feat: json rpc serialization

rpc/rpc.go

@@ -0,0 +1,42 @@
+package rpc
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+func EncodeMessage(message any) string {
+	content, err := json.Marshal(message)
+	if err != nil {
+		panic(err)
+	}
+
+	return fmt.Sprintf("Content-Length: %d\r\n\r\n%s", len(content), content)
+}
+
+type BaseMessage struct {
+	Method string `json:"method"`
+}
+
+func DecodeMessage(msg []byte) (BaseMessage, []byte, error) {
+	header, content, found := bytes.Cut(msg, []byte{'\r', '\n', '\r', '\n'})
+	if !found {
+		return BaseMessage{}, nil, errors.New("No separator found")
+	}
+	contentLengthBytes := header[len("Content-Length: "):]
+	contentLength, err := strconv.Atoi(string(contentLengthBytes))
+	if err != nil {
+		return BaseMessage{}, nil, err
+	}
+	content = content[:contentLength]
+	var message BaseMessage
+	err = json.Unmarshal(content, &message)
+	if err != nil {
+		return message, nil, err
+	}
+
+	return message, content, nil
+}

rpc/rpc_test.go

@@ -0,0 +1,30 @@
+package rpc_test
+
+import (
+	"testing"
+	"github.com/benpueschel/conventional-commit-lsp/rpc"
+)
+
+type EncodingExample struct {
+	Method string `json:"method"`
+}
+var incommingMessage = "Content-Length: 15\r\n\r\n{\"method\":\"hi\"}"
+func TestEncodeMessage(t *testing.T) {
+	actual := rpc.EncodeMessage(EncodingExample{Method: "hi"})
+	if incommingMessage != actual {
+		t.Fatalf("Expected %s, got %s", incommingMessage, actual)
+	}
+}
+
+func TestDecodeMessage(t *testing.T) {
+	message, content, err := rpc.DecodeMessage([]byte(incommingMessage))
+	if err != nil {
+		t.Fatalf("Error decoding message: %s", err)
+	}
+	if message.Method != "hi" {
+		t.Fatalf("Expected %s, got %s", "hi", message.Method)
+	}
+	if len(content) != 15 {
+		t.Fatalf("Expected %d, got %d", 15, len(content))
+	}
+}