Fixed RmFront panic.

api/modem/at/response.go

@@ -12,6 +12,10 @@ func (resp Resp) RmFront(str string) Resp {
 	return Resp(string(resp)[len(str):])
 }
 
+func (resp Resp) CheckFront(str string) bool {
+	return len(resp) >= len(str) && resp[:len(str)].String() == str
+}
+
 func (resp Resp) String() string {
 	return string(resp)
 }

api/modem/gps/data.go

@@ -2,6 +2,8 @@ package gps
 
 import (
 	"fmt"
+	"io"
+	"log"
 	"math"
 	"strconv"
 	"strings"
@@ -44,14 +46,18 @@ func (gps *Data) decode(str string) error {
 	var err error
 	newGpsInfo := Data{}
 	strs := strings.Split(strings.Split(strings.Replace(str, " ", "", -1), "\n")[0], ",")
+	logger := log.New(io.Discard, "modem-gps", log.LstdFlags)
 
+	if len(strs) < 7 {
+		return fmt.Errorf("ERROR: too small msg: %s", strs)
+	}
 	newGpsInfo.Latitude, err = strconv.ParseFloat(strs[0], 64)
 	if err != nil {
-		return fmt.Errorf("parse latitude: %w", err)
+		logger.Println("ERROR parse latitude:", err.Error())
 	}
 	newGpsInfo.Longitude, err = strconv.ParseFloat(strs[2], 64)
 	if err != nil {
-		return fmt.Errorf("parse longitude: %w", err)
+		logger.Println("ERROR parse longitude:", err.Error())
 	}
 	newGpsInfo.Latitude /= 100
 	newGpsInfo.Longitude /= 100
@@ -61,17 +67,17 @@ func (gps *Data) decode(str string) error {
 	newGpsInfo.Time = strs[5]
 	newGpsInfo.Altitude, err = strconv.ParseFloat(strs[6], 64)
 	if err != nil {
-		return fmt.Errorf("parse altitude: %w", err)
+		logger.Println("ERROR parse altitude:", err.Error())
 	}
 	newGpsInfo.Speed, err = strconv.ParseFloat(strs[7], 64)
 	if err != nil {
-		return fmt.Errorf("parse speed: %w", err)
+		logger.Println("ERROR parse speed:", err.Error())
 	}
 	// Course sometimes may be null
 	if len(strs[8]) > 0 {
 		newGpsInfo.Course, err = strconv.ParseFloat(strs[8], 64)
 		if err != nil {
-			return fmt.Errorf("parse course: %w", err)
+			logger.Println("ERROR parse course:", err.Error())
 		}
 	}
 	*gps = newGpsInfo

api/modem/gps/gps.go

@@ -49,9 +49,10 @@ func (g *gps) Update() error {
 	if err != nil {
 		return fmt.Errorf("receive GPS data: %w", err)
 	}
-	if !resp.Check() {
+	if !resp.Check() || !resp.CheckFront("+CGPSINFO:") {
 		return fmt.Errorf("get GPS info: error response: %s", resp)
 	}
+
 	if err := g.data.decode(strings.Split(strings.Replace(resp.RmFront("+CGPSINFO:").String(), "\r", "", -1), "\n")[0]); err != nil {
 		g.logger.Printf("error decode: %s\n", err.Error())
 	}
@@ -86,7 +87,7 @@ func (g *gps) switchGpsMode(on bool) error {
 	if err != nil {
 		return fmt.Errorf("make at ask: %w", err)
 	}
-	if !resp.Check() {
+	if !resp.Check() || !resp.CheckFront("+CGPS:") {
 		return fmt.Errorf("get GPS mode: error response: %s", resp)
 	}
 	ans := strings.Replace(strings.Split(strings.Split(resp.RmFront("+CGPS:").String(), "\n")[0], ",")[0], " ", "", -1)

main.go

@@ -18,6 +18,7 @@ func main() {
 func mainE() error {
 	logger := log.New(os.Stdout, "main : ", log.LstdFlags)
 	m := modem.New(log.New(logger.Writer(), "modem : ", log.LstdFlags))
+
 	logger.Println("||||||||||||||||| INIT |||||||||||||||")
 	if err := m.Init(); err != nil {
 		logger.Println("Init ended with error:", err.Error())
@@ -34,6 +35,10 @@ func mainE() error {
 		logger.Println("AAAAAAAAAAAAAAA Modem is not connected")
 		return nil
 	}
+	// m.PowerOff()
+	// time.Sleep(10 * time.Second)
+	// m.PowerOn()
+
 	logger.Println("||||||||||||||||| GET INFO |||||||||||||||||")
 	logger.Println(m.Update())
 	logger.Printf("DATA: %+v\n", m.GetData())