return ErrSignatureVersionNotSupported
	case authTypePresignedV2, authTypeSignedV2:
		if s3Err = isReqAuthenticatedV2(r); s3Err != ErrNone {
			return s3Err
		}
		cred, owner, s3Err = getReqAccessKeyV2(r)
	case authTypeSigned, authTypePresigned:
		region := globalSite.Region
		switch action {
		case policy.GetBucketLocationAction, policy.ListAllMyBucketsAction:
			region = ""
		}

func getReqAccessCred(r *http.Request, region string) (cred auth.Credentials) {
	cred, _, _ = getReqAccessKeyV4(r, region, serviceS3)
	if cred.AccessKey == "" {
		cred, _, _ = getReqAccessKeyV2(r)
	}
	return cred
}

// Extract request params to be sent with event notification.
func extractReqParams(r *http.Request) map[string]string {
	if r == nil {
		return nil
	}