Enhance RedirectsPanel with customizable redirect response hook (#2104)

* Add interception_response hook
* Fix comments for SimpleTemplateResponse
* Docs for Custom RedirectPanel
* Moved the changelog entry to the correct place.

Author: blingblin-g

Diff for: debug_toolbar/panels/redirects.py

@@ -22,20 +22,8 @@ def _process_response(self, response):
         Common response processing logic.
         """
         if 300 <= response.status_code < 400:
-            redirect_to = response.get("Location")
-            if redirect_to:
-                status_line = f"{response.status_code} {response.reason_phrase}"
-                cookies = response.cookies
-                context = {
-                    "redirect_to": redirect_to,
-                    "status_line": status_line,
-                    "toolbar": self.toolbar,
-                }
-                # Using SimpleTemplateResponse avoids running global context processors.
-                response = SimpleTemplateResponse(
-                    "debug_toolbar/redirect.html", context
-                )
-                response.cookies = cookies
+            if redirect_to := response.get("Location"):
+                response = self.get_interception_response(response, redirect_to)
                 response.render()
         return response
 
@@ -53,3 +41,22 @@ def process_request(self, request):
         if iscoroutine(response):
             return self.aprocess_request(request, response)
         return self._process_response(response)
+
+    def get_interception_response(self, response, redirect_to):
+        """
+        Hook method to allow subclasses to customize the interception response.
+        """
+        status_line = f"{response.status_code} {response.reason_phrase}"
+        cookies = response.cookies
+        original_response = response
+        context = {
+            "redirect_to": redirect_to,
+            "status_line": status_line,
+            "toolbar": self.toolbar,
+            "original_response": original_response,
+        }
+        # Using SimpleTemplateResponse avoids running global context processors.
+        response = SimpleTemplateResponse("debug_toolbar/redirect.html", context)
+        response.cookies = cookies
+        response.original_response = original_response
+        return response

Diff for: docs/changes.rst

@@ -4,6 +4,8 @@ Change log
 Pending
 -------
 
+* Added hook to RedirectsPanel for subclass customization.
+
 5.1.0 (2025-03-20)
 ------------------
 * Added Django 5.2 to the tox matrix.

Diff for: docs/panels.rst

@@ -122,6 +122,11 @@ Since this behavior is annoying when you aren't debugging a redirect, this
 panel is included but inactive by default. You can activate it by default with
 the ``DISABLE_PANELS`` configuration option.
 
+To further customize the behavior, you can subclass the ``RedirectsPanel``
+and override the ``get_interception_response`` method to manipulate the
+response directly. To use a custom ``RedirectsPanel``, you need to replace
+the original one in ``DEBUG_TOOLBAR_PANELS`` in your ``settings.py``.
+
 .. _profiling-panel:
 
 Profiling

Diff for: tests/panels/test_redirects.py

@@ -85,3 +85,16 @@ async def get_response(request):
         response = await self.panel.process_request(self.request)
         self.assertIsInstance(response, HttpResponse)
         self.assertTrue(response is await_response)
+
+    def test_original_response_preserved(self):
+        redirect = HttpResponse(status=302)
+        redirect["Location"] = "http://somewhere/else/"
+        self._get_response = lambda request: redirect
+        response = self.panel.process_request(self.request)
+        self.assertFalse(response is redirect)
+        self.assertTrue(hasattr(response, "original_response"))
+        self.assertTrue(response.original_response is redirect)
+        self.assertIsNone(response.get("Location"))
+        self.assertEqual(
+            response.original_response.get("Location"), "http://somewhere/else/"
+        )