Files
sideline/engine/display/backends/websocket.py
David Gwilliam 36afbacb6b refactor(display)!: remove deprecated backends, simplify protocol, and add BorderMode/UI rendering
- Remove SixelDisplay and KittyDisplay backends (unmaintained)
- Simplify Display protocol: reduce docstring noise, emphasize duck typing
- Add BorderMode enum (OFF, SIMPLE, UI) for flexible border rendering
- Rename render_border to _render_simple_border
- Add render_ui_panel() to compose main viewport with right-side UI panel
- Add new render_border() dispatcher supporting BorderMode
- Update __all__ to expose BorderMode, render_ui_panel, PygameDisplay
- Clean up DisplayRegistry: remove deprecated method docstrings
- Update tests: remove SixelDisplay import, assert sixel not in registry
- Add TODO comment to WebSocket backend about streaming improvements

This is a breaking change (removal of backends) but enables cleaner architecture and interactive UI panel.

Closes #13, #21
2026-03-18 12:18:02 -07:00

286 lines
8.8 KiB
Python

"""
WebSocket display backend - broadcasts frame buffer to connected web clients.
TODO: Transform to a true streaming backend with:
- Proper WebSocket message streaming (currently sends full buffer each frame)
- Connection pooling and backpressure handling
- Binary protocol for efficiency (instead of JSON)
- Client management with proper async handling
- Mark for deprecation if replaced by a new streaming implementation
Current implementation: Simple broadcast of text frames to all connected clients.
"""
import asyncio
import json
import threading
import time
try:
import websockets
except ImportError:
websockets = None
def get_monitor():
"""Get the performance monitor."""
try:
from engine.effects.performance import get_monitor as _get_monitor
return _get_monitor()
except Exception:
return None
class WebSocketDisplay:
"""WebSocket display backend - broadcasts to HTML Canvas clients."""
width: int = 80
height: int = 24
def __init__(
self,
host: str = "0.0.0.0",
port: int = 8765,
http_port: int = 8766,
):
self.host = host
self.port = port
self.http_port = http_port
self.width = 80
self.height = 24
self._clients: set = set()
self._server_running = False
self._http_running = False
self._server_thread: threading.Thread | None = None
self._http_thread: threading.Thread | None = None
self._available = True
self._max_clients = 10
self._client_connected_callback = None
self._client_disconnected_callback = None
self._frame_delay = 0.0
try:
import websockets as _ws
self._available = _ws is not None
except ImportError:
self._available = False
def is_available(self) -> bool:
"""Check if WebSocket support is available."""
return self._available
def init(self, width: int, height: int, reuse: bool = False) -> None:
"""Initialize display with dimensions and start server.
Args:
width: Terminal width in characters
height: Terminal height in rows
reuse: If True, skip starting servers (assume already running)
"""
self.width = width
self.height = height
if not reuse or not self._server_running:
self.start_server()
self.start_http_server()
def show(self, buffer: list[str], border: bool = False) -> None:
"""Broadcast buffer to all connected clients."""
t0 = time.perf_counter()
# Get metrics for border display
fps = 0.0
frame_time = 0.0
monitor = get_monitor()
if monitor:
stats = monitor.get_stats()
avg_ms = stats.get("pipeline", {}).get("avg_ms", 0) if stats else 0
frame_count = stats.get("frame_count", 0) if stats else 0
if avg_ms and frame_count > 0:
fps = 1000.0 / avg_ms
frame_time = avg_ms
# Apply border if requested
if border:
from engine.display import render_border
buffer = render_border(buffer, self.width, self.height, fps, frame_time)
if self._clients:
frame_data = {
"type": "frame",
"width": self.width,
"height": self.height,
"lines": buffer,
}
message = json.dumps(frame_data)
disconnected = set()
for client in list(self._clients):
try:
asyncio.run(client.send(message))
except Exception:
disconnected.add(client)
for client in disconnected:
self._clients.discard(client)
if self._client_disconnected_callback:
self._client_disconnected_callback(client)
elapsed_ms = (time.perf_counter() - t0) * 1000
monitor = get_monitor()
if monitor:
chars_in = sum(len(line) for line in buffer)
monitor.record_effect("websocket_display", elapsed_ms, chars_in, chars_in)
def clear(self) -> None:
"""Broadcast clear command to all clients."""
if self._clients:
clear_data = {"type": "clear"}
message = json.dumps(clear_data)
for client in list(self._clients):
try:
asyncio.run(client.send(message))
except Exception:
pass
def cleanup(self) -> None:
"""Stop the servers."""
self.stop_server()
self.stop_http_server()
async def _websocket_handler(self, websocket):
"""Handle WebSocket connections."""
if len(self._clients) >= self._max_clients:
await websocket.close()
return
self._clients.add(websocket)
if self._client_connected_callback:
self._client_connected_callback(websocket)
try:
async for message in websocket:
try:
data = json.loads(message)
if data.get("type") == "resize":
self.width = data.get("width", 80)
self.height = data.get("height", 24)
except json.JSONDecodeError:
pass
except Exception:
pass
finally:
self._clients.discard(websocket)
if self._client_disconnected_callback:
self._client_disconnected_callback(websocket)
async def _run_websocket_server(self):
"""Run the WebSocket server."""
async with websockets.serve(self._websocket_handler, self.host, self.port):
while self._server_running:
await asyncio.sleep(0.1)
async def _run_http_server(self):
"""Run simple HTTP server for the client."""
import os
from http.server import HTTPServer, SimpleHTTPRequestHandler
client_dir = os.path.join(
os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "client"
)
class Handler(SimpleHTTPRequestHandler):
def __init__(self, *args, **kwargs):
super().__init__(*args, directory=client_dir, **kwargs)
def log_message(self, format, *args):
pass
httpd = HTTPServer((self.host, self.http_port), Handler)
while self._http_running:
httpd.handle_request()
def _run_async(self, coro):
"""Run coroutine in background."""
try:
asyncio.run(coro)
except Exception as e:
print(f"WebSocket async error: {e}")
def start_server(self):
"""Start the WebSocket server in a background thread."""
if not self._available:
return
if self._server_thread is not None:
return
self._server_running = True
self._server_thread = threading.Thread(
target=self._run_async, args=(self._run_websocket_server(),), daemon=True
)
self._server_thread.start()
def stop_server(self):
"""Stop the WebSocket server."""
self._server_running = False
self._server_thread = None
def start_http_server(self):
"""Start the HTTP server in a background thread."""
if not self._available:
return
if self._http_thread is not None:
return
self._http_running = True
self._http_running = True
self._http_thread = threading.Thread(
target=self._run_async, args=(self._run_http_server(),), daemon=True
)
self._http_thread.start()
def stop_http_server(self):
"""Stop the HTTP server."""
self._http_running = False
self._http_thread = None
def client_count(self) -> int:
"""Return number of connected clients."""
return len(self._clients)
def get_ws_port(self) -> int:
"""Return WebSocket port."""
return self.port
def get_http_port(self) -> int:
"""Return HTTP port."""
return self.http_port
def set_frame_delay(self, delay: float) -> None:
"""Set delay between frames in seconds."""
self._frame_delay = delay
def get_frame_delay(self) -> float:
"""Get delay between frames."""
return self._frame_delay
def set_client_connected_callback(self, callback) -> None:
"""Set callback for client connections."""
self._client_connected_callback = callback
def set_client_disconnected_callback(self, callback) -> None:
"""Set callback for client disconnections."""
self._client_disconnected_callback = callback
def get_dimensions(self) -> tuple[int, int]:
"""Get current dimensions.
Returns:
(width, height) in character cells
"""
return (self.width, self.height)