GitHub Copilot
316 lines
12 KiB
Python
316 lines
12 KiB
Python
from __future__ import annotations
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import array
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import asyncio
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import contextlib
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import fcntl
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import logging
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import os
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import pty
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import shlex
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import signal
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import termios
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from collections import deque
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from typing import TYPE_CHECKING
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import pyte
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from importlib_metadata import version
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from .session import Session, SessionConnector
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if TYPE_CHECKING:
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from .poller import Poller
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from .types import Meta, SessionID
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log = logging.getLogger("textual-web")
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# Maximum bytes to keep in replay buffer for reconnection
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REPLAY_BUFFER_SIZE = 256 * 1024 # 256KB
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# Default screen size for pyte emulator
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DEFAULT_SCREEN_WIDTH = 132
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DEFAULT_SCREEN_HEIGHT = 45
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class TerminalSession(Session):
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"""A session that manages a terminal."""
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def __init__(
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self,
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poller: Poller,
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session_id: SessionID,
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command: str,
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) -> None:
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self.poller = poller
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self.session_id = session_id
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self.command = command or os.environ.get("SHELL", "sh")
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self.master_fd: int | None = None
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self.pid: int | None = None
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self._task: asyncio.Task | None = None
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self._replay_buffer: deque[bytes] = deque()
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self._replay_buffer_size = 0
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self._replay_lock = asyncio.Lock()
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# pyte screen for accurate terminal state tracking
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self._screen = pyte.Screen(DEFAULT_SCREEN_WIDTH, DEFAULT_SCREEN_HEIGHT)
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self._stream = pyte.Stream(self._screen)
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self._screen_lock = asyncio.Lock()
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# Track last known terminal size for reconnection
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self._last_width = DEFAULT_SCREEN_WIDTH
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self._last_height = DEFAULT_SCREEN_HEIGHT
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super().__init__()
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def __repr__(self) -> str:
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return f"TerminalSession(session_id={self.session_id!r}, command={self.command!r})"
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async def open(self, width: int = 80, height: int = 24) -> None:
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log.info("Opening terminal session %s with command: %s", self.session_id, self.command)
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# Track the initial size
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self._last_width = width
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self._last_height = height
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# Initialize pyte screen with the requested size (under lock to prevent races)
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async with self._screen_lock:
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self._screen = pyte.Screen(width, height)
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self._stream = pyte.Stream(self._screen)
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pid, master_fd = pty.fork()
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self.pid = pid
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self.master_fd = master_fd
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if pid == pty.CHILD:
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os.environ["TERM_PROGRAM"] = "textual-webterm"
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os.environ["TERM_PROGRAM_VERSION"] = version("textual-webterm")
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try:
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argv = shlex.split(self.command)
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except ValueError:
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os._exit(1)
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if not argv:
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os._exit(1)
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try:
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os.execvp(argv[0], argv) ## Exits the app
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except OSError:
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os._exit(1)
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try:
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self._set_terminal_size(width, height)
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except OSError:
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# Clean up on failure
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os.close(master_fd)
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self.master_fd = None
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raise
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log.debug("Terminal session %s opened successfully", self.session_id)
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def _set_terminal_size(self, width: int, height: int) -> None:
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buf = array.array("h", [height, width, 0, 0])
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assert self.master_fd is not None
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fcntl.ioctl(self.master_fd, termios.TIOCSWINSZ, buf)
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def _get_terminal_size(self) -> tuple[int, int]:
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"""Get actual PTY size. Returns (width, height)."""
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assert self.master_fd is not None
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buf = array.array("h", [0, 0, 0, 0])
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fcntl.ioctl(self.master_fd, termios.TIOCGWINSZ, buf)
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return (buf[1], buf[0]) # cols, rows
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async def _sync_pyte_to_pty(self) -> None:
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"""Sync pyte screen size to actual PTY size."""
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if self.master_fd is None:
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return
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loop = asyncio.get_running_loop()
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# Hold lock during PTY read to ensure consistency with concurrent set_terminal_size
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async with self._screen_lock:
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width, height = await loop.run_in_executor(None, self._get_terminal_size)
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if self._screen.columns != width or self._screen.lines != height:
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log.debug(
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"Syncing pyte screen from %dx%d to %dx%d",
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self._screen.columns,
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self._screen.lines,
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width,
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height,
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)
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self._screen.resize(height, width)
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self._last_width = width
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self._last_height = height
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async def set_terminal_size(self, width: int, height: int) -> None:
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"""Set terminal size."""
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loop = asyncio.get_running_loop()
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# Hold lock during PTY write to ensure consistency with concurrent _sync_pyte_to_pty
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async with self._screen_lock:
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self._last_width = width
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self._last_height = height
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await loop.run_in_executor(None, self._set_terminal_size, width, height)
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# Resize pyte screen to match
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self._screen.resize(height, width)
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async def force_redraw(self) -> None:
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"""Force a terminal redraw by re-sending current size."""
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loop = asyncio.get_running_loop()
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await loop.run_in_executor(
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None, self._set_terminal_size, self._last_width, self._last_height
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)
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async def _add_to_replay_buffer(self, data: bytes) -> None:
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"""Add data to replay buffer, maintaining size limit."""
