-
Notifications
You must be signed in to change notification settings - Fork 0
/
paintserver.go
136 lines (114 loc) · 2.91 KB
/
paintserver.go
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
package main
import (
"html/template"
"io"
"log"
"net/http"
"github.com/gorilla/websocket"
)
var websocketUpgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
}
var templates = template.Must(template.ParseFiles("index.html"))
func indexHandler(w http.ResponseWriter, r *http.Request) {
err := templates.ExecuteTemplate(w, "index.html", nil)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
func makeWebSocketUpgrader(session *Session) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
conn, err := websocketUpgrader.Upgrade(w, r, nil)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
log.Printf("HTTP connection upgraded to WebSocket connection: %v\n", r)
client := NewClient(conn)
session.Join(client)
go client.ReadLoop(session)
go client.WriteLoop()
}
}
type Client struct {
conn *websocket.Conn
OutgoingQueue chan string
}
func NewClient(conn *websocket.Conn) *Client {
return &Client{
conn: conn,
OutgoingQueue: make(chan string),
}
}
func (c *Client) ReadLoop(session *Session) {
for {
_, message, err := c.conn.ReadMessage()
if err == io.EOF {
session.Leave(c)
break
}
session.Share(string(message))
}
}
func (c *Client) WriteLoop() {
for message := range c.OutgoingQueue {
c.conn.WriteMessage(websocket.TextMessage, []byte(message))
}
}
type Session struct {
members map[*Client]bool
pendingLeaves chan *Client
pendingJoins chan *Client
pendingBroadcasts chan string
allUpdates []string
}
func NewSession() *Session {
return &Session{
members: make(map[*Client]bool),
pendingLeaves: make(chan *Client),
pendingJoins: make(chan *Client),
pendingBroadcasts: make(chan string),
allUpdates: make([]string, 0),
}
}
func (s *Session) Start() {
for {
select {
case client := <-s.pendingLeaves:
delete(s.members, client)
close(client.OutgoingQueue)
log.Printf("Client left: %v\n", client)
case client := <-s.pendingJoins:
s.members[client] = true
for _, message := range s.allUpdates {
client.OutgoingQueue <- message
}
log.Printf("Client joined: %v\n", client)
case message := <-s.pendingBroadcasts:
log.Printf("Broadcasting message: %v\n", message)
s.allUpdates = append(s.allUpdates, message)
for client := range s.members {
client.OutgoingQueue <- message
}
}
}
}
func (s *Session) Join(client *Client) {
s.pendingJoins <- client
}
func (s *Session) Leave(client *Client) {
s.pendingLeaves <- client
}
func (s *Session) Share(message string) {
s.pendingBroadcasts <- message
}
func main() {
// TODO(aryann): Add support for multiple sessions.
session := NewSession()
go session.Start()
http.HandleFunc("/", indexHandler)
http.HandleFunc("/websocket/", makeWebSocketUpgrader(session))
http.ListenAndServe(":8080", nil)
}