PHP多进程(4) ：内部多进程

                            class
                             Http_MultiRequest
{
    
                            //
                            要并行抓取的url 列表
                            private $urls = array();
 
    //curl 的选项private $options;
 
    //构造函数
    function __construct($options = array())
    {
        $this->setOptions($options);
    }
 
    //设置url 列表    function setUrls($urls)
    {
        $this->urls = $urls;
        return $this;
    }
 
    //设置选项    function setOptions($options)
    {
        $options[CURLOPT_RETURNTRANSFER] = 1;
        if (isset($options[‘HTTP_POST‘]))
        {
            curl_setopt($ch, CURLOPT_POST, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $options[‘HTTP_POST‘]);
            unset($options[‘HTTP_POST‘]);
        }
 
        if (!isset($options[CURLOPT_USERAGENT]))
        {
            $options[CURLOPT_USERAGENT] = ‘Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1;)‘;
        }
 
        if (!isset($options[CURLOPT_FOLLOWLOCATION]))
        {
            $options[CURLOPT_FOLLOWLOCATION] = 1;
        }
 
        if (!isset($options[CURLOPT_HEADER]))
        {
            $options[CURLOPT_HEADER] = 0;
        }
        $this->options = $options;
    }
 
    //并行抓取所有的内容    function exec()
    {
        if(empty($this->urls) || !is_array($this->urls))
        {
            returnfalse;
        }
        $curl = $data = array();
        $mh = curl_multi_init();
        foreach($this->urls as $k => $v)
        {
            $curl[$k] = $this->addHandle($mh, $v);
        }
        $this->execMulitHandle($mh);
        foreach($this->urls as $k => $v)
        {
            $data[$k] = curl_multi_getcontent($curl[$k]);
            curl_multi_remove_handle($mh, $curl[$k]);
        }
        curl_multi_close($mh);
        return $data;
    }
 
    //只抓取一个网页的内容。    function execOne($url)
    {
        if (empty($url)) {
            returnfalse;
        }
        $ch = curl_init($url);
        $this->setOneOption($ch);
        $content = curl_exec($ch);
        curl_close($ch);
        return $content;
    }
 
    //内部函数，设置某个handle 的选项private function setOneOption($ch)
    {
        curl_setopt_array($ch, $this->options);
    }
 
    //添加一个新的并行抓取 handleprivate function addHandle($mh, $url)
    {
        $ch = curl_init($url);
        $this->setOneOption($ch);
        curl_multi_add_handle($mh, $ch);
        return $ch;
    }
 
    //并行执行(这样的写法是一个常见的错误，我这里还是采用这样的写法，这个写法
    //下载一个小文件都可能导致cup占用100%, 并且，这个循环会运行10万次以上
    //这是一个典型的不懂原理产生的错误。这个错误在PHP官方的文档上都相当的常见。）private function execMulitHandle2($mh)
    {
        $i = 0;
        $running = null;
        do {
            curl_multi_exec($mh, $running);
            $i++;
        } while ($running > 0);
        //var_dump($i);    }
 
    //应该用这样的写法private function execMulitHandle($mh)
    {
        $i = 0;
        do {$mrc = curl_multi_exec($mh,$active); $i++;} while ($mrc == CURLM_CALL_MULTI_PERFORM);
        while ($active && $mrc == CURLM_OK)
        {
            if (curl_multi_select($mh) != -1)
            {
                do {$mrc = curl_multi_exec($mh, $active); $i++;} while ($mrc == CURLM_CALL_MULTI_PERFORM);
            }
            $i++;
        }
        //var_dump($i);    }
}

$urls = array("http://baidu.com", "http://baidu.com", "http://baidu.com", "http://baidu.com", "http://baidu.com", "http://baidu.com", "http://www.google.com", "http://www.sina.com.cn", );
$m = new Http_MultiRequest();
 
$t = microtime(true);
$m->setUrls($urls);
 
//parallel fetch（并行抓取）:
$data = $m->exec();
$parallel_time = microtime(true) - $t;
echo $parallel_time . "\n";
 
$t = microtime(true);
 
//serial fetch（串行抓取）:foreach ($urls as $url)
{
    $data[] = $m->execOne($url);
}
$serial_time = microtime(true) - $t;
echo $serial_time . "\n";