diff options
Diffstat (limited to 'venv/lib/python3.8/site-packages/flask/ctx.py')
| -rw-r--r-- | venv/lib/python3.8/site-packages/flask/ctx.py | 449 |
1 files changed, 449 insertions, 0 deletions
diff --git a/venv/lib/python3.8/site-packages/flask/ctx.py b/venv/lib/python3.8/site-packages/flask/ctx.py new file mode 100644 index 0000000..9b164d3 --- /dev/null +++ b/venv/lib/python3.8/site-packages/flask/ctx.py @@ -0,0 +1,449 @@ +from __future__ import annotations + +import contextvars +import sys +import typing as t +from functools import update_wrapper +from types import TracebackType + +from werkzeug.exceptions import HTTPException + +from . import typing as ft +from .globals import _cv_app +from .globals import _cv_request +from .signals import appcontext_popped +from .signals import appcontext_pushed + +if t.TYPE_CHECKING: # pragma: no cover + from _typeshed.wsgi import WSGIEnvironment + + from .app import Flask + from .sessions import SessionMixin + from .wrappers import Request + + +# a singleton sentinel value for parameter defaults +_sentinel = object() + + +class _AppCtxGlobals: + """A plain object. Used as a namespace for storing data during an + application context. + + Creating an app context automatically creates this object, which is + made available as the :data:`g` proxy. + + .. describe:: 'key' in g + + Check whether an attribute is present. + + .. versionadded:: 0.10 + + .. describe:: iter(g) + + Return an iterator over the attribute names. + + .. versionadded:: 0.10 + """ + + # Define attr methods to let mypy know this is a namespace object + # that has arbitrary attributes. + + def __getattr__(self, name: str) -> t.Any: + try: + return self.__dict__[name] + except KeyError: + raise AttributeError(name) from None + + def __setattr__(self, name: str, value: t.Any) -> None: + self.__dict__[name] = value + + def __delattr__(self, name: str) -> None: + try: + del self.__dict__[name] + except KeyError: + raise AttributeError(name) from None + + def get(self, name: str, default: t.Any | None = None) -> t.Any: + """Get an attribute by name, or a default value. Like + :meth:`dict.get`. + + :param name: Name of attribute to get. + :param default: Value to return if the attribute is not present. + + .. versionadded:: 0.10 + """ + return self.__dict__.get(name, default) + + def pop(self, name: str, default: t.Any = _sentinel) -> t.Any: + """Get and remove an attribute by name. Like :meth:`dict.pop`. + + :param name: Name of attribute to pop. + :param default: Value to return if the attribute is not present, + instead of raising a ``KeyError``. + + .. versionadded:: 0.11 + """ + if default is _sentinel: + return self.__dict__.pop(name) + else: + return self.__dict__.pop(name, default) + + def setdefault(self, name: str, default: t.Any = None) -> t.Any: + """Get the value of an attribute if it is present, otherwise + set and return a default value. Like :meth:`dict.setdefault`. + + :param name: Name of attribute to get. + :param default: Value to set and return if the attribute is not + present. + + .. versionadded:: 0.11 + """ + return self.__dict__.setdefault(name, default) + + def __contains__(self, item: str) -> bool: + return item in self.__dict__ + + def __iter__(self) -> t.Iterator[str]: + return iter(self.__dict__) + + def __repr__(self) -> str: + ctx = _cv_app.get(None) + if ctx is not None: + return f"<flask.g of '{ctx.app.name}'>" + return object.__repr__(self) + + +def after_this_request( + f: ft.AfterRequestCallable[t.Any], +) -> ft.AfterRequestCallable[t.Any]: + """Executes a function after this request. This is useful to modify + response objects. The function is passed the response object and has + to return the same or a new one. + + Example:: + + @app.route('/') + def index(): + @after_this_request + def add_header(response): + response.headers['X-Foo'] = 'Parachute' + return response + return 'Hello World!' + + This is more useful if a function other than the view function wants to + modify a response. For instance think of a decorator that wants to add + some headers without converting the return value into a response object. + + .. versionadded:: 0.9 + """ + ctx = _cv_request.get(None) + + if ctx is None: + raise RuntimeError( + "'after_this_request' can only be used when a request" + " context is active, such as in a view function." + ) + + ctx._after_request_functions.append(f) + return f + + +F = t.TypeVar("F", bound=t.Callable[..., t.Any]) + + +def copy_current_request_context(f: F) -> F: + """A helper function that decorates