server.py

# server.py

import asyncio
import importlib.metadata
import json
import logging
import secrets
import uuid
from dataclasses import dataclass, asdict
from typing import Any, AsyncGenerator, Dict, Tuple, Union

from quart import Quart, websocket, request, send_from_directory
from quart_schema import QuartSchema, validate_request, validate_response
from starlette.middleware.proxy_headers import ProxyHeadersMiddleware  # Importar ProxyHeadersMiddleware de Starlette

# Configuraciones
TIMEOUT: int = 40
LOG_LEVEL: int = logging.DEBUG
TRUSTED_HOSTS: list[str] = ["127.0.0.1", "172.18.0.3"]

# Inicialización de la aplicación Quart
app = Quart(__name__)
QuartSchema(app)
app.asgi_app = ProxyHeadersMiddleware(
    app.asgi_app,
    x_for=1,
    x_proto=1,
    x_host=1,
    x_port=1,
    x_prefix=1
)
app.logger.setLevel(LOG_LEVEL)

# Excepciones personalizadas

class SessionDoesNotExist(Exception):
    """Error al solicitar un ID de sesión que no existe."""
    pass

class SessionAlreadyExists(Exception):
    """Error al crear una sesión con un ID que ya existe."""
    pass

class ClientError(Exception):
    """Error cuando el cliente devuelve un error."""
    def __init__(self, message: str):
        super().__init__(message)
        self.message = message

# Clases de datos para solicitudes y respuestas

@dataclass
class ClientRequest:
    request_id: str
    data: Any 

@dataclass
class ClientResponse:
    request_id: str
    error: bool
    data: Any

@dataclass
class Status:
    status: str
    version: str

@dataclass
class Session:
    session_id: str

@dataclass
class Command:
    session_id: str
    command: str

@dataclass
class Read:
    session_id: str
    path: str

@dataclass
class Write:
    session_id: str
    path: str
    content: str

@dataclass
class CommandResponse:
    return_code: int
    stdout: str
    stderr: str

@dataclass
class ReadResponse:
    content: str

@dataclass
class WriteResponse:
    size: int

@dataclass
class ErrorResponse:
    error: str

# Broker para manejar sesiones y comunicaciones

class SessionBroker:
    def __init__(self):
        """Diccionario de session_id -> cola de mensajes pendientes por enviar al cliente"""
        self.sessions: Dict[str, asyncio.Queue] = {}
        """Diccionario de (session_id, request_id) -> futuro de la respuesta del cliente"""
        self.pending_responses: Dict[Tuple[str, str], asyncio.Future] = {}

    async def send_request(self, session_id: str, data: Any, timeout: int = 60) -> Any:
        if session_id not in self.sessions:
            raise SessionDoesNotExist()

        request_id = str(uuid.uuid4())
        loop = asyncio.get_event_loop()
        future = loop.create_future()
        self.pending_responses[(session_id, request_id)] = future

        await self.sessions[session_id].put(ClientRequest(request_id=request_id, data=data))

        try:
            return await asyncio.wait_for(future, timeout)
        except asyncio.TimeoutError:
            raise
        finally:
            self.pending_responses.pop((session_id, request_id), None)

    async def receive_response(self, session_id: str, response: ClientResponse) -> None:
        key = (session_id, response.request_id)
        future = self.pending_responses.pop(key, None)
        if future and not future.done():
            if response.error:
                future.set_exception(ClientError(message=response.data))
            else:
                future.set_result(response.data)

    async def subscribe(self, session_id: str) -> AsyncGenerator[ClientRequest, None]:
        if session_id in self.sessions:
            raise SessionAlreadyExists()

        queue = asyncio.Queue()
        self.sessions[session_id] = queue

        try:
            while True:
                yield await queue.get()
        finally:
            del self.sessions[session_id]
            # Eliminar todas las respuestas pendientes de esta sesión
            keys_to_remove = [key for key in self.pending_responses if key[0] == session_id]
            for key in keys_to_remove:
                future = self.pending_responses.pop(key)
                if not future.done():
                    future.set_exception(SessionDoesNotExist())

