websocket/examples/chat/conn.go

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// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"github.com/gorilla/websocket"
"log"
"net/http"
"time"
)
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 upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
}
// Conn is an middleman between the websocket connection and the hub.
type Conn struct {
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// The websocket connection.
ws *websocket.Conn
// Buffered channel of outbound messages.
send chan []byte
}
// readPump pumps messages from the websocket connection to the hub.
func (c *Conn) readPump() {
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defer func() {
hub.unregister <- c
c.ws.Close()
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}()
c.ws.SetReadLimit(maxMessageSize)
c.ws.SetReadDeadline(time.Now().Add(pongWait))
c.ws.SetPongHandler(func(string) error { c.ws.SetReadDeadline(time.Now().Add(pongWait)); return nil })
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for {
_, message, err := c.ws.ReadMessage()
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if err != nil {
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
log.Printf("error: %v", err)
}
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break
}
hub.broadcast <- message
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}
}
// write writes a message with the given message type and payload.
func (c *Conn) write(mt int, payload []byte) error {
c.ws.SetWriteDeadline(time.Now().Add(writeWait))
return c.ws.WriteMessage(mt, payload)
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}
// writePump pumps messages from the hub to the websocket connection.
func (c *Conn) writePump() {
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ticker := time.NewTicker(pingPeriod)
defer func() {
ticker.Stop()
c.ws.Close()
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}()
for {
select {
case message, ok := <-c.send:
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if !ok {
c.write(websocket.CloseMessage, []byte{})
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return
}
if err := c.write(websocket.TextMessage, message); err != nil {
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return
}
case <-ticker.C:
if err := c.write(websocket.PingMessage, []byte{}); err != nil {
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return
}
}
}
}
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// serveWs handles websocket requests from the peer.
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func serveWs(w http.ResponseWriter, r *http.Request) {
ws, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
log.Println(err)
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return
}
conn := &Conn{send: make(chan []byte, 256), ws: ws}
hub.register <- conn
go conn.writePump()
conn.readPump()
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}