feature/length-padding

.dockerignore

@@ -26,4 +26,4 @@
 
 Dockerfile
 docker-compose.yml
-Makefile
+Makefile

.gitignore

@@ -29,3 +29,4 @@
 
 ^decoder$
 dist/
+.vscode/

cmd/http.go

@@ -54,11 +54,18 @@ var httpCmd = &cobra.Command{
 				"tagxl/v1",
 				tagxl.NewTagXLv1Decoder(
 					loracloud.NewLoracloudMiddleware(accessToken),
+					tagxl.WithAutoPadding(AutoPadding),
 				),
 			},
-			{"tagsl/v1", tagsl.NewTagSLv1Decoder()},
-			{"nomadxs/v1", nomadxs.NewNomadXSv1Decoder()},
-			{"nomadxl/v1", nomadxl.NewNomadXLv1Decoder()},
+			{"tagsl/v1", tagsl.NewTagSLv1Decoder(
+				tagsl.WithAutoPadding(AutoPadding),
+			)},
+			{"nomadxs/v1", nomadxs.NewNomadXSv1Decoder(
+				nomadxs.WithAutoPadding(AutoPadding),
+			)},
+			{"nomadxl/v1", nomadxl.NewNomadXLv1Decoder(
+				nomadxl.WithAutoPadding(AutoPadding),
+			)},
 		}
 
 		// add the decoders

cmd/nomadxl.go

@@ -18,7 +18,9 @@ var nomadxlCmd = &cobra.Command{
 	Args:  cobra.ExactArgs(2),
 	Run: func(cmd *cobra.Command, args []string) {
 		slog.Debug("initializing nomadxs decoder")
-		d := nomadxl.NewNomadXLv1Decoder()
+		d := nomadxl.NewNomadXLv1Decoder(
+			nomadxl.WithAutoPadding(AutoPadding),
+		)
 
 		port, err := strconv.Atoi(args[0])
 		if err != nil {

cmd/nomadxs.go

@@ -18,7 +18,9 @@ var nomadxsCmd = &cobra.Command{
 	Args:  cobra.ExactArgs(2),
 	Run: func(cmd *cobra.Command, args []string) {
 		slog.Debug("initializing nomadxs decoder")
-		d := nomadxs.NewNomadXSv1Decoder()
+		d := nomadxs.NewNomadXSv1Decoder(
+			nomadxs.WithAutoPadding(AutoPadding),
+		)
 
 		port, err := strconv.Atoi(args[0])
 		if err != nil {

cmd/root.go

@@ -21,6 +21,7 @@ var banner = []string{
 var Debug bool
 var Verbose bool
 var Json bool
+var AutoPadding bool
 
 func init() {
 	rootCmd.PersistentFlags().BoolVarP(&Verbose, "verbose", "v", false, "Display more verbose output in console output. (default: false)")
@@ -40,6 +41,12 @@ func init() {
 	if err != nil {
 		slog.Error("error while binding json flag", slog.Any("error", err))
 	}
+
+	rootCmd.PersistentFlags().BoolVarP(&AutoPadding, "auto-padding", "", false, "Enable automatic padding of payload. (default: false)\nWarning: this may lead to corrupted data.")
+	err = viper.BindPFlag("auto-padding", rootCmd.PersistentFlags().Lookup("auto-padding"))
+	if err != nil {
+		slog.Error("error while binding auto-padding flag", slog.Any("error", err))
+	}
 }
 
 var rootCmd = &cobra.Command{

cmd/tagsl.go

@@ -18,7 +18,9 @@ var tagslCmd = &cobra.Command{
 	Args:  cobra.ExactArgs(2),
 	Run: func(cmd *cobra.Command, args []string) {
 		slog.Debug("initializing tagsl decoder")
-		d := tagsl.NewTagSLv1Decoder()
+		d := tagsl.NewTagSLv1Decoder(
+			tagsl.WithAutoPadding(AutoPadding),
+		)
 
 		port, err := strconv.Atoi(args[0])
 		if err != nil {

cmd/tagxl.go

@@ -31,6 +31,7 @@ var tagxlCmd = &cobra.Command{
 		slog.Debug("initializing tagxl decoder")
 		d := tagxl.NewTagXLv1Decoder(
 			loracloud.NewLoracloudMiddleware(accessToken),
+			tagxl.WithAutoPadding(AutoPadding),
 		)
 
 		port, err := strconv.Atoi(args[0])

pkg/decoder/helpers/helpers.go

@@ -3,7 +3,9 @@ package helpers
 import (
 	h "encoding/hex"
 	"fmt"
+	"log/slog"
 	"reflect"
+	"strings"
 	"time"
 
 	"github.com/truvami/decoder/pkg/decoder"
@@ -155,3 +157,20 @@ func UintToBinaryArray(value uint64, length int) []byte {
 func ToIntPointer(value int) *int {
 	return &value
 }
+
+func HexNullPad(payload *string, config *decoder.PayloadConfig) string {
+	var requiredBits = 0
+	for _, field := range config.Fields {
+		if !field.Optional {
+			requiredBits = (field.Start + field.Length) * 8
+		}
+	}
+	var providedBits = len(*payload) * 4
+
+	if providedBits < requiredBits {
+		var paddingBits = (requiredBits - providedBits) / 4
+		slog.Debug("padding payload with bits\n", slog.Int("bits", paddingBits))
+		*payload = strings.Repeat("0", paddingBits) + *payload
+	}
+	return *payload
+}

pkg/decoder/nomadxl/v1/decoder.go

@@ -8,10 +8,26 @@ import (
 	"github.com/truvami/decoder/pkg/decoder/helpers"
 )
 
