fix: netcup and DuckDNS.

vendor/github.com/ldez/go-auroradns/auth.go

@@ -0,0 +1,98 @@
+package auroradns
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// TokenTransport HTTP transport for API authentication
+type TokenTransport struct {
+	userID string
+	key    string
+
+	// Transport is the underlying HTTP transport to use when making requests.
+	// It will default to http.DefaultTransport if nil.
+	Transport http.RoundTripper
+}
+
+// NewTokenTransport Creates a  new TokenTransport
+func NewTokenTransport(userID, key string) (*TokenTransport, error) {
+	if userID == "" || key == "" {
+		return nil, fmt.Errorf("credentials missing")
+	}
+
+	return &TokenTransport{userID: userID, key: key}, nil
+}
+
+// RoundTrip executes a single HTTP transaction
+func (t *TokenTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	enrichedReq := &http.Request{}
+	*enrichedReq = *req
+
+	enrichedReq.Header = make(http.Header, len(req.Header))
+	for k, s := range req.Header {
+		enrichedReq.Header[k] = append([]string(nil), s...)
+	}
+
+	if t.userID != "" && t.key != "" {
+		timestamp := time.Now().UTC()
+
+		fmtTime := timestamp.Format("20060102T150405Z")
+		req.Header.Set("X-AuroraDNS-Date", fmtTime)
+
+		token, err := newToken(t.userID, t.key, req.Method, req.URL.Path, timestamp)
+		if err == nil {
+			req.Header.Set("Authorization", fmt.Sprintf("AuroraDNSv1 %s", token))
+		}
+	}
+
+	return t.transport().RoundTrip(enrichedReq)
+}
+
+// Wrap Wrap a HTTP client Transport with the TokenTransport
+func (t *TokenTransport) Wrap(client *http.Client) *http.Client {
+	backup := client.Transport
+	t.Transport = backup
+	client.Transport = t
+	return client
+}
+
+// Client Creates a new HTTP client
+func (t *TokenTransport) Client() *http.Client {
+	return &http.Client{
+		Transport: t,
+		Timeout:   30 * time.Second,
+	}
+}
+
+func (t *TokenTransport) transport() http.RoundTripper {
+	if t.Transport != nil {
+		return t.Transport
+	}
+	return http.DefaultTransport
+}
+
+// newToken generates a token for accessing a specific method of the API
+func newToken(userID string, key string, method string, action string, timestamp time.Time) (string, error) {
+	fmtTime := timestamp.Format("20060102T150405Z")
+	message := strings.Join([]string{method, action, fmtTime}, "")
+
+	signatureHmac := hmac.New(sha256.New, []byte(key))
+	_, err := signatureHmac.Write([]byte(message))
+	if err != nil {
+		return "", err
+	}
+
+	signature := base64.StdEncoding.EncodeToString(signatureHmac.Sum(nil))
+
+	userIDAndSignature := fmt.Sprintf("%s:%s", userID, signature)
+
+	token := base64.StdEncoding.EncodeToString([]byte(userIDAndSignature))
+
+	return token, nil
+}