client.go

// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package websocketserver

import (
	"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,
	// 解决跨域问题
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

type MsgHandler func(ClientInterface, []byte)

type ClientInterface interface {
	new(id uint64, center *Center, conn *websocket.Conn, send *chan []byte, handler MsgHandler) ClientInterface
	GetId() uint64
	Delete()
	run()
}

// Client is a middleman between the websocket connection and the center.
type Client struct {
	id uint64

	center *Center

	// The websocket connection.
	conn *websocket.Conn

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

	msgHandler func(ClientInterface, []byte)
}

func (c Client) new(id uint64, center *Center, conn *websocket.Conn, send *chan []byte, handler MsgHandler) ClientInterface {
	c.id = id
	c.center = center
	c.conn = conn
	c.send = send
	c.msgHandler = handler
	return c
}

func (c Client) GetId() uint64 {
	return c.id
}
func (c Client) Delete() {
	close(*c.send)
}
func (c Client) run() {
	go c.writePump()
	go c.readPump()
}

// readPump pumps messages from the websocket connection to the center.
//
// 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.center.unregister <- c.id
		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
		}
		c.msgHandler(c, message)
	}
}

// writePump pumps messages from the center 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 center 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
			}
		}
	}
}

func (c *Client) Send(message []byte) {
	*c.send <- message
}