Mqtt: fix publishing built-in struct types, add tests

server/mqtt.go

@@ -24,18 +24,21 @@ var deprecatedTopics = []string{
 
 // MQTT is the MQTT server. It uses the MQTT client for publishing.
 type MQTT struct {
-	log     *util.Logger
-	Handler *mqtt.Client
-	root    string
+	log       *util.Logger
+	Handler   *mqtt.Client
+	root      string
+	publisher func(topic string, retained bool, payload string)
 }
 
 // NewMQTT creates MQTT server
 func NewMQTT(root string) *MQTT {
-	return &MQTT{
+	m := &MQTT{
 		log:     util.NewLogger("mqtt"),
 		Handler: mqtt.Instance,
 		root:    root,
 	}
+	m.publisher = m.publishString
+	return m
 }
 
 func (m *MQTT) encode(v interface{}) string {
@@ -65,7 +68,7 @@ func (m *MQTT) encode(v interface{}) string {
 }
 
 func (m *MQTT) publishComplex(topic string, retained bool, payload interface{}) {
-	if payload == nil {
+	if _, ok := payload.(fmt.Stringer); ok || payload == nil {
 		m.publishSingleValue(topic, retained, payload)
 		return
 	}
@@ -105,11 +108,15 @@ func (m *MQTT) publishComplex(topic string, retained bool, payload interface{})
 	}
 }
 
-func (m *MQTT) publishSingleValue(topic string, retained bool, payload interface{}) {
+func (m *MQTT) publishString(topic string, retained bool, payload string) {
 	token := m.Handler.Client.Publish(topic, m.Handler.Qos, retained, m.encode(payload))
 	go m.Handler.WaitForToken("send", topic, token)
 }
 
+func (m *MQTT) publishSingleValue(topic string, retained bool, payload interface{}) {
+	m.publisher(topic, retained, m.encode(payload))
+}
+
 func (m *MQTT) publish(topic string, retained bool, payload interface{}) {
 	// publish phase values
 	if slice, ok := payload.([]float64); ok && len(slice) == 3 {

server/mqtt_test.go

@@ -2,13 +2,55 @@ package server
 
 import (
 	"math"
+	"strconv"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestMqttNaNInf(t *testing.T) {
 	m := &MQTT{}
 	assert.Equal(t, "NaN", m.encode(math.NaN()), "NaN not encoded as string")
 	assert.Equal(t, "+Inf", m.encode(math.Inf(0)), "Inf not encoded as string")
 }
+
+func TestPublishTypes(t *testing.T) {
+	var topics, payloads []string
+
+	reset := func() {
+		topics = topics[:0]
+		payloads = payloads[:0]
+	}
+
+	m := &MQTT{
+		publisher: func(topic string, retained bool, payload string) {
+			topics = append(topics, topic)
+			payloads = append(payloads, payload)
+		},
+	}
+
+	now := time.Now()
+	m.publish("test", false, now)
+	require.Len(t, topics, 1)
+	assert.Equal(t, strconv.FormatInt(now.Unix(), 10), payloads[0], "time not encoded as unix timestamp")
+	reset()
+
+	m.publish("test", false, struct {
+		Foo string
+	}{
+		Foo: "bar",
+	})
+	require.Len(t, topics, 1)
+	assert.Equal(t, `test/foo`, topics[0], "struct mismatch")
+	assert.Equal(t, `bar`, payloads[0], "struct mismatch")
+	reset()
+
+	slice := []int{10, 20}
+	m.publish("test", false, slice)
+	require.Len(t, topics, 3)
+	assert.Equal(t, []string{`test`, `test/1`, `test/2`}, topics, "slice mismatch")
+	assert.Equal(t, []string{`2`, `10`, `20`}, payloads, "slice mismatch")
+	reset()
+}