go__socialnetwork/ch3/ex3rpc.go

package main

/*
Sample request content:
	Method: POST
	Content-type: application/json -> without it JSON-RPC returns a 415.
	Accept header is not needed.

{
  "method": "StringService.Length",
  "params" : [
    {
      "Message": "Hello, world"
    }
  ],
  "id": 1
}

Sample Curl usage:

curl -X POST -H "Content-type: application/json" -d '{"method": "StringService.Length", "params": [{"Message": "Hello, world"}], "Id": 1}' http://localhost:8080/rpc

 */

import (
	"net/http"

	"github.com/gorilla/rpc/v2"
	"github.com/gorilla/rpc/v2/json"

	"fmt"
	"unicode/utf8"
	"github.com/davecgh/go-spew/spew"
)

type RPCApiArguments struct {
	Message string
}

type RPCAPIResponse struct {
	Message string
}

type StringService struct{}

func (s *StringService) Length(q *http.Request, args *RPCApiArguments, r *RPCAPIResponse) error {
	r.Message = fmt.Sprintf("Your request [%s] is %d characters long",
		args.Message,
		utf8.RuneCountInString(args.Message))
	spew.Dump(r)
	return nil
}

func main() {
	address := ":8080"
	fmt.Printf("API started on %s\n", address)
	s := rpc.NewServer()
	s.RegisterCodec(json.NewCodec(), "application/json")
	s.RegisterService(new(StringService), "")
	http.Handle("/rpc", s)
	http.ListenAndServe(address, nil)
}