codec: simplify codec interface

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

codec/codec.go

@@ -3,17 +3,6 @@ package codec // import "go.unistack.org/micro/v3/codec"
 
 import (
 	"errors"
-	"io"
-
-	"go.unistack.org/micro/v3/metadata"
-)
-
-// Message types
-const (
-	Error MessageType = iota
-	Request
-	Response
-	Event
 )
 
 var (
@@ -32,42 +21,13 @@ var (
 	DefaultTagName = "codec"
 )
 
-// MessageType specifies message type for codec
+// Codec encodes/decodes various types of messages.
-type MessageType int
-
-// Codec encodes/decodes various types of messages used within micro.
-// ReadHeader and ReadBody are called in pairs to read requests/responses
-// from the connection. Close is called when finished with the
-// connection. ReadBody may be called with a nil argument to force the
-// body to be read and discarded.
 type Codec interface {
-	ReadHeader(r io.Reader, m *Message, mt MessageType) error
-	ReadBody(r io.Reader, v interface{}) error
-	Write(w io.Writer, m *Message, v interface{}) error
 	Marshal(v interface{}, opts ...Option) ([]byte, error)
 	Unmarshal(b []byte, v interface{}, opts ...Option) error
 	String() string
 }
 
-// Message represents detailed information about
-// the communication, likely followed by the body.
-// In the case of an error, body may be nil.
-type Message struct {
-	Header   metadata.Metadata
-	Target   string
-	Method   string
-	Endpoint string
-	Error    string
-	ID       string
-	Body     []byte
-	Type     MessageType
-}
-
-// NewMessage creates new codec message
-func NewMessage(t MessageType) *Message {
-	return &Message{Type: t, Header: metadata.New(0)}
-}
-
 // MarshalAppend calls codec.Marshal(v) and returns the data appended to buf.
 // If codec implements MarshalAppend, that is called instead.
 func MarshalAppend(buf []byte, c Codec, v interface{}, opts ...Option) ([]byte, error) {

codec/noop.go

@@ -2,70 +2,14 @@ package codec
 
 import (
 	"encoding/json"
-	"io"
+
+	codecpb "go.unistack.org/micro-proto/v3/codec"
 )
 
 type noopCodec struct {
 	opts Options
 }
 
-func (c *noopCodec) ReadHeader(conn io.Reader, m *Message, t MessageType) error {
-	return nil
-}
-
-func (c *noopCodec) ReadBody(conn io.Reader, b interface{}) error {
-	// read bytes
-	buf, err := io.ReadAll(conn)
-	if err != nil {
-		return err
-	}
-
-	if b == nil {
-		return nil
-	}
-
-	switch v := b.(type) {
-	case *string:
-		*v = string(buf)
-	case *[]byte:
-		*v = buf
-	case *Frame:
-		v.Data = buf
-	default:
-		return json.Unmarshal(buf, v)
-	}
-
-	return nil
-}
-
-func (c *noopCodec) Write(conn io.Writer, m *Message, b interface{}) error {
-	if b == nil {
-		return nil
-	}
-
-	var v []byte
-	switch vb := b.(type) {
-	case *Frame:
-		v = vb.Data
-	case string:
-		v = []byte(vb)
-	case *string:
-		v = []byte(*vb)
-	case *[]byte:
-		v = *vb
-	case []byte:
-		v = vb
-	default:
-		var err error
-		v, err = json.Marshal(vb)
-		if err != nil {
-			return err
-		}
-	}
-	_, err := conn.Write(v)
-	return err
-}
-
 func (c *noopCodec) String() string {
 	return "noop"
 }
@@ -91,8 +35,8 @@ func (c *noopCodec) Marshal(v interface{}, opts ...Option) ([]byte, error) {
 		return ve, nil
 	case *Frame:
 		return ve.Data, nil
-	case *Message:
+	case *codecpb.Frame:
-		return ve.Body, nil
+		return ve.Data, nil
 	}
 
 	return json.Marshal(v)
@@ -115,8 +59,8 @@ func (c *noopCodec) Unmarshal(d []byte, v interface{}, opts ...Option) error {
 	case *Frame:
 		ve.Data = d
 		return nil
-	case *Message:
+	case *codecpb.Frame:
-		ve.Body = d
+		ve.Data = d
 		return nil
 	}
 

server/noop.go

@@ -1,7 +1,6 @@
 package server
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"reflect"
@@ -691,7 +690,7 @@ func (n *noopServer) createSubHandler(sb *subscriber, opts Options) broker.Handl
 				req = req.Elem()
 			}
 
-			if err = cf.ReadBody(bytes.NewBuffer(msg.Body), req.Interface()); err != nil {
+			if err = cf.Unmarshal(msg.Body, req.Interface()); err != nil {
 				return err
 			}