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conn.go
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conn.go
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// @author cold bin
// @date 2022/7/23
package mini_websocket
import (
"bufio"
"bytes"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"log"
"net"
)
const (
SendCriticalSize = 1024 * 1000 * 2 //发送数据大小限制,避免恶意数据
shardSize = 65535 //分片大小
minReadBufferSize = 65535 //网络连接缓冲区的读的最少字节数
minWriteBufferSize = 65535 //网络连接缓冲区的读的少字节数
maxReadBufferSize = 65535 * 10 //网络连接缓冲区的读的最多字节数
maxWriteBufferSize = 65535 * 10 //网络连接缓冲区的写的最多字节数
)
// WsConn websocket连接
type WsConn struct {
Conn net.Conn
BufRD *bufio.Reader // 读,缓冲区的数据
BufWR *bufio.Writer // 写,缓冲区的数据
IsServer bool //标记服务端,服务端向客户端发送帧数据时,不需要掩码处理
CompressLevel int //压缩等级
}
// NewWsConn 构造websocket.Conn
func NewWsConn(netConn net.Conn, isServer bool, ReadBufferSize, WriteBufferSize int, compressLevel int) *WsConn {
if ReadBufferSize < minReadBufferSize || ReadBufferSize > maxReadBufferSize {
ReadBufferSize = minReadBufferSize
}
if WriteBufferSize < minWriteBufferSize || WriteBufferSize > maxWriteBufferSize {
WriteBufferSize = minWriteBufferSize
}
c := &WsConn{
Conn: netConn,
IsServer: isServer,
BufRD: bufio.NewReaderSize(netConn, ReadBufferSize),
BufWR: bufio.NewWriterSize(netConn, WriteBufferSize),
CompressLevel: compressLevel,
}
return c
}
func (wc *WsConn) LocalAddr() net.Addr {
return wc.Conn.LocalAddr()
}
func (wc *WsConn) RemoteAddr() net.Addr {
return wc.Conn.RemoteAddr()
}
// ReadMessage 读取text、binary、延续帧
func (wc *WsConn) ReadMessage() (mt MessageType, msg []byte, err error) {
frame, err := readFrame(wc)
if err != nil {
log.Printf("Conn.ReadMessage failed to c.readFrame, err=%v\n", err)
return NoFrame, nil, err
}
mt = MessageType(frame.OpCode)
frame.MaskPayload()
log.Println("frame decode mask payload: ", string(frame.Payload))
// 根据读到的帧判断是否还有后续的帧,如果有分片,那就读完将payload组装到一起
buf := bytes.NewBuffer(nil)
buf.Write(frame.Payload)
for !frame.IsFinal() {
if frame, err = readFrame(wc); err != nil {
log.Printf("Conn.ReadMessage failed to c.readFrame, err=%v", err)
return NoFrame, nil, err
}
frame.MaskPayload()
log.Println("frame decode mask payload: ", string(frame.Payload))
// todo
//zipBytes := tool.UGZipBytes(frame.Payload)
//log.Println(len(zipBytes), zipBytes)
//buf.Write(zipBytes)
buf.Write(frame.Payload)
}
msg = buf.Bytes()
return
}
// read 从网络缓冲区取出指定字节数量的数据
func read(wc *WsConn, n int) ([]byte, error) {
//谨慎探测
p, err := wc.BufRD.Peek(n)
if err == io.EOF {
return nil, err
}
//探测没问题
_, _ = wc.BufRD.Discard(len(p))
return p, err
}
// readFrame 从字节流里读出一个完整帧的数据,由于控制帧只能是一个帧,所以在读取帧的时候应当处理完控制帧
func readFrame(wc *WsConn) (*Frame, error) {
//1000 0001 1000 1011
// 读2Byte的数据,取出字节流的帧头部
p, err := read(wc, 2)
if err != nil {
log.Printf("Conn.readFrame failed to c.read(header), err=%v", err)
return nil, err
}
log.Println("Conn.readFrame got frameWithoutPayload bytes: ", p)
// 解析WebSocket帧头部
frameWithoutPayload := ParseToFrameHeader(p)
log.Printf("Conn.readFrame got frameWithoutPayload=%+v", frameWithoutPayload)
remainBytesNum := uint64(frameWithoutPayload.PayloadLen) //payload的字节数,默认等于PayloadLen
// 126 : 16bits,2bytes
// 127 : 64bits,8bytes
switch frameWithoutPayload.PayloadLen {
case 126:
//再从p中取出2个字节
if p, err = read(wc, 2); err != nil {
log.Printf("Conn.readFrame failed to c.read(2) payloadlen with 16bit, err=%v", err)
return nil, err
}
payloadExtLen16 := binary.BigEndian.Uint16(p[:2])
frameWithoutPayload.PayloadExtendLen16 = payloadExtLen16
remainBytesNum = uint64(payloadExtLen16)
case 127:
// 再从p中取出8个字节
if p, err = read(wc, 8); err != nil {
log.Printf("Conn.readFrame failed to c.read(8) payloadlen with 16bit, err=%v", err)
return nil, err
}
payloadExtLen64 := binary.BigEndian.Uint64(p[:8])
frameWithoutPayload.PayloadExtendLen64 = payloadExtLen64
remainBytesNum = payloadExtLen64
}
if frameWithoutPayload.Mask == 1 {
// 再从字节流里读出4个字节的maskingKey
if p, err = read(wc, 4); err != nil {
log.Printf("Conn.readFrame failed to c.read(header), err=%v", err)
return nil, err
}
frameWithoutPayload.MaskingKey = binary.BigEndian.Uint32(p)
}
// frame校验,先校验非负载数据
if err = CheckFrameWithoutPayload(frameWithoutPayload); err != nil {
log.Printf("Conn.readFrame failed to c.read(header), err=%v", err)
if err := wc.CloseWrongProtocol(); err != nil {
return nil, err
}
return nil, err
}
// 读取payload数据并填充到frame中去
payload := make([]byte, 0, remainBytesNum)
log.Printf("Conn.readFrame c.read(%d) into payload data", remainBytesNum)
// WsConn.Read 能接受的类型是 int 不能读取太大的数据,避免大类型强转小类型数据丢失
// -> uint64 > int(64位os里是有符号);因此需要分片读取
for remainBytesNum > shardSize {
//数据可能变小了: wc.Read(int(remainBytesNum))
p, err := read(wc, shardSize)
if err != nil {
log.Printf("Conn.readFrame failed to c.read(payload), err=%v", err)
return nil, err
}
payload = append(payload, p...)
