参考文档：https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/industry/virtual-payment.html

调用接口：

https://api.weixin.qq.com/xpay/query_user_balance?access_token=71_n_O9fO__O0bLuVr-kjIgNXmxHmsOU7fURFSpfTTRvYp7tReFzt4bDrGEqNgGFpCZfnbaZMAaOneDFfTOh_Il9QtRkpOlZxmGNlgWjSnSbdmNb0nX8Wwx27LLfYoYMGcABANBV&pay_sig=ef671bb980a4de54f6f6a93f54165701aad5ba4835b4d117f52381d6ca07df4f&signature=96fb3d84dc5d09a7accb2df460a8cb934ed5ad863d99c37f83907e8065989608

请求参数：

{"openid":"oSOB25Id4x-dMBmicDnvEPycdMnM","user_ip":"127.0.0.1","env":1}

php生成签名的方法（对标上面文档中提供的python脚本改写）：

/**
 * pay_sig签名算法计算示例
 * @param $uri
 * @param $postBody
 * @param $appKey
 * @return string
 */
public function calcPaySig($uri, $postBody, $appKey): string
{
    $needSignMsg = $uri . '&' . $postBody;
    return bin2hex(hash_hmac('sha256', $needSignMsg, $appKey, true));
}


/**
 * 用户登录态signature签名算法
 * @param $postBody
 * @param $sessionKey
 * @return string
 */
public function calcSignature($postBody, $sessionKey)
{
    return bin2hex(hash_hmac('sha256', $postBody, $sessionKey, true));
}

返回错误：

{"errcode":268490003,"errmsg":"签名校验失败 rid: 64ca5e2f-6884c3cf-184aa397"}