lib/WebHook.js
function(hmac, bodyData) {
    if (arguments.length < 2) {
      throw paramError;
    }
    var calculatedHmac = crypto.createHmac('sha256', this.token).update(bodyData, 'utf8').digest('base64');
    return hmac === calculatedHmac;
  }
function(hmac, bodyData) {
    if (arguments.length < 2) {
      throw paramError;
    }
    var calculatedHmac = crypto.createHmac('sha256', this.token).update(bodyData, 'utf8').digest('base64');
    return hmac === calculatedHmac;
  }
验证 Hmac
@param {string} hmac
@param {string} bodyData 响应体数据
@return {boolean}