php curl 文件下载函数

function curlDownFile($img_url, $save_path = '', $filename = '') {
    if (trim($img_url) == '') {
        return false;
    }
    if (trim($save_path) == '') {
        $save_path = './';
    }

    //创建保存目录
    if (!file_exists($save_path) && !mkdir($save_path, 0777, true)) {
        return false;
    }
    if (trim($filename) == '') {
        $img_ext = strrchr($img_url, '.');
        $img_exts = array('.gif', '.jpg', '.png', '.mp4');
        if (!in_array($img_ext, $img_exts)) {
            return false;
        }
        $filename = time() . $img_ext;
    }

    // curl下载文件
    $ch = curl_init();
    $timeout = 5;
    curl_setopt($ch, CURLOPT_URL, $img_url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    $img = curl_exec($ch);
    curl_close($ch);

    // 保存文件到制定路径
    file_put_contents($filename, $img);

    unset($img, $url);
    return true;
}
//curlDownFile('http://mimg.127.net/logo/163logo.gif');
curlDownFile('http://ww1.rs.fanjian.net/iv/76/15/9b/e376ab3f5e1593342f9b53ba017c8bce.mp4');
die;