support: Return json error if the POST request is invalid.

analytics/tests/test_views.py

@@ -698,8 +698,8 @@ class TestSupportEndpoint(ZulipTestCase):
             self.assert_in_success_response(["Lear & Co. scrubbed"], result)
 
         with mock.patch("analytics.views.do_scrub_realm") as m:
-            with self.assertRaises(AssertionError):
-                result = self.client_post("/activity/support", {"realm_id": f"{lear_realm.id}"})
+            result = self.client_post("/activity/support", {"realm_id": f"{lear_realm.id}"})
+            self.assert_json_error(result, "Invalid parameters")
             m.assert_not_called()
 
 class TestGetChartDataHelpers(ZulipTestCase):

analytics/views.py

@@ -53,7 +53,7 @@ from zerver.lib.actions import (
 from zerver.lib.exceptions import JsonableError
 from zerver.lib.realm_icon import realm_icon_url
 from zerver.lib.request import REQ, has_request_variables
-from zerver.lib.response import json_success
+from zerver.lib.response import json_error, json_success
 from zerver.lib.subdomains import get_subdomain_from_hostname
 from zerver.lib.timestamp import convert_to_UTC, timestamp_to_datetime
 from zerver.lib.validator import to_non_negative_int
@@ -1125,7 +1125,8 @@ def support(request: HttpRequest) -> HttpResponse:
         keys = set(request.POST.keys())
         if "csrfmiddlewaretoken" in keys:
             keys.remove("csrfmiddlewaretoken")
-        assert(len(keys) == 2)
+        if len(keys) != 2:
+            return json_error(_("Invalid parameters"))
 
         realm_id = request.POST.get("realm_id")
         realm = Realm.objects.get(id=realm_id)