dndmusicbot/ws.go

package main

import (
	"context"
	"encoding/json"
	"log"
	"net/http"
	"sync"
	"time"

	"github.com/gorilla/websocket"
	"github.com/grafov/bcast"
	"github.com/kataras/go-events"
)

func init() {
	log.Println("ws.go loading..")
	go ws_clients.Broadcast(0)
	ws_msg = make(chan interface{})

	go func() {
		for {
			select {
			case msg := <-ws_msg:
				ws_clients.Send(msg)
			}
		}
	}()

	// Since httprouter seems to not like doing websocket stuff, we run a seperate server for it.. for now..
	go func() {
		app.mux.HandleFunc("/ws", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			log.Printf("WS connection from %v\n", r.RemoteAddr)
			conn, err := upgrader.Upgrade(w, r, nil)
			if err != nil {
				log.Println(err)
				return
			}

			err = handleWS(conn)
			if err != nil {
				log.Printf("WS connection closed, %v\n", r.RemoteAddr)
			}
		}))
	}()

	log.Println("ws.go done.")
}

type WSmsg struct {
	Event   string
	Payload json.RawMessage
}

var ws_clients = bcast.NewGroup()
var ws_msg chan interface{}
var WSMutex = &sync.Mutex{}

var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
}

func handleWS(c *websocket.Conn) error {
	memb := ws_clients.Join()
	defer memb.Close()

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	go func() {
		ticker := time.NewTicker(30 * time.Second)

		for {
			select {
			case <-ctx.Done():
				return
			case <-ticker.C:
				c.WriteControl(websocket.PingMessage, []byte{}, time.Now().Add(10*time.Second))
			case msg := <-memb.Read:
				c.SetWriteDeadline(time.Now().Add(10 * time.Second))
				c.WriteJSON(msg)
			}
		}
	}()

	c.SetPongHandler(func(d string) error {
		return nil
	})

	msg := app.songInfoEvent("song_info")

	c.SetWriteDeadline(time.Now().Add(10 * time.Second))
	c.WriteJSON(msg)

	if app.ambiance.IsPlaying() {
		msg := make(map[string]interface{})
		out := make(map[string]interface{})
		msg["event"] = "ambiance_play"
		out["type"] = app.curamb
		msg["payload"] = out
		c.WriteJSON(msg)
	} else {
		msg := make(map[string]interface{})
		msg["event"] = "ambiance_stop"
		c.WriteJSON(msg)
	}

	for {
		var msg WSmsg
		err := c.ReadJSON(&msg)
		if err != nil {
			return err
		}

		app.events.Emit(events.EventName(msg.Event), msg.Payload)
	}
}