From c7454c13cc8da06f5520e5ca2141e1233dd6dce2 Mon Sep 17 00:00:00 2001
From: Khairul Hidayat <khai@rul.sh>
Date: Mon, 18 Mar 2024 03:01:39 +0700
Subject: [PATCH] feat: start vnc server if not started yet

---
 backend/.env.example |  1 +
 backend/lib/vnc.ts   | 38 ++++++++++++++++++++++++++++++++++++++
 backend/websocket.ts |  6 ++----
 3 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 backend/lib/vnc.ts

diff --git a/backend/.env.example b/backend/.env.example
index 3792cb7..da4364e 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -9,3 +9,4 @@ PC_MAC_ADDR=
 TERMINAL_SHELL=
 FILE_DIRS="/some/path;/another/path"
 VNC_PORT=5901
+VNC_START_CMD=vncserver :1
diff --git a/backend/lib/vnc.ts b/backend/lib/vnc.ts
new file mode 100644
index 0000000..b864a1d
--- /dev/null
+++ b/backend/lib/vnc.ts
@@ -0,0 +1,38 @@
+import type { WebSocket } from "ws";
+import { websockify } from "./websockify";
+import net from "node:net";
+import { spawn } from "node:child_process";
+
+const VNC_PORT = parseInt(process.env.VNC_PORT || "") || 5901;
+const VNC_START_CMD = process.env.VNC_START_CMD;
+
+export const createVNCSession = async (ws: WebSocket) => {
+  const isVncStarted = await isPortOpen(VNC_PORT);
+
+  // VNC is not started, start it.
+  if (!isVncStarted && VNC_START_CMD) {
+    const cmd = VNC_START_CMD.split(" ");
+    const child = spawn(cmd[0], cmd.slice(1));
+
+    await new Promise((resolve) => {
+      child.on("close", () => resolve(null));
+    });
+  }
+
+  websockify(ws, "localhost", VNC_PORT);
+};
+
+async function isPortOpen(port: number) {
+  return new Promise((resolve) => {
+    const tester = net
+      .createServer()
+      .once("error", function (err: any) {
+        resolve(err.code === "EADDRINUSE");
+      })
+      .once("listening", function () {
+        tester.close();
+        resolve(false);
+      })
+      .listen(port);
+  });
+}
diff --git a/backend/websocket.ts b/backend/websocket.ts
index 04d8d5c..4e48232 100644
--- a/backend/websocket.ts
+++ b/backend/websocket.ts
@@ -1,9 +1,7 @@
 import { WebSocketServer } from "ws";
 import { verifyToken } from "./lib/jwt";
 import { createTerminalSession } from "./lib/terminal";
-import { websockify } from "./lib/websockify";
-
-const VNC_PORT = parseInt(process.env.VNC_PORT || "") || 5901;
+import { createVNCSession } from "./lib/vnc";
 
 const createWsServer = (server: any) => {
   const wss = new WebSocketServer({ server: server as never });
@@ -25,7 +23,7 @@ const createWsServer = (server: any) => {
     }
 
     if (url.pathname === "/vnc") {
-      websockify(ws, "localhost", VNC_PORT);
+      createVNCSession(ws);
     }
 
     ws.on("error", console.error);