Marshal/Unmarshal arguments and return values separately to allow struct tags to take effect for each codec

client/client.go

@@ -26,7 +26,6 @@ import (
 	"sync"
 
 	"go.arsenm.dev/lrpc/codec"
-	"go.arsenm.dev/lrpc/internal/reflectutil"
 	"go.arsenm.dev/lrpc/internal/types"
 
 	"github.com/gofrs/uuid"
@@ -81,12 +80,17 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 	c.chs[idStr] = make(chan *types.Response, 1)
 	c.chMtx.Unlock()
 
+	argData, err := c.codec.Marshal(arg)
+	if err != nil {
+		return err
+	}
+
 	// Encode request using codec
 	err = c.codec.Encode(types.Request{
 		ID:       idStr,
 		Receiver: rcvr,
 		Method:   method,
-		Arg:      arg,
+		Arg:      argData,
 	})
 	if err != nil {
 		return err
@@ -124,7 +128,11 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 			return ErrReturnNotChannel
 		}
 		// Get channel ID returned in response
-		chID := resp.Return.(string)
+		var chID string
+		err = c.codec.Unmarshal(resp.Return, &chID)
+		if resp.Return == nil {
+			return nil
+		}
 
 		// Create new channel using channel ID
 		c.chMtx.Lock()
@@ -149,21 +157,16 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 					retVal.Close()
 					break
 				}
-				// Get reflect value from channel response
-				rVal := reflect.ValueOf(val.Return)
 
-				// If return value is not the same as the channel
+				outVal := reflect.New(chElemType)
-				if rVal.Type() != chElemType {
+				err = c.codec.Unmarshal(val.Return, outVal.Interface())
-					// Attempt to convert value, skip if impossible
+				if err != nil {
-					newVal, err := reflectutil.Convert(rVal, chElemType)
+					continue
-					if err != nil {
-						continue
-					}
-					rVal = newVal
 				}
+				outVal = outVal.Elem()
 
 				chosen, _, _ := reflect.Select([]reflect.SelectCase{
-					{Dir: reflect.SelectSend, Chan: retVal, Send: rVal},
+					{Dir: reflect.SelectSend, Chan: retVal, Send: outVal},
 					{Dir: reflect.SelectRecv, Chan: ctxDoneVal, Send: reflect.Value{}},
 				})
 				if chosen == 1 {
@@ -179,28 +182,10 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 			}
 		}()
 	} else if resp.Type == types.ResponseTypeNormal {
-		// IF return value is not a pointer, return error
+		err = c.codec.Unmarshal(resp.Return, ret)
-		if retVal.Kind() != reflect.Ptr {
+		if err != nil {
-			return ErrReturnNotPointer
+			return err
 		}
-
-		// Get return type
-		retType := retVal.Type().Elem()
-		// Get refkect value from response
-		rVal := reflect.ValueOf(resp.Return)
-
-		// If types do not match
-		if rVal.Type() != retType {
-			// Attempt to convert types, return error if not possible
-			newVal, err := reflectutil.Convert(rVal, retType)
-			if err != nil {
-				return err
-			}
-			rVal = newVal
-		}
-
-		// Set return value to received value
-		retVal.Elem().Set(rVal)
 	}
 
 	return nil

codec/codec.go

@@ -19,6 +19,7 @@
 package codec
 
 import (
+	"bytes"
 	"encoding/gob"
 	"encoding/json"
 	"io"
@@ -38,42 +39,76 @@ type CodecFunc func(io.ReadWriter) Codec
 type Codec interface {
 	Encode(val any) error
 	Decode(val any) error
+	Unmarshal(data []byte, v any) error
+	Marshal(v any) ([]byte, error)
 }
 
