Restore compatibility with iptools.IpRangeList (#1929)

Author: quinox

debug_toolbar/middleware.py

@@ -20,8 +20,14 @@ def show_toolbar(request):
     """
     Default function to determine whether to show the toolbar on a given page.
     """
-    internal_ips = list(settings.INTERNAL_IPS)
+    if not settings.DEBUG:
+        return False
 
+    # Test: settings
+    if request.META.get("REMOTE_ADDR") in settings.INTERNAL_IPS:
+        return True
+
+    # Test: Docker
     try:
         # This is a hack for docker installations. It attempts to look
         # up the IP address of the docker host.
@@ -31,11 +37,14 @@ def show_toolbar(request):
             ".".join(socket.gethostbyname("host.docker.internal").rsplit(".")[:-1])
             + ".1"
         )
-        internal_ips.append(docker_ip)
+        if request.META.get("REMOTE_ADDR") == docker_ip:
+            return True
     except socket.gaierror:
         # It's fine if the lookup errored since they may not be using docker
         pass
-    return settings.DEBUG and request.META.get("REMOTE_ADDR") in internal_ips
+
+    # No test passed
+    return False
 
 
 @lru_cache(maxsize=None)

tests/test_integration.py

@@ -75,6 +75,28 @@ def test_show_toolbar_docker(self, mocked_gethostbyname):
             self.assertTrue(show_toolbar(self.request))
         mocked_gethostbyname.assert_called_once_with("host.docker.internal")
 
+    def test_not_iterating_over_INTERNAL_IPS(self):
+        """Verify that the middleware does not iterate over INTERNAL_IPS in some way.
+
+        Some people use iptools.IpRangeList for their INTERNAL_IPS. This is a class
+        that can quickly answer the question if the setting contain a certain IP address,
+        but iterating over this object will drain all performance / blow up.
+        """
+
+        class FailOnIteration:
+            def __iter__(self):
+                raise RuntimeError(
+                    "The testcase failed: the code should not have iterated over INTERNAL_IPS"
+                )
+
+            def __contains__(self, x):
+                return True
+
+        with self.settings(INTERNAL_IPS=FailOnIteration()):
+            response = self.client.get("/regular/basic/")
+            self.assertEqual(response.status_code, 200)
+            self.assertContains(response, "djDebug")  # toolbar
+
     def test_should_render_panels_RENDER_PANELS(self):
         """
         The toolbar should force rendering panels on each request