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async with self._replay_lock:
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self._replay_buffer.append(data)
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self._replay_buffer_size += len(data)
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while self._replay_buffer_size > REPLAY_BUFFER_SIZE and self._replay_buffer:
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old_data = self._replay_buffer.popleft()
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self._replay_buffer_size -= len(old_data)
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async def _update_screen(self, data: bytes) -> None:
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"""Update the pyte screen with new terminal data."""
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async with self._screen_lock:
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try:
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text = data.decode("utf-8", errors="replace")
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self._stream.feed(text)
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except Exception:
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# Don't let pyte errors crash the session
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pass
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async def get_replay_buffer(self) -> bytes:
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"""Get the contents of the replay buffer."""
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async with self._replay_lock:
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return b"".join(self._replay_buffer)
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async def get_screen_lines(self) -> list[str]:
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"""Get the current screen state as a list of lines.
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Returns properly rendered terminal content with all escape sequences
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interpreted, suitable for screenshot generation.
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"""
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async with self._screen_lock:
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return [line.rstrip() for line in self._screen.display]
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async def get_screen_has_changes(self) -> bool:
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"""Check if the screen has changed since the last snapshot."""
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await self._sync_pyte_to_pty()
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async with self._screen_lock:
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return len(self._screen.dirty) > 0
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async def get_screen_state(self) -> tuple[int, int, list, bool]:
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"""Get the current screen state including dimensions and character buffer.
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Returns:
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Tuple of (width, height, buffer, has_changes) where:
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- width: screen width in columns
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- height: screen height in rows
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- buffer: list of rows, each containing character data with styling
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- has_changes: True if screen has changed since last call
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"""
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# Sync pyte to actual PTY size before reading state
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await self._sync_pyte_to_pty()
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async with self._screen_lock:
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width = self._screen.columns
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height = self._screen.lines
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# Check if any rows are dirty (changed since last clear)
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has_changes = len(self._screen.dirty) > 0
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# Clear dirty set after checking
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self._screen.dirty.clear()
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# Snapshot buffer cells quickly to minimize lock hold time
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snapshot = [
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[self._screen.buffer[row][col] for col in range(width)] for row in range(height)
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]
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buffer = []
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for row_data in snapshot:
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row_chars = []
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for char in row_data:
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row_chars.append(
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{
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"data": char.data if char.data else " ",
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"fg": char.fg,
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"bg": char.bg,
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"bold": char.bold,
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"italics": char.italics,
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"underscore": char.underscore,
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"reverse": char.reverse,
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}
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)
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buffer.append(row_chars)
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return (width, height, buffer, has_changes)
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def update_connector(self, connector: SessionConnector) -> None:
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"""Update the connector for reconnection without restarting the session."""
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self._connector = connector
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log.debug("Updated connector for session %s", self.session_id)
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async def start(self, connector: SessionConnector) -> asyncio.Task:
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self._connector = connector
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assert self.master_fd is not None
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if self._task is not None:
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# Already running, just update connector (handled by update_connector)
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return self._task
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self._task = asyncio.create_task(self.run())
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return self._task
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async def run(self) -> None:
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assert self.master_fd is not None
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queue = self.poller.add_file(self.master_fd)
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try:
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while True:
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data = await queue.get()
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if not data:
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break
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# Store in replay buffer for reconnection
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await self._add_to_replay_buffer(data)
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# Update pyte screen state for screenshots
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await self._update_screen(data)
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# Send to current connector
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if self._connector:
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await self._connector.on_data(data)
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except OSError:
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log.exception("error in terminal.run")
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finally:
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if self._connector:
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await self._connector.on_close()
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if self.master_fd is not None:
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fd = self.master_fd
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self.master_fd = None
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# Remove from poller first (while fd is still valid), then close
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self.poller.remove_file(fd)
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os.close(fd)
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async def send_bytes(self, data: bytes) -> bool:
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fd = self.master_fd
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if fd is None:
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return False
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try:
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await self.poller.write(fd, data)
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except (KeyError, OSError):
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return False
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return True
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async def send_meta(self, data: Meta) -> bool:
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return True
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async def close(self) -> None:
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# Cancel the read task first to unblock any waiting queue.get()
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if self._task is not None and not self._task.done():
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self._task.cancel()
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if self.pid is not None:
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try:
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os.kill(self.pid, signal.SIGHUP)
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except ProcessLookupError:
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pass # Process already gone
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except Exception as e:
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log.warning("Error closing terminal session %s: %s", self.session_id, e)
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async def wait(self, timeout: float = 2.0) -> None:
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if self._task is not None:
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with contextlib.suppress(asyncio.CancelledError, TimeoutError):
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await asyncio.wait_for(asyncio.shield(self._task), timeout=timeout)
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def is_running(self) -> bool:
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"""Check if the terminal session is still running."""
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if self.master_fd is None or self._task is None:
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return False
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# Check if process is actually alive
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if self.pid is not None:
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try:
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os.kill(self.pid, 0) # Signal 0 checks existence
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return True
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except OSError:
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return False
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# pid is None means process not started or already exited
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return False
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