[#1830] Prevent deletion of last website

src/open_inwoner/configurations/admin.py

@@ -1,12 +1,17 @@
 from django import forms
 from django.contrib import admin, messages
+from django.contrib.admin.actions import delete_selected as default_delete_selected
 from django.contrib.flatpages.admin import FlatPageAdmin
 from django.contrib.flatpages.forms import FlatpageForm
 from django.contrib.flatpages.models import FlatPage
+from django.contrib.sites.admin import SiteAdmin
+from django.contrib.sites.models import Site
 from django.core import exceptions
 from django.core.validators import URLValidator
 from django.forms import ValidationError
-from django.urls import resolve
+from django.http import HttpResponseRedirect
+from django.shortcuts import redirect
+from django.urls import resolve, reverse
 from django.urls.exceptions import Resolver404
 from django.utils.html import format_html, format_html_join
 from django.utils.translation import ugettext_lazy as _
@@ -23,6 +28,44 @@
 from .models import SiteConfiguration, SiteConfigurationPage
 
 
+@admin.action(description=_("Delete selected websites"))
+def delete_selected(modeladmin, request, queryset):
+    """
+    Override `delete_selected` action to prevent accidental deletion of all websites
+    """
+    if queryset.count() == Site.objects.all().count():
+        messages.add_message(
+            request,
+            messages.WARNING,
+            _("You cannot delete all websites; at least one site must remain."),
+        )
+        return HttpResponseRedirect(reverse("admin:sites_site_changelist"))
+    return default_delete_selected(modeladmin, request, queryset)
+
+
+class CustomSiteAdmin(SiteAdmin):
+    """
+    Overrides `SiteAdmin` to prevent deletion of last website
+    """
+
+    model = Site
+    actions = [delete_selected]
+
+    def delete_model(self, request, obj):
+        if self.model.objects.count() < 2:
+            messages.add_message(
+                request, messages.WARNING, _("You cannot delete the last site.")
+            )
+            return redirect("admin:sites_site_changelist")
+        else:
+            super().delete_model(request, obj)
+
+
+# re-register `Site` with our CustomSiteAdmin
+admin.site.unregister(Site)
+admin.site.register(Site, CustomSiteAdmin)
+
+
 class SiteConfigurationPageInline(OrderedTabularInline):
     model = SiteConfigurationPage
     fields = (

src/open_inwoner/configurations/tests/test_admin.py

@@ -1,13 +1,107 @@
+from django.contrib.sites.models import Site
 from django.urls import reverse
 from django.utils.translation import ugettext_lazy as _
 
 from django_webtest import WebTest
+from pyquery import PyQuery
 
 from open_inwoner.accounts.tests.factories import UserFactory
 
 from ..models import SiteConfiguration
 
 
+class TestAdminSite(WebTest):
+    csrf_checks = False
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.user = UserFactory(is_superuser=True, is_staff=True)
+
+    def test_delete_site_success(self):
+        site2 = Site.objects.create(id=2, domain="example2.com", name="example2")
+
+        # delete site
+        response = self.app.get(
+            reverse("admin:sites_site_delete", kwargs={"object_id": site2.id}),
+            user=self.user,
+        )
+        response = response.form.submit().follow()
+
+        # check sites
+        sites = Site.objects.all()
+        self.assertEqual(len(sites), 1)
+
+        # check message
+        doc = PyQuery(response.content)
+
+        success_msg = doc.find(".success").text()
+        self.assertIn("met succes verwijderd.", success_msg)
+
+    def test_delete_last_site_fail(self):
+        # attempt to delete site
+        response = self.app.get(
+            reverse("admin:sites_site_delete", kwargs={"object_id": 1}), user=self.user
+        )
+        response = response.form.submit().follow()
+
+        # check sites
+        sites = Site.objects.all()
+        self.assertEqual(len(sites), 1)
+
+        # check message
+        doc = PyQuery(response.content)
+
+        warning_msg = doc.find(".warning").text()
+        self.assertEqual(warning_msg, "You cannot delete the last site.")
+
+    def test_bulk_delete_success(self):
+        site2 = Site.objects.create(id=2, domain="example2.com", name="example2")
+        site3 = Site.objects.create(id=3, domain="example3.com", name="example3")
+
+        # delete sites
+        data = {"action": "delete_selected", "_selected_action": [site2.pk, site3.pk]}
+        response = self.app.post(
+            reverse("admin:sites_site_changelist"), data, user=self.user
+        )
+        response = response.form.submit().follow()  # confirmation form
+
+        # check sites
+        sites = Site.objects.all()
+        self.assertEqual(len(sites), 1)
+
+        # check message
+        doc = PyQuery(response.content)
+
+        success_msg = doc.find(".success").text()
+        self.assertEqual(success_msg, "2 websites met succes verwijderd.")
+
+    def test_bulk_delete_fail(self):
+        Site.objects.create(id=2, domain="example2.com", name="example2")
+        Site.objects.create(id=3, domain="example3.com", name="example3")
+
+        # attempt to delete sites
+        data = {
+            "action": "delete_selected",
+            "_selected_action": [site.pk for site in Site.objects.all()],
+        }
+        response = self.app.post(
+            reverse("admin:sites_site_changelist"), data, user=self.user
+        ).follow()
+
+        # check sites
+        sites = Site.objects.all()
+        self.assertEqual(len(sites), 3)
+
+        # check message
+        doc = PyQuery(response.content)
+
+        warning_msg = doc.find(".warning").text()
+        self.assertEqual(
+            warning_msg,
+            "You cannot delete all websites; at least one site must remain.",
+        )
+
+
 class TestAdminForm(WebTest):
     def setUp(self):
         self.user = UserFactory(is_superuser=True, is_staff=True)