:sig
WS(Request& context)

:desc
Defines the WebSocket message handler for the current `.ws.uce` page.

The same page may expose both `RENDER(Request& context)` and `WS(Request& context)`. `RENDER(Request& context)` serves the initial HTTP response, while `WS(Request& context)` is called whenever a complete WebSocket message arrives for that page.

UCE reassembles fragmented messages before calling `WS(Request& context)`. Text and binary frames are both delivered. Use `context.call`, `context.connection`, `ws_opcode()`, and `ws_is_binary()` to inspect the current message.

`context.connection` is a broker-owned `DTree` for the current socket. It starts empty for a new client and persists across later `WS(Request& context)` calls on that same connection.

The current message data is available in `context.call`:

- `context.call["message"]`: current message payload
- `context.call["connection_id"]`: sender connection ID
- `context.call["scope"]`: current endpoint scope
- `context.call["opcode"]`: WebSocket opcode of the current message
- `context.call["document_uri"]`: request URI of the current endpoint

:related
**PHP:** Ratchet `onMessage`, Workerman WebSocket handlers, or lower-level callbacks around accepted socket connections.
**JavaScript / Node.js:** Browser `WebSocket` `message` handlers and Node `ws` server `connection` and `message` callbacks.

:see
>websocket
