server.go

// MIT License
//
// Copyright (c) 2020 Lack
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package jsonrpc

import (
	"fmt"
	"io"

	json "github.com/json-iterator/go"
	"github.com/vine-io/vine/core/codec"
)

type serverCodec struct {
	dec *json.Decoder // for reading JSON values
	enc *json.Encoder // for writing JSON values
	c   io.Closer

	// temporary work space
	req  serverRequest
	resp serverResponse
}

type serverRequest struct {
	Method string           `json:"method"`
	Params *json.RawMessage `json:"params"`
	ID     interface{}      `json:"id"`
}

type serverResponse struct {
	ID     interface{} `json:"id"`
	Result interface{} `json:"result"`
	Error  interface{} `json:"error"`
}

func newServerCodec(conn io.ReadWriteCloser) *serverCodec {
	return &serverCodec{
		dec: json.NewDecoder(conn),
		enc: json.NewEncoder(conn),
		c:   conn,
	}
}

func (r *serverRequest) reset() {
	r.Method = ""
	if r.Params != nil {
		*r.Params = (*r.Params)[0:0]
	}
	if r.ID != nil {
		r.ID = nil
	}
}

func (c *serverCodec) ReadHeader(m *codec.Message) error {
	c.req.reset()
	if err := c.dec.Decode(&c.req); err != nil {
		return err
	}
	m.Method = c.req.Method
	m.Id = fmt.Sprintf("%v", c.req.ID)
	c.req.ID = nil
	return nil
}

func (c *serverCodec) ReadBody(x interface{}) error {
	if x == nil {
		return nil
	}
	var params [1]interface{}
	params[0] = x
	return json.Unmarshal(*c.req.Params, &params)
}

var null = json.RawMessage([]byte("null"))

func (c *serverCodec) Write(m *codec.Message, x interface{}) error {
	var resp serverResponse
	resp.ID = m.Id
	resp.Result = x
	if m.Error == "" {
		resp.Error = nil
	} else {
		resp.Error = m.Error
	}
	return c.enc.Encode(resp)
}

func (c *serverCodec) Close() error {
	return c.c.Close()
}