# Instanciación del broker
broker = SessionBroker()

# Funciones y rutas de la API

async def _receive(session_id: str) -> None:
    while True:
        try:
            message = await websocket.receive()
            response_data = json.loads(message)
            client_response = ClientResponse(**response_data)
            app.logger.info(f"{websocket.remote_addr} - RESPONSE - {session_id} - {json.dumps(asdict(client_response))}")
            await broker.receive_response(session_id, client_response)
        except Exception as e:
            app.logger.error(f"Error al recibir respuesta: {e}")
            break

@app.get("/wss/status")
@validate_response(Status)
async def status() -> Status:
    try:
        version = importlib.metadata.version('serverwitch-api')
    except importlib.metadata.PackageNotFoundError:
        version = "unknown"
    return Status(status="OK", version=version)

@app.websocket('/wss/session')
async def session_handler():
    session_id = secrets.token_hex()
    app.logger.info(f"{websocket.remote_addr} - NEW SESSION - {session_id}")
    session_message = Session(session_id=session_id)
    await websocket.send(json.dumps(asdict(session_message)))

    task = asyncio.create_task(_receive(session_id))
    try:
        async for request_data in broker.subscribe(session_id):
            app.logger.info(f"{websocket.remote_addr} - REQUEST - {session_id} - {json.dumps(asdict(request_data))}")
            await websocket.send(json.dumps(asdict(request_data)))
    except SessionAlreadyExists:
        error_response = ErrorResponse(error="Session already exists.")
        await websocket.send(json.dumps(asdict(error_response)))
    finally:
        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass

@app.post('/wss/command')
@validate_request(Command)
@validate_response(CommandResponse, 200)
@validate_response(ErrorResponse, 500)
async def command(data: Command) -> Tuple[Union[CommandResponse, ErrorResponse], int]:
    try:
        response_data = await broker.send_request(
            data.session_id,
            {'action': 'command', 'command': data.command},
            timeout=TIMEOUT
        )
        response = CommandResponse(**response_data)
        return response, 200
    except SessionDoesNotExist:
        app.logger.warning(f"{request.remote_addr} - INVALID SESSION ID - {repr(data.session_id)}")
        return ErrorResponse(error='Session does not exist.'), 500
    except ClientError as e:
        return ErrorResponse(error=e.message), 500
    except asyncio.TimeoutError:
        return ErrorResponse(error='Timeout when waiting for client.'), 500

@app.post('/wss/read')
@validate_request(Read)
@validate_response(ReadResponse, 200)
@validate_response(ErrorResponse, 500)
async def read(data: Read) -> Tuple[Union[ReadResponse, ErrorResponse], int]:
    try:
        response_data = await broker.send_request(
            data.session_id,
            {'action': 'read', 'path': data.path},
            timeout=TIMEOUT
        )
        response = ReadResponse(**response_data)
        return response, 200
    except SessionDoesNotExist:
        app.logger.warning(f"{request.remote_addr} - INVALID SESSION ID - {repr(data.session_id)}")
        return ErrorResponse(error='Session does not exist.'), 500
    except ClientError as e:
        return ErrorResponse(error=e.message), 500
    except asyncio.TimeoutError:
        return ErrorResponse(error='Timeout when waiting for client.'), 500

@app.post('/wss/write')
@validate_request(Write)
@validate_response(WriteResponse, 200)
@validate_response(ErrorResponse, 500)
async def write(data: Write) -> Tuple[Union[WriteResponse, ErrorResponse], int]:
    try:
        response_data = await broker.send_request(
            data.session_id,
            {'action': 'write', 'path': data.path, 'content': data.content},
            timeout=TIMEOUT
        )
        response = WriteResponse(**response_data)
        return response, 200
    except SessionDoesNotExist:
        app.logger.warning(f"{request.remote_addr} - INVALID SESSION ID - {repr(data.session_id)}")
        return ErrorResponse(error='Session does not exist.'), 500
    except ClientError as e:
        return ErrorResponse(error=e.message), 500
    except asyncio.TimeoutError:
        return ErrorResponse(error='Timeout when waiting for client.'), 500

# Rutas para servir archivos estáticos y OpenAPI
@app.route('/static/<path:path>')
async def send_static(path):
    return await send_from_directory('static', path)

@app.route('/openapi.yaml')
async def openapi_spec():
    return await send_from_directory('.', 'openapi.yaml')

# No se necesita ejecutar nada aquí, ya que Hypercorn se encargará de iniciar la aplicación