remainBytesNum -= shardSize
}
// 读取剩余部分的payload
p, err = read(wc, int(remainBytesNum))
if err != nil {
log.Printf("Conn.readFrame failed to c.read(payload), err=%v", err)
return nil, err
}
payload = append(payload, p...)
frameWithoutPayload.Payload = payload
// 只处理ping pong close 帧
switch MessageType(frameWithoutPayload.OpCode) {
case TextFrame, BinaryFrame, ContinuationFrame:
//不处理可能有连续帧的类型
case PingFrame:
err = wc.ReplyPing(frameWithoutPayload)
case PongFrame:
err = wc.ReplyPong()
case ConnectionCloseFrame:
//解析帧中收到关闭帧时,正常关闭
err = wc.CloseRight()
default:
//不能接受的类型 TODO: 扩展协议接受类型
err = wc.CloseNotAccept()
}
return frameWithoutPayload, err
}
func (wc *WsConn) Ping() (err error) {
return sendControlFrame(wc, PingFrame, []byte("ping"))
}
// ReplyPing 响应ping帧数据,将ping帧的负载数据,装入pong帧中即可
func (wc *WsConn) ReplyPing(frame *Frame) (err error) {
return wc.Pong(frame.Payload)
}
func (wc *WsConn) Pong(pingPayload []byte) (err error) {
return sendControlFrame(wc, PongFrame, pingPayload)
}
// ReplyPong 响应pong帧
func (wc *WsConn) ReplyPong() (err error) {
return wc.Ping()
}
// SendMessage 发送text数据
func (wc *WsConn) SendMessage(text string) (err error) {
//zipBytes, err := tool.GZipBytes([]byte(text), wc.CompressLevel)
//if err != nil {
// if err := wc.CloseInternalError(); err != nil {
// return err
// }
// return err
//}
//fmt.Println(len(zipBytes), zipBytes)
// todo
return sendDataFrame(wc, []byte(text), TextFrame)
}
// SendBinary 发送二进制数据
func (wc *WsConn) SendBinary(r io.Reader) (err error) {
payload, err := ioutil.ReadAll(r)
if err != nil {
log.Printf("c.SendBinary failed to ioutil.ReadAll, err=%v", err)
return err
}
return sendDataFrame(wc, payload, BinaryFrame)
}
// sendDataFrame 发送数据帧:opcode应限制为text和binary
func sendDataFrame(wc *WsConn, data []byte, opcode MessageType) (err error) {
switch opcode {
case TextFrame, BinaryFrame:
default:
return fmt.Errorf("invalid opcode=%d for data frame", opcode)
}
log.Printf("data frame...")
if len(data) > SendCriticalSize {
return wc.CloseTooBigData()
}
//分片传输
if len(data) > shardSize {
frames := fragmentDataFrames(data, wc.IsServer, opcode)
for _, frame := range frames {
if err = sendFrame(wc, frame); err != nil {
log.Printf("c.send failed to c.sendFrame err=%v", err)
return
}
}
return
}
//未分片传输
frame := constructDataFrame(data, wc.IsServer, opcode)
if err = sendFrame(wc, frame); err != nil {
log.Printf("c.send failed to c.sendFrame err=%v", err)
return
}
return
}
// fragmentDataFrames 将大片数据拆分成若干 shardSize 大小的数据
func fragmentDataFrames(data []byte, noMask bool, opcode MessageType) []*Frame {
s := len(data)
start, end, n := 0, 0, s/shardSize
frames := make([]*Frame, 0, n+1)
//将大数据分成 s / shardSize 份,每份 shardSize
for i := 1; i <= n; i++ {
start, end = (i-1)*shardSize, i*shardSize
frames = append(frames, constructDataFrame(data[start:end], noMask, ContinuationFrame))
}
//追加剩余数据
if end < s {
frames = append(frames, constructDataFrame(data[end:], noMask, ContinuationFrame))
}
//分片传输,第一个帧的opcode设置为0x1或0x2,其余位都是0
frames[0].OpCode = uint16(opcode)
//最后一位的Fin为1,其余要设置为0
frames[len(frames)-1].Fin = 1
return frames
}
// sendControlFrame 发送控制帧(ping、pong、close)
func sendControlFrame(wc *WsConn, msgType MessageType, payload []byte) (err error) {
frame := constructControlFrame(msgType, wc.IsServer, payload)
log.Printf("control frame...")