 // Default is the default CodecFunc
 var Default = Msgpack
 
+type JsonCodec struct {
+	*json.Encoder
+	*json.Decoder
+}
+
+func (JsonCodec) Unmarshal(data []byte, v any) error {
+	return json.Unmarshal(data, v)
+}
+
+func (JsonCodec) Marshal(v any) ([]byte, error) {
+	return json.Marshal(v)
+}
+
 // JSON is a CodecFunc that creates a JSON Codec
 func JSON(rw io.ReadWriter) Codec {
-	type jsonCodec struct {
+	return JsonCodec{
-		*json.Encoder
-		*json.Decoder
-	}
-	return jsonCodec{
 		Encoder: json.NewEncoder(rw),
 		Decoder: json.NewDecoder(rw),
 	}
 }
 
+type MsgpackCodec struct {
+	*msgpack.Encoder
+	*msgpack.Decoder
+}
+
+func (MsgpackCodec) Unmarshal(data []byte, v any) error {
+	return msgpack.Unmarshal(data, v)
+}
+
+func (MsgpackCodec) Marshal(v any) ([]byte, error) {
+	return msgpack.Marshal(v)
+}
+
 // Msgpack is a CodecFunc that creates a Msgpack Codec
 func Msgpack(rw io.ReadWriter) Codec {
-	type msgpackCodec struct {
+	return MsgpackCodec{
-		*msgpack.Encoder
-		*msgpack.Decoder
-	}
-	return msgpackCodec{
 		Encoder: msgpack.NewEncoder(rw),
 		Decoder: msgpack.NewDecoder(rw),
 	}
 }
 
+type GobCodec struct {
+	*gob.Encoder
+	*gob.Decoder
+}
+
+func (GobCodec) Unmarshal(data []byte, v any) error {
+	return gob.NewDecoder(bytes.NewReader(data)).Decode(v)
+}
+
+func (GobCodec) Marshal(v any) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	err := gob.NewEncoder(buf).Encode(v)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
 // Gob is a CodecFunc that creates a Gob Codec
 func Gob(rw io.ReadWriter) Codec {
-	type gobCodec struct {
+	return GobCodec{
-		*gob.Encoder
-		*gob.Decoder
-	}
-	return gobCodec{
 		Encoder: gob.NewEncoder(rw),
 		Decoder: gob.NewDecoder(rw),
 	}

internal/types/types.go

@@ -26,7 +26,7 @@ type Request struct {
 	ID       string
 	Receiver string
 	Method   string
-	Arg      any
+	Arg      []byte
 }
 
 type ResponseType uint8
@@ -43,5 +43,5 @@ type Response struct {
 	Type   ResponseType
 	ID     string
 	Error  string
-	Return any
+	Return []byte
 }

lrpc_test.go

@@ -122,7 +122,7 @@ func TestCodecs(t *testing.T) {
 		if err != nil {
 			t.Errorf("codec/%s: %v", name, err)
 		}
-
+		
 		if add != 4 {
 			t.Errorf("codec/%s: add: expected 4, got %d", name, add)
 		}

server/server.go

@@ -28,7 +28,6 @@ import (
 	"sync"
 
 	"go.arsenm.dev/lrpc/codec"
-	"go.arsenm.dev/lrpc/internal/reflectutil"
 	"go.arsenm.dev/lrpc/internal/types"
 	"golang.org/x/net/websocket"
 )
@@ -37,12 +36,11 @@ import (
 type any = interface{}
 
 var (
-	ErrInvalidType        = errors.New("type must be struct or pointer to struct")
+	ErrInvalidType    = errors.New("type must be struct or pointer to struct")
-	ErrNoSuchReceiver     = errors.New("no such receiver registered")
+	ErrNoSuchReceiver = errors.New("no such receiver registered")
-	ErrNoSuchMethod       = errors.New("no such method was found")
+	ErrNoSuchMethod   = errors.New("no such method was found")
-	ErrInvalidMethod      = errors.New("method invalid for lrpc call")
+	ErrInvalidMethod  = errors.New("method invalid for lrpc call")
-	ErrUnexpectedArgument = errors.New("argument provided but the function does not accept any arguments")
+	ErrArgNotProvided = errors.New("method expected an argument, but none was provided")
-	ErrArgNotProvided     = errors.New("method expected an argument, but none was provided")
 )
 
