django/django/utils/asyncio.py
Andrew Godwin a415ce70be Fixed #30451 -- Added ASGI handler and coroutine-safety.
This adds an ASGI handler, asgi.py file for the default project layout,
a few async utilities and adds async-safety to many parts of Django.
2019-06-20 12:29:43 +02:00

32 lines
1 KiB
Python

import asyncio
import functools
from django.core.exceptions import SynchronousOnlyOperation
def async_unsafe(message):
"""
Decorator to mark functions as async-unsafe. Someone trying to access
the function while in an async context will get an error message.
"""
def decorator(func):
@functools.wraps(func)
def inner(*args, **kwargs):
# Detect a running event loop in this thread.
try:
event_loop = asyncio.get_event_loop()
except RuntimeError:
pass
else:
if event_loop.is_running():
raise SynchronousOnlyOperation(message)
# Pass onwards.
return func(*args, **kwargs)
return inner
# If the message is actually a function, then be a no-arguments decorator.
if callable(message):
func = message
message = 'You cannot call this from an async context - use a thread or sync_to_async.'
return decorator(func)
else:
return decorator