Real-time WebSocket chat

Create the connection when the screen is active and close it when the screen is destroyed. Messages sent during the handshake are queued by the client.

from apkpy_lib import Screen, button, inputs, label, lifecycle, run, websocket

room = Screen(id="room")
status = label("Offline", id="status", screen=room)
latest = label("No messages yet", id="latest", screen=room)
message = inputs("Write a message", id="message", screen=room)

def connected():
    status.set_value("Live")

def received(text):
    latest.set_value(text)

def failed(error):
    status.set_value("Reconnecting")

def connect_room():
    websocket.connect(
        "support-room",
        "wss://api.example.com/chat",
        headers={"Authorization": "Bearer YOUR_TOKEN"},
        on_open=connected,
        on_message=received,
        on_error=failed,
        reconnect=True,
    )

def send_message():
    text = message.get_value()
    if text != "":
        websocket.send("support-room", text)
        message.set_value("")

button("Send", command=send_message, screen=room)
lifecycle(
    room,
    on_resume=connect_room,
    on_destroy=lambda: websocket.close("support-room"),
)
run(room)

Production responsibilities

• authenticate the WebSocket upgrade;
• validate messages on the server;
• persist delivery state and message history;
• define ordering, deduplication and retry semantics;
• use push notifications when the process is not connected.

ApkPy provides WSS framing, ping/pong handling, bounded pending sends and backoff reconnection. It does not provide end-to-end encryption or a chat backend.