if err = sendFrame(wc, frame); err != nil {
log.Printf("c.send failed to c.sendFrame err=%v", err)
return
}
return nil
}
// sendFrame 发送完好的帧到连接里
func sendFrame(wc *WsConn, frame *Frame) error {
//校验帧
if err := CheckFrameWithoutPayload(frame); err != nil {
//协议问题关闭连接
if err := wc.CloseWrongProtocol(); err != nil {
return err
}
return err
}
//序列化为帧协议字节流
frameBytes := FrameToBytes(frame)
//将序列化的字节流数据写入连接的缓存区
if _, err := wc.BufWR.Write(frameBytes); err != nil {
return err
}
//将数据从缓存里移到io
if err := wc.BufWR.Flush(); err != nil {
return err
}
return nil
}
// constructDataFrame 构造数据类型的帧(binary、text)
func constructDataFrame(payload []byte, noMask bool, msgType MessageType) *Frame {
final := msgType != ContinuationFrame
frame := constructFrame(msgType, final, noMask)
frame.SetPayload(payload)
return frame
}
// constructControlFrame 构造控制帧(ping、pong、close)
func constructControlFrame(msgType MessageType, isServer bool, payload []byte) *Frame {
//只有客户端想服务端发送帧时,才会对帧进行掩码处理
frame := constructFrame(msgType, true, isServer)
if len(payload) > 0 {
frame.SetPayload(payload)
}
return frame
}
func constructFrame(msgType MessageType, final bool, noMask bool) *Frame {
fin := uint16(1)
mask := uint16(1)
//不是最后一个帧,需要设置fin字段为0
if !final {
fin = 0
}
//没有mask,标志mask为0
if noMask {
mask = 0
}
frame := Frame{
Fin: fin,
RSV1: 0,
RSV2: 0,
RSV3: 0,
OpCode: uint16(msgType),
Mask: mask,
PayloadLen: 0,
PayloadExtendLen16: 0,
PayloadExtendLen64: 0,
MaskingKey: 0,
}
//需要时设置maskingKey字段
if frame.Mask == 1 {
(&frame).CreateMaskingKey()
}
return &frame
}
// CloseRight 正常关闭连接
func (wc *WsConn) CloseRight() error {
return close(wc, CloseRight)
}
// CloseAsideLeaving 某端点离开连接
func (wc *WsConn) CloseAsideLeaving() error {
return close(wc, CloseAsideLeaving)
}
// CloseWrongProtocol 表示端点由于协议错误正在终止连接
func (wc *WsConn) CloseWrongProtocol() error {
return close(wc, CloseWrongProtocol)
}
// CloseNotAccept 关闭连接,因某端点接收到一种它不能接受的数据
func (wc *WsConn) CloseNotAccept() error {
return close(wc, CloseNotAccept)
}
// CloseAbnormal 异常关闭
func (wc *WsConn) CloseAbnormal() error {
return close(wc, CloseAbnormal)
}
// CloseDifferentMsgType 表示端点正在终止连接 ,因为它在消息中接收到与消息类型不一致的数据
func (wc *WsConn) CloseDifferentMsgType() error {
return close(wc, CloseDifferentMsgType)
}
// CloseInternalError 端点内部错误,关闭连接
func (wc *WsConn) CloseInternalError() error {
return close(wc, CloseInternalError)
}
// CloseTooBigData 表示端点正在终止连接 ,因为它收到了一条太大而无法处理的消息。
func (wc *WsConn) CloseTooBigData() error {
return close(wc, CloseTooBigData)
}
func close(wc *WsConn, closeCode int) (err error) {
p := make([]byte, 2, 16)
//前两个字节放入code
binary.BigEndian.PutUint16(p[:2], uint16(closeCode))
//后续放入原因
p = append(p, []byte(Error(closeCode))...)
log.Printf("c.close sending close frame, payload=%s", p)
//发送关闭帧
if err = sendControlFrame(wc, ConnectionCloseFrame, p); err != nil {
log.Printf("c.handleClose failed to c.sendControlFrame, err=%v", err)
return
}
//关闭底层tcp连接
if wc.Conn != nil {
defer func(wc *WsConn) {
err := closeTcp(wc)
if err != nil {
log.Println("close tcp err: ", err)
}
}(wc)
}
return nil
}
// closeTcp 关闭底层tcp
func closeTcp(wc *WsConn) error {
return wc.Conn.Close()
}