function download($url,$id,$cookie,$format){
	$ch = curl_init($url);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER,TRUE);//是否直接显示内容
	curl_setopt($ch, CURLOPT_TIMEOUT, 50);
	curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
	
	if($cookie)curl_setopt ($ch, CURLOPT_COOKIE , $cookie );
	curl_setopt($ch, CURLOPT_FAILONERROR, true);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
	
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
	curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
	
	$localPath=dirname(__FILE__).'/shutt/'.$id.'.'.$format;
	//var_dump($localPath);exit;
	curl_setopt($ch, CURLOPT_BINARYTRANSFER, true); 
	curl_setopt($ch, CURLOPT_BUFFERSIZE, 5242880);//20971520
	curl_setopt($ch, CURLOPT_WRITEFUNCTION,function ($ch, $string) use ($localPath) {
		$fp = fopen($localPath,'a');
		$length = fwrite($fp, $string);
		fclose($fp);
		return $length;
	});
	
	$resp = curl_exec($ch);
	$curl_eno = curl_errno($ch);
	$curl_err = curl_error($ch);
	
	if($curl_eno){
		file_put_contents('./tmp.log', 'step2.0:'.json_encode($resp),FILE_APPEND);
	}
	
	curl_close($ch);
	return $curl_eno;
}

//断点续传相关参数
//CURLOPT_RESUME_FROM
//CURLOPT_PROGRESSDATA