green-screen-client

Python client for green-screen-proxy — typed async REST + WebSocket adapter for TN5250, TN3270, VT, and HP 6530 terminal emulation.

This is a standalone package. It is not bundled with or required by green-screen-react — install it separately when your integration runs on Python.

Install

pip install green-screen-client

Three layers, pick what fits

1. Low-level REST (RestClient)

Thin wrapper over the proxy's HTTP endpoints. One method per endpoint, dataclasses in/out.

from green_screen_client import RestClient, ConnectConfig

async with RestClient("http://proxy:3001") as client:
    await client.connect(ConnectConfig(
        host="pub400.com",
        protocol="tn5250",
        username="alice",
        password="secret",
    ))
    screen = await client.get_screen()
    print(screen.content)
    await client.send_text("1")
    await client.send_key("Enter")

2. Low-level WebSocket (WsClient)

Single WebSocket, real-time screen pushes, reattach for session recovery, lifecycle events (session.lost, session.resumed).

from green_screen_client import WsClient

async with WsClient("http://proxy:3001") as client:
    await client.reattach("abc-123")   # reattach after page reload / process restart
    client.on_screen(lambda s: print("screen update:", s.cursor_row, s.cursor_col))
    client.on_session_lost(lambda sid, status: print("lost:", sid, status.status))
    async for event in client.events():
        if event.type == "screen":
            ...

3. High-level ProxyTerminalClient + ScreenBuffer

Drop-in shape for integrations that already read client.screen.fields, client.screen.cursor_row, etc.

from green_screen_client import ProxyTerminalClient

async with ProxyTerminalClient("http://proxy:3001", host="pub400.com") as client:
    await client.login("alice", "secret")
    await client.send_key("PF3")
    print(client.screen.cursor_row, client.screen.cursor_col)
    for field in client.screen.fields:
        print(field)

v1.2.0 primitives

• read_mdt(modified_only=True) — cheap post-write verification via per-field MDT bits.
• resume_session(session_id) — REST probe for "is this session still alive?"
• mark_authenticated(username) — flip session status after your own sign-on cascade (the proxy stays protocol-generic).
• wait_for_fields(min_fields, timeout_ms=...) — wait until a form with N input fields appears.

License

MIT.