add vendoring

vendor/gitlab.com/etke.cc/go/validator/domains.go

@@ -0,0 +1,72 @@
+package validator
+
+import (
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/publicsuffix"
+)
+
+// based on W3C email regex, ref: https://www.w3.org/TR/2016/REC-html51-20161101/sec-forms.html#email-state-typeemail
+var domainRegex = regexp.MustCompile(`^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z0-9][a-zA-Z0-9-]{0,61}[a-zA-Z0-9]$`)
+var privateSuffix = []string{".etke.host"}
+
+// Domain checks if domain is valid
+func (v *V) Domain(domain string) bool {
+	if domain == "" {
+		return !v.enforce.Domain
+	}
+
+	if !v.DomainString(domain) {
+		return false
+	}
+
+	return true
+}
+
+// DomainString checks if domain string / value is valid using string checks like length and regexp
+func (v *V) DomainString(domain string) bool {
+	if len(domain) < 4 || len(domain) > 77 {
+		v.log.Info("domain %s invalid, reason: length", domain)
+		return false
+	}
+
+	if !domainRegex.MatchString(domain) {
+		v.log.Info("domain %s invalid, reason: regexp", domain)
+		return false
+	}
+
+	return true
+}
+
+// GetBase returns base domain/host of the provided domain
+func (v *V) GetBase(domain string) string {
+	// domain without subdomain "example.com" has parts: example com
+	minSize := 2
+	if v.hasSuffix(domain) {
+		// domain with a certain TLDs contains 3 parts: example.co.uk -> example co uk
+		minSize = 3
+	}
+
+	parts := strings.Split(domain, ".")
+	size := len(parts)
+	// If domain contains only 2 parts (or less) - consider it without subdomains
+	if size <= minSize {
+		return domain
+	}
+
+	// return domain without subdomain (sub.example.com -> example.com; sub.example.co.uk -> example.co.uk)
+	return strings.Join(parts[size-minSize:], ".")
+}
+
+// hasSuffix checks if domain has a suffix from public suffix list or from predefined suffix list
+func (v *V) hasSuffix(domain string) bool {
+	for _, suffix := range privateSuffix {
+		if strings.HasSuffix(domain, suffix) {
+			return true
+		}
+	}
+
+	eTLD, _ := publicsuffix.PublicSuffix(domain)
+	return strings.IndexByte(eTLD, '.') >= 0
+}