a function to retain the current + request context. This is useful when working with greenlets. The moment + the function is decorated a copy of the request context is created and + then pushed when the function is called. The current session is also + included in the copied request context. + + Example:: + + import gevent + from flask import copy_current_request_context + + @app.route('/') + def index(): + @copy_current_request_context + def do_some_work(): + # do some work here, it can access flask.request or + # flask.session like you would otherwise in the view function. + ... + gevent.spawn(do_some_work) + return 'Regular response' + + .. versionadded:: 0.10 + """ + ctx = _cv_request.get(None) + + if ctx is None: + raise RuntimeError( + "'copy_current_request_context' can only be used when a" + " request context is active, such as in a view function." + ) + + ctx = ctx.copy() + + def wrapper(*args: t.Any, **kwargs: t.Any) -> t.Any: + with ctx: # type: ignore[union-attr] + return ctx.app.ensure_sync(f)(*args, **kwargs) # type: ignore[union-attr] + + return update_wrapper(wrapper, f) # type: ignore[return-value] + + +def has_request_context() -> bool: + """If you have code that wants to test if a request context is there or + not this function can be used. For instance, you may want to take advantage + of request information if the request object is available, but fail + silently if it is unavailable. + + :: + + class User(db.Model): + + def __init__(self, username, remote_addr=None): + self.username = username + if remote_addr is None and has_request_context(): + remote_addr = request.remote_addr + self.remote_addr = remote_addr + + Alternatively you can also just test any of the context bound objects + (such as :class:`request` or :class:`g`) for truthness:: + + class User(db.Model): + + def __init__(self, username, remote_addr=None): + self.username = username + if remote_addr is None and request: + remote_addr = request.remote_addr + self.remote_addr = remote_addr + + .. versionadded:: 0.7 + """ + return _cv_request.get(None) is not None + + +def has_app_context() -> bool: + """Works like :func:`has_request_context` but for the application + context. You can also just do a boolean check on the + :data:`current_app` object instead. + + .. versionadded:: 0.9 + """ + return _cv_app.get(None) is not None + + +class AppContext: + """The app context contains application-specific information. An app + context is created and pushed at the beginning of each request if + one is not already active. An app context is also pushed when + running CLI commands. + """ + + def __init__(self, app: Flask) -> None: + self.app = app + self.url_adapter = app.create_url_adapter(None) + self.g: _AppCtxGlobals = app.app_ctx_globals_class() + self._cv_tokens: list[contextvars.Token[AppContext]] = [] + + def push(self) -> None: + """Binds the app context to the current context.""" + self._cv_tokens.append(_cv_app.set(self)) + appcontext_pushed.send(self.app, _async_wrapper=self.app.ensure_sync) + + def pop(self, exc: BaseException | None = _sentinel) -> None: # type: ignore + """Pops the app context.""" + try: + if len(self._cv_tokens) == 1: + if exc is _sentinel: + exc = sys.exc_info()[1] + self.app.do_teardown_appcontext(exc) + finally: + ctx = _cv_app.get() + _cv_app.reset(self._cv_tokens.pop()) + + if ctx is not self: + raise AssertionError( + f"Popped wrong app context. ({ctx!r} instead of {self!r})" + ) + + appcontext_popped.send(self.app, _async_wrapper=self.app.ensure_sync) + + def __enter__(self) -> AppContext: + self.push() + return self + + def __exit__( + self, + exc_type: type | None, + exc_value: BaseException | None, + tb: TracebackType | None, + ) -> None: + self.pop(exc_value) + + +class RequestContext: + """The request context contains per-request information. The Flask + app creates and pushes it at the beginning of the request, then pops + it at the end of the request. It will create the URL adapter and + request object for the WSGI environment provided. + + Do not attempt to use this class directly, instead use + :meth:`~flask.Flask.test_request_context` and + :meth:`~flask.Flask.request_context` to create this object. + + When the request context is popped, it will evaluate all the + functions registered on the application for teardown execution + (:meth:`~flask.Flask.teardown_request`). + + The request context is automatically popped at the end of the + request. When using the interactive debugger, the context will be + restored so ``request`` is still