JezK
Edit File: compatibility.py
import inspect from .sync import iscoroutinefunction def is_double_callable(application): """ Tests to see if an application is a legacy-style (double-callable) application. """ # Look for a hint on the object first if getattr(application, "_asgi_single_callable", False): return False if getattr(application, "_asgi_double_callable", False): return True # Uninstanted classes are double-callable if inspect.isclass(application): return True # Instanted classes depend on their __call__ if hasattr(application, "__call__"): # We only check to see if its __call__ is a coroutine function - # if it's not, it still might be a coroutine function itself. if iscoroutinefunction(application.__call__): return False # Non-classes we just check directly return not iscoroutinefunction(application) def double_to_single_callable(application): """ Transforms a double-callable ASGI application into a single-callable one. """ async def new_application(scope, receive, send): instance = application(scope) return await instance(receive, send) return new_application def guarantee_single_callable(application): """ Takes either a single- or double-callable application and always returns it in single-callable style. Use this to add backwards compatibility for ASGI 2.0 applications to your server/test harness/etc. """ if is_double_callable(application): application = double_to_single_callable(application) return application