src/base.js
function getAuth(params) {
    var self = this;
    return util.getAuth({
        SecretId: params.SecretId || this.options.SecretId || '',
        SecretKey: params.SecretKey || this.options.SecretKey || '',
        Method: params.Method,
        Key: params.Key,
        Query: params.Query,
        Headers: params.Headers,
        Expires: params.Expires,
        UseRawKey: self.options.UseRawKey,
        SystemClockOffset: self.options.SystemClockOffset,
    });
}
function getAuth(params) {
    var self = this;
    return util.getAuth({
        SecretId: params.SecretId || this.options.SecretId || '',
        SecretKey: params.SecretKey || this.options.SecretKey || '',
        Method: params.Method,
        Key: params.Key,
        Query: params.Query,
        Headers: params.Headers,
        Expires: params.Expires,
        UseRawKey: self.options.UseRawKey,
        SystemClockOffset: self.options.SystemClockOffset,
    });
}
获取签名
@param  {Object}  params             参数对象，必须
@param  {String}  params.Method  请求方法，必须
@param  {String}  params.Key     object名称，必须
@param  {String}  params.Expires 名超时时间，单位秒，可选
@return  {String}  data              返回签名字符串