main.go

package main

import (
	"github.com/gorilla/rpc/v2"
	"github.com/gorilla/rpc/v2/json"
	"log"
	"net/http"
)

type MathArgs struct {
	Numbers []int `json:"numbers"`
}

type MathReply struct {
	Value int
}

type MathService struct{}

func (h *MathService) Sum(r *http.Request, args *MathArgs, reply *MathReply) error {
	var v int
	for _, num := range args.Numbers {
		v = v + num
	}
	reply.Value = v
	return nil
}

func (h *MathService) Subtract(r *http.Request, args *MathArgs, reply *MathReply) error {
	v := args.Numbers[0]
	for _, num := range args.Numbers[1:] {
		v = v - num
	}
	reply.Value = v
	return nil
}

func main() {
	s := rpc.NewServer()
	s.RegisterCodec(json.NewCodec(), "application/json")
	s.RegisterService(new(MathService), "Math")
	http.Handle("/rpc", s)
	log.Fatal(http.ListenAndServe(":8888", nil))
}

rpctest.json

[
    {"jsonrpc": "2.0", "method": "Math.Sum", "params": [{"Numbers": [1,2,4]}], "id": "1"},
    {"foo": "boo"},
    {"jsonrpc": "2.0", "method": "Math.Subtract", "params": [{"Numbers": [42,23]}], "id": "2"}
]

$rpcexample % curl -X POST -H "Content-Type: application/json" -d "@rpctest.json" http://localhost:8888/rpc
{"result":null,"error":"json: cannot unmarshal array into Go value of type json.serverRequest","id":null}