Ensure case contact form selects klanten backend from API group

src/open_inwoner/cms/cases/tests/test_contactform.py

@@ -31,7 +31,11 @@
 from open_inwoner.openklant.tests.data import CONTACTMOMENTEN_ROOT, KLANTEN_ROOT
 from open_inwoner.openklant.tests.factories import OpenKlant2ConfigFactory
 from open_inwoner.openklant.tests.mocks import MockOpenKlant2Service
-from open_inwoner.openzaak.models import CatalogusConfig, OpenZaakConfig
+from open_inwoner.openzaak.models import (
+    CatalogusConfig,
+    OpenZaakConfig,
+    ZGWApiGroupConfig,
+)
 from open_inwoner.openzaak.tests.factories import (
     ServiceFactory,
     ZaakTypeConfigFactory,
@@ -530,6 +534,12 @@ def test_form_success_with_api_esuite(
         self._setUpOpenKlantMocks(m)
 
         response = self.app.get(self.case_detail_url, user=self.user)
+
+        # Set the primary to the opposite API, to ensure we pick the connected
+        # backend from the ZGWApiGroup
+        self.klant_config.primary_backend = KlantenServiceType.OPENKLANT2.value
+        self.klant_config.save()
+
         form = response.forms["contact-form"]
         form.action = reverse(
             "cases:case_detail_contact_form",
@@ -595,7 +605,9 @@ def test_form_success_with_api_openklant(
             subject="oip_subject",
         )
 
-        self.klant_config.primary_backend = KlantenServiceType.OPENKLANT2.value
+        # Set the primary to the opposite API, to ensure we pick the connected
+        # backend from the ZGWApiGroup
+        self.klant_config.primary_backend = KlantenServiceType.ESUITE.value
         self.klant_config.save()
 
         response = self.app.get(self.case_detail_url, user=self.user)
@@ -886,3 +898,23 @@ def test_send_email_confirmation_is_configurable__send_disabled(
         form["question"] = "Sample text"
         response = form.submit()
         mock_send_confirm.assert_not_called()
+
+    def test_non_existent_zgw_api_group_passed(
+        self, m, mock_contactmoment, mock_send_confirm
+    ):
+        self._setUpMocks(m)
+        self._setUpExtraMocks(m)
+        self._setUpOpenKlantMocks(m)
+
+        response = self.app.get(self.case_detail_url, user=self.user)
+        form = response.forms["contact-form"]
+
+        self.assertFalse(ZGWApiGroupConfig.objects.filter(id=8888).exists())
+
+        form.action = reverse(
+            "cases:case_detail_contact_form",
+            kwargs={"object_id": self.zaak["uuid"], "api_group_id": 8888},
+        )
+        response = form.submit()
+
+        self.assertEqual(response.status_code, 404)

src/open_inwoner/cms/cases/views/status.py

@@ -914,6 +914,12 @@ class CaseContactFormView(CaseAccessMixin, LogMixin, FormView):
     form_class = CaseContactForm
 
     def post(self, request, *args, **kwargs):
+        try:
+            api_group = ZGWApiGroupConfig.objects.get(pk=self.kwargs["api_group_id"])
+        except ZGWApiGroupConfig.DoesNotExist as exc:
+            logger.exception("Non-existent ZGWApiGroupConfig passed")
+            raise Http404 from exc
+
         form = self.get_form()
 
         if form.is_valid():
@@ -933,7 +939,7 @@ def post(self, request, *args, **kwargs):
                 send_confirmation = email_success
 
             if klant_config.register_contact_via_api:
-                api_success = self.register_by_api(form, config=klant_config)
+                api_success = self.register_by_api(form, api_group)
                 if api_success:
                     send_confirmation = klant_config.send_email_confirmation
                 # else keep the send_confirmation if email set it
@@ -1000,10 +1006,23 @@ def register_by_email(self, form, recipient_email):
             )
             return False
 
-    def register_by_api(self, form, config: KlantenSysteemConfig):
-        if config.primary_backend == KlantenServiceType.ESUITE.value:
-            return self._register_via_esuite(form, config=ESuiteKlantConfig.get_solo())
-        return self._register_via_openklant(form, config=OpenKlant2Config.get_solo())
+    def register_by_api(self, form, api_group: ZGWApiGroupConfig):
+        if not api_group.klant_backend:
+            return
+
+        match api_group.klant_backend:
+            case KlantenServiceType.ESUITE.value:
+                return self._register_via_esuite(
+                    form, config=ESuiteKlantConfig.get_solo()
+                )
+            case KlantenServiceType.OPENKLANT2.value:
+                return self._register_via_openklant(
+                    form, config=OpenKlant2Config.get_solo()
+                )
+            case _:
+                logger.error(
+                    "Got non-existent klanten backend %s", api_group.klant_backend
+                )
 
     def _register_via_openklant(self, form, config: OpenKlant2Config) -> bool:
         user = self.request.user