php异步调用

a.php

<?php

echo 'starttime:'.date('H:i:s', time()).'<br>';
$url = 'http://localhost/b.php';
$param = ['time'=>date('H:i:s', time())];
doAsyncRequest($url, $param);
echo 'endtime'.date('H:i:s', time());

function doAsyncRequest($url, $param=array()){
    $urlinfo = parse_url($url);
    $host = $urlinfo['host'];
    $path = $urlinfo['path'];
    $query = isset($param)? http_build_query($param) : '';
    $port = 80;
    $errno = 0;
    $errstr = '';
    $timeout = 10;
    //fsockopen 打开一个网络连接或者一个Unix套接字连接
    $fp = fsockopen($host, $port, $errno, $errstr, $timeout);
    if (!$fp) {
        echo 'ERROR:'.$errno.' - '.$errstr.'<br>';
        //端口改成800，下面会输出 ERROR:10061 - 由于目标计算机积极拒绝，无法连接。
    } else {
        $out = "POST ".$path." HTTP/1.1\r\n";
        $out .= "host:".$host."\r\n";
        $out .= "content-length:".strlen($query)."\r\n";
        $out .= "content-type:application/x-www-form-urlencoded\r\n";
        $out .= "connection:close\r\n\r\n";
        $out .= $query;
        fputs($fp, $out);
        fclose($fp);
    }
}

b.php

<?php

sleep(2);//等待2秒
file_put_contents('file.txt', $_POST['time'].' - '.date('H:i:s', time())); exit;

访问结果 file.txt

08:17:05 - 08:17:07