sanic/sanic/mixins/signals.py

83 lines
2.6 KiB
Python

from enum import Enum
from typing import Any, Callable, Dict, Optional, Set, Union
from sanic.base.meta import SanicMeta
from sanic.models.futures import FutureSignal
from sanic.models.handler_types import SignalHandler
from sanic.signals import Signal
from sanic.types import HashableDict
class SignalMixin(metaclass=SanicMeta):
def __init__(self, *args, **kwargs) -> None:
self._future_signals: Set[FutureSignal] = set()
def _apply_signal(self, signal: FutureSignal) -> Signal:
raise NotImplementedError # noqa
def signal(
self,
event: Union[str, Enum],
*,
apply: bool = True,
condition: Dict[str, Any] = None,
exclusive: bool = True,
) -> Callable[[SignalHandler], SignalHandler]:
"""
For creating a signal handler, used similar to a route handler:
.. code-block:: python
@app.signal("foo.bar.<thing>")
async def signal_handler(thing, **kwargs):
print(f"[signal_handler] {thing=}", kwargs)
:param event: Representation of the event in ``one.two.three`` form
:type event: str
:param apply: For lazy evaluation, defaults to ``True``
:type apply: bool, optional
:param condition: For use with the ``condition`` argument in dispatch
filtering, defaults to ``None``
:param exclusive: When ``True``, the signal can only be dispatched
when the condition has been met. When ``False``, the signal can
be dispatched either with or without it. *THIS IS INAPPLICABLE TO
BLUEPRINT SIGNALS. THEY ARE ALWAYS NON-EXCLUSIVE*, defaults
to ``True``
:type condition: Dict[str, Any], optional
"""
event_value = str(event.value) if isinstance(event, Enum) else event
def decorator(handler: SignalHandler):
future_signal = FutureSignal(
handler, event_value, HashableDict(condition or {}), exclusive
)
self._future_signals.add(future_signal)
if apply:
self._apply_signal(future_signal)
return handler
return decorator
def add_signal(
self,
handler: Optional[Callable[..., Any]],
event: str,
condition: Dict[str, Any] = None,
exclusive: bool = True,
):
if not handler:
async def noop():
...
handler = noop
self.signal(event=event, condition=condition, exclusive=exclusive)(
handler
)
return handler
def event(self, event: str):
raise NotImplementedError