138 lines
3.3 KiB
Go
138 lines
3.3 KiB
Go
// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"bytes"
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"log"
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"net/http"
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"time"
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"github.com/gorilla/websocket"
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)
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const (
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// Time allowed to write a message to the peer.
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writeWait = 10 * time.Second
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// Time allowed to read the next pong message from the peer.
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pongWait = 60 * time.Second
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// Send pings to peer with this period. Must be less than pongWait.
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pingPeriod = (pongWait * 9) / 10
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// Maximum message size allowed from peer.
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maxMessageSize = 512
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)
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var (
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newline = []byte{'\n'}
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space = []byte{' '}
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)
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var upgrader = websocket.Upgrader{
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ReadBufferSize: 1024,
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WriteBufferSize: 1024,
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}
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// Client is a middleman between the websocket connection and the hub.
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type Client struct {
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hub *Hub
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// The websocket connection.
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conn *websocket.Conn
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// Buffered channel of outbound messages.
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send chan []byte
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}
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// readPump pumps messages from the websocket connection to the hub.
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//
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// The application runs readPump in a per-connection goroutine. The application
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// ensures that there is at most one reader on a connection by executing all
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// reads from this goroutine.
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func (c *Client) readPump() {
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defer func() {
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c.hub.unregister <- c
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c.conn.Close()
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}()
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c.conn.SetReadLimit(maxMessageSize)
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c.conn.SetReadDeadline(time.Now().Add(pongWait))
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c.conn.SetPongHandler(func(string) error { c.conn.SetReadDeadline(time.Now().Add(pongWait)); return nil })
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for {
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_, message, err := c.conn.ReadMessage()
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if err != nil {
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if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
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log.Printf("error: %v", err)
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}
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break
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}
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message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1))
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c.hub.broadcast <- message
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}
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}
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// writePump pumps messages from the hub to the websocket connection.
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//
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// A goroutine running writePump is started for each connection. The
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// application ensures that there is at most one writer to a connection by
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// executing all writes from this goroutine.
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func (c *Client) writePump() {
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ticker := time.NewTicker(pingPeriod)
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defer func() {
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ticker.Stop()
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c.conn.Close()
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}()
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for {
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select {
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case message, ok := <-c.send:
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c.conn.SetWriteDeadline(time.Now().Add(writeWait))
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if !ok {
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// The hub closed the channel.
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c.conn.WriteMessage(websocket.CloseMessage, []byte{})
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return
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}
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w, err := c.conn.NextWriter(websocket.TextMessage)
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if err != nil {
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return
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}
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w.Write(message)
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// Add queued chat messages to the current websocket message.
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n := len(c.send)
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for i := 0; i < n; i++ {
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w.Write(newline)
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w.Write(<-c.send)
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}
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if err := w.Close(); err != nil {
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return
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}
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case <-ticker.C:
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c.conn.SetWriteDeadline(time.Now().Add(writeWait))
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if err := c.conn.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
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return
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}
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}
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}
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}
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// serveWs handles websocket requests from the peer.
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func serveWs(hub *Hub, w http.ResponseWriter, r *http.Request) {
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conn, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
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log.Println(err)
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return
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}
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client := &Client{hub: hub, conn: conn, send: make(chan []byte, 256)}
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client.hub.register <- client
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// Allow collection of memory referenced by the caller by doing all work in
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// new goroutines.
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go client.writePump()
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go client.readPump()
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}
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