Impersonate through a middleware. refs: #12

backend/models.py

@@ -49,6 +49,7 @@ class PersonManager(BaseUserManager):
 
     def create_superuser(self, email, **other_fields):
         other_fields["is_superuser"] = True
+        other_fields["is_staff"] = True
         return self.create_user(email, **other_fields)
 
     def get_or_none(self, *args, **kw):

backend/unittest.py

@@ -103,7 +103,8 @@ class TestBase(nm2.lib.unittest.TestBase):
             else:
                 raise NotImplementedError(f"{identity.issuer} not supported as identity during testing")
 
-        person = self.persons[person]
+        if isinstance(person, str):
+            person = self.persons[person]
         if person is not None:
             client.force_login(person, backend=self.TEST_AUTH_BACKEND)
         client.visitor = person
@@ -128,7 +129,8 @@ class TestBase(nm2.lib.unittest.TestBase):
             else:
                 raise NotImplementedError(f"{identity.issuer} not supported as identity during testing")
 
-        person = self.persons[person]
+        if isinstance(person, str):
+            person = self.persons[person]
         if person is not None:
             client.force_login(person, backend=self.TEST_AUTH_BACKEND)
         client.visitor = person

impersonate/middleware.py

+from __future__ import annotations
+from django.core.exceptions import ImproperlyConfigured
+from django.contrib.auth import get_user_model
+
+
+class ImpersonateMiddleware:
+    def __init__(self, get_response):
+        self.get_response = get_response
+        self.User = get_user_model()
+
+    def __call__(self, request):
+        # AuthenticationMiddleware is required so that request.user exists.
+        if not hasattr(request, 'user'):
+            raise ImproperlyConfigured(
+                "The impersonator middleware requires the authentication middleware"
+                " to be installed.  Edit your MIDDLEWARE setting to insert"
+                " 'django.contrib.auth.middleware.AuthenticationMiddleware'"
+                " before the ImpersonateMiddleware class.")
+
+        if request.user.is_authenticated:
+            # Implement impersonation if requested in session
+            if request.user.is_staff:
+                pk = request.session.get("impersonate", None)
+                if pk is not None:
+                    try:
+                        user = self.User.objects.get(pk=pk)
+                    except self.User.DoesNotExist:
+                        user = None
+
+                    if user is not None:
+                        request.impersonator = request.user
+                        request.user = user
+
+        return self.get_response(request)

impersonate/tests.py

 from __future__ import annotations
 from django.test import TestCase
 from django.urls import reverse
-from backend.unittest import PersonFixtureMixin
+from backend.unittest import TestBase
+from django.contrib.auth import get_user_model
 
 
-class TestPermissions(PersonFixtureMixin, TestCase):
-    @classmethod
-    def __add_extra_tests__(cls):
-        non_fd = ["pending", "dc", "dc_ga", "dm", "dm_ga", "dd_nu", "dd_u", "dd_e", "dd_r", "activeam", "oldam"]
-        fd = ["fd", "dam"]
-
-        for visitor in [None] + non_fd:
-            for visited in non_fd + fd:
-                cls._add_method(cls._test_impersonate_fail, visitor, visited)
+class TestPermissions(TestBase, TestCase):
+    def test_impersonate_staff(self):
+        User = get_user_model()
+        visitor = User.objects.create_superuser(email="admin@example.org", fullname="Admin", audit_skip=True)
+        visited = User.objects.create_user(email="user@example.org", fullname="User", audit_skip=True)
+        client = self.make_test_client(visitor)
 
-        for visitor in fd:
-            for visited in non_fd + fd:
-                cls._add_method(cls._test_impersonate_success, visitor, visited)
+        response = client.get(reverse("impersonate:whoami"))
+        self.assertJSONEqual(response.content, {
+            'impersonator': None,
+            'impersonator_desc': None,
+            'user': visitor.pk,
+            'user_desc': str(visitor),
+        })
 
