)
from ..utils.networking import HTTPHeaderDict, normalize_url
-if typing.TYPE_CHECKING:
- RequestData = bytes | Iterable[bytes] | typing.IO | None
+
+def register_preference(*handlers: type[RequestHandler]):
+ assert all(issubclass(handler, RequestHandler) for handler in handlers)
+
+ def outer(preference: Preference):
+ @functools.wraps(preference)
+ def inner(handler, *args, **kwargs):
+ if not handlers or isinstance(handler, handlers):
+ return preference(handler, *args, **kwargs)
+ return 0
+ _RH_PREFERENCES.add(inner)
+ return inner
+ return outer
class RequestDirector:
Helper class that, when given a request, forward it to a RequestHandler that supports it.
+ Preference functions in the form of func(handler, request) -> int
+ can be registered into the `preferences` set. These are used to sort handlers
+ in order of preference.
+
@param logger: Logger instance.
@param verbose: Print debug request information to stdout.
"""
def __init__(self, logger, verbose=False):
self.handlers: dict[str, RequestHandler] = {}
+ self.preferences: set[Preference] = set()
self.logger = logger # TODO(Grub4k): default logger
self.verbose = verbose
assert isinstance(handler, RequestHandler), 'handler must be a RequestHandler'
self.handlers[handler.RH_KEY] = handler
+ def _get_handlers(self, request: Request) -> list[RequestHandler]:
+ """Sorts handlers by preference, given a request"""
+ preferences = {
+ rh: sum(pref(rh, request) for pref in self.preferences)
+ for rh in self.handlers.values()
+ }
+ self._print_verbose('Handler preferences for this request: %s' % ', '.join(
+ f'{rh.RH_NAME}={pref}' for rh, pref in preferences.items()))
+ return sorted(self.handlers.values(), key=preferences.get, reverse=True)
+
def _print_verbose(self, msg):
if self.verbose:
self.logger.stdout(f'director: {msg}')
unexpected_errors = []
unsupported_errors = []
- # TODO (future): add a per-request preference system
- for handler in reversed(list(self.handlers.values())):
+ for handler in self._get_handlers(request):
self._print_verbose(f'Checking if "{handler.RH_NAME}" supports this request.')
try:
handler.validate(request)
def getheader(self, name, default=None):
deprecation_warning('Response.getheader() is deprecated, use Response.get_header', stacklevel=2)
return self.get_header(name, default)
+
+
+if typing.TYPE_CHECKING:
+ RequestData = bytes | Iterable[bytes] | typing.IO | None
+ Preference = typing.Callable[[RequestHandler, Request], int]
+
+_RH_PREFERENCES: set[Preference] = set()