from __future__ import annotations import asyncio import inspect import time import uuid from collections import defaultdict from contextlib import contextmanager from pathlib import Path from typing import TYPE_CHECKING, Any, Awaitable, Callable, ClassVar, Dict, Iterable, Iterator, List, Optional, Union from fastapi import Request from fastapi.responses import Response from fastapi.templating import Jinja2Templates from typing_extensions import Self from . import background_tasks, binding, core, helpers, json, storage from .awaitable_response import AwaitableResponse from .dependencies import generate_resources from .element import Element from .favicon import get_favicon_url from .javascript_request import JavaScriptRequest from .logging import log from .observables import ObservableDict from .outbox import Outbox from .translations import translations from .version import __version__ if TYPE_CHECKING: from .page import page templates = Jinja2Templates(Path(__file__).parent / 'templates') class Client: page_routes: ClassVar[Dict[Callable[..., Any], str]] = {} '''Maps page builders to their routes.''' instances: ClassVar[Dict[str, Client]] = {} '''Maps client IDs to clients.''' auto_index_client: Client '''The client that is used to render the auto-index page.''' shared_head_html = '' '''HTML to be inserted in the of every page template.''' shared_body_html = '' '''HTML to be inserted in the of every page template.''' def __init__(self, page: page, *, request: Optional[Request]) -> None: self.request: Optional[Request] = request self.id = str(uuid.uuid4()) self.created = time.time() self.instances[self.id] = self self.elements: Dict[int, Element] = {} self.next_element_id: int = 0 self._waiting_for_connection: asyncio.Event = asyncio.Event() self.is_waiting_for_connection: bool = False self.is_waiting_for_disconnect: bool = False self.environ: Optional[Dict[str, Any]] = None self.shared = request is None self.on_air = False self._num_connections: defaultdict[str, int] = defaultdict(int) self._delete_tasks: Dict[str, asyncio.Task] = {} self._deleted = False self._socket_to_document_id: Dict[str, str] = {} self.tab_id: Optional[str] = None self.page = page self.outbox = Outbox(self) with Element('q-layout', _client=self).props('view="hhh lpr fff"').classes('nicegui-layout') as self.layout: with Element('q-page-container') as self.page_container: with Element('q-page'): self.content = Element('div').classes('nicegui-content') self.title: Optional[str] = None self._head_html = '' self._body_html = '' self.storage = ObservableDict() self.connect_handlers: List[Union[Callable[..., Any], Awaitable]] = [] self.disconnect_handlers: List[Union[Callable[..., Any], Awaitable]] = [] self._temporary_socket_id: Optional[str] = None @property def is_auto_index_client(self) -> bool: """Return True if this client is the auto-index client.""" return self is self.auto_index_client @property def ip(self) -> Optional[str]: """Return the IP address of the client, or None if it is an `auto-index page `_. *Updated in version 2.0.0: The IP address is available even before the client connects.* """ return self.request.client.host if self.request is not None and self.request.client is not None else None @property def has_socket_connection(self) -> bool: """Return True if the client is connected, False otherwise.""" return self.tab_id is not None @property def head_html(self) -> str: """Return the HTML code to be inserted in the of the page template.""" return self.shared_head_html + self._head_html @property def body_html(self) -> str: """Return the HTML code to be inserted in the of the page template.""" return self.shared_body_html + self._body_html def __enter__(self) -> Self: self.content.__enter__() return self def __exit__(self, *_) -> None: self.content.__exit__() def build_response(self, request: Request, status_code: int = 200) -> Response: """Build a FastAPI response for the client.""" self.outbox.updates.clear() prefix = request.headers.get('X-Forwarded-Prefix', request.scope.get('root_path', '')) elements = json.dumps({ id: element._to_dict() for id, element in self.elements.items() # pylint: disable=protected-access }) socket_io_js_query_params = { **core.app.config.socket_io_js_query_params, 'client_id': self.id, 'next_message_id': self.outbox.next_message_id, } vue_html, vue_styles, vue_scripts, imports, js_imports, js_imports_urls = \ generate_resources(prefix, self.elements.values()) return templates.TemplateResponse( request=request, name='index.html', context={ 'request': request, 'version': __version__, 'elements': elements.replace('&', '&') .replace('<', '<') .replace('>', '>') .replace('`', '`') .replace('$', '$'), 