src/base.js
function submitRequest(params, callback) {
    var self = this;

    // 处理 headers
    !params.headers && (params.headers = {});

    // 处理 query
    !params.qs && (params.qs = {});
    params.VersionId && (params.qs.versionId = params.VersionId);
    params.qs = util.clearKey(params.qs);

    // 清理 undefined 和 null 字段
    params.headers && (params.headers = util.clearKey(params.headers));
    params.qs && (params.qs = util.clearKey(params.qs));

    var Query = util.clone(params.qs);
    params.action && (Query[params.action] = '');

    var next = function (tryIndex) {
        var oldClockOffset = self.options.SystemClockOffset;
        getAuthorizationAsync.call(self, {
            Bucket: params.Bucket || '',
            Region: params.Region || '',
            Method: params.method,
            Key: params.Key,
            Query: Query,
            Headers: params.headers,
            Action: params.Action,
            ResourceKey: params.ResourceKey,
            Scope: params.Scope,
        }, function (err, AuthData) {
            params.AuthData = AuthData;
            _submitRequest.call(self, params, function (err, data) {
                if (err && tryIndex < 2 && (oldClockOffset !== self.options.SystemClockOffset || allowRetry.call(self, err))) {
                    if (params.headers) {
                        delete params.headers.Authorization;
                        delete params.headers['token'];
                        delete params.headers['clientIP'];
                        delete params.headers['clientUA'];
                        delete params.headers['x-cos-security-token'];
                    }
                    next(tryIndex + 1);
                } else {
                    callback(err, data);
                }
            });
        });
    };
    next(0);

}
function submitRequest(params, callback) {
    var self = this;

    // 处理 headers
    !params.headers && (params.headers = {});

    // 处理 query
    !params.qs && (params.qs = {});
    params.VersionId && (params.qs.versionId = params.VersionId);
    params.qs = util.clearKey(params.qs);

    // 清理 undefined 和 null 字段
    params.headers && (params.headers = util.clearKey(params.headers));
    params.qs && (params.qs = util.clearKey(params.qs));

    var Query = util.clone(params.qs);
    params.action && (Query[params.action] = '');

    var next = function (tryIndex) {
        var oldClockOffset = self.options.SystemClockOffset;
        getAuthorizationAsync.call(self, {
            Bucket: params.Bucket || '',
            Region: params.Region || '',
            Method: params.method,
            Key: params.Key,
            Query: Query,
            Headers: params.headers,
            Action: params.Action,
            ResourceKey: params.ResourceKey,
            Scope: params.Scope,
        }, function (err, AuthData) {
            params.AuthData = AuthData;
            _submitRequest.call(self, params, function (err, data) {
                if (err && tryIndex < 2 && (oldClockOffset !== self.options.SystemClockOffset || allowRetry.call(self, err))) {
                    if (params.headers) {
                        delete params.headers.Authorization;
                        delete params.headers['token'];
                        delete params.headers['clientIP'];
                        delete params.headers['clientUA'];
                        delete params.headers['x-cos-security-token'];
                    }
                    next(tryIndex + 1);
                } else {
                    callback(err, data);
                }
            });
        });
    };
    next(0);

}
获取签名并发起请求