We’ve abstracted the Codec interface to unify the serialization/deserialization logic for processing requests, and you can implement your own Codec to support more formats. The specific source code is inencoding。

These formats are battery-included.

• json
• protobuf
• xml
• yaml

Interface

You should implement the following Codec interface for your custom codec.

// Codec interface is for serialization and deserialization, notice that these methods must be thread-safe.
type Codec interface {
    Marshal(v interface{}) ([]byte, error)
    Unmarshal(data []byte, v interface{}) error
    Name() string
}

Example of Codec Implementation

You may refer to the included implementations in kratos, such as json when you implementing custom Codec.

// https://github.com/go-kratos/kratos/blob/main/encoding/json/json.go
package json
import (
    "encoding/json"
    "reflect"
    "github.com/go-kratos/kratos/v2/encoding"
    "google.golang.org/protobuf/encoding/protojson"
    "google.golang.org/protobuf/proto"
)
// Name is the name registered for the json codec.
const Name = "json"
var (
    // MarshalOptions is a configurable JSON format marshaller.
    MarshalOptions = protojson.MarshalOptions{
        EmitUnpopulated: true,
    }
    // UnmarshalOptions is a configurable JSON format parser.
    UnmarshalOptions = protojson.UnmarshalOptions{
        DiscardUnknown: true,
    }
)
func init() {
    encoding.RegisterCodec(codec{})
}
// codec is a Codec implementation with json.
type codec struct{}
func (codec) Marshal(v interface{}) ([]byte, error) {
    if m, ok := v.(proto.Message); ok {
        return MarshalOptions.Marshal(m)
    }
    return json.Marshal(v)
}
func (codec) Unmarshal(data []byte, v interface{}) error {
    rv := reflect.ValueOf(v)
    for rv.Kind() == reflect.Ptr {
        if rv.IsNil() {
            rv.Set(reflect.New(rv.Type().Elem()))
        }
        rv = rv.Elem()
    }
    if m, ok := v.(proto.Message); ok {
        return UnmarshalOptions.Unmarshal(data, m)
    } else if m, ok := reflect.Indirect(reflect.ValueOf(v)).Interface().(proto.Message); ok {
        return UnmarshalOptions.Unmarshal(data, m)
    }
    return json.Unmarshal(data, v)
}
func (codec) Name() string {
    return Name
}

Usage

Register Custom Codec

encoding.RegisterCodec(codec{})

Get the Codec

jsonCodec := encoding.GetCodec("json")

Serialization

// You should manually import this package if you use it directly: import _ "github.com/go-kratos/kratos/v2/encoding/json"
jsonCode := encoding.GetCodec("json")
type user struct {
    Name string
    Age string
    state bool
}
u := &user{
    Name:  "kratos",
    Age:   "2",
    state: false,
}
bytes, _ := jsonCode.Marshal(u)
// output {"Name":"kratos","Age":"2"}

Deserialization

// You should manually import this package if you use it directly:import _ "github.com/go-kratos/kratos/v2/encoding/json"
jsonCode := encoding.GetCodec("json")
type user struct {
    Name string
    Age string
    state bool
}
u := &user{}
jsonCode.Unmarshal([]byte(`{"Name":"kratos","Age":"2"}`), &u)
//output &{kratos 2 false}