PHP pcntl_fork多进程下载图片实例

# mkdir php
# cd php
# apt-get source php5
# cd php5-(WHATEVER_RELEASE)/ext/pcntl
# phpize
# ./configure (注一)
# make
# make install phpize 命令是用来准备 PHP 外挂模块的编译环境的。

$cmds=array(

array('/home/jerry/projects/www/test2.php'),

array('/home/jerry/projects/www/test3.php')

);

foreach($cmds as $cmd){

$pid=pcntl_fork();

if($pid==-1){

//进程创建失败

echo '创建子进程失败时返回-1';

exit(-1);

}

else if($pid){

//父进程会得到子进程号，所以这里是父进程执行的逻辑

pcntl_wait($status,WNOHANG);

}

else{

//子进程处理逻辑

sleep(5);

pcntl_exec('/usr/bin/php',$cmd);

exit(0);

}

}

#!/usr/bin/php
// 需要抓取的网页地址
$url = 'https://www.111cn.net';
$content = file_get_contents($url);
preg_match_all('/ echo "已发现".count($matches)."张图片n";

list($sm, $ss) = explode(" ", microtime());
foreach ($matches as $k => $val)
{
$pid[$k] = pcntl_fork();
if(!$pid[$k])
{
download($url, $val);
// 子进程要exit否则会进行递归多进程，父进程不要exit否则终止多进程
exit(0);
}

if ($pid[$k])
{
// pcntl_waitpid($pid[$k], $status, WUNTRACED);
}

}
echo "下载完成n";

list($em, $es) = explode(" ", microtime());

echo "用时：",($es+$em) - ($ss + $sm),"n";
/**
* 抓取网页图片
*
*/
function download($url, $val)
{
$pic_url = $val[1];
if (strpos($val[1], '//') !== false)
{
;
}
elseif (preg_match('@^(.*?)/@', $val[1], $inner_matches) == 0)
{
$pic_url = $url.$val[1];
}
elseif (preg_match('@[:.]@', $inner_matches[1], $tmp_matches) == 0)
{
$pic_url = $url.$val[1];
}

$pic = file_get_contents($pic_url);

if ($pic === false)
{
return;
}

preg_match('@/([^/]+)$@', $pic_url, $tmp_matches);
// 可使用assert处理异常
$pic_file_name = $tmp_matches[1];
$f = fopen("tmp/".$pic_file_name, "wb"); #
fwrite($f, $pic);
fclose($f);
}

/* End of file pcntl_fork.php */