Implement RPC client Node.js with server written

Question

I implement RPC server using Go. Now, I want to write the client using Node.js, how can I make RPC call from Node.js client to a Go server.

Here is the code of the server written in Go.

server.go

package main

type HelloService struct{}

func (p *HelloService) Hello(request string, reply *string) error {
    *reply = "Hello " + request
    return nil
}

func main() {
    rpc.RegisterName("HelloService", new(HelloService))

    // run rpc on port 1234
    listener, err := net.Listen("tcp", ":1234")

    if err != nil {
        log.Fatal("ListenTCP error: ", err)
    }

    // use for-while for serve client
    for {
        conn, err := listener.Accept()
        log.Println("New connection: ", conn)

        if err != nil {
            log.Fatal("Accept error: ", err)
        }

        go rpc.ServeConn(conn)
    }
}
 

Answer 1

The net/rpc package uses encoding/gob as the default wire format. It's a Go specific binary serialization format which is efficient, but, in practice, only useful when communicating between Go applications.

However, net/rpc supports utilizing different codecs for (de)serializing data and the net/rpc/jsonrpc package provides a JSON-RPC 1.0 complaint codec implementation.

Here's an example of using it, along with a Node.js client which utilizes the jayson package (nothing particular about it, just the first one I stumbled across that supports JSON-RPC 1.0):

server.go

package main

import (
        "log"
        "net"
        "net/rpc"
        "net/rpc/jsonrpc"
)

type HelloService struct{}

func (p *HelloService) Hello(request string, reply *string) error {
        *reply = "Hello " + request
        return nil
}

func main() {
        rpc.RegisterName("HelloService", new(HelloService))
        listener, err := net.Listen("tcp", ":1234")
        if err != nil {
                log.Fatal("ListenTCP error: ", err)
        }
        for {
                conn, err := listener.Accept()
                if err != nil {
                        log.Fatal("Accept error: ", err)
                }
                log.Printf("New connection: %+v\n", conn.RemoteAddr())
                go jsonrpc.ServeConn(conn)
        }
}

client.js

const jayson = require("jayson");

const client = jayson.client.tcp({
        host: "172.17.0.2",
        port: "1234",
        version: 1,
});

client.request("HelloService.Hello", ["chuckx"], (err, response) => {
        if (err) throw err;
        if (response.error) throw response.error;
        console.log("response:", response.result);
});

Output

Server

$ go run server.go
2021/03/12 06:46:21 New connection: 172.17.0.3:51016

Client

$ node client.js
response: Hello chuckx

---

Note that the net/rpc package is no longer accepting new features, so you may be better off using something like gRPC for more features and better cross-language compatibility.