file_get_contents가 false를 반환하는 문제를 해결하는 방법

/**
     * 通用CURL请求
     * @param $url  需要请求的url
     * @param null $data
     * return mixed 返回值 json格式的数据
     */
    public function http_request($url, $data = null)
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);        if (!empty($data)) {
            curl_setopt($curl, CURLOPT_POST, 1);
            curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
        }
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);        $info = curl_exec($curl);
        curl_close($curl);        return $info;
    }