Function asciiServerNameForMatch

modules/caddytls/matchers.go:83–118

(name string)

}

func asciiServerNameForMatch(name string) string {
	if name == "" {
		return name
	}

	// Fast path: if the name is pure ASCII, skip idna.ToASCII.
	// SNI values on the wire are always ASCII (RFC 6066), and most
	// config patterns are also ASCII. For pure ASCII input, idna.ToASCII
	// only validates and lowercases, which is equivalent to our fallback.
	if isPureASCII(name) {
		return strings.ToLower(name)
	}

	// Config can use Unicode IDNs.
	ascii, err := idna.ToASCII(name)
	if err == nil {
		return strings.ToLower(ascii)
	}

	if !strings.Contains(name, "*") {
		return strings.ToLower(name)
	}

	labels := strings.Split(name, ".")
	for i, label := range labels {
		if label == "" || label == "*" {
			continue
		}
		ascii, err := idna.ToASCII(label)
		if err != nil {
			return strings.ToLower(name)
		}
		labels[i] = strings.ToLower(ascii)
	}
	return strings.Join(labels, ".")
}

func isPureASCII(s string) bool {
	for i := 0; i < len(s); i++ {