accessible. Similarly, the test + client can preserve the context after the request ends. However, + teardown functions may already have closed some resources such as + database connections. + """ + + def __init__( + self, + app: Flask, + environ: WSGIEnvironment, + request: Request | None = None, + session: SessionMixin | None = None, + ) -> None: + self.app = app + if request is None: + request = app.request_class(environ) + request.json_module = app.json + self.request: Request = request + self.url_adapter = None + try: + self.url_adapter = app.create_url_adapter(self.request) + except HTTPException as e: + self.request.routing_exception = e + self.flashes: list[tuple[str, str]] | None = None + self.session: SessionMixin | None = session + # Functions that should be executed after the request on the response + # object. These will be called before the regular "after_request" + # functions. + self._after_request_functions: list[ft.AfterRequestCallable[t.Any]] = [] + + self._cv_tokens: list[ + tuple[contextvars.Token[RequestContext], AppContext | None] + ] = [] + + def copy(self) -> RequestContext: + """Creates a copy of this request context with the same request object. + This can be used to move a request context to a different greenlet. + Because the actual request object is the same this cannot be used to + move a request context to a different thread unless access to the + request object is locked. + + .. versionadded:: 0.10 + + .. versionchanged:: 1.1 + The current session object is used instead of reloading the original + data. This prevents `flask.session` pointing to an out-of-date object. + """ + return self.__class__( + self.app, + environ=self.request.environ, + request=self.request, + session=self.session, + ) + + def match_request(self) -> None: + """Can be overridden by a subclass to hook into the matching + of the request. + """ + try: + result = self.url_adapter.match(return_rule=True) # type: ignore + self.request.url_rule, self.request.view_args = result # type: ignore + except HTTPException as e: + self.request.routing_exception = e + + def push(self) -> None: + # Before we push the request context we have to ensure that there + # is an application context. + app_ctx = _cv_app.get(None) + + if app_ctx is None or app_ctx.app is not self.app: + app_ctx = self.app.app_context() + app_ctx.push() + else: + app_ctx = None + + self._cv_tokens.append((_cv_request.set(self), app_ctx)) + + # Open the session at the moment that the request context is available. + # This allows a custom open_session method to use the request context. + # Only open a new session if this is the first time the request was + # pushed, otherwise stream_with_context loses the session. + if self.session is None: + session_interface = self.app.session_interface + self.session = session_interface.open_session(self.app, self.request) + + if self.session is None: + self.session = session_interface.make_null_session(self.app) + + # Match the request URL after loading the session, so that the + # session is available in custom URL converters. + if self.url_adapter is not None: + self.match_request() + + def pop(self, exc: BaseException | None = _sentinel) -> None: # type: ignore + """Pops the request context and unbinds it by doing that. This will + also trigger the execution of functions registered by the + :meth:`~flask.Flask.teardown_request` decorator. + + .. versionchanged:: 0.9 + Added the `exc` argument. + """ + clear_request = len(self._cv_tokens) == 1 + + try: + if clear_request: + if exc is _sentinel: + exc = sys.exc_info()[1] + self.app.do_teardown_request(exc) + + request_close = getattr(self.request, "close", None) + if request_close is not None: + request_close() + finally: + ctx = _cv_request.get() + token, app_ctx = self._cv_tokens.pop() + _cv_request.reset(token) + + # get rid of circular dependencies at the end of the request + # so that we don't require the GC to be active. + if clear_request: + ctx.request.environ["werkzeug.request"] = None + + if app_ctx is not None: + app_ctx.pop(exc) + + if ctx is not self: + raise AssertionError( + f"Popped wrong request context. ({ctx!r} instead of {self!r})" + ) + + def __enter__(self) -> RequestContext: + self.push() + return self + + def __exit__( + self, + exc_type: type | None, + exc_value: BaseException | None, + tb: TracebackType | None, + ) -> None: + self.pop(exc_value) + + def __repr__(self) -> str: + return ( + f"<{type(self).__name__} {self.request.url!r}" + f" [{self.request.method}] of {self.app.name}>" + ) |