Add local ADB web remote for Android TV

Node/Express server shells out to adb (connect/pair/keyevent/text/app
launch) and serves a mobile-first installable PWA remote: power, mute,
input switch, volume/channel rockers, D-pad, media transport, text
entry, and one-tap streaming app launch. Supports multiple saved TVs
and the Android 11+ wireless-debugging pairing flow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RSVyYcrjrbmrMKT85G4fyn

server/src/adb.js

@@ -0,0 +1,111 @@
+import { execFile } from "node:child_process";
+import { promisify } from "node:util";
+
+const execFileAsync = promisify(execFile);
+
+const ADB_BIN = process.env.ADB_BIN || "adb";
+const EXEC_TIMEOUT_MS = 8000;
+
+class AdbError extends Error {
+  constructor(message, { code, stderr } = {}) {
+    super(message);
+    this.name = "AdbError";
+    this.code = code;
+    this.stderr = stderr;
+  }
+}
+
+function run(args) {
+  return execFileAsync(ADB_BIN, args, { timeout: EXEC_TIMEOUT_MS }).catch((err) => {
+    if (err.code === "ENOENT") {
+      throw new AdbError(
+        "adb binary not found on this machine. Install Android platform-tools and make sure `adb` is on PATH.",
+        { code: "ADB_NOT_FOUND" }
+      );
+    }
+    throw new AdbError(err.stderr?.trim() || err.message, {
+      code: "ADB_COMMAND_FAILED",
+      stderr: err.stderr,
+    });
+  });
+}
+
+// Accepts "host" or "host:port" and rejects anything that isn't a plausible
+// address, since this value is passed straight to execFile as a single arg
+// (no shell involved, but we still don't want to hand adb garbage).
+const HOST_PORT_RE = /^[a-zA-Z0-9.\-]+(:\d{1,5})?$/;
+
+export function normalizeTarget(hostOrHostPort) {
+  const trimmed = String(hostOrHostPort || "").trim();
+  if (!HOST_PORT_RE.test(trimmed)) {
+    throw new AdbError(`"${hostOrHostPort}" doesn't look like a valid host or host:port`, {
+      code: "INVALID_TARGET",
+    });
+  }
+  return trimmed.includes(":") ? trimmed : `${trimmed}:5555`;
+}
+
+export async function connect(hostOrHostPort) {
+  const target = normalizeTarget(hostOrHostPort);
+  const { stdout } = await run(["connect", target]);
+  const text = stdout.trim();
+  // adb prints "failed to connect..." on stdout with exit code 0, so we
+  // have to sniff the message instead of relying on the exit status.
+  if (/failed|unable|cannot/i.test(text)) {
+    throw new AdbError(text, { code: "CONNECT_FAILED" });
+  }
+  return { target, message: text };
+}
+
+export async function disconnect(hostOrHostPort) {
+  const target = normalizeTarget(hostOrHostPort);
+  const { stdout } = await run(["disconnect", target]);
+  return { target, message: stdout.trim() };
+}
+
+export async function pair(hostAndPort, code) {
+  if (!/^\d{6}$/.test(String(code))) {
+    throw new AdbError("Pairing code must be exactly 6 digits", { code: "INVALID_PAIR_CODE" });
+  }
+  const target = normalizeTarget(hostAndPort);
+  const { stdout } = await run(["pair", target, String(code)]);
+  const text = stdout.trim();
+  if (/failed|unable|cannot/i.test(text)) {
+    throw new AdbError(text, { code: "PAIR_FAILED" });
+  }
+  return { target, message: text };
+}
+
+export async function listDevices() {
+  const { stdout } = await run(["devices", "-l"]);
+  return stdout
+    .split("\n")
+    .slice(1)
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .map((line) => {
+      const [serial, state, ...rest] = line.split(/\s+/);
+      return { serial, state, details: rest.join(" ") };
+    });
+}
+
+export async function shell(serial, ...shellArgs) {
+  const target = normalizeTarget(serial);
+  return run(["-s", target, "shell", ...shellArgs]);
+}
+
+export async function keyevent(serial, code) {
+  await shell(serial, "input", "keyevent", String(code));
+}
+
+export async function sendText(serial, text) {
+  // Android's `input text` treats spaces specially; %s is the documented escape.
+  const escaped = String(text).replace(/ /g, "%s");
+  await shell(serial, "input", "text", escaped);
+}
+
+export async function launchApp(serial, packageName) {
+  await shell(serial, "monkey", "-p", packageName, "-c", "android.intent.category.LAUNCHER", "1");
+}
+
+export { AdbError };