allow Node to work on a client interface instead of a concrete implementation

client.go

@@ -122,6 +122,22 @@ func (a bySecurityLevel) Len() int           { return len(a) }
 func (a bySecurityLevel) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a bySecurityLevel) Less(i, j int) bool { return a[i].SecurityLevel < a[j].SecurityLevel }
 
+type ClientInterface interface {
+	Browse(context.Context, *ua.BrowseRequest) (*ua.BrowseResponse, error)
+	BrowseNext(context.Context, *ua.BrowseNextRequest) (*ua.BrowseNextResponse, error)
+
+	Node(*ua.NodeID) *Node
+	NodeFromExpandedNodeID(*ua.ExpandedNodeID) *Node
+
+	Read(context.Context, *ua.ReadRequest) (*ua.ReadResponse, error)
+	Send(context.Context, ua.Request, func(ua.Response) error) error
+
+	ForgetSubscription(context.Context, uint32)
+	RegisterSubscription_NeedsSubMuxLock(*Subscription) error
+
+	RequestTimeout() time.Duration
+}
+
 // Client is a high-level client for an OPC/UA server.
 // It establishes a secure channel and a session.
 type Client struct {
@@ -989,14 +1005,14 @@ func (c *Client) sendWithTimeout(ctx context.Context, req ua.Request, timeout ti
 // Node returns a node object which accesses its attributes
 // through this client connection.
 func (c *Client) Node(id *ua.NodeID) *Node {
-	return &Node{ID: id, c: c}
+	return NewNode(id, c)
 }
 
 // NodeFromExpandedNodeID returns a node object which accesses its attributes
 // through this client connection. This is usually needed when working with node ids returned
 // from browse responses by the server.
 func (c *Client) NodeFromExpandedNodeID(id *ua.ExpandedNodeID) *Node {
-	return &Node{ID: ua.NewNodeIDFromExpandedNodeID(id), c: c}
+	return NewNode(ua.NewNodeIDFromExpandedNodeID(id), c)
 }
 
 // FindServers finds the servers available at an endpoint
@@ -1342,6 +1358,10 @@ func (c *Client) UpdateNamespaces(ctx context.Context) error {
 	return nil
 }
 
+func (c *Client) RequestTimeout() time.Duration {
+	return c.cfg.sechan.RequestTimeout
+}
+
 // safeAssign implements a type-safe assign from T to *T.
 func safeAssign(t, ptrT interface{}) error {
 	if reflect.TypeOf(t) != reflect.TypeOf(ptrT).Elem() {

client_sub.go

@@ -211,8 +211,8 @@ func (c *Client) sendRepublishRequests(ctx context.Context, sub *Subscription, a
 	}
 }
 
-// registerSubscription_NeedsSubMuxLock registers a subscription
-func (c *Client) registerSubscription_NeedsSubMuxLock(sub *Subscription) error {
+// RegisterSubscription_NeedsSubMuxLock registers a subscription
+func (c *Client) RegisterSubscription_NeedsSubMuxLock(sub *Subscription) error {
 	if sub.SubscriptionID == 0 {
 		return ua.StatusBadSubscriptionIDInvalid
 	}
@@ -225,7 +225,7 @@ func (c *Client) registerSubscription_NeedsSubMuxLock(sub *Subscription) error {
 	return nil
 }
 
-func (c *Client) forgetSubscription(ctx context.Context, id uint32) {
+func (c *Client) ForgetSubscription(ctx context.Context, id uint32) {
 	c.subMux.Lock()
 	c.forgetSubscription_NeedsSubMuxLock(ctx, id)
 	c.subMux.Unlock()

node.go

@@ -19,7 +19,11 @@ type Node struct {
 	// ID is the node id of the node.
 	ID *ua.NodeID
 
-	c *Client
+	c ClientInterface
+}
+
+func NewNode(id *ua.NodeID, c ClientInterface) *Node {
+	return &Node{ID: id, c: c}
 }
 
 func (n *Node) String() string {

subscription.go

@@ -34,7 +34,7 @@ type Subscription struct {
 	itemsMu                   sync.Mutex
 	lastSeq                   uint32
 	nextSeq                   uint32
-	c                         *Client
+	c                         ClientInterface
 }
 
 type SubscriptionParameters struct {
@@ -82,7 +82,7 @@ type PublishNotificationData struct {
 // from the client and the server.
 func (s *Subscription) Cancel(ctx context.Context) error {
 	stats.Subscription().Add("Cancel", 1)
-	s.c.forgetSubscription(ctx, s.SubscriptionID)
+	s.c.ForgetSubscription(ctx, s.SubscriptionID)
 	return s.delete(ctx)
 }
 
@@ -321,8 +321,8 @@ func (s *Subscription) publishTimeout() time.Duration {
 	if timeout > uasc.MaxTimeout {
 		return uasc.MaxTimeout
 	}
-	if timeout < s.c.cfg.sechan.RequestTimeout {
-		return s.c.cfg.sechan.RequestTimeout
+	if requestTimeout := s.c.RequestTimeout(); timeout < requestTimeout {
+		return requestTimeout
 	}
 	return timeout
 }
@@ -447,7 +447,7 @@ func (s *Subscription) recreate_create(ctx context.Context) error {
 	s.lastSeq = 0
 	s.nextSeq = 1
 
-	if err := s.c.registerSubscription_NeedsSubMuxLock(s); err != nil {
+	if err := s.c.RegisterSubscription_NeedsSubMuxLock(s); err != nil {
 		return err
 	}
 	dlog.Printf("subscription registered")