feat: add xterm.js web terminal frontend

WebSocket-to-SSH proxy on :8080. Browser connects via xterm.js,
server bridges to localhost:2222 SSH. Single HTML file, CDN deps.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-03-24 13:33:08 +09:00
parent 09af632ed9
commit c555ff6e92
6 changed files with 294 additions and 1 deletions

161
web/server.go Normal file
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package web
import (
"embed"
"encoding/json"
"fmt"
"io"
"log"
"net/http"
"sync"
"github.com/gorilla/websocket"
"golang.org/x/crypto/ssh"
)
//go:embed static
var staticFiles embed.FS
var upgrader = websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool { return true },
}
type resizeMsg struct {
Type string `json:"type"`
Cols int `json:"cols"`
Rows int `json:"rows"`
}
// Start launches the HTTP server for the web terminal.
func Start(addr string, sshPort int) error {
mux := http.NewServeMux()
// Serve static files from embedded FS
mux.Handle("/", http.FileServer(http.FS(staticFiles)))
// WebSocket endpoint
mux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
handleWS(w, r, sshPort)
})
log.Printf("Starting web terminal on %s", addr)
return http.ListenAndServe(addr, mux)
}
func handleWS(w http.ResponseWriter, r *http.Request, sshPort int) {
ws, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Printf("WebSocket upgrade error: %v", err)
return
}
defer ws.Close()
// Connect to local SSH server
sshConfig := &ssh.ClientConfig{
User: "web-player",
Auth: []ssh.AuthMethod{
ssh.Password(""),
},
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
}
sshAddr := fmt.Sprintf("localhost:%d", sshPort)
client, err := ssh.Dial("tcp", sshAddr, sshConfig)
if err != nil {
log.Printf("SSH dial error: %v", err)
ws.WriteMessage(websocket.TextMessage, []byte(fmt.Sprintf("Failed to connect to game server: %v\r\n", err)))
return
}
defer client.Close()
session, err := client.NewSession()
if err != nil {
log.Printf("SSH session error: %v", err)
return
}
defer session.Close()
// Request PTY
if err := session.RequestPty("xterm-256color", 24, 80, ssh.TerminalModes{
ssh.ECHO: 1,
ssh.TTY_OP_ISPEED: 14400,
ssh.TTY_OP_OSPEED: 14400,
}); err != nil {
log.Printf("PTY request error: %v", err)
return
}
stdin, err := session.StdinPipe()
if err != nil {
log.Printf("stdin pipe error: %v", err)
return
}
stdout, err := session.StdoutPipe()
if err != nil {
log.Printf("stdout pipe error: %v", err)
return
}
if err := session.Shell(); err != nil {
log.Printf("shell error: %v", err)
return
}
var once sync.Once
done := make(chan struct{})
cleanup := func() {
once.Do(func() {
close(done)
})
}
// SSH stdout → WebSocket
go func() {
defer cleanup()
buf := make([]byte, 4096)
for {
n, err := stdout.Read(buf)
if n > 0 {
if writeErr := ws.WriteMessage(websocket.TextMessage, buf[:n]); writeErr != nil {
return
}
}
if err != nil {
return
}
}
}()
// WebSocket → SSH stdin (text frames) or resize (binary frames)
go func() {
defer cleanup()
for {
msgType, data, err := ws.ReadMessage()
if err != nil {
return
}
switch msgType {
case websocket.TextMessage:
if _, err := stdin.Write(data); err != nil {
return
}
case websocket.BinaryMessage:
var msg resizeMsg
if json.Unmarshal(data, &msg) == nil && msg.Type == "resize" {
session.WindowChange(msg.Rows, msg.Cols)
}
}
}
}()
// Wait for either side to close
select {
case <-done:
}
// Ensure SSH session ends
_ = session.Close()
_ = client.Close()
_ = io.WriteCloser(stdin).Close()
}

120
web/static/index.html Normal file
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Catacombs</title>
<link rel="stylesheet" href="https://unpkg.com/@xterm/xterm@5.5.0/css/xterm.css">
<style>
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; overflow: hidden; background: #1a1a2e; }
#terminal { height: 100%; width: 100%; }
#overlay {
display: none;
position: fixed; top: 0; left: 0; right: 0; bottom: 0;
background: rgba(26, 26, 46, 0.9);
justify-content: center; align-items: center;
z-index: 10;
}
#overlay.visible { display: flex; }
#overlay-text {
color: #e0e0e0; font-family: monospace; font-size: 18px;
text-align: center; line-height: 2;
}
#overlay-text span { color: #51d0ff; }
</style>
</head>
<body>
<div id="terminal"></div>
<div id="overlay">
<div id="overlay-text">
Connection lost.<br>
<span>Press any key to reconnect.</span>
</div>
</div>
<script src="https://unpkg.com/@xterm/xterm@5.5.0/lib/xterm.js"></script>
<script src="https://unpkg.com/@xterm/addon-fit@0.10.0/lib/addon-fit.js"></script>
<script>
const termEl = document.getElementById('terminal');
const overlay = document.getElementById('overlay');
const term = new Terminal({
cursorBlink: true,
fontSize: 16,
fontFamily: "'Cascadia Code', 'Fira Code', 'JetBrains Mono', monospace",
theme: {
background: '#1a1a2e',
foreground: '#e0e0e0',
cursor: '#51d0ff',
selectionBackground: '#44475a',
},
allowProposedApi: true,
});
const fitAddon = new FitAddon.FitAddon();
term.loadAddon(fitAddon);
term.open(termEl);
fitAddon.fit();
let ws = null;
let connected = false;
function connect() {
const proto = location.protocol === 'https:' ? 'wss:' : 'ws:';
ws = new WebSocket(`${proto}//${location.host}/ws`);
ws.onopen = () => {
connected = true;
overlay.classList.remove('visible');
term.clear();
term.focus();
sendResize();
};
ws.onmessage = (e) => {
term.write(e.data);
};
ws.onclose = () => {
connected = false;
overlay.classList.add('visible');
};
ws.onerror = () => {
connected = false;
overlay.classList.add('visible');
};
}
function sendResize() {
if (ws && ws.readyState === WebSocket.OPEN) {
const msg = JSON.stringify({ type: 'resize', cols: term.cols, rows: term.rows });
ws.send(new Blob([msg]));
}
}
term.onData((data) => {
if (ws && ws.readyState === WebSocket.OPEN) {
ws.send(data);
}
});
window.addEventListener('resize', () => {
fitAddon.fit();
sendResize();
});
// Reconnect on any key when disconnected
document.addEventListener('keydown', (e) => {
if (!connected) {
e.preventDefault();
connect();
}
});
// Initial connection
connect();
</script>
</body>
</html>