Allow models.PROTECT in the models

bootstrap_modal_forms/mixins.py

@@ -1,7 +1,7 @@
 from django.contrib import messages
 from django.contrib.auth import login as auth_login
 from django.http import HttpResponseRedirect
-
+from django.db.models import ProtectedError
 
 class PassRequestMixin(object):
     """
@@ -48,11 +48,18 @@ def save(self, commit=True):
 class DeleteMessageMixin(object):
     """
     Mixin which adds message to BSModalDeleteView.
+    Catch exceptions fired up by "on_delete=models.PROTECT" in the model fields.
     """
 
     def post(self, request, *args, **kwargs):
-        messages.success(request, self.success_message)
-        return super(DeleteMessageMixin, self).delete(request, *args, **kwargs)
+        try:
+            httpResponse = super(DeleteMessageMixin, self).delete(request, *args, **kwargs)
+            messages.success(request, self.success_message)
+            return httpResponse
+        except ProtectedError:
+            messages.error(request, "Can not remove this item, has a relation in the database.")
+            return HttpResponseRedirect(self.success_url)
+
 
 
 class LoginAjaxMixin(object):

examples/migrations/0001_initial.py

@@ -1,6 +1,7 @@
-# Generated by Django 2.1 on 2019-03-30 16:15
+# Generated by Django 2.1 on 2020-04-10 21:15
 
 from django.db import migrations, models
+import django.db.models.deletion
 
 
 class Migration(migrations.Migration):
@@ -11,6 +12,13 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.CreateModel(
+            name='Vat',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('vat_percentage', models.IntegerField()),
+            ],
+        ),
         migrations.CreateModel(
             name='Book',
             fields=[
@@ -22,6 +30,7 @@ class Migration(migrations.Migration):
                 ('pages', models.IntegerField(blank=True, null=True)),
                 ('book_type', models.PositiveSmallIntegerField(choices=[(1, 'Hardcover'), (2, 'Paperback'), (3, 'E-book')])),
                 ('timestamp', models.DateField(auto_now_add=True)),
+                ('vat', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='examples.Vat')),
             ],
         ),
     ]

examples/models.py

@@ -1,6 +1,9 @@
 from django.db import models
 
 
+class Vat(models.Model):
+    vat_percentage = models.IntegerField()
+
 class Book(models.Model):
     HARDCOVER = 1
     PAPERBACK = 2
@@ -16,5 +19,5 @@ class Book(models.Model):
     price = models.DecimalField(max_digits=5, decimal_places=2)
     pages = models.IntegerField(blank=True, null=True)
     book_type = models.PositiveSmallIntegerField(choices=BOOK_TYPES)
-
+    vat = models.ForeignKey(Vat, on_delete=models.PROTECT, blank=True, null=True)
     timestamp = models.DateField(auto_now_add=True, auto_now=False)

examples/templates/examples/delete_vat.html

@@ -0,0 +1,22 @@
+{% load widget_tweaks %}
+
+<form method="post" action="">
+  {% csrf_token %}
+
+  <div class="modal-header">
+    <h3 class="modal-title">Delete Vat</h3>
+    <button type="button" class="close" data-dismiss="modal" aria-label="Close">
+      <span aria-hidden="true">&times;</span>
+    </button>
+  </div>
+
+  <div class="modal-body">
+    <p class="delete-text">Are you sure you want to delete vat
+      <strong>{{ vat.vat_percentage }}</strong>?</p>
+  </div>
+
+  <div class="modal-footer">
+    <button type="submit" class="delete-btn btn btn-danger">Delete</button>
+  </div>
+
+</form>

examples/urls.py

@@ -9,6 +9,7 @@
     path('update/<int:pk>', views.BookUpdateView.as_view(), name='update_book'),
     path('read/<int:pk>', views.BookReadView.as_view(), name='read_book'),
     path('delete/<int:pk>', views.BookDeleteView.as_view(), name='delete_book'),
+    path('delete_vat/<int:pk>', views.VatDeleteView.as_view(), name='delete_vat'),
     path('signup/', views.SignUpView.as_view(), name='signup'),
     path('login/', views.CustomLoginView.as_view(), name='login'),
 ]

