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import sys
from contextlib import contextmanager
from typing import TYPE_CHECKING, Any, Generator, Optional
try:
from contextvars import ContextVar
except ImportError:
from prompt_toolkit.eventloop.dummy_contextvars import ContextVar # type: ignore
if TYPE_CHECKING:
from prompt_toolkit.input.base import Input
from prompt_toolkit.output.base import Output
from .application import Application
__all__ = [
"AppSession",
"get_app_session",
"get_app",
"get_app_or_none",
"set_app",
"create_app_session",
"create_app_session_from_tty",
]
class AppSession:
"""
An AppSession is an interactive session, usually connected to one terminal.
Within one such session, interaction with many applications can happen, one
after the other.
The input/output device is not supposed to change during one session.
Warning: Always use the `create_app_session` function to create an
instance, so that it gets activated correctly.
:param input: Use this as a default input for all applications
running in this session, unless an input is passed to the `Application`
explicitely.
:param output: Use this as a default output.
"""
def __init__(
self, input: Optional["Input"] = None, output: Optional["Output"] = None
) -> None:
self._input = input
self._output = output
# The application will be set dynamically by the `set_app` context
# manager. This is called in the application itself.
self.app: Optional["Application[Any]"] = None
def __repr__(self) -> str:
return f"AppSession(app={self.app!r})"
@property
def input(self) -> "Input":
if self._input is None:
from prompt_toolkit.input.defaults import create_input
self._input = create_input()
return self._input
@property
def output(self) -> "Output":
if self._output is None:
from prompt_toolkit.output.defaults import create_output
self._output = create_output()
return self._output
_current_app_session: ContextVar["AppSession"] = ContextVar(
"_current_app_session", default=AppSession()
)
def get_app_session() -> AppSession:
return _current_app_session.get()
def get_app() -> "Application[Any]":
"""
Get the current active (running) Application.
An :class:`.Application` is active during the
:meth:`.Application.run_async` call.
We assume that there can only be one :class:`.Application` active at the
same time. There is only one terminal window, with only one stdin and
stdout. This makes the code significantly easier than passing around the
:class:`.Application` everywhere.
If no :class:`.Application` is running, then return by default a
:class:`.DummyApplication`. For practical reasons, we prefer to not raise
an exception. This way, we don't have to check all over the place whether
an actual `Application` was returned.
(For applications like pymux where we can have more than one `Application`,
we'll use a work-around to handle that.)
"""
session = _current_app_session.get()
if session.app is not None:
return session.app
from .dummy import DummyApplication
return DummyApplication()
def get_app_or_none() -> Optional["Application[Any]"]:
"""
Get the current active (running) Application, or return `None` if no
application is running.
"""
session = _current_app_session.get()
return session.app
@contextmanager
def set_app(app: "Application[Any]") -> Generator[None, None, None]:
"""
Context manager that sets the given :class:`.Application` active in an
`AppSession`.
This should only be called by the `Application` itself.
The application will automatically be active while its running. If you want
the application to be active in other threads/coroutines, where that's not
the case, use `contextvars.copy_context()`, or use `Application.context` to
run it in the appropriate context.
"""
session = _current_app_session.get()
previous_app = session.app
session.app = app
try:
yield
finally:
session.app = previous_app
@contextmanager
def create_app_session(
input: Optional["Input"] = None, output: Optional["Output"] = None
) -> Generator[AppSession, None, None]:
"""
Create a separate AppSession.
This is useful if there can be multiple individual `AppSession`s going on.
Like in the case of an Telnet/SSH server. This functionality uses
contextvars and requires at least Python 3.7.
"""
if sys.version_info <= (3, 6):
raise RuntimeError("Application sessions require Python 3.7.")
# If no input/output is specified, fall back to the current input/output,
# whatever that is.
if input is None:
input = get_app_session().input
if output is None:
output = get_app_session().output
# Create new `AppSession` and activate.
session = AppSession(input=input, output=output)
token = _current_app_session.set(session)
try:
yield session
finally:
_current_app_session.reset(token)
@contextmanager
def create_app_session_from_tty() -> Generator[AppSession, None, None]:
"""
Create `AppSession` that always prefers the TTY input/output.
Even if `sys.stdin` and `sys.stdout` are connected to input/output pipes,
this will still use the terminal for interaction (because `sys.stderr` is
still connected to the terminal).
Usage::
from prompt_toolkit.shortcuts import prompt
with create_app_session_from_tty():
prompt('>')
"""
from prompt_toolkit.input.defaults import create_input
from prompt_toolkit.output.defaults import create_output
input = create_input(always_prefer_tty=True)
output = create_output(always_prefer_tty=True)
with create_app_session(input=input, output=output) as app_session:
yield app_session
|
