go-socket.io

go-socket.io is an implementation of Socket.IO in Golang, which is a realtime application framework.

Currently this library supports 1.4 version of the Socket.IO client. It supports room and namespaces.

Help wanted This project is looking for contributors to help fix bugs and implement new features. Please check Issue 192. All help is much appreciated.

• for compatibility with Socket.IO 0.9.x, please use branch 0.9.x *

Install

Install the package with:

go get github.com/googollee/go-socket.io

Import it with:

import "github.com/googollee/go-socket.io"

and use socketio as the package name inside the code.

Example

Please check the example folder for details.

package main

import (
	"log"
	"net/http"

	"github.com/googollee/go-socket.io"
)

func main() {
	server, err := socketio.NewServer(nil)
	if err != nil {
		log.Fatal(err)
	}
	server.OnConnect("/", func(s socketio.Conn) error {
		s.SetContext("")
		fmt.Println("connected:", s.ID())
		return nil
	})
	server.OnEvent("/", "notice", func(s socketio.Conn, msg string) {
		fmt.Println("notice:", msg)
		s.Emit("reply", "have "+msg)
	})
	server.OnEvent("/chat", "msg", func(s socketio.Conn, msg string) string {
		s.SetContext(msg)
		return "recv " + msg
	})
	server.OnEvent("/", "bye", func(s socketio.Conn) string {
		last := s.Context().(string)
		s.Emit("bye", last)
		s.Close()
		return last
	})
	server.OnError("/", func(e error) {
		fmt.Println("meet error:", e)
	})
	server.OnDisconnect("/", func(s socketio.Conn, msg string) {
		fmt.Println("closed", msg)
	})
	go server.Serve()
	defer server.Close()

	http.Handle("/socket.io/", server)
	http.Handle("/", http.FileServer(http.Dir("./asset")))
	log.Println("Serving at localhost:8000...")
	log.Fatal(http.ListenAndServe(":8000", nil))
}

Acknowledgements in go-socket.io 1.X.X

See documentation about acknowledgements

Sending ACK with data from SERVER to CLIENT

• Client-side

 //using client-side socket.io-1.X.X.js
 socket.emit('some:event', JSON.stringify(someData), function(data){
       console.log('ACK from server wtih data: ', data));
 });

• Server-side

// The return type may vary depending on whether you will return
// In golang implementation of Socket.IO don't used callbacks for acknowledgement,
// but used return value, which wrapped into ack package and returned to the client's callback in JavaScript
so.On("some:event", func(msg string) string {
	return msg //Sending ack with data in msg back to client, using "return statement"
})

Sending ACK with data from CLIENT to SERVER

• Client-side

//using client-side socket.io-1.X.X.js
//last parameter of "on" handler is callback for sending ack to server with data or without data
socket.on('some:event', function (msg, sendAckCb) {
    //Sending ACK with data to server after receiving some:event from server
    sendAckCb(JSON.stringify(data)); // for example used serializing to JSON
}

• Server-side

//You can use Emit or BroadcastTo with last parameter as callback for handling ack from client
//Sending packet to room "room_name" and event "some:event"
so.BroadcastTo("room_name", "some:event", dataForClient, func (so socketio.Socket, data string) {
	log.Println("Client ACK with data: ", data)
})

// Or

so.Emit("some:event", dataForClient, func (so socketio.Socket, data string) {
	log.Println("Client ACK with data: ", data)
})

License

The 3-clause BSD License - see LICENSE for more details