diff --git a/synapse/http/server.py b/synapse/http/server.py
index 19f42159b8..6068a94b40 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -33,7 +33,6 @@ from typing import (
Optional,
Pattern,
Tuple,
- TypeVar,
Union,
)
@@ -64,6 +63,7 @@ from synapse.logging.context import defer_to_thread, preserve_fn, run_in_backgro
from synapse.logging.opentracing import active_span, start_active_span, trace_servlet
from synapse.util import json_encoder
from synapse.util.caches import intern_dict
+from synapse.util.cancellation import is_function_cancellable
from synapse.util.iterutils import chunk_seq
if TYPE_CHECKING:
@@ -94,68 +94,6 @@ HTML_ERROR_TEMPLATE = """<!DOCTYPE html>
HTTP_STATUS_REQUEST_CANCELLED = 499
-F = TypeVar("F", bound=Callable[..., Any])
-
-
-_cancellable_method_names = frozenset(
- {
- # `RestServlet`, `BaseFederationServlet` and `BaseFederationServerServlet`
- # methods
- "on_GET",
- "on_PUT",
- "on_POST",
- "on_DELETE",
- # `_AsyncResource`, `DirectServeHtmlResource` and `DirectServeJsonResource`
- # methods
- "_async_render_GET",
- "_async_render_PUT",
- "_async_render_POST",
- "_async_render_DELETE",
- "_async_render_OPTIONS",
- # `ReplicationEndpoint` methods
- "_handle_request",
- }
-)
-
-
-def cancellable(method: F) -> F:
- """Marks a servlet method as cancellable.
-
- Methods with this decorator will be cancelled if the client disconnects before we
- finish processing the request.
-
- During cancellation, `Deferred.cancel()` will be invoked on the `Deferred` wrapping
- the method. The `cancel()` call will propagate down to the `Deferred` that is
- currently being waited on. That `Deferred` will raise a `CancelledError`, which will
- propagate up, as per normal exception handling.
-
- Before applying this decorator to a new endpoint, you MUST recursively check
- that all `await`s in the function are on `async` functions or `Deferred`s that
- handle cancellation cleanly, otherwise a variety of bugs may occur, ranging from
- premature logging context closure, to stuck requests, to database corruption.
-
- Usage:
- class SomeServlet(RestServlet):
- @cancellable
- async def on_GET(self, request: SynapseRequest) -> ...:
- ...
- """
- if method.__name__ not in _cancellable_method_names and not any(
- method.__name__.startswith(prefix) for prefix in _cancellable_method_names
- ):
- raise ValueError(
- "@cancellable decorator can only be applied to servlet methods."
- )
-
- method.cancellable = True # type: ignore[attr-defined]
- return method
-
-
-def is_method_cancellable(method: Callable[..., Any]) -> bool:
- """Checks whether a servlet method has the `@cancellable` flag."""
- return getattr(method, "cancellable", False)
-
-
def return_json_error(
f: failure.Failure, request: SynapseRequest, config: Optional[HomeServerConfig]
) -> None:
@@ -389,7 +327,7 @@ class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
method_handler = getattr(self, "_async_render_%s" % (request_method,), None)
if method_handler:
- request.is_render_cancellable = is_method_cancellable(method_handler)
+ request.is_render_cancellable = is_function_cancellable(method_handler)
raw_callback_return = method_handler(request)
@@ -551,7 +489,7 @@ class JsonResource(DirectServeJsonResource):
async def _async_render(self, request: SynapseRequest) -> Tuple[int, Any]:
callback, servlet_classname, group_dict = self._get_handler_for_request(request)
- request.is_render_cancellable = is_method_cancellable(callback)
+ request.is_render_cancellable = is_function_cancellable(callback)
# Make sure we have an appropriate name for this handler in prometheus
# (rather than the default of JsonResource).
|
