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fix: support jt808 versioned header

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lingniu
2026-07-01 22:12:47 +08:00
parent 665122b23b
commit e0068a750d
2 changed files with 79 additions and 7 deletions
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35
go/vehicle-gateway/internal/protocol/jt808/parser.go
View File

@@ -77,31 +77,52 @@ func ParseFrame(raw []byte, receivedAtMS int64, sourceEndpoint string) (envelope
messageID := binary.BigEndian.Uint16(raw[0:2])
props := binary.BigEndian.Uint16(raw[2:4])
bodySize := props & 0x03ff
versioned := props&0x4000 != 0
headerLen := 12
phoneStart := 4
phoneEnd := 10
serialStart := 10
packageInfo := map[string]any(nil)
protocolVersion := byte(0)
if versioned {
headerLen = 17
if len(raw) < headerLen {
return envelope.FrameEnvelope{}, fmt.Errorf("%w: versioned header len=%d", ErrFrameTooShort, len(raw))
}
protocolVersion = raw[4]
phoneStart = 5
phoneEnd = 15
serialStart = 15
}
if props&0x2000 != 0 {
headerLen = 16
headerLen += 4
packageInfo = map[string]any{
"total": binary.BigEndian.Uint16(raw[12:14]),
"index": binary.BigEndian.Uint16(raw[14:16]),
"total": binary.BigEndian.Uint16(raw[serialStart+2 : serialStart+4]),
"index": binary.BigEndian.Uint16(raw[serialStart+4 : serialStart+6]),
}
}
if len(raw) < headerLen+int(bodySize)+1 {
return envelope.FrameEnvelope{}, fmt.Errorf("%w: bodySize=%d len=%d", ErrFrameTooShort, bodySize, len(raw))
}
phoneBCD := raw[4:10]
phoneBCD := raw[phoneStart:phoneEnd]
phone := bcdString(phoneBCD)
phoneTrimZero := strings.TrimLeft(phone, "0")
if versioned && phoneTrimZero != "" {
phone = phoneTrimZero
}
body := raw[headerLen : headerLen+int(bodySize)]
parsed := map[string]any{
"header": map[string]any{
"message_id": fmt.Sprintf("0x%04X", messageID),
"protocol_version": protocolVersion,
"versioned": versioned,
"properties": props,
"body_size": bodySize,
"phone_bcd_hex": strings.ToUpper(hex.EncodeToString(phoneBCD)),
"phone": phone,
"phone_trim_zero": strings.TrimLeft(phone, "0"),
"sequence": binary.BigEndian.Uint16(raw[10:12]),
"phone_trim_zero": phoneTrimZero,
"sequence": binary.BigEndian.Uint16(raw[serialStart : serialStart+2]),
"subpackage": props&0x2000 != 0,
"package_info": packageInfo,
"encryption_flags": (props >> 10) & 0x07,
@@ -135,7 +156,7 @@ func ParseFrame(raw []byte, receivedAtMS int64, sourceEndpoint string) (envelope
env := envelope.FrameEnvelope{
Protocol: envelope.ProtocolJT808,
MessageID: fmt.Sprintf("0x%04X", messageID),
Sequence: binary.BigEndian.Uint16(raw[10:12]),
Sequence: binary.BigEndian.Uint16(raw[serialStart : serialStart+2]),
Phone: phone,
SourceEndpoint: sourceEndpoint,
EventTimeMS: eventTimeMS,

51
go/vehicle-gateway/internal/protocol/jt808/parser_test.go
View File

@@ -8,6 +8,7 @@ import (
)
const sampleLocationFrame = "7E020000320133077954250001000000000048000301D2C4C707376139000A00E6004F26063016235701040001900C2504000000000202000030011F31010F867E"
const real2019LocationFrame = "7E02004046010000000001489413506007CB00000000004C000301D276AB06FBFF4B000D014E00E826070122092214040000000017020000010400013361030201402504000000012A02000030011D310112EA0402008000C57E"
func TestExtractFramesUnescapesAndParsesLocationWithTotalMileage(t *testing.T) {
stream, err := hex.DecodeString(sampleLocationFrame + "7E02000000")
@@ -63,6 +64,56 @@ func TestExtractFramesUnescapesAndParsesLocationWithTotalMileage(t *testing.T) {
}
}
func TestParseFrameSupportsJT8082019VersionedHeader(t *testing.T) {
stream, err := hex.DecodeString(real2019LocationFrame)
if err != nil {
t.Fatal(err)
}
frames, remainder, err := ExtractFrames(stream)
if err != nil {
t.Fatalf("ExtractFrames() error = %v", err)
}
if len(frames) != 1 || len(remainder) != 0 {
t.Fatalf("unexpected split result frames=%d remainder=%s", len(frames), hex.EncodeToString(remainder))
}
env, err := ParseFrame(frames[0], 1782914967713, "115.231.168.135:43625")
if err != nil {
t.Fatalf("ParseFrame() error = %v", err)
}
if env.MessageID != "0x0200" {
t.Fatalf("message id = %q", env.MessageID)
}
if env.Phone != "14894135060" {
t.Fatalf("phone = %q", env.Phone)
}
if env.Sequence != 1995 {
t.Fatalf("sequence = %d", env.Sequence)
}
assertFloatField(t, env, envelope.FieldLatitude, 30.570155)
assertFloatField(t, env, envelope.FieldLongitude, 117.178187)
assertFloatField(t, env, envelope.FieldSpeedKMH, 33.4)
assertFloatField(t, env, envelope.FieldTotalMileageKM, 7868.9)
if env.Fields["altitude_m"] != uint16(13) {
t.Fatalf("altitude = %#v", env.Fields["altitude_m"])
}
if env.Fields["direction_deg"] != uint16(232) {
t.Fatalf("direction = %#v", env.Fields["direction_deg"])
}
header, ok := env.Parsed["header"].(map[string]any)
if !ok {
t.Fatalf("parsed header missing: %#v", env.Parsed)
}
if header["versioned"] != true || header["protocol_version"] != byte(1) {
t.Fatalf("unexpected versioned header: %#v", header)
}
if header["phone_bcd_hex"] != "00000000014894135060" {
t.Fatalf("phone bcd = %#v", header["phone_bcd_hex"])
}
}
func TestExtractFramesHandlesEscapedPayload(t *testing.T) {
payload := []byte{0x02, 0x00, 0x00, 0x02, 0x01, 0x33, 0x07, 0x79, 0x54, 0x25, 0x00, 0x01, 0x7e, 0x7d}
frame := append([]byte{0x7e}, escape(append(payload, checksum(payload)))...)