-type NomadXLv1Decoder struct{}
+type Option func(*NomadXLv1Decoder)
 
-func NewNomadXLv1Decoder() decoder.Decoder {
-	return NomadXLv1Decoder{}
+type NomadXLv1Decoder struct {
+	autoPadding bool
+}
+
+func NewNomadXLv1Decoder(options ...Option) decoder.Decoder {
+	nomadXLv1Decoder := &NomadXLv1Decoder{}
+
+	for _, option := range options {
+		option(nomadXLv1Decoder)
+	}
+
+	return nomadXLv1Decoder
+}
+
+func WithAutoPadding(autoPadding bool) Option {
+	return func(t *NomadXLv1Decoder) {
+		t.autoPadding = autoPadding
+	}
 }
 
 // https://docs.truvami.com/docs/payloads/nomad-XL
@@ -74,6 +90,10 @@ func (t NomadXLv1Decoder) Decode(data string, port int16, devEui string) (interf
 		return nil, nil, err
 	}
 
+	if t.autoPadding {
+		data = helpers.HexNullPad(&data, &config)
+	}
+
 	decodedData, err := helpers.Parse(data, config)
 	if err != nil {
 		return nil, nil, err

pkg/decoder/nomadxl/v1/decoder_test.go

@@ -7,13 +7,15 @@ import (
 
 func TestDecode(t *testing.T) {
 	tests := []struct {
-		payload  string
-		port     int16
-		expected interface{}
+		payload     string
+		port        int16
+		autoPadding bool
+		expected    interface{}
 	}{
 		{
-			payload: "00000001fdd5c693000079300001b45d000000000000000000f600000000000000000b3fd7249f4a00420000000000001501",
-			port:    101,
+			payload:     "00000001fdd5c693000079300001b45d000000000000000000f600000000000000000b3fd724",
+			port:        101,
+			autoPadding: false,
 			expected: Port101Payload{
 				SystemTime:         8553612947,
 				UTCDate:            31024,
@@ -29,8 +31,39 @@ func TestDecode(t *testing.T) {
 			},
 		},
 		{
-			payload: "0000793000020152004B6076000C838C00003994",
-			port:    103,
+			payload:     "1fdd5c693000079300001b45d000000000000000000f600000000000000000b3fd724",
+			port:        101,
+			autoPadding: true,
+			expected: Port101Payload{
+				SystemTime:         8553612947,
+				UTCDate:            31024,
+				UTCTime:            111709,
+				Temperature:        24.6,
+				Pressure:           0,
+				TimeToFix:          36,
+				AccelerometerXAxis: 0,
+				AccelerometerYAxis: 0,
+				AccelerometerZAxis: 0,
+				Battery:            2.879,
+				BatteryLorawan:     215,
+			},
+		},
+		{
+			payload:     "0000793000020152004B6076000C838C00003994",
+			port:        103,
+			autoPadding: false,
+			expected: Port103Payload{
+				UTCDate:   31024,
+				UTCTime:   131410,
+				Latitude:  49.39894,
+				Longitude: 8.20108,
+				Altitude:  147.4,
+			},
+		},
+		{
+			payload:     "793000020152004B6076000C838C00003994",
+			port:        103,
+			autoPadding: true,
 			expected: Port103Payload{
 				UTCDate:   31024,
 				UTCTime:   131410,
@@ -43,7 +76,7 @@ func TestDecode(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(fmt.Sprintf("TestPort%vWith%v", test.port, test.payload), func(t *testing.T) {
-			decoder := NewNomadXLv1Decoder()
+			decoder := NewNomadXLv1Decoder(WithAutoPadding(test.autoPadding))
 			got, _, err := decoder.Decode(test.payload, test.port, "")
 			if err != nil {
 				t.Fatalf("unexpected error: %v", err)

pkg/decoder/nomadxs/v1/decoder.go

@@ -8,10 +8,26 @@ import (
 	"github.com/truvami/decoder/pkg/decoder/helpers"
 )
 
-type NomadXSv1Decoder struct{}
+type Option func(*NomadXSv1Decoder)
 
-func NewNomadXSv1Decoder() decoder.Decoder {
-	return NomadXSv1Decoder{}
+type NomadXSv1Decoder struct {
+	autoPadding bool
+}
+
+func NewNomadXSv1Decoder(options ...Option) decoder.Decoder {
+	nomadXSv1Decoder := &NomadXSv1Decoder{}
+
+	for _, option := range options {
+		option(nomadXSv1Decoder)
+	}
+
+	return nomadXSv1Decoder
+}
+
+func WithAutoPadding(autoPadding bool) Option {
+	return func(t *NomadXSv1Decoder) {
+		t.autoPadding = autoPadding
+	}
 }
 
 // https://docs.truvami.com/docs/payloads/nomad-xs
@@ -111,6 +127,10 @@ func (t NomadXSv1Decoder) Decode(data string, port int16, devEui string) (interf
 		return nil, nil, err
 	}
 
+	if t.autoPadding {
+		data = helpers.HexNullPad(&data, &config)
+	}
+
 	decodedData, err := helpers.Parse(data, config)
 	if err != nil {
 		return nil, nil, err