php判断token有效期

         /*判断token文件是否存在*/
        if (file_exists("access_token.json"))
        {
            $result = json_decode(file_get_contents("access_token.json"),true);
             //file_get_content()读取文件可以使用
             //$fp = fopen($filename, 'r')
             //$content = fread($fp, filesize($filename));
             // fclose($fp);

            $token = $result['token'];
        }else{
            $result['token'] = '';
            $result['expires_in'] = '';
        }


        /*判断token是否过期*/
        if( $result['token'] == '' || $result['expires_in'] < time() ){
                $str = $this->AppID.$this->AppSecret.$this->SignKey;
                $Sign= MD5($str);/*签名*/
                $data = array(
                    'AppID' => $this->AppID,
                    'AppSecret' => $this->AppSecret,
                    'Sign' =>$Sign,
                );
                $token_json = $this->http_request($this->tokeurl,$data);
                $token = json_decode($token_json,true)['token'];

                $reflesh = [];
                $reflesh['expires_in'] = time()+3600;
                $reflesh['token'] = $token;
                $fp = fopen("access_token.json", "w");
                fwrite($fp, json_encode($reflesh));
                fclose($fp);

        }
        return $this->token =$token;                                                                    

　　2

/**
 * 写入文件
 * @param string $filename 完整文件名称(包括路径和后缀)
 * @param string $writetext 要写入的字符串
 * @param string $openmod
 *
 * return bool
 */
function write_file($filename, $text, $openmod='w')
{
        if(@$fp = fopen($filename, $openmod))
        {
                flock($fp, 2);
                fwrite($fp, $text);
                fclose($fp);
                return true;
        }
        else
        {
                return false;
        }
}

function read_file($filename)
{
        $content = '';
        if(function_exists('file_get_contents'))
        {
                @$content = file_get_contents($filename);
        }
        else
        {
                if(@$fp = fopen($filename, 'r'))
                {
                        @$content = fread($fp, filesize($filename));
                        @fclose($fp);
                }
        }
        return $content;
}

  var $token_file    = ROOT_PATH . 'data/zmyf_token.txt';
  public function __construct(){
        //读取本地保存的token
        if (file_exists($this->token_file))
        {
            $token_str = read_file($this->token_file);
            $token_arr = json_decode($token_str,true,512,JSON_BIGINT_AS_STRING);
        }
        //判断token是否过期
        if ($token_arr['token'] == '' || $token_arr['expires_time'] < gmtime()) {
            $data = array(
                'grant_type' => $this->grant_type,
                'client_id' => $this->client_id,
                'client_secret' => $this->client_secret,
            );
            $url = $this->apiurl . 'v1/auth/token';
            $token_json = $this->http_request($url, $data);
            $token_arr = json_decode($token_json, true);
            $token_arr['expires_time'] = gmtime() + $token_arr['expires_at'];
            $token_str = json_encode($token_arr,JSON_UNESCAPED_SLASHES);
            write_file($this->token_file, $token_str);
        }
        return $this->token = $token_arr['data']['token'];
    }