jsonrpc

JSON-RPC 2.0

Simple idiomatic package with simple api for implement JSON-RPC 2.0 server. It use common interfaces as io.Reader and io.Writer. Package based on standard library and don't used empty interfaces and reflect package. Ready for use with go mod.

Install

$ go get -u github.com/reviz0r/jsonrpc

Usage

In common case you must write function with signature func(ctx context.Context, params io.Reader, result io.Writer) error and register it. That's all, folks!

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"

	"github.com/reviz0r/jsonrpc"
)

// Params of your method
type GreetingReq struct {
	Name string `json:"name"`
}

// Result of your method
type GreetingRes struct {
	Greeting string `json:"greeting"`
}

// Your method
func Greeting(ctx context.Context, params io.Reader, result io.Writer) error {
	var req GreetingReq
	var res GreetingRes

	// Decode request from reader
	if err := json.NewDecoder(params).Decode(&req); err != nil {
		return jsonrpc.ErrInvalidParams(err.Error())
	}

	// Your logic
	{
		log.Printf("incoming request with id %s", jsonrpc.RequestID(ctx))
		if req.Name == "" {
			req.Name = "stranger"
		}
		res.Greeting = fmt.Sprintf("Hello, %s", req.Name)
	}

	// Encode response to writer
	return json.NewEncoder(result).Encode(&res)
}

func main() {
	repo := jsonrpc.New()
	repo.RegisterMethod(jsonrpc.MethodFunc("greeting", Greeting))

	http.Handle("/rpc", repo)
	http.ListenAndServe(":8080", http.DefaultServeMux)
}

POST /rpc
Content-Type: application/json
User-Agent: PostmanRuntime/7.13.0
Accept: */*
Cache-Control: no-cache
Host: localhost:8080
accept-encoding: gzip, deflate
content-length: 143
Connection: keep-alive
{
  "id": "9f8c46cd-3aa8-43c8-bcb1-8324421826cf",
  "jsonrpc": "2.0",
  "method": "greeting",
  "params": {
    "name": "user"
  }
}

HTTP/1.1 200
status: 200
Content-Type: application/json
Date: Sun, 04 Aug 2019 00:00:00 GMT
Content-Length: 98
{
  "id": 9f8c46cd-3aa8-43c8-bcb1-8324421826cf",
  "jsonrpc": "2.0",
  "result": {
    "greeting": "Hello, user"
  }
}

License

Released under the MIT License.