implement sub/unsub topic

example/main.go

@@ -55,4 +55,9 @@ func main() {
 		Category: "order",
 	})
 	fmt.Println("Count: 2", total, err)
+
+	err = c.Subscribe("test", []string{
+		"eX1gEc7WokSHh-zJ3WR5Hn:APA91bFZDuzkjjFFL6TNpMg0ot93a0wsypWi4aCdm7M2x6AihgjS_QWsbKSFCT4hNhv_d8wKGy-DG6_3e8OlwPiWiJB4R33xLbbUekgxKcfCiiFooIC1E1OE3XWkvUtn4egn8aLG5jqv",
+	})
+	fmt.Println("Subscribe err: ", err)
 }

model.go

@@ -75,11 +75,6 @@ type Read struct {
 	ID string `json:"id"`
 }
 
-// ReadResponse ...
-type ReadResponse struct {
-	Error string `json:"error"`
-}
-
 type read struct {
 	APIKey string `json:"apiKey"`
 	ID     string `json:"id"`
@@ -101,3 +96,19 @@ type countUnread struct {
 	User     string `json:"user"`
 	Category string `json:"category"`
 }
+
+// CommonError ...
+type CommonError struct {
+	Error string `json:"error"`
+}
+
+// Subscribe ...
+type Subscribe struct {
+	Tokens []string `json:"tokens"`
+	Topic  string   `json:"topic"`
+}
+
+type subscribe struct {
+	Subscribe
+	APIKey string `json:"apiKey"`
+}

notification.go

@@ -18,6 +18,8 @@ const (
 	SubjectGetNotification         = "get_notification"
 	SubjectReadNotification        = "read_notification"
 	SubjectCountUnreadNotification = "count_unread_notification"
+	SubjectSubscribeTopic          = "subscribe_topic"
+	SubjectUnsubscribeTopic        = "unsubscribe_topic"
 )
 
 // Client ...
@@ -137,7 +139,53 @@ func (c *Client) Read(notificationID string) error {
 	if err != nil {
 		return err
 	}
-	var res ReadResponse
+	var res CommonError
+	if err := json.Unmarshal(msg.Data, &res); err != nil {
+		return err
+	}
+	if res.Error != "" {
+		err = errors.New(res.Error)
+	}
+	return err
+}
+
+// Subscribe tokens to topic
+func (c *Client) Subscribe(topic string, tokens []string) error {
+	p := subscribe{
+		Subscribe: Subscribe{
+			Tokens: tokens,
+			Topic:  topic,
+		},
+		APIKey: c.Config.APIKey,
+	}
+	msg, err := c.natsServer.Request(SubjectSubscribeTopic, toBytes(p))
+	if err != nil {
+		return err
+	}
+	var res CommonError
+	if err := json.Unmarshal(msg.Data, &res); err != nil {
+		return err
+	}
+	if res.Error != "" {
+		err = errors.New(res.Error)
+	}
+	return err
+}
+
+// Unsubscribe tokens from topic
+func (c *Client) Unsubscribe(topic string, tokens []string) error {
+	p := subscribe{
+		Subscribe: Subscribe{
+			Tokens: tokens,
+			Topic:  topic,
+		},
+		APIKey: c.Config.APIKey,
+	}
+	msg, err := c.natsServer.Request(SubjectUnsubscribeTopic, toBytes(p))
+	if err != nil {
+		return err
+	}
+	var res CommonError
 	if err := json.Unmarshal(msg.Data, &res); err != nil {
 		return err
 	}