 // Server is an lrpc server
@@ -101,7 +99,7 @@ func (s *Server) Register(v any) error {
 }
 
 // execute runs a method of a registered value
-func (s *Server) execute(pCtx context.Context, typ string, name string, arg any, c codec.Codec) (a any, ctx *Context, err error) {
+func (s *Server) execute(pCtx context.Context, typ string, name string, data []byte, c codec.Codec) (a any, ctx *Context, err error) {
 	// Try to get value from receivers map
 	val, ok := s.rcvrs[typ]
 	if !ok {
@@ -122,29 +120,19 @@ func (s *Server) execute(pCtx context.Context, typ string, name string, arg any,
 	// Get method type
 	mtdType := mtd.Type()
 
-	// Return error if argument provided but isn't expected
+	//TODO: if arg not nil but fn has no arg, err
-	if mtdType.NumIn() == 1 && arg != nil {
-		return nil, nil, ErrUnexpectedArgument
-	}
 
-	// IF argument is []any
+	argType := mtdType.In(1)
-	anySlice, ok := arg.([]any)
+	argVal := reflect.New(argType)
-	if ok {
+	arg := argVal.Interface()
-		// Convert slice to the method's arg type and
-		// set arg to the newly-converted slice
-		arg = reflectutil.ConvertSlice(anySlice, mtdType.In(1))
-	}
 
-	// Get argument value
+	err = c.Unmarshal(data, arg)
-	argVal := reflect.ValueOf(arg)
+	if err != nil {
-	// If argument's type does not match method's argument type
+		return nil, nil, err
-	if arg != nil && argVal.Type() != mtdType.In(1) {
-		val, err = reflectutil.Convert(argVal, mtdType.In(1))
-		if err != nil {
-			return nil, nil, err
-		}
-		arg = val.Interface()
 	}
+	
+	arg = argVal.Elem().Interface()
+	
 
 	ctx = newContext(pCtx, c)
 	// Get reflect value of context
@@ -327,18 +315,30 @@ func (s *Server) handleConn(pCtx context.Context, c codec.Codec) {
 		if err != nil {
 			s.sendErr(c, call, val, err)
 		} else {
+			valData, err := c.Marshal(val)
+			if err != nil {
+				s.sendErr(c, call, val, err)
+				continue
+			}
+
 			// Create response
 			res := types.Response{
 				ID:     call.ID,
-				Return: val,
+				Return: valData,
 			}
 
 			// If function has created a channel
 			if ctx.isChannel {
+				idData, err := c.Marshal(ctx.channelID)
+				if err != nil {
+					s.sendErr(c, call, val, err)
+					continue
+				}
+
 				// Set IsChannel to true
 				res.Type = types.ResponseTypeChannel
 				// Overwrite return value with channel ID
-				res.Return = ctx.channelID
+				res.Return = idData
 
 				// Store context in map for future use
 				s.contextsMtx.Lock()
@@ -349,11 +349,18 @@ func (s *Server) handleConn(pCtx context.Context, c codec.Codec) {
 					// For every value received from channel
 					for val := range ctx.channel {
 						codecMtx.Lock()
+
+						valData, err := c.Marshal(val)
+						if err != nil {
+							continue
+						}
+
 						// Encode response using codec
 						c.Encode(types.Response{
 							ID:     ctx.channelID,
-							Return: val,
+							Return: valData,
 						})
+
 						codecMtx.Unlock()
 					}
 
@@ -383,12 +390,14 @@ func (s *Server) handleConn(pCtx context.Context, c codec.Codec) {
 
 // sendErr sends an error response
 func (s *Server) sendErr(c codec.Codec, req types.Request, val any, err error) {
+	valData, _ := c.Marshal(val)
+
 	// Encode error response using codec
 	c.Encode(types.Response{
 		Type:   types.ResponseTypeError,
 		ID:     req.ID,
 		Error:  err.Error(),
-		Return: val,
+		Return: valData,
 	})
 }