allow deleting of Food part of Ingredient, but not recipe

cookbook/models.py

@@ -12,7 +12,7 @@ from django.contrib.postgres.search import SearchVectorField
 from django.core.files.uploadedfile import UploadedFile, InMemoryUploadedFile
 from django.core.validators import MinLengthValidator
 from django.db import models
-from django.db.models import Index
+from django.db.models import Index, ProtectedError
 from django.utils import timezone
 from django.utils.translation import gettext as _
 from treebeard.mp_tree import MP_Node, MP_NodeManager
@@ -385,6 +385,12 @@ class Food(ExportModelOperationsMixin('food'), TreeModel, PermissionModelMixin):
     def __str__(self):
         return self.name
 
+    def delete(self):
+        if len(self.ingredient_set.all().exclude(step=None)) > 0:
+            raise ProtectedError(self.name + _(" is part of a recipe step and cannot be deleted"), self.ingredient_set.all().exclude(step=None))
+        else:
+            return super().delete()
+
     class Meta:
         constraints = [
             models.UniqueConstraint(fields=['space', 'name'], name='f_unique_name_per_space')
@@ -393,7 +399,8 @@ class Food(ExportModelOperationsMixin('food'), TreeModel, PermissionModelMixin):
 
 
 class Ingredient(ExportModelOperationsMixin('ingredient'), models.Model, PermissionModelMixin):
-    food = models.ForeignKey(Food, on_delete=models.PROTECT, null=True, blank=True)
+    # a pre-delete signal on Food checks if the Ingredient is part of a Step, if it is raises a ProtectedError instead of cascading the delete
+    food = models.ForeignKey(Food, on_delete=models.CASCADE, null=True, blank=True)
     unit = models.ForeignKey(Unit, on_delete=models.PROTECT, null=True, blank=True)
     amount = models.DecimalField(default=0, decimal_places=16, max_digits=32)
     note = models.CharField(max_length=256, null=True, blank=True)

cookbook/tests/api/test_api_food.py

@@ -243,6 +243,42 @@ def test_delete(u1_s1, u1_s2, obj_1, obj_1_1, obj_1_1_1):
         assert Food.find_problems() == ([], [], [], [], [])
 
 
+def test_integrity(u1_s1, recipe_1_s1):
+    with scopes_disabled():
+        assert Food.objects.count() == 10
+        assert Ingredient.objects.count() == 10
+        f_1 = Food.objects.first()
+
+    # deleting food will fail because food is part of recipe
+    r = u1_s1.delete(
+        reverse(
+            DETAIL_URL,
+            args={f_1.id}
+        )
+    )
+    assert r.status_code == 403
+
+    with scopes_disabled():
+        i_1 = f_1.ingredient_set.first()
+        # remove Ingredient that references Food from recipe step
+        i_1.step_set.first().ingredients.remove(i_1)
+        assert Food.objects.count() == 10
+        assert Ingredient.objects.count() == 10
+    
+    # deleting food will succeed because its not part of recipe and delete will cascade to Ingredient
+    r = u1_s1.delete(
+        reverse(
+            DETAIL_URL,
+            args={f_1.id}
+        )
+    )
+    assert r.status_code == 204
+    
+    with scopes_disabled():
+        assert Food.objects.count() == 9
+        assert Ingredient.objects.count() == 9
+
+
 def test_move(u1_s1, obj_1, obj_1_1, obj_1_1_1, obj_2, obj_3, space_1):
     url = reverse(MOVE_URL, args=[obj_1_1.id, obj_2.id])
     with scopes_disabled():

cookbook/views/api.py

@@ -12,7 +12,7 @@ from django.contrib.auth.models import User
 from django.contrib.postgres.search import TrigramSimilarity
 from django.core.exceptions import FieldError, ValidationError
 from django.core.files import File
-from django.db.models import Case, Q, Value, When
+from django.db.models import Case, ProtectedError, Q, Value, When
 from django.db.models.fields.related import ForeignObjectRel
 from django.http import FileResponse, HttpResponse, JsonResponse
 from django_scopes import scopes_disabled
@@ -380,6 +380,13 @@ class FoodViewSet(viewsets.ModelViewSet, TreeMixin):
     permission_classes = [CustomIsUser]
     pagination_class = DefaultPagination
 
+    def destroy(self, *args, **kwargs):
+        try:
+            return (super().destroy(self, *args, **kwargs))
+        except ProtectedError as e:
+            content = {'error': True, 'msg': e.args[0]}
+            return Response(content, status=status.HTTP_403_FORBIDDEN)
+
 
 class RecipeBookViewSet(viewsets.ModelViewSet, StandardFilterMixin):
     queryset = RecipeBook.objects

docs/index.md

@@ -16,6 +16,7 @@
 ## Coming Next
 - Heirarchical Ingredients
 - Faceted Search
+- Search filter by rating
 - What Can I Make Now?
 - Better ingredient/unit matching on import
 - Custom word replacement on import (e.g. 'grams' automatically imported as 'g')