Don't use authorization for the first get system time call

We use get system time to compute time skew of the onvif device.
However, some cameras would reject the call if credentials are provided
with the wrong time. We should not add credentials for this initial
call to prevent it form being rejected.

Author: osery

pkg/gonvif/client.go

@@ -62,16 +62,15 @@ type impl struct {
 }
 
 func New(ctx context.Context, baseURL, username, password string, verbose bool) (Client, error) {
-	soapClient, err := serviceSOAPClient(baseURL, "onvif/device_service", username, password, verbose, 0)
+	diff, err := getTimeDiff(ctx, baseURL, verbose)
 	if err != nil {
 		return nil, err
 	}
-	d := device.NewDevice(soapClient)
-	diff, err := getTimeDiff(ctx, d)
+	soapClient, err := serviceSOAPClient(baseURL, "onvif/device_service", username, password, verbose, diff)
 	if err != nil {
 		return nil, err
 	}
-	soapClient.SetTimeDiff(diff)
+	d := device.NewDevice(soapClient)
 	resp, err := d.GetServicesContext(ctx, &device.GetServices{})
 	if err != nil {
 		return nil, fmt.Errorf("listing available Onvif services: %w", err)
@@ -116,7 +115,12 @@ func New(ctx context.Context, baseURL, username, password string, verbose bool)
 	return &result, nil
 }
 
-func getTimeDiff(ctx context.Context, d device.Device) (time.Duration, error) {
+func getTimeDiff(ctx context.Context, baseURL string, verbose bool) (time.Duration, error) {
+	soapClient, err := unauthorizedServiceSOAPClient(baseURL, "onvif/device_service", verbose)
+	if err != nil {
+		return 0, err
+	}
+	d := device.NewDevice(soapClient)
 	resp, err := d.GetSystemDateAndTimeContext(ctx, &device.GetSystemDateAndTime{})
 	if err != nil {
 		return 0, fmt.Errorf("getting Onvif device time: %w", err)
@@ -223,6 +227,14 @@ func sanitizeServiceURL(baseURL, advertisedURL string) (string, error) {
 	return serviceURL(baseURL, u.RequestURI())
 }
 
+func unauthorizedServiceSOAPClient(baseURL, advertisedURL string, verbose bool) (*soap.Client, error) {
+	u, err := sanitizeServiceURL(baseURL, advertisedURL)
+	if err != nil {
+		return nil, err
+	}
+	return UnauthorizedSOAPClient(u, verbose), nil
+}
+
 func serviceSOAPClient(
 	baseURL, advertisedURL, username, password string, verbose bool, diff time.Duration,
 ) (*soap.Client, error) {
@@ -233,6 +245,17 @@ func serviceSOAPClient(
 	return AuthorizedSOAPClient(u, username, password, verbose, diff), nil
 }
 
+func UnauthorizedSOAPClient(serviceURL string, verbose bool) *soap.Client {
+	httpClient := http.DefaultClient
+	if verbose {
+		httpClient = verboseHTTPClient
+	}
+	client := soap.NewClient(serviceURL,
+		soap.WithHTTPClient(httpClient),
+	)
+	return client
+}
+
 func AuthorizedSOAPClient(
 	serviceURL, username, password string, verbose bool, diff time.Duration,
 ) *soap.Client {