微信上传素材返回 '{"errcode":41005,"errmsg":"media data missing"}'，php5.6返回

function curl_post($url, $data, $header = array()){
            if(function_exists(‘curl_init‘)) {
                $ch = curl_init();
                curl_setopt($ch, CURLOPT_URL, $url);
                if(is_array($header) && !empty($header)){
                    $set_head = array();
                    foreach ($header as $k=>$v){
                        $set_head[] = "$k:$v";
                    }
                    curl_setopt($ch, CURLOPT_HTTPHEADER, $set_head);
                }
                curl_setopt($ch, CURLOPT_HEADER, 0);
                curl_setopt($ch, CURLOPT_POST, 1);
                curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
                curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
                curl_setopt($ch, CURLOPT_TIMEOUT, 0);// 1s to timeout.
                $response = curl_exec($ch);
                if(curl_errno($ch)){
                    //error
                    return curl_error($ch);
                }
                $reslut = curl_getinfo($ch);
                print_r($reslut);
                curl_close($ch);
                $info = array();
                if($response){
                    $info = json_decode($response, true);
                }
                return $info;
            } else {
                throw new Exception(‘Do not support CURL function.‘);
            }
    }

$file = "a.jpg";
$data = array(
			‘media‘=> new CURLFile($file)
		);
		$result = $this->curl_post(self::WEIXIN_API . ‘media/upload?access_token=‘ . $this->get_access_token($app_id, $app_secret) . ‘&type=‘ . $type ,$data);