Add custom typing to config and ctx (#2785)

sanic/request/types.py

@@ -2,11 +2,13 @@ from __future__ import annotations
 
 from contextvars import ContextVar
 from inspect import isawaitable
+from types import SimpleNamespace
 from typing import (
     TYPE_CHECKING,
     Any,
     DefaultDict,
     Dict,
+    Generic,
     List,
     Optional,
     Tuple,
@@ -15,6 +17,7 @@ from typing import (
 )
 
 from sanic_routing.route import Route
+from typing_extensions import TypeVar
 
 from sanic.http.constants import HTTP  # type: ignore
 from sanic.http.stream import Stream
@@ -23,13 +26,13 @@ from sanic.models.http_types import Credentials
 
 
 if TYPE_CHECKING:
-    from sanic.server import ConnInfo
     from sanic.app import Sanic
+    from sanic.config import Config
+    from sanic.server import ConnInfo
 
 import uuid
 
 from collections import defaultdict
-from types import SimpleNamespace
 from urllib.parse import parse_qs, parse_qsl, urlunparse
 
 from httptools import parse_url
@@ -68,8 +71,21 @@ try:
 except ImportError:
     from json import loads as json_loads  # type: ignore
 
+if TYPE_CHECKING:
+    # The default argument of TypeVar is proposed to be added in Python 3.13
+    # by PEP 696 (https://www.python.org/dev/peps/pep-0696/).
+    # Therefore, we use typing_extensions.TypeVar for compatibility.
+    # For more information, see:
+    # https://discuss.python.org/t/pep-696-type-defaults-for-typevarlikes
+    sanic_type = TypeVar(
+        "sanic_type", bound=Sanic, default=Sanic[Config, SimpleNamespace]
+    )
+else:
+    sanic_type = TypeVar("sanic_type")
+ctx_type = TypeVar("ctx_type")
 
-class Request:
+
+class Request(Generic[sanic_type, ctx_type]):
     """
     Properties of an HTTP request such as URL, headers, etc.
     """
@@ -80,6 +96,7 @@ class Request:
     __slots__ = (
         "__weakref__",
         "_cookies",
+        "_ctx",
         "_id",
         "_ip",
         "_parsed_url",
@@ -96,7 +113,6 @@ class Request:
         "app",
         "body",
         "conn_info",
-        "ctx",
         "head",
         "headers",
         "method",
@@ -125,7 +141,7 @@ class Request:
         version: str,
         method: str,
         transport: TransportProtocol,
-        app: Sanic,
+        app: sanic_type,
         head: bytes = b"",
         stream_id: int = 0,
     ):
@@ -149,7 +165,7 @@ class Request:
         # Init but do not inhale
         self.body = b""
         self.conn_info: Optional[ConnInfo] = None
-        self.ctx = SimpleNamespace()
+        self._ctx: Optional[ctx_type] = None
         self.parsed_accept: Optional[AcceptList] = None
         self.parsed_args: DefaultDict[
             Tuple[bool, bool, str, str], RequestParameters
@@ -176,6 +192,10 @@ class Request:
         class_name = self.__class__.__name__
         return f"<{class_name}: {self.method} {self.path}>"
 
+    @staticmethod
+    def make_context() -> ctx_type:
+        return cast(ctx_type, SimpleNamespace())
+
     @classmethod
     def get_current(cls) -> Request:
         """
@@ -205,6 +225,15 @@ class Request:
     def generate_id(*_):
         return uuid.uuid4()
 
+    @property
+    def ctx(self) -> ctx_type:
+        """
+        :return: The current request context
+        """
+        if not self._ctx:
+            self._ctx = self.make_context()
+        return self._ctx
+
     @property
     def stream_id(self):
         """