// accordingly. Client receives a HTTP error for invalid/unsupported
	// signatures.
	//
	// Validates all incoming requests to have a valid date header.
	setAuthMiddleware,
	// Redirect some pre-defined browser request paths to a static location
	// prefix.
	setBrowserRedirectMiddleware,
	// Adds 'crossdomain.xml' policy middleware to serve legacy flash clients.

// Validate if the authType is valid and supported.
func isSupportedS3AuthType(aType authType) bool {
	_, ok := supportedS3AuthTypes[aType]
	return ok
}

// setAuthMiddleware to validate authorization header for the incoming request.
func setAuthMiddleware(h http.Handler) http.Handler {
	// handler for validating incoming authorization headers.
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {