Subscribe multiple

subscribe.go

@@ -80,6 +80,17 @@ func (c *Client) Subscribe(ctx context.Context, topic string, qos QOS) error {
 	return err
 }
 
+// SubscribeMultiple subscribes to multiple topics and errors if this fails.
+func (c *Client) SubscribeMultiple(ctx context.Context, subscriptions map[string]QOS) error {
+	subs := make(map[string]byte, len(subscriptions))
+	for topic, qos := range subscriptions {
+		subs[topic] = byte(qos)
+	}
+	token := c.client.SubscribeMultiple(subs, nil)
+	err := tokenWithContext(ctx, token)
+	return err
+}
+
 // Unsubscribe unsubscribes from a certain topic and errors if this fails.
 func (c *Client) Unsubscribe(ctx context.Context, topic string) error {
 	token := c.client.Unsubscribe(topic)

subscribe_test.go

@@ -73,6 +73,66 @@ func TestSubcribeSuccess(t *testing.T) {
 	message.Acknowledge()
 }
 
+// TestSubcribeMultipleSuccess checks that a message gets recieved correctly
+func TestSubcribeMultipleSuccess(t *testing.T) {
+	client, err := mqtt.NewClient(mqtt.ClientOptions{
+		Servers: []string{
+			"tcp://test.mosquitto.org:1883",
+		},
+	})
+	if err != nil {
+		t.Fatalf("creating client should not have failed: %v", err)
+	}
+	err = client.Connect(ctx())
+	defer client.DisconnectImmediately()
+	if err != nil {
+		t.Fatalf("connect should not have failed: %v", err)
+	}
+
+	receiver := make(chan mqtt.Message)
+	err = client.SubscribeMultiple(ctx(), map[string]mqtt.QOS{testUUID + "/TestSubcribeMultipleSuccess/#": mqtt.ExactlyOnce})
+	client.Handle(testUUID+"/TestSubcribeMultipleSuccess/#", func(message mqtt.Message) {
+		receiver <- message
+	})
+	if err != nil {
+		t.Fatalf("subscribe should not have failed: %v", err)
+	}
+	err = client.PublishString(ctx(), testUUID+"/TestSubcribeMultipleSuccess/abc", "[1, 2]", mqtt.ExactlyOnce)
+	if err != nil {
+		t.Fatalf("publish should not have failed: %v", err)
+	}
+	message := <-receiver
+	if string(message.Payload()) != "[1, 2]" {
+		t.Fatalf("message payload should have been byte array '%v' but is %v", []byte("[1, 2]"), message.Payload())
+	}
+	if message.PayloadString() != "[1, 2]" {
+		t.Fatalf("message payload should have been '[1, 2]' but is %v", message.PayloadString())
+	}
+	v := []int{}
+	err = message.PayloadJSON(&v)
+	if err != nil {
+		t.Fatalf("json should have unmarshalled: %v", err)
+	}
+	if len(v) != 2 || v[0] != 1 || v[1] != 2 {
+		t.Fatalf("message payload should have been []int{1, 2} but is %v", v)
+	}
+	if message.Topic() != testUUID+"/TestSubcribeMultipleSuccess/abc" {
+		t.Fatalf("message topic should be %v but is %v", testUUID+"/TestSubcribeMultipleSuccess/abc", message.Topic())
+	}
+	if message.QOS() != mqtt.ExactlyOnce {
+		t.Fatalf("message qos should be mqtt.ExactlyOnce but is %v", message.QOS())
+	}
+	if message.IsDuplicate() != false {
+		t.Fatalf("message IsDuplicate should be false but is %v", message.IsDuplicate())
+	}
+	vars := message.TopicVars()
+	if len(vars) != 1 && vars[0] != "abc" {
+		t.Fatalf("message TopicVars should be ['abc'] but is %v", vars)
+	}
+
+	message.Acknowledge()
+}
+
 // TestListenSuccess checks that a listener recieves a message correctly
 func TestListenSuccess(t *testing.T) {
 	client, err := mqtt.NewClient(mqtt.ClientOptions{