Golang: Gin + Gorilla to build a websocket application

package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"net/http"
)

var upgrader = websocket.Upgrader{
    //check origin will check the cross region source (note : please not using in production)
	CheckOrigin: func(r *http.Request) bool {
        //Here we just allow the chrome extension client accessable (you should check this verify accourding your client source)
		return origin == "chrome-extension://cbcbkhdmedgianpaifchdaddpnmgnknn"
	},
}

func main() {
	r := gin.Default()
	r.GET("/", func(c *gin.Context) {
		//upgrade get request to websocket protocol
		ws, err := upgrader.Upgrade(c.Writer, c.Request, nil)
		if err != nil {
			fmt.Println(err)
			return
		}
		defer ws.Close()
		for {
			//Read Message from client
			mt, message, err := ws.ReadMessage()
			if err != nil {
				fmt.Println(err)
				break
			}
			//If client message is ping will return pong
			if string(message) == "ping" {
				message = []byte("pong")
			}
			//Response message to client
			err = ws.WriteMessage(mt, message)
			if err != nil {
				fmt.Println(err)
				break
			}
		}
	})
	r.Run() // listen and serve on 0.0.0.0:8080
}

package main

import (
	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()
	hub := newHub()
	go hub.run()
	r.GET("/", func(c *gin.Context) {
		serveWs(hub, c.Writer, c.Request)
	})
	r.Run() // listen and serve on 0.0.0.0:8080
}

package main

import (
	"bytes"
	"encoding/json"
	"github.com/google/uuid"
	"log"
	"net/http"
	"time"

	"github.com/gorilla/websocket"
)

const (
	// Time allowed to write a message to the peer.
	writeWait = 10 * time.Second

	// Time allowed to read the next pong message from the peer.
	pongWait = 60 * time.Second

	// Send pings to peer with this period. Must be less than pongWait.
	pingPeriod = (pongWait * 9) / 10

	// Maximum message size allowed from peer.
	maxMessageSize = 512
)

var (
	newline = []byte{'\n'}
	space   = []byte{' '}
)

var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

type User struct {
	ID      string
	Addr    string
	EnterAt time.Time
}

// Client is a middleman between the websocket connection and the hub.
type Client struct {
	hub *Hub

	// The websocket connection.
	conn *websocket.Conn

	// Buffered channel of outbound messages.
	send chan []byte

	User
}

// readPump pumps messages from the websocket connection to the hub.
//
// The application runs readPump in a per-connection goroutine. The application
// ensures that there is at most one reader on a connection by executing all
// reads from this goroutine.
func (c *Client) readPump() {
	defer func() {
		c.hub.unregister <- c
		c.conn.Close()
	}()
	c.conn.SetReadLimit(maxMessageSize)
	c.conn.SetReadDeadline(time.Now().Add(pongWait))
	c.conn.SetPongHandler(func(string) error { c.conn.SetReadDeadline(time.Now().Add(pongWait)); return nil })
	for {
		_, message, err := c.conn.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				log.Printf("error: %v", err)
			}
			break
		}
		message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1))
		data := map[string][]byte{
			"message": message,
			"id":      []byte(c.ID),
		}
		userMessage, _ := json.Marshal(data)
		c.hub.broadcast <- userMessage
	}
}

// writePump pumps messages from the hub to the websocket connection.
//
// A goroutine running writePump is started for each connection. The
// application ensures that there is at most one writer to a connection by
// executing all writes from this goroutine.
func (c *Client) writePump() {
	ticker := time.NewTicker(pingPeriod)
	defer func() {
		ticker.Stop()
		c.conn.Close()
	}()
	for {
		select {
		case message, ok := <-c.send:
			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
			if !ok {
				// The hub closed the channel.
				c.conn.WriteMessage(websocket.CloseMessage, []byte{})
				return
			}

			w, err := c.conn.NextWriter(websocket.TextMessage)
			if err != nil {
				return
			}
			w.Write(message)

			// Add queued chat messages to the current websocket message.
			n := len(c.send)
			for i := 0; i < n; i++ {
				w.Write(newline)
				w.Write(<-c.send)
			}

			if err := w.Close(); err != nil {
				return
			}
		case <-ticker.C:
			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
			if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
				return
			}
		}
	}
}

// serveWs handles websocket requests from the peer.
func serveWs(hub *Hub, w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Println(err)
		return
	}
	client := &Client{hub: hub, conn: conn, send: make(chan []byte, 256)}
	client.hub.register <- client
	client.ID = GenUserId()
	client.Addr = conn.RemoteAddr().String()
	client.EnterAt = time.Now()

	// Allow collection of memory referenced by the caller by doing all work in
	// new goroutines.
	go client.writePump()
	go client.readPump()

	client.send <- []byte("Welcome")
}

func GenUserId() string {
	uid := uuid.NewString()
	return uid
}

package main

import (
	"encoding/json"
)

// Hub maintains the set of active clients and broadcasts messages to the
// clients.
type Hub struct {
	// Registered clients.
	clients map[*Client]bool

	// Inbound messages from the clients.
	broadcast chan []byte

	// Register requests from the clients.
	register chan *Client

	// Unregister requests from clients.
	unregister chan *Client
}

func newHub() *Hub {
	return &Hub{
		broadcast:  make(chan []byte),
		register:   make(chan *Client),
		unregister: make(chan *Client),
		clients:    make(map[*Client]bool),
	}
}

func (h *Hub) run() {
	for {
		select {
		case client := <-h.register:
			clientId := client.ID
			for client := range h.clients {
				msg := []byte("some one join room (ID: " + clientId + ")")
				client.send <- msg
			}

			h.clients[client] = true

		case client := <-h.unregister:
			clientId := client.ID
			if _, ok := h.clients[client]; ok {
				delete(h.clients, client)
				close(client.send)
			}
			for client := range h.clients {
				msg := []byte("some one leave room (ID:" + clientId + ")")
				client.send <- msg
			}
		case userMessage := <-h.broadcast:
			var data map[string][]byte
			json.Unmarshal(userMessage, &data)

			for client := range h.clients {
				//prevent self receive the message
				if client.ID == string(data["id"]) {
					continue
				}
				select {
				case client.send <- data["message"]:
				default:
					close(client.send)
					delete(h.clients, client)
				}
			}
		}
	}
}

go run *.go