-    def _test_impersonate_success(self, visitor, visited):
-        client = self.make_test_client(visitor)
-        response = client.post(reverse("impersonate"), data={"pk": self.persons[visited].pk, "next": "/"})
+        response = client.post(reverse("impersonate:impersonate"), data={"pk": visited.pk, "next": "/"})
         self.assertRedirectMatches(response, "^/$")
 
-    def _test_impersonate_fail(self, visitor, visited):
+        response = client.get(reverse("impersonate:whoami"))
+        self.assertJSONEqual(response.content, {
+            'impersonator': visitor.pk,
+            'impersonator_desc': str(visitor),
+            'user': visited.pk,
+            'user_desc': str(visited),
+        })
+
+    def test_impersonate_user(self):
+        User = get_user_model()
+        visitor = User.objects.create_user(email="user@example.org", fullname="User", audit_skip=True)
+        visited = User.objects.create_user(email="user1@example.org", fullname="User1", audit_skip=True)
         client = self.make_test_client(visitor)
-        response = client.post(reverse("impersonate"), data={"pk": self.persons[visited].pk})
+        response = client.post(reverse("impersonate:impersonate"), data={"pk": visited.pk})
         self.assertPermissionDenied(response)
+
+        response = client.get(reverse("impersonate:whoami"))
+        self.assertJSONEqual(response.content, {
+            'impersonator': None,
+            'impersonator_desc': None,
+            'user': visitor.pk,
+            'user_desc': str(visitor),
+        })
+
+    def test_impersonate_anonymous(self):
+        User = get_user_model()
+        visited = User.objects.create_user(email="user@example.org", fullname="User", audit_skip=True)
+        client = self.make_test_client(None)
+        response = client.post(reverse("impersonate:impersonate"), data={"pk": visited.pk})
+        self.assertPermissionDenied(response)
+
+        response = client.get(reverse("impersonate:whoami"))
+        self.assertJSONEqual(response.content, {
+            'impersonator': None,
+            'impersonator_desc': None,
+            'user': None,
+            'user_desc': "AnonymousUser",
+        })

impersonate/urls.py

@@ -6,4 +6,5 @@ app_name = "impersonate"
 urlpatterns = [
     # Impersonate a user
     path('impersonate/', views.Impersonate.as_view(), name="impersonate"),
+    path('whoami/', views.Whoami.as_view(), name="whoami"),
 ]

impersonate/views.py

@@ -5,6 +5,7 @@ from django.shortcuts import redirect
 from django.core.exceptions import PermissionDenied
 from django.contrib import messages
 from django.contrib.auth import get_user_model
+from django import http
 
 
 class Impersonate(View):
@@ -13,7 +14,7 @@ class Impersonate(View):
         effective_user = getattr(request, "impersonator", None)
         if effective_user is None:
             effective_user = request.user
-        if not effective_user.is_authenticated or not effective_user.is_admin:
+        if not effective_user.is_authenticated or not effective_user.is_staff:
             raise PermissionDenied
         pk = request.POST.get("pk")
         if pk is None:
@@ -33,3 +34,14 @@ class Impersonate(View):
             return redirect(user.get_absolute_url())
         else:
             return redirect(url)
+
+
+class Whoami(View):
+    def get(self, request, *args, **kw):
+        impersonator = getattr(request, "impersonator", None)
+        return http.JsonResponse({
+            "user": request.user.pk,
+            "user_desc": str(request.user),
+            "impersonator": None if impersonator is None else impersonator.pk,
+            "impersonator_desc": None if impersonator is None else str(impersonator),
+        })

nm2/settings.py

@@ -88,6 +88,7 @@ MIDDLEWARE = [
     'signon.middleware.SignonMiddleware',
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
+    'impersonate.middleware.ImpersonateMiddleware',
 ]
 
 AUTHENTICATION_BACKENDS = [