Switch event hooks to also run on redirects. (#1806)

* Switch event hooks to also run on redirects

* Bump coverage

* Add pragma: no cover, because sometime ya just gotta be pragmatic

* Update docs with note about response.read()

Author: tomchristie

docs/advanced.md

@@ -255,12 +255,19 @@ def raise_on_4xx_5xx(response):
 client = httpx.Client(event_hooks={'response': [raise_on_4xx_5xx]})
 ```
 
+!!! note
+    Response event hooks are called before determining if the response body
+    should be read or not.
+
+    If you need access to the response body inside an event hook, you'll
+    need to call `response.read()`.
+
 The hooks are also allowed to modify `request` and `response` objects.
 
 ```python
 def add_timestamp(request):
     request.headers['x-request-timestamp'] = datetime.now(tz=datetime.utc).isoformat()
-    
+
 client = httpx.Client(event_hooks={'request': [add_timestamp]})
 ```
 

httpx/_client.py

@@ -886,9 +886,6 @@ def send(
             if not stream:
                 response.read()
 
-            for hook in self._event_hooks["response"]:
-                hook(response)
-
             return response
 
         except Exception as exc:
@@ -907,9 +904,6 @@ def _send_handling_auth(
         try:
             request = next(auth_flow)
 
-            for hook in self._event_hooks["request"]:
-                hook(request)
-
             while True:
                 response = self._send_handling_redirects(
                     request,
@@ -947,8 +941,13 @@ def _send_handling_redirects(
                     "Exceeded maximum allowed redirects.", request=request
                 )
 
+            for hook in self._event_hooks["request"]:
+                hook(request)
+
             response = self._send_single_request(request, timeout)
             try:
+                for hook in self._event_hooks["response"]:
+                    hook(response)
                 response.history = list(history)
 
                 if not response.is_redirect:
@@ -1595,12 +1594,9 @@ async def send(
             if not stream:
                 await response.aread()
 
-            for hook in self._event_hooks["response"]:
-                await hook(response)
-
             return response
 
-        except Exception as exc:
+        except Exception as exc:  # pragma: no cover
             await response.aclose()
             raise exc
 
@@ -1616,9 +1612,6 @@ async def _send_handling_auth(
         try:
             request = await auth_flow.__anext__()
 
-            for hook in self._event_hooks["request"]:
-                await hook(request)
-
             while True:
                 response = await self._send_handling_redirects(
                     request,
@@ -1656,8 +1649,14 @@ async def _send_handling_redirects(
                     "Exceeded maximum allowed redirects.", request=request
                 )
 
+            for hook in self._event_hooks["request"]:
+                await hook(request)
+
             response = await self._send_single_request(request, timeout)
             try:
+                for hook in self._event_hooks["response"]:
+                    await hook(response)
+
                 response.history = list(history)
 
                 if not response.is_redirect:

tests/client/test_event_hooks.py

@@ -117,7 +117,7 @@ async def raise_on_4xx_5xx(response):
 
 def test_event_hooks_with_redirect():
     """
-    A redirect request should not trigger a second 'request' event hook.
+    A redirect request should trigger additional 'request' and 'response' event hooks.
     """
 
     events = []
@@ -136,6 +136,21 @@ def on_response(response):
         http.get("http://127.0.0.1:8000/redirect", auth=("username", "password"))
 
     assert events == [
+        {
+            "event": "request",
+            "headers": {
+                "host": "127.0.0.1:8000",
+                "user-agent": f"python-httpx/{httpx.__version__}",
+                "accept": "*/*",
+                "accept-encoding": "gzip, deflate, br",
+                "connection": "keep-alive",
+                "authorization": "Basic dXNlcm5hbWU6cGFzc3dvcmQ=",
+            },
+        },
+        {
+            "event": "response",
+            "headers": {"location": "/", "server": "testserver"},
+        },
         {
             "event": "request",
             "headers": {
@@ -157,7 +172,7 @@ def on_response(response):
 @pytest.mark.usefixtures("async_environment")
 async def test_async_event_hooks_with_redirect():
     """
-    A redirect request should not trigger a second 'request' event hook.
+    A redirect request should trigger additional 'request' and 'response' event hooks.
     """
 
     events = []
@@ -176,6 +191,21 @@ async def on_response(response):
         await http.get("http://127.0.0.1:8000/redirect", auth=("username", "password"))
 
     assert events == [
+        {
+            "event": "request",
+            "headers": {
+                "host": "127.0.0.1:8000",
+                "user-agent": f"python-httpx/{httpx.__version__}",
+                "accept": "*/*",
+                "accept-encoding": "gzip, deflate, br",
+                "connection": "keep-alive",
+                "authorization": "Basic dXNlcm5hbWU6cGFzc3dvcmQ=",
+            },
+        },
+        {
+            "event": "response",
+            "headers": {"location": "/", "server": "testserver"},
+        },
         {
             "event": "request",
             "headers": {