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 = 'http://www.111com.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 */