retStr := "{"
	retStr = retStr + expirationStr + ","
	retStr += conditionStr
	retStr += "}"

	return []byte(retStr)
}

// newPostPolicyBytesV4 - creates a bare bones postpolicy string with key and bucket matches.
func newPostPolicyBytesV4(credential, bucketName, objectKey string, expiration time.Time) []byte {
	t := UTCNow()
	// Add the expiration date.

		// PutBucket
		router.Methods(http.MethodPut).
			HandlerFunc(s3APIMiddleware(api.PutBucketHandler))
		// HeadBucket
		router.Methods(http.MethodHead).
			HandlerFunc(s3APIMiddleware(api.HeadBucketHandler))
		// PostPolicy
		router.Methods(http.MethodPost).
			MatcherFunc(func(r *http.Request, _ *mux.RouteMatch) bool {
				return isRequestPostPolicySignatureV4(r)
			}).