sere.go

package main

import(
	"fmt"
	"net/http"
	"encoding/json"
	"time"
	"math"
	"log/syslog"

	"github.com/julienschmidt/httprouter"
//	bh1750 "github.com/d2r2/go-bh1750"
	bsbmp "github.com/d2r2/go-bsbmp"
	i2c "github.com/d2r2/go-i2c"
)

const(
	ip		= "0.0.0.0"
	port	= 10000
	alt		= 223		// Altitude for pressure correction 
	li		= 5			// log interval in minutes
)

type(
	Data struct{
//		Ligh uint16 `json:"illuminance"`
		Temp float32 `json:"temperature"`
		Pres float32 `json:"pressure"`
		Humi float32 `json:"humidity"`
	}
)

var log *syslog.Writer

func GetSen(){
//	i2cl, _ := i2c.NewI2C(0x23, 1) // light sen
	i2co, _ := i2c.NewI2C(0x76, 0) // temp, pres, humi sen
//	defer i2cl.Close()
	defer i2co.Close()
//	sensorl := bh1750.NewBH1750()
//	sensorl.ChangeSensivityFactor(i2cl, 255)
	sensoro, _ := bsbmp.NewBMP(bsbmp.BME280, i2co)
	lt := time.Now()

	for{
//		datag.Ligh, _ = sensorl.MeasureAmbientLight(i2cl, bh1750.HighestResolution)
		datag.Temp, _ = sensoro.ReadTemperatureC(bsbmp.ACCURACY_STANDARD)
		datag.Pres, _ = sensoro.ReadPressurePa(bsbmp.ACCURACY_STANDARD)
		_, datag.Humi, _ = sensoro.ReadHumidityRH(bsbmp.ACCURACY_STANDARD)

		t := time.Now()
		if t.After(lt.Add(li * time.Minute)){
			log.Info(fmt.Sprintf("temperature: %.1f; pressure: %.1f; humidity: %.f",
			datag.Humi, datag.Temp, float32(float64(datag.Pres)/math.Pow(1-alt/44330.0, 5.255))))
//			log.Info(fmt.Sprintf("lighting: %d;", datag.Ligh))
			lt = t
		}
		time.Sleep(10000 * time.Millisecond)
	}
}

var datag Data

func main(){
	log, _ = syslog.New(syslog.LOG_INFO|syslog.LOG_ERR, "sere")
	r := httprouter.New()
	r.GET("/", func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
		data := Data{
//			Ligh:	datag.Ligh,
			Temp:	datag.Temp,
			Pres:	float32(float64(datag.Pres)/math.Pow(1-alt/44330.0, 5.255)),
			Humi:	datag.Humi,
		}
		dataj, _ := json.Marshal(data)

		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(200)
		fmt.Fprintf(w, "%s", dataj)
	})

	go GetSen()	// sensors thread
	http.ListenAndServe(fmt.Sprintf("%s:%d", ip, port), r)	// server thread
}