110 lines
2.6 KiB
Go
110 lines
2.6 KiB
Go
package sauna
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import (
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"encoding/json"
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"log"
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"math/rand"
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"net/http"
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"strconv"
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"sync"
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"time"
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mqtt "github.com/eclipse/paho.mqtt.golang"
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)
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type temperature struct {
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Value float64 `json:"value"`
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Unit string `json:"unit"`
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Time time.Time `json:"time"`
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Valid bool `json:"valid"`
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}
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var (
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logger log.Logger = *log.Default()
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sauna_mutex sync.Mutex
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sauna_temperature = temperature{
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Value: 0.0,
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Unit: "°C",
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}
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)
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var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
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logger.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
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}
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var saunaHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
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logger.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
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sauna_mutex.Lock()
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err := json.Unmarshal(msg.Payload(), &sauna_temperature)
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sauna_temperature.Time = time.Now()
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if err != nil {
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sauna_temperature.Valid = false
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sauna_mutex.Unlock()
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logger.Print(err)
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return
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}
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sauna_temperature.Valid = true
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sauna_mutex.Unlock()
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}
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var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
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logger.Println("Connected")
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subscribe(client)
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}
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var connectLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
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logger.Printf("Connect lost: %v", err)
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}
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func init() {
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logger.SetPrefix("apiservice/sauna: ")
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}
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func http_endpoint_sauna(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("Content-type", "application/json; charset=utf-8;")
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if r.Method == http.MethodGet {
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sauna_mutex.Lock()
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data, err := json.Marshal(sauna_temperature)
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sauna_mutex.Unlock()
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if err != nil {
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w.WriteHeader(http.StatusInternalServerError)
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w.Write(json.RawMessage(`{"error": "cannot marshal object to json"}`))
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} else {
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w.WriteHeader(http.StatusOK)
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w.Write(data)
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}
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} else {
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w.WriteHeader(http.StatusMethodNotAllowed)
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}
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}
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func connect() mqtt.Client {
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// MQTT connection
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opts := mqtt.NewClientOptions()
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opts.AddBroker("tcp://nuc:1883")
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opts.SetClientID("apiservice/sauna/" + strconv.Itoa(rand.Int()))
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opts.SetDefaultPublishHandler(messagePubHandler)
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opts.OnConnect = connectHandler
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opts.OnConnectionLost = connectLostHandler
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client := mqtt.NewClient(opts)
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if token := client.Connect(); token.Wait() && token.Error() != nil {
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logger.Panic(token.Error())
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}
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return client
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}
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func subscribe(client mqtt.Client) {
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// MQTT subscribtion
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topic := "sauna/temperature"
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token := client.Subscribe(topic, 1, saunaHandler)
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token.Wait()
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logger.Printf("Subscribed to topic %s", topic)
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}
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func Start() {
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client := connect()
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subscribe(client)
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http.HandleFunc("/api/sauna", http_endpoint_sauna)
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}
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