Prevent Client and AsyncClient from sending a request when it has bee…

…n closed (#871)

httpx/_client.py

@@ -56,6 +56,18 @@
 KEEPALIVE_EXPIRY = 5.0
 
 
+def check_not_closed(method: typing.Callable) -> typing.Callable:
+    @functools.wraps(method)
+    def wrapper(
+        self: "BaseClient", *args: typing.Any, **kwargs: typing.Any
+    ) -> typing.Any:
+        if self.is_closed:
+            raise RuntimeError(f"{self!r} is closed. We cannot use the closed client!")
+        return method(self, *args, **kwargs)
+
+    return wrapper
+
+
 class BaseClient:
     def __init__(
         self,
@@ -79,6 +91,14 @@ def __init__(
         self.max_redirects = max_redirects
         self._trust_env = trust_env
         self._netrc = NetRCInfo()
+        self._is_closed = False
+
+    @property
+    def is_closed(self) -> bool:
+        """
+        Check if the client being closed
+        """
+        return self._is_closed
 
     @property
     def trust_env(self) -> bool:
@@ -619,6 +639,7 @@ def _transport_for_url(self, url: URL) -> httpcore.SyncHTTPTransport:
 
         return self._transport
 
+    @check_not_closed
     def request(
         self,
         method: str,
@@ -1015,6 +1036,7 @@ def delete(
             timeout=timeout,
         )
 
+    @check_not_closed
     def close(self) -> None:
         """
         Close transport and proxies.
@@ -1024,6 +1046,8 @@ def close(self) -> None:
             if proxy is not None:
                 proxy.close()
 
+        self._is_closed = True
+
     def __enter__(self) -> "Client":
         return self
 
@@ -1220,6 +1244,7 @@ def _transport_for_url(self, url: URL) -> httpcore.AsyncHTTPTransport:
 
         return self._transport
 
+    @check_not_closed
     async def request(
         self,
         method: str,
@@ -1619,6 +1644,7 @@ async def delete(
             timeout=timeout,
         )
 
+    @check_not_closed
     async def aclose(self) -> None:
         """
         Close transport and proxies.
@@ -1628,6 +1654,8 @@ async def aclose(self) -> None:
             if proxy is not None:
                 await proxy.aclose()
 
+        self._is_closed = True
+
     async def __aenter__(self) -> "AsyncClient":
         return self
 

tests/client/test_async_client.py

@@ -166,3 +166,40 @@ async def test_100_continue(server):
 
     assert response.status_code == 200
     assert response.content == data
+
+
+@pytest.mark.usefixtures("async_environment")
+async def test_that_async_client_is_closed_after_with_block():
+    async with httpx.AsyncClient() as client:
+        pass
+
+    assert client.is_closed
+
+
+@pytest.mark.usefixtures("async_environment")
+async def test_that_async_client_is_closed_after_aclose():
+    client = httpx.AsyncClient()
+
+    await client.aclose()
+
+    assert client.is_closed
+
+
+@pytest.mark.usefixtures("async_environment")
+async def test_that_async_client_cannot_be_closed_after_being_closed():
+    client = httpx.AsyncClient()
+
+    await client.aclose()
+
+    with pytest.raises(RuntimeError):
+        await client.aclose()
+
+
+@pytest.mark.usefixtures("async_environment")
+async def test_that_async_client_cannot_send_request_after_being_closed():
+    client = httpx.AsyncClient()
+
+    await client.aclose()
+
+    with pytest.raises(RuntimeError):
+        await client.get("http://example.com")

tests/client/test_client.py

@@ -208,3 +208,36 @@ def test_pool_limits_deprecated():
 
     with pytest.warns(DeprecationWarning):
         httpx.AsyncClient(pool_limits=limits)
+
+
+def test_that_client_is_closed_after_with_block():
+    with httpx.Client() as client:
+        pass
+
+    assert client.is_closed
+
+
+def test_that_client_is_closed_after_close():
+    client = httpx.Client()
+
+    client.close()
+
+    assert client.is_closed
+
+
+def test_that_client_cannot_be_closed_after_being_closed():
+    client = httpx.Client()
+
+    client.close()
+
+    with pytest.raises(RuntimeError):
+        client.close()
+
+
+def test_that_client_cannot_send_request_after_being_closed():
+    client = httpx.Client()
+
+    client.close()
+
+    with pytest.raises(RuntimeError):
+        client.get("http://example.com")