examples/views.py

@@ -8,7 +8,7 @@
                                            BSModalDeleteView)
 
 from .forms import BookForm, CustomUserCreationForm, CustomAuthenticationForm
-from .models import Book
+from .models import Book, Vat
 
 
 class Index(generic.ListView):
@@ -43,7 +43,12 @@ class BookDeleteView(BSModalDeleteView):
     success_message = 'Success: Book was deleted.'
     success_url = reverse_lazy('index')
 
-
+class VatDeleteView(BSModalDeleteView):
+    model = Vat
+    template_name = 'examples/delete_vat.html'
+    success_message = 'Success: Vat was deleted.'
+    success_url = reverse_lazy('index')
+
 class SignUpView(BSModalCreateView):
     form_class = CustomUserCreationForm
     template_name = 'examples/signup.html'

tests/tests_unit.py

@@ -2,19 +2,27 @@
 from django.contrib.messages import get_messages
 from django.test import TestCase
 
+from examples.models import Vat
 from examples.models import Book
 
 
 class MixinsTest(TestCase):
 
     def setUp(self):
+        self.vat_1 = Vat.objects.create(
+            vat_percentage=28
+        )
+        self.vat_2 = Vat.objects.create(
+            vat_percentage=13
+        )
         self.book = Book.objects.create(
             title='Life of Jane Doe',
             publication_date='2019-01-01',
             author='Jane Doe',
             price=29.99,
             pages=477,
-            book_type=2
+            book_type=2,
+            vat=self.vat_1
         )
         self.user = User.objects.create_user(
             username='user',
@@ -56,7 +64,8 @@ def test_CreateUpdateAjaxMixin(self):
                 'price': 19.99,
                 'pages': 449,
                 # Wrong value
-                'book_type': 'wrong_value'
+                'book_type': 'wrong_value',
+                'vat': 1
             },
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
@@ -78,7 +87,8 @@ def test_CreateUpdateAjaxMixin(self):
                 'author': 'John Doe',
                 'price': 19.99,
                 'pages': 449,
-                'book_type': 1
+                'book_type': 1,
+                'vat': 1
             }
         )
 
@@ -103,7 +113,8 @@ def test_CreateUpdateAjaxMixin(self):
                 'price': 29.99,
                 'pages': 477,
                 # Wrong value
-                'book_type': 'wrong_value'
+                'book_type': 'wrong_value',
+                'vat': 1
             },
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
@@ -125,7 +136,8 @@ def test_CreateUpdateAjaxMixin(self):
                 'author': 'Jane Doe',
                 'price': 29.99,
                 'pages': 477,
-                'book_type': 2
+                'book_type': 2,
+                'vat': 1
             },
         )
 
@@ -140,11 +152,22 @@ def test_DeleteMessageMixin(self):
         """
         Delete object through BSModalDeleteView.
         """
+
+        response = self.client.post('/delete_vat/1')
+        messages = get_messages(response.wsgi_request)
+        self.assertEqual(len(messages), 1)
+        self.assertEqual(str(list(iter(messages))[0]), 'Can not remove this item, has a relation in the database.')
+
+        response = self.client.post('/delete_vat/2')
+        messages = get_messages(response.wsgi_request)
+        self.assertEqual(str(list(iter(messages))[1]), 'Success: Vat was deleted.')
 
         # Request to delete view passes message to the response
         response = self.client.post('/delete/1')
         messages = get_messages(response.wsgi_request)
-        self.assertEqual(len(messages), 1)
+        self.assertEqual(len(messages), 3)
+        self.assertEqual(str(list(iter(messages))[2]), 'Success: Book was deleted.')
+
 
     def test_LoginAjaxMixin(self):
         """