1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/*
* This file is part of caronte (https://github.com/eciavatta/caronte).
* Copyright (c) 2020 Emiliano Ciavatta.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package main
import (
"github.com/gin-gonic/gin"
"github.com/gorilla/websocket"
log "github.com/sirupsen/logrus"
"net"
"net/http"
"time"
)
const (
writeWait = 10 * time.Second
pongWait = 60 * time.Second
pingPeriod = (pongWait * 9) / 10
maxMessageSize = 512
)
type NotificationController struct {
upgrader websocket.Upgrader
clients map[net.Addr]*client
broadcast chan interface{}
register chan *client
unregister chan *client
applicationContext *ApplicationContext
}
func NewNotificationController(applicationContext *ApplicationContext) *NotificationController {
return &NotificationController{
upgrader: websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
},
clients: make(map[net.Addr]*client),
broadcast: make(chan interface{}),
register: make(chan *client),
unregister: make(chan *client),
applicationContext: applicationContext,
}
}
type client struct {
conn *websocket.Conn
send chan interface{}
notificationController *NotificationController
}
func (wc *NotificationController) NotificationHandler(w http.ResponseWriter, r *http.Request) error {
conn, err := wc.upgrader.Upgrade(w, r, nil)
if err != nil {
log.WithError(err).Error("failed to set websocket upgrade")
return err
}
client := &client{
conn: conn,
send: make(chan interface{}),
notificationController: wc,
}
wc.register <- client
go client.readPump()
go client.writePump()
return nil
}
func (wc *NotificationController) Run() {
for {
select {
case client := <-wc.register:
wc.clients[client.conn.RemoteAddr()] = client
payload := gin.H{"event": "connected", "message": gin.H{
"version": wc.applicationContext.Version,
"is_configured": wc.applicationContext.IsConfigured,
"connected_clients": len(wc.clients),
}}
client.send <- payload
log.WithField("connected_clients", len(wc.clients)).
WithField("remote_address", client.conn.RemoteAddr()).
Info("[+] a websocket client connected")
case client := <-wc.unregister:
if _, ok := wc.clients[client.conn.RemoteAddr()]; ok {
close(client.send)
_ = client.conn.WriteMessage(websocket.CloseMessage, nil)
_ = client.conn.Close()
delete(wc.clients, client.conn.RemoteAddr())
log.WithField("connected_clients", len(wc.clients)).
WithField("remote_address", client.conn.RemoteAddr()).
Info("[-] a websocket client disconnected")
}
case payload := <-wc.broadcast:
for _, client := range wc.clients {
select {
case client.send <- payload:
default:
close(client.send)
delete(wc.clients, client.conn.RemoteAddr())
}
}
}
}
}
func (wc *NotificationController) Notify(event string, message interface{}) {
wc.broadcast <- gin.H{"event": event, "message": message}
}
func (c *client) readPump() {
c.conn.SetReadLimit(maxMessageSize)
if err := c.conn.SetReadDeadline(time.Now().Add(pongWait)); err != nil {
c.close()
return
}
c.conn.SetPongHandler(func(string) error { return c.conn.SetReadDeadline(time.Now().Add(pongWait)) })
for {
if _, _, err := c.conn.ReadMessage(); err != nil {
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
log.WithError(err).WithField("remote_address", c.conn.RemoteAddr()).
Warn("unexpected websocket disconnection")
}
break
}
}
c.close()
}
func (c *client) writePump() {
ticker := time.NewTicker(pingPeriod)
defer ticker.Stop()
for {
select {
case payload, ok := <-c.send:
if !ok {
return
}
if err := c.conn.SetWriteDeadline(time.Now().Add(writeWait)); err != nil {
c.close()
return
}
if err := c.conn.WriteJSON(payload); err != nil {
c.close()
return
}
case <-ticker.C:
if err := c.conn.SetWriteDeadline(time.Now().Add(writeWait)); err != nil {
c.close()
return
}
if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
c.close()
return
}
}
}
}
func (c *client) close() {
c.notificationController.unregister <- c
}
|
