worker: set binaryType = "arraybuffer" to fix 1003 "binary messages required"

[avost]

Problem

Workers deployed with a compatibility date of 2026-03-17 or later drop every tunnel immediately. The client log shows:

Сбой туннеля DC2 через <name>.workers.dev: WebSocket закрыт: 1003 binary messages required

and TGLock stays on "Ищем новый маршрут" whenever direct routes are blocked.

Cause: starting with compatibility date 2026-03-17 Cloudflare enables the websocket_standard_binary_type flag, so binary WebSocket messages are delivered as Blob instead of ArrayBuffer (changelog). The message handler accepts only ArrayBuffer / ArrayBuffer.isView, treats the Blob as a non-binary message and closes the socket with 1003.

This affects every newly created worker, and existing ones once the compatibility date is bumped (which docs/CLOUDFLARE_WORKER.md suggests for cloudflare:sockets errors).

Fix

Set server.binaryType = "arraybuffer" before server.accept(). Per Cloudflare docs this restores ArrayBuffer delivery regardless of the compatibility flag, so it is safe for both old and new compatibility dates.

const [client, server] = Object.values(new WebSocketPair());
server.binaryType = "arraybuffer";
server.accept();

Testing

• macOS, tglock-cli with --worker, ISP blocks direct kws*.web.telegram.org (tls handshake eof).
• Before: tunnels via the worker closed with 1003, route never established.
• After: no 1003 errors, 7–9 stable tunnels on DC2 via Cloudflare Worker, 0 failures; Telegram works normally.

Workaround for users who can't update the code: set compatibility date ≤ 2026-03-16 or add the no_websocket_standard_binary_type compatibility flag.