From 49e5636bcd919a4898e3061180156095998bc634 Mon Sep 17 00:00:00 2001
From: Asim Aslam <asim@chuhnk.me>
Date: Tue, 6 Dec 2016 18:56:57 +0000
Subject: [PATCH] add transport codec

---
 transport/codec/codec.go     | 10 ++++++++++
 transport/codec/json/json.go | 25 +++++++++++++++++++++++++
 transport/codec/noop/noop.go | 35 +++++++++++++++++++++++++++++++++++
 transport/options.go         | 10 ++++++++++
 4 files changed, 80 insertions(+)
 create mode 100644 transport/codec/codec.go
 create mode 100644 transport/codec/json/json.go
 create mode 100644 transport/codec/noop/noop.go

diff --git a/transport/codec/codec.go b/transport/codec/codec.go
new file mode 100644
index 00000000..85e89320
--- /dev/null
+++ b/transport/codec/codec.go
@@ -0,0 +1,10 @@
+package codec
+
+// Codec is used for encoding where the transport doesn't natively support
+// headers in the message type. In this case the entire message is
+// encoded as the payload
+type Codec interface {
+	Marshal(interface{}) ([]byte, error)
+	Unmarshal([]byte, interface{}) error
+	String() string
+}
diff --git a/transport/codec/json/json.go b/transport/codec/json/json.go
new file mode 100644
index 00000000..0adaab04
--- /dev/null
+++ b/transport/codec/json/json.go
@@ -0,0 +1,25 @@
+package json
+
+import (
+	"encoding/json"
+
+	"github.com/micro/go-micro/transport/codec"
+)
+
+type jsonCodec struct{}
+
+func (j jsonCodec) Marshal(v interface{}) ([]byte, error) {
+	return json.Marshal(v)
+}
+
+func (j jsonCodec) Unmarshal(d []byte, v interface{}) error {
+	return json.Unmarshal(d, v)
+}
+
+func (j jsonCodec) String() string {
+	return "json"
+}
+
+func NewCodec() codec.Codec {
+	return jsonCodec{}
+}
diff --git a/transport/codec/noop/noop.go b/transport/codec/noop/noop.go
new file mode 100644
index 00000000..44ac91a1
--- /dev/null
+++ b/transport/codec/noop/noop.go
@@ -0,0 +1,35 @@
+package noop
+
+import (
+	"errors"
+
+	"github.com/micro/go-micro/transport"
+	"github.com/micro/go-micro/transport/codec"
+)
+
+type noopCodec struct{}
+
+func (n noopCodec) Marshal(v interface{}) ([]byte, error) {
+	msg, ok := v.(*transport.Message)
+	if !ok {
+		return nil, errors.New("invalid message")
+	}
+	return msg.Body, nil
+}
+
+func (n noopCodec) Unmarshal(d []byte, v interface{}) error {
+	msg, ok := v.(*transport.Message)
+	if !ok {
+		return errors.New("invalid message")
+	}
+	msg.Body = d
+	return nil
+}
+
+func (n noopCodec) String() string {
+	return "noop"
+}
+
+func NewCodec() codec.Codec {
+	return noopCodec{}
+}
diff --git a/transport/options.go b/transport/options.go
index de5ee039..36b48225 100644
--- a/transport/options.go
+++ b/transport/options.go
@@ -4,11 +4,13 @@ import (
 	"crypto/tls"
 	"time"
 
+	"github.com/micro/go-micro/transport/codec"
 	"golang.org/x/net/context"
 )
 
 type Options struct {
 	Addrs     []string
+	Codec     codec.Codec
 	Secure    bool
 	TLSConfig *tls.Config
 	// Timeout sets the timeout for Send/Recv
@@ -46,6 +48,14 @@ func Addrs(addrs ...string) Option {
 	}
 }
 
+// Codec sets the codec used for encoding where the transport
+// does not support message headers
+func Codec(c codec.Codec) Option {
+	return func(o *Options) {
+		o.Codec = c
+	}
+}
+
 // Timeout sets the timeout for Send/Recv execution
 func Timeout(t time.Duration) Option {
 	return func(o *Options) {