'head_html': self.head_html, 'body_html': '\n' + self.body_html + '\n' + '\n'.join(vue_html), 'vue_scripts': '\n'.join(vue_scripts), 'imports': json.dumps(imports), 'js_imports': '\n'.join(js_imports), 'js_imports_urls': js_imports_urls, 'vue_config': json.dumps(core.app.config.quasar_config), 'vue_config_script': core.app.config.vue_config_script, 'title': self.resolve_title(), 'viewport': self.page.resolve_viewport(), 'favicon_url': get_favicon_url(self.page, prefix), 'dark': str(self.page.resolve_dark()), 'language': self.page.resolve_language(), 'translations': translations.get(self.page.resolve_language(), translations['en-US']), 'prefix': prefix, 'tailwind': core.app.config.tailwind, 'prod_js': core.app.config.prod_js, 'socket_io_js_query_params': socket_io_js_query_params, 'socket_io_js_extra_headers': core.app.config.socket_io_js_extra_headers, 'socket_io_js_transports': core.app.config.socket_io_js_transports, }, status_code=status_code, headers={'Cache-Control': 'no-store', 'X-NiceGUI-Content': 'page'}, ) def resolve_title(self) -> str: """Return the title of the page.""" return self.page.resolve_title() if self.title is None else self.title async def connected(self, timeout: float = 3.0, check_interval: float = 0.1) -> None: """Block execution until the client is connected.""" self.is_waiting_for_connection = True self._waiting_for_connection.set() deadline = time.time() + timeout while not self.has_socket_connection: if time.time() > deadline: raise TimeoutError(f'No connection after {timeout} seconds') await asyncio.sleep(check_interval) self.is_waiting_for_connection = False async def disconnected(self, check_interval: float = 0.1) -> None: """Block execution until the client disconnects.""" if not self.has_socket_connection: await self.connected() self.is_waiting_for_disconnect = True while self.id in self.instances: await asyncio.sleep(check_interval) self.is_waiting_for_disconnect = False def run_javascript(self, code: str, *, timeout: float = 1.0) -> AwaitableResponse: """Execute JavaScript on the client. The client connection must be established before this method is called. You can do this by `await client.connected()` or register a callback with `client.on_connect(...)`. If the function is awaited, the result of the JavaScript code is returned. Otherwise, the JavaScript code is executed without waiting for a response. :param code: JavaScript code to run :param timeout: timeout in seconds (default: `1.0`) :return: AwaitableResponse that can be awaited to get the result of the JavaScript code """ request_id = str(uuid.uuid4()) target_id = self._temporary_socket_id or self.id def send_and_forget(): self.outbox.enqueue_message('run_javascript', {'code': code}, target_id) async def send_and_wait(): if self is self.auto_index_client: raise RuntimeError('Cannot await JavaScript responses on the auto-index page. ' 'There could be multiple clients connected and it is not clear which one to wait for.') self.outbox.enqueue_message('run_javascript', {'code': code, 'request_id': request_id}, target_id) return await JavaScriptRequest(request_id, timeout=timeout) return AwaitableResponse(send_and_forget, send_and_wait) def open(self, target: Union[Callable[..., Any], str], new_tab: bool = False) -> None: """Open a new page in the client.""" path = target if isinstance(target, str) else self.page_routes[target] self.outbox.enqueue_message('open', {'path': path, 'new_tab': new_tab}, self.id) def download(self, src: Union[str, bytes], filename: Optional[str] = None, media_type: str = '') -> None: """Download a file from a given URL or raw bytes.""" self.outbox.enqueue_message('download', {'src': src, 'filename': filename, 'media_type': media_type}, self.id) def on_connect(self, handler: Union[Callable[..., Any], Awaitable]) -> None: """Add a callback to be invoked when the client connects.""" self.connect_handlers.append(handler) def on_disconnect(self, handler: Union[Callable[..., Any], Awaitable]) -> None: """Add a callback to be invoked when the client disconnects.""" self.disconnect_handlers.append(handler) def handle_handshake(self, socket_id: str, document_id: str, next_message_id: Optional[int]) -> None: """Cancel pending disconnect task and invoke connect handlers.""" self._socket_to_document_id[socket_id] = document_id self._cancel_delete_task(document_id) self._num_connections[document_id] += 1 if next_message_id is not None: self.outbox.try_rewind(next_message_id) storage.request_contextvar.set(self.request) for t in self.connect_handlers: self.safe_invoke(t) for t in core.app._connect_handlers: # pylint: disable=protected-access self.safe_invoke(t) def handle_disconnect(self, socket_id: str) -> None: """Wait for the browser to reconnect; invoke disconnect handlers if it doesn't. NOTE: In contrast to connect handlers, disconnect handlers are not called during a reconnect. This behavior should be fixed in version 3.0. """ if socket_id not in self._socket_to_document_id: return document_id = self._socket_to_document_id.pop(socket_id) self._cancel_delete_task(document_id) self._num_connections[document_id] -= 1 async def delete_content() -> None: await asyncio.sleep(self.page.resolve_reconnect_timeout()) if self._num_connections[document_id] == 0: for t in self.disconnect_handlers: self.safe_invoke(t) for t in core.app._disconnect_handlers: # pylint: disable=protected-access self.safe_invoke(t) self._num_connections.pop(document_id) self._delete_tasks.pop(document_id) if not self.shared: self.delete() self._delete_tasks[document_id] = \ background_tasks.create(delete_content(), name=f'delete content {document_id}') def _cancel_delete_task(self, document_id: str) -> None: if document_id in self._delete_tasks: self._delete_tasks.pop(document_id).cancel() def handle_event(self, msg: Dict) -> None: """Forward an event to the corresponding element.""" with self: sender = self.elements.get(msg['id']) if sender is not None and not sender.is_ignoring_events: msg['args'] = [None if arg is None else json.loads(arg) for arg in msg.get('args', [])] if len(msg['args']) == 1: msg['args'] = msg['args'][0] sender._handle_event(msg) # pylint: disable=protected-access def handle_javascript_response(self, msg: Dict) -> None: """Store the result of a JavaScript command.""" JavaScriptRequest.resolve(msg['request_id'], msg.get('result')) def safe_invoke(self, func: Union[Callable[..., Any], Awaitable]) -> None: """Invoke the potentially async function in the client context and catch any exceptions.""" func_name = func.__name__ if hasattr(func, '__name__') else str(func) try: if isinstance(func, Awaitable): async def func_with_client(): with self: await func background_tasks.create(func_with_client(), name=f'func with client {self.id} {func_name}') else: with self: result = func(self) if len(inspect.signature(func).parameters) == 1 else func() if helpers.is_coroutine_function(func) and not isinstance(result, asyncio.Task): async def result_with_client(): with self: await result background_tasks.create(result_with_client(), name=f'result with client {self.id} {func_name}') except Exception as e: core.app.handle_exception(e) def remove_elements(self, elements: Iterable[Element]) -> None: """Remove the given elements from the client.""" element_list = list(elements) # NOTE: we need to iterate over the elements multiple times binding.remove(element_list) for element in element_list: element._handle_delete() # pylint: disable=protected-access element._deleted = True # pylint: disable=protected-access self.outbox.enqueue_delete(element) self.elements.pop(element.id, None) def remove_all_elements(self) -> None: """Remove all elements from the client.""" self.remove_elements(self.elements.values()) def delete(self) -> None: """Delete a client and all its elements. If the global clients dictionary does not contain the client, its elements are still removed and a KeyError is raised. Normally this should never happen, but has been observed (see #1826). """ self.remove_all_elements() self.outbox.stop() del Client.instances[self.id] self._deleted = True def check_existence(self) -> None: """Check if the client still exists and print a warning if it doesn't.""" if self._deleted: helpers.warn_once('Client has been deleted but is still being used. ' 'This is most likely a bug in your application code. ' 'See https://github.com/zauberzeug/nicegui/issues/3028 for more information.', stack_info=True) @contextmanager def individual_target(self, socket_id: str) -> Iterator[None]: """Use individual socket ID while in this context. This context is useful for limiting messages from the shared auto-index page to a single client. """ self._temporary_socket_id = socket_id yield self._temporary_socket_id = None @classmethod async def prune_instances(cls) -> None: """Prune stale clients in an endless loop.""" while True: try: stale_clients = [ client for client in cls.instances.values() if not client.shared and not client.has_socket_connection and client.created < time.time() - 60.0 ] for client in stale_clients: client.delete() except Exception: # NOTE: make sure the loop doesn't crash log.exception('Error while pruning clients') try: await asyncio.sleep(10) except asyncio.CancelledError: break