php curl批处理--可控并发异步
在php的手册里面有一段代码：

$mrc = curl_multi_init();
//发出请求
.......
$active = null;
		do {
		    $mrc = curl_multi_exec($mh, $active);
		} while ($mrc == CURLM_CALL_MULTI_PERFORM);
		
		while ($active && $mrc == CURLM_OK) {
		    if (curl_multi_select($mh) != -1) {
		        do {
		            $mrc = curl_multi_exec($mh, $active);
		        } while ($mrc == CURLM_CALL_MULTI_PERFORM);
		    }
		}
//下面是处理请求返回的结果

这段do...while是用来控制并发的，效果是将$mrc所有的请求完毕，再执行response结果

但如果我有1000个请求，那么curl批处理将并发1000个请求，显然是不合理，所以应该要控制一个并发数，并且将剩余的连接添加到请求队列里：
参考：http://www.onlineaspect.com/2009/01/26/how-to-use-curl_multi-without-blocking/

  $mh = curl_multi_init();
        $ch = array();
        $chunck = 10; //并发控制数
        $all = count($urls);//所有的请求url数组
        $chunck = $all > $chunck ? $chunck : $all;
		
		$options = array(
			CURLOPT_HEADER=>FALSE,
			CURLOPT_RETURNTRANSFER=>TRUE,
			CURLOPT_FOLLOWLOCATION=>TRUE,
			CURLOPT_MAXREDIRS=>5,
			CURLOPT_USERAGENT=>'Mozilla/5.0 (Windows NT 6.1; rv:6.0) Gecko/20100101 Firefox/6.0'
		);
		
		for($i = 0 ; $i < $chunck ; $i++){
			$ch[$i] = curl_init();
			curl_setopt($ch[$i],CURLOPT_URL,$urls[$i]);
			curl_setopt_array($ch[$i],$options);
			curl_multi_add_handle($mh,$ch[$i]);
		}
		
		do {
	        while(($execrun = curl_multi_exec($mh, $running)) == CURLM_CALL_MULTI_PERFORM);
	        if($execrun != CURLM_OK)break;
	        // a request was just completed -- find out which one
	        while($done = curl_multi_info_read($mh)) {
                //获取已经返回的url在urls数组里德的index
	            $index = array_search($done['handle'],$ch);
	            
	            $info = curl_getinfo($done['handle']);
	            
	            if ($info['http_code'] == 200){
	                $output = curl_multi_getcontent($ch[$index]);
	                // request successful.  process output using the callback function.
	                $save_path = $i.'.txt';//数据保存路径
					file_put_contents($save_path,$output);
	
	                // start a new request (it's important to do this before removing the old one)
	                $next = $i++;// increment i
	                $ch[$next] = curl_init();
	                $options[CURLOPT_URL] = $urls[$next];//将下一个请求添加到队列 
	                curl_setopt_array($ch[$next],$options);
	                curl_multi_add_handle($mh, $ch[$next]);
	
	                // remove the curl handle that just completed
	                curl_multi_remove_handle($mh, $done['handle']);
	            } else {
	                // request failed.  add error handling.
	            }
	        }
    	} while ($running);
		
		curl_multi_close($mh);
    

使用下来效果很好，没有副作用，并发数可控，应用之处多多，自己发挥想象吧