implement ordering

Author: ozer550

morango/models/core.py

@@ -781,6 +781,7 @@ class SyncableModel(UUIDModelMixin):
 
     _morango_internal_fields_not_to_serialize = ("_morango_dirty_bit",)
     morango_model_dependencies = ()
+    morango_ordering = ()
     morango_fields_not_to_serialize = ()
     morango_profile = None
 

morango/registry.py

@@ -8,7 +8,7 @@
 from collections import OrderedDict
 from typing import Generator
 
-from django.db.models import QuerySet
+from django.db.models import F, QuerySet
 from django.db.models.fields.related import ForeignKey
 
 from morango.constants import transfer_stages
@@ -85,7 +85,26 @@ def get_model_querysets(self, profile) -> Generator[QuerySet, None, None]:
         (particularly, an order) that is aware of FK dependencies.
         """
         for model in self.get_models(profile):
-            yield model.syncing_objects.all()
+            queryset = model.syncing_objects.all()
+            ordering = getattr(model, "morango_ordering", ())
+            if ordering:
+                queryset = queryset.order_by(*self._get_nulls_last_ordering(ordering))
+            yield queryset
+
+    @staticmethod
+    def _get_nulls_last_ordering(ordering):
+        normalized = []
+        for order_expr in ordering:
+            if isinstance(order_expr, str):
+                descending = order_expr.startswith("-")
+                field_name = order_expr[1:] if descending else order_expr
+                if descending:
+                    normalized.append(F(field_name).desc(nulls_last=True))
+                else:
+                    normalized.append(F(field_name).asc(nulls_last=True))
+            else:
+                normalized.append(order_expr)
+        return normalized
 
     def _insert_model_in_dependency_order(self, model, profile):
         # When we add models to be synced, we need to make sure

tests/testapp/tests/integration/test_syncing_models.py

@@ -1,11 +1,12 @@
 import json
 
 from django.test import TestCase
-from facility_profile.models import MyUser, TestModel
+from facility_profile.models import Facility, MyUser, TestModel
 
 from morango.models.core import Store
 from morango.models.manager import SyncableModelManager
 from morango.models.query import SyncableModelQuerySet
+from morango.registry import syncable_models
 from morango.sync.controller import MorangoProfileController
 
 
@@ -140,3 +141,40 @@ def test_hidden_models_deletion_during_deserialization(self):
 
         # The store record should still exist but marked as deleted
         self.assertTrue(Store.objects.filter(id=hidden_obj.id, deleted=True).exists())
+
+    def test_get_model_querysets_applies_morango_ordering(self):
+        old_ordering = Facility.morango_ordering
+        Facility.morango_ordering = ("-name",)
+        try:
+            Facility.objects.create(name="a-facility")
+            Facility.objects.create(name="z-facility")
+            queryset = next(
+                qs
+                for qs in syncable_models.get_model_querysets(Facility.morango_profile)
+                if qs.model is Facility
+            )
+            self.assertEqual(
+                list(queryset.values_list("name", flat=True)),
+                ["z-facility", "a-facility"],
+            )
+        finally:
+            Facility.morango_ordering = old_ordering
+
+    def test_get_model_querysets_uses_nulls_last_for_string_ordering(self):
+        old_ordering = Facility.morango_ordering
+        Facility.morango_ordering = ("parent_id", "name")
+        try:
+            root_b = Facility.objects.create(name="root-b", parent=None)
+            root_a = Facility.objects.create(name="root-a", parent=None)
+            child = Facility.objects.create(name="child", parent=root_a)
+            queryset = next(
+                qs
+                for qs in syncable_models.get_model_querysets(Facility.morango_profile)
+                if qs.model is Facility
+            )
+            self.assertEqual(
+                list(queryset.values_list("id", flat=True)),
+                [child.id, root_a.id, root_b.id],
+            )
+        finally:
+            Facility.morango_ordering = old_ordering