fixes context, make global_context threadsafe (#131)

Changes:

- make global context request specific as documented and thread safe
- fix repr
- expose token in set and cleanup

lilya/context.py

@@ -3,7 +3,6 @@
 import contextvars
 import copy
 import warnings
-from functools import lru_cache
 from typing import TYPE_CHECKING, Annotated, Any, cast
 
 from lilya.datastructures import URL
@@ -233,12 +232,50 @@ def __repr__(self: G) -> str:
         return f"{self.__class__.__name__}()"
 
 
-@lru_cache
+g_context: contextvars.ContextVar[G] = contextvars.ContextVar("g_context")
+
+
 def get_g() -> G:
-    return G()
+    return g_context.get()
+
+
+class LazyGProxy:
+    """
+    A proxy to lazily evaluate attributes of the current request.
+    """
 
+    @property
+    def store(self) -> Any:
+        return get_g().store
 
-g = get_g()
+    def __getattr__(self, item: str) -> Any:
+        return getattr(get_g(), item)
+
+    def __setattr__(self, key: Any, value: Any) -> None:
+        get_g().__setattr__(key, value)
+
+    def __delattr__(self, key: Any) -> None:
+        delattr(get_g(), key)
+
+    def __copy__(self) -> G:
+        try:
+            return get_g()
+        except LookupError:
+            return G()
+
+    def __len__(self) -> int:
+        return len(get_g())
+
+    def __getitem__(self, key: str) -> Any:
+        return get_g()[key]
+
+    def __repr__(self: LazyRequestProxy) -> str:
+        if get_g() is None:
+            return "<LazyGProxy [Unevaluated]>"
+        return '<LazyGProxy "G()">'
+
+
+g: G = cast("G", LazyGProxy())
 
 
 class LazyRequestProxy:
@@ -258,7 +295,7 @@ def __getattr__(self, item: str) -> Any:
         return getattr(request, item)
 
     def __repr__(self: LazyRequestProxy) -> str:
-        if self._request_getter is None:
+        if self._request_getter() is None:
             return "<LazyRequestProxy [Unevaluated]>"
         return '<LazyRequestProxy "Request()">'
 
@@ -275,11 +312,11 @@ class RequestContext:
     lazy_request = LazyRequestProxy(lambda: RequestContext._request_context.get(None))
 
     @classmethod
-    def set_request(cls, request: Request) -> None:
+    def set_request(cls, request: Request) -> contextvars.Token:
         """
         Set the current request in the context.
         """
-        cls._request_context.set(request)
+        return cls._request_context.set(request)
 
     @classmethod
     def get_request(cls) -> Request:

lilya/middleware/global_context.py

@@ -2,7 +2,7 @@
 
 from abc import ABC
 
-from lilya.context import g
+from lilya.context import G, g_context
 from lilya.protocols.middleware import MiddlewareProtocol
 from lilya.types import ASGIApp, Receive, Scope, Send
 
@@ -47,7 +47,8 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         Returns:
             None
         """
+        token = g_context.set(G())
         try:
             await self.app(scope, receive, send)
         finally:
-            g.clear()
+            g_context.reset(token)

lilya/middleware/request_context.py

@@ -55,7 +55,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
             return
 
         global_request = Request(scope, receive)
-        token = RequestContext._request_context.set(global_request)
+        token = RequestContext.set_request(global_request)
         try:
             await self.app(scope, receive, send)
         finally:

tests/test_global_context.py

@@ -1,6 +1,8 @@
 import functools
 
-from lilya.context import g
+import pytest
+
+from lilya.context import g, get_g as lilya_get_g
 from lilya.routing import Path
 from lilya.testclient import create_client
 
@@ -14,14 +16,23 @@ async def show_g() -> dict[str, str]:
     return g.store
 
 
-def test_global_context():
+async def activate_g() -> dict[str, str]:
     activate_stuff()
+    return await show_g()
 
-    with create_client(routes=[Path("/show", show_g)]) as client:
-        response = client.get("/show")
+
+def test_global_context():
+    with pytest.raises(LookupError):
+        lilya_get_g()
+    with create_client(routes=[Path("/activate", activate_g), Path("/show", show_g)]) as client:
+        response = client.get("/activate")
         assert response.status_code == 200
         assert response.json() == {"name": "Lilya", "age": 25}
 
+        response = client.get("/show")
+        assert response.status_code == 200
+        assert response.json() == {}
+
 
 def test_empty_global_context():
     with create_client(routes=[Path("/show", show_g)]) as client: