在最近一次需求里，需要实现一个webSSH的功能，就是把terminal搬到web中来。要实现这个功能，可以采用websocket+ssh来说实现

1.第一步实现websocket

websocket主要是ws或wss协议，其原理就是http协议升级成ws协议，即ws是建立在http上的，所有路由正常写http的路由，然后处理一下websocket升级。

注：我用的echo框架：

路由：

backendApi.GET("/tools/ssh/ws", tools.WebSSH).Name = "webssh"

handler

func WebSSH(e echo.Context) error {var param tools.WebSShReqif err := utils.BindAndValidate(e, &param); err != nil {return err}if err := tools.Upgrade(e.Response().Writer, e.Request(), param); err != nil {return err}return e.JSON(http.StatusOK, "'")
}

:

websocket协议升级：

var upgrader = websocket.Upgrader{ReadBufferSize:  1024,WriteBufferSize: 1024,CheckOrigin: func(r *http.Request) bool {return true},
}func Upgrade(w http.ResponseWriter, r *http.Request, param WebSShReq) (err error) {conn, err := upgrader.Upgrade(w, r, nil)if err != nil {return}client := NewSSHClient(param)client.Ws = connerr = client.GenerateClient()if err != nil {fmt.Println("链接ssh错误", err)conn.WriteMessage(1, []byte(err.Error()))conn.Close()return err}go client.Write()return nil
}

2.第一版ssh实现

type SSHClient struct {Username  string `json:"username"`Password  string `json:"password"`IpAddress string `json:"ipaddress"`Port      int    `json:"port"`Client    *ssh.ClientWs        *websocket.ConnSession   *ssh.Session
}// NewSSHClient 创建新的ssh客户端时
func NewSSHClient(param WebSShReq) SSHClient {client := SSHClient{}client.Username = param.Usernameclient.Port = param.Portclient.IpAddress = param.IpAddressclient.Password = param.Passwordreturn client
}
func (t *SSHClient) GenerateClient() error {var (auth         []ssh.AuthMethodaddr         stringclientConfig *ssh.ClientConfigclient       *ssh.Clientconfig       ssh.Configerr          error)auth = make([]ssh.AuthMethod, 0)auth = append(auth, ssh.Password(t.Password))config = ssh.Config{Ciphers: []string{"aes128-ctr", "aes192-ctr", "aes256-ctr", "arcfour256", "arcfour128", "aes128-cbc", "3des-cbc", "aes192-cbc", "aes256-cbc"},}clientConfig = &ssh.ClientConfig{User:    t.Username,Auth:    auth,Timeout: 5 * time.Second,Config:  config,HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error {return nil},}addr = fmt.Sprintf("%s:%d", t.IpAddress, t.Port)if client, err = ssh.Dial("tcp", addr, clientConfig); err != nil {return err}t.Client = clientreturn nil
}func (t *SSHClient) send(out, stderr *bytes.Buffer, cmd []byte) error {session, err := t.Client.NewSession()if err != nil {return errors.New("ssh session创建失败")}defer session.Close()session.Stdout = outsession.Stderr = stderrreturn session.Run(string(cmd))
}
func (t *SSHClient) Write() {defer t.Client.Close()for {// p为用户输入_, p, err := t.Ws.ReadMessage()if err != nil {return}fmt.Println("webssh:", string(p))go func(data []byte) {var (out   bytes.BufferstdEr bytes.Buffer)err2 := t.send(&out, &stdEr, data)if err2 != nil {t.Ws.WriteMessage(1, stdEr.Bytes())return}t.Ws.WriteMessage(1, out.Bytes())}(p)}
}

这样能实现正常指令，但是有个问题；不能切换目录，不完善

3.改进

使用终端交互模式，做到真正的webssh， 直接上代码

改进方法：

func (t *SSHClient) RunTerminal(stdout, stderr io.Writer, stdin io.Reader) error {session, err := t.Client.NewSession()if err != nil {return err}defer session.Close()session.Stdout = io.MultiWriter(os.Stdout, stdout)session.Stderr = io.MultiWriter(os.Stderr, stderr)session.Stdin = stdinmodes := ssh.TerminalModes{ssh.ECHO:          0,ssh.TTY_OP_ISPEED: 14400,ssh.TTY_OP_OSPEED: 14400,}if err := session.RequestPty("xterm", 32, 160, modes); err != nil {return err}if err = session.Shell(); err != nil {log.Fatalf("start shell error: %s", err.Error())}if err = session.Wait(); err != nil {log.Fatalf("return error: %s", err.Error())}return nil
}

此方法需要输入，输出，和错误，使用标准的输入及标准输出，能实现交互，但是我是需要接收websocket发的消息，及返回websocket输出。

故，需要实现io.writer和io.reader接口

type stdout struct {ws *websocket.Conn
}func (s *stdout) Write(p []byte) (n int, err error) {// fmt.Println("SSH output:", string(p))err = s.ws.WriteMessage(1, p)return len(p), err
}type stdIn struct {ws *websocket.Conn
}func (s *stdIn) Read(p []byte) (n int, err error) {_, p2, err := s.ws.ReadMessage()// 指令需要加一个回车if err != nil {return 0, err}n = copy(p, []byte(fmt.Sprintf("%s\n", string(p2))))// fmt.Println("####", string(p))return n, err
}
func (s *stdIn) Close() error {return nil
}

注: 实现read方法时，注意加个回车，不然指令是不会执行的，我在这里就卡了很久......

最后，将upgrade方法中的，

go client.Write() 

换成

go client.RunTerminal(&stdout{conn}, &stdout{conn}, &stdIn{conn})

就ok了。

4.最终效果如图：