Support AIOHTTPClient init without running event loop (#1271)

OldSneerJaw · web-flow · commit c71b88d42a46 · 2024-03-20T12:46:15.000-07:00
* Support AIOHTTPClient init without running event loop

Lazily instantiates and caches an aiohttp `ClientSession` at the points that it is actually used so that `AIOHTTPClient` can be initialized without a running event loop (e.g. when setting `stripe.default_http_client = stripe.AIOHTTPClient()` at the top level of a module).

* Format

* Assert aiohttp module is present in AIOHTTPClient

Fixes a type checking error by having `AIOHTTPClient`'s `_session` property assert that the `aiohttp` module exists

* Remove dependence on cached_property

The `functools.cached_property` decorator did not exist in Python 3.7, so `AIOHTTPClient`'s `_session` has been changed into a regular property that performs caching manually by storing the `ClientSession` object as a member of the instance.

* Define aiohttp cached session attribute in init

Ensures `AIOHTTPClient`'s `_cached_session` attribute is defined in the initializer.
diff --git a/stripe/_http_client.py b/stripe/_http_client.py
@@ -1394,17 +1394,26 @@ def __init__(
                 "Unexpected: tried to initialize AIOHTTPClient but the aiohttp module is not present."
             )
 
-        kwargs = {}
-        if self._verify_ssl_certs:
-            ssl_context = ssl.create_default_context(
-                cafile=stripe.ca_bundle_path
-            )
-            kwargs["connector"] = aiohttp.TCPConnector(ssl=ssl_context)
-        else:
-            kwargs["connector"] = aiohttp.TCPConnector(verify_ssl=False)
-
-        self._session = aiohttp.ClientSession(**kwargs)
         self._timeout = timeout
+        self._cached_session = None
+
+    @property
+    def _session(self):
+        assert aiohttp is not None
+
+        if self._cached_session is None:
+            kwargs = {}
+            if self._verify_ssl_certs:
+                ssl_context = ssl.create_default_context(
+                    cafile=stripe.ca_bundle_path
+                )
+                kwargs["connector"] = aiohttp.TCPConnector(ssl=ssl_context)
+            else:
+                kwargs["connector"] = aiohttp.TCPConnector(verify_ssl=False)
+
+            self._cached_session = aiohttp.ClientSession(**kwargs)
+
+        return self._cached_session
 
     def sleep_async(self, secs):
         return asyncio.sleep(secs)
diff --git a/tests/test_http_client.py b/tests/test_http_client.py
@@ -70,16 +70,7 @@ def check_default(self, none_libs, expected):
     def test_new_http_client_async_fallback_httpx(self, request_mocks):
         self.check_default((), _http_client.HTTPXClient)
 
-    # Using the AIOHTTPClient constructor will complain if there's
-    # no active asyncio event loop. This test can pass in isolation
-    # but if it runs after another asyncio-enabled test that closes
-    # the asyncio event loop it will fail unless it is declared to
-    # use the asyncio backend.
-    @pytest.mark.anyio
-    @pytest.mark.parametrize("anyio_backend", ["asyncio"])
-    async def test_new_http_client_async_fallback_aiohttp(
-        self, request_mocks, anyio_backend
-    ):
+    def test_new_http_client_async_fallback_aiohttp(self, request_mocks):
         self.check_default(
             (("httpx"),),
             _http_client.AIOHTTPClient,
