/52871316
6、swoole教程第一节:进程管理模块(Process)-中(消息队列)
https://segmentfault.com/a/1190000003073389
7、PHP编程中尝试程序并发的几种方式总结
http://www.jb51.net/article/81245.htm
8、1.8.0 使用内置Http异步客户端
https://wiki.swoole.com/wiki/page/678.html
9、异步Http/WebSocket客户端
https://wiki.swoole.com/wiki/page/p-http_client.html