[management] Streamline domain validation (#5211)

shared/management/domain/validate.go

@@ -10,7 +10,30 @@ const maxDomains = 32
 
 var domainRegex = regexp.MustCompile(`^(?:\*\.)?(?:(?:xn--)?[a-zA-Z0-9_](?:[a-zA-Z0-9-_]{0,61}[a-zA-Z0-9])?\.)*(?:xn--)?[a-zA-Z0-9](?:[a-zA-Z0-9-_]{0,61}[a-zA-Z0-9])?$`)
 
-// ValidateDomains checks if each domain in the list is valid and returns a punycode-encoded DomainList.
+// IsValidDomain checks if a single domain string is valid.
+// Does not convert unicode to punycode - domain must already be ASCII/punycode.
+// Allows wildcard prefix (*.example.com).
+func IsValidDomain(domain string) bool {
+	if domain == "" {
+		return false
+	}
+	return domainRegex.MatchString(strings.ToLower(domain))
+}
+
+// IsValidDomainNoWildcard checks if a single domain string is valid without wildcard prefix.
+// Use for zone domains and CNAME targets where wildcards are not allowed.
+func IsValidDomainNoWildcard(domain string) bool {
+	if domain == "" {
+		return false
+	}
+	if strings.HasPrefix(domain, "*.") {
+		return false
+	}
+	return domainRegex.MatchString(strings.ToLower(domain))
+}
+
+// ValidateDomains validates domains and converts unicode to punycode.
+// Allows wildcard prefix (*.example.com). Maximum 32 domains.
 func ValidateDomains(domains []string) (List, error) {
 	if len(domains) == 0 {
 		return nil, fmt.Errorf("domains list is empty")
@@ -37,7 +60,10 @@ func ValidateDomains(domains []string) (List, error) {
 	return domainList, nil
 }
 
-// ValidateDomainsList checks if each domain in the list is valid
+// ValidateDomainsList validates domains without punycode conversion.
+// Use this for domains that must already be in ASCII/punycode format (e.g., extra DNS labels).
+// Unlike ValidateDomains, this does not convert unicode to punycode - unicode domains will fail.
+// Allows wildcard prefix (*.example.com). Maximum 32 domains.
 func ValidateDomainsList(domains []string) error {
 	if len(domains) == 0 {
 		return nil