func parseCert()

in api/internal/filter/schema.go [54:108]
48 lines of code
16 McCabe index (conditional complexity)

func parseCert(crt, key string) ([]string, error) {
	if crt == "" || key == "" {
		return nil, errors.New("empty certificate or private key")
	}

	certDERBlock, _ := pem.Decode([]byte(crt))
	if certDERBlock == nil {
		return nil, errors.New("Certificate resolution failed")
	}
	// match
	_, err := tls.X509KeyPair([]byte(crt), []byte(key))
	if err != nil {
		return nil, errors.New("key and cert don't match")
	}

	x509Cert, err := x509.ParseCertificate(certDERBlock.Bytes)

	if err != nil {
		return nil, errors.New("Certificate resolution failed")
	}

	//domain
	var snis []string
	if x509Cert.DNSNames != nil && len(x509Cert.DNSNames) > 0 {
		snis = x509Cert.DNSNames
	} else if x509Cert.IPAddresses != nil && len(x509Cert.IPAddresses) > 0 {
		for _, ip := range x509Cert.IPAddresses {
			snis = append(snis, ip.String())
		}
	} else {
		if x509Cert.Subject.Names != nil && len(x509Cert.Subject.Names) > 0 {
			var attributeTypeNames = map[string]string{
				"2.5.4.6":  "C",
				"2.5.4.10": "O",
				"2.5.4.11": "OU",
				"2.5.4.3":  "CN",
				"2.5.4.5":  "SERIALNUMBER",
				"2.5.4.7":  "L",
				"2.5.4.8":  "ST",
				"2.5.4.9":  "STREET",
				"2.5.4.17": "POSTALCODE",
			}
			for _, tv := range x509Cert.Subject.Names {
				oidString := tv.Type.String()
				typeName, ok := attributeTypeNames[oidString]
				if ok && typeName == "CN" {
					valueString := fmt.Sprint(tv.Value)
					snis = append(snis, valueString)
				}
			}
		}
	}

	return snis, nil
}