Refactor kafka to pure Go (franz-go), fix DBC stubs, update Dockerfile

pkg/can-go/frame_json.go

@@ -0,0 +1,95 @@
+package can
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strconv"
+)
+
+type jsonFrame struct {
+	ID       uint32  `json:"id"`
+	Data     *string `json:"data"`
+	Length   *uint16 `json:"length"`
+	Extended *bool   `json:"extended"`
+	Remote   *bool   `json:"remote"`
+}
+
+// JSON returns the JSON-encoding of f, using hex-encoding for the data.
+//
+// Examples:
+//
+//  {"id":32,"data":"0102030405060708"}
+//  {"id":32,"extended":true,"remote":true,"length":4}
+func (f Frame) JSON() string {
+	switch {
+	case f.IsRemote && f.IsExtended:
+		return `{"id":` + strconv.Itoa(int(f.ID)) +
+			`,"extended":true,"remote":true,"length":` +
+			strconv.Itoa(int(f.Length)) + `}`
+	case f.IsRemote:
+		return `{"id":` + strconv.Itoa(int(f.ID)) +
+			`,"remote":true,"length":` +
+			strconv.Itoa(int(f.Length)) + `}`
+	case f.IsExtended && f.Length == 0:
+		return `{"id":` + strconv.Itoa(int(f.ID)) + `,"extended":true}`
+	case f.IsExtended:
+		return `{"id":` + strconv.Itoa(int(f.ID)) +
+			`,"data":"` + hex.EncodeToString(f.Data[:f.Length]) + `"` +
+			`,"extended":true}`
+	case f.Length == 0:
+		return `{"id":` + strconv.Itoa(int(f.ID)) + `}`
+	default:
+		return `{"id":` + strconv.Itoa(int(f.ID)) +
+			`,"data":"` + hex.EncodeToString(f.Data[:f.Length]) + `"}`
+	}
+}
+
+// MarshalJSON returns the JSON-encoding of f, using hex-encoding for the data.
+//
+// See JSON for an example of the JSON schema.
+func (f Frame) MarshalJSON() ([]byte, error) {
+	return []byte(f.JSON()), nil
+}
+
+// UnmarshalJSON sets *f using the provided JSON-encoded values.
+//
+// See MarshalJSON for an example of the expected JSON schema.
+//
+// The result should be checked with Validate to guard against invalid JSON data.
+func (f *Frame) UnmarshalJSON(jsonData []byte) error {
+	jf := jsonFrame{}
+	if err := json.Unmarshal(jsonData, &jf); err != nil {
+		return err
+	}
+	if jf.Data != nil {
+		data, err := hex.DecodeString(*jf.Data)
+		if err != nil {
+			return fmt.Errorf("failed to hex-decode CAN data: %v: %w", string(jsonData), err)
+		}
+		f.Data = Data{}
+		copy(f.Data[:], data)
+		f.Length = uint16(len(data))
+	} else {
+		f.Data = Data{}
+		f.Length = 0
+	}
+	f.ID = jf.ID
+	if jf.Remote != nil {
+		f.IsRemote = *jf.Remote
+	} else {
+		f.IsRemote = false
+	}
+	if f.IsRemote {
+		if jf.Length == nil {
+			return fmt.Errorf("missing length field for remote JSON frame: %v", string(jsonData))
+		}
+		f.Length = *jf.Length
+	}
+	if jf.Extended != nil {
+		f.IsExtended = *jf.Extended
+	} else {
+		f.IsExtended = false
+	}
+	return nil
+}