Merge pull request #73 from Aristotle-Metadata-Enterprises/fix-custom-prep-save

added support for custom get_db_prep_save

Author: ChengwuShi

garnett/fields.py

@@ -114,6 +114,18 @@ def get_prep_value(self, value):
             return value
         return super().get_prep_value(value)
 
+    def get_db_prep_save(self, value, connection):
+        """This ensures that any custom get_db_prep_save() method in self.field can be triggered"""
+        if hasattr(value, "items"):
+            value = {
+                lang_code: self.field.get_db_prep_save(text, connection)
+                for lang_code, text in value.items()
+            }
+        elif type(value) == str:
+            value = self.field.get_db_prep_save(value, connection)
+            return value
+        return super().get_db_prep_save(value, connection)
+
     def from_db_value(self, value, expression, connection):
         value = super().from_db_value(value, expression, connection)
         if hasattr(self.field, "from_db_value"):

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "django-garnett"
-version = "0.4.7"
+version = "0.4.8"
 description = "Simple translatable Django fields"
 authors = ["Aristotle Metadata Enterprises"]
 license = "BSD-3-Clause"

tests/library_app/migrations/0001_initial.py

@@ -49,6 +49,7 @@ class Migration(migrations.Migration):
                     ),
                 ),
                 ("category", models.JSONField(blank=True, null=True)),
+                ("other_info", library_app.models.CustomTestingField(blank=True, default=''))
             ],
         ),
         migrations.CreateModel(

tests/library_app/migrations/0002_make_translatable.py

@@ -7,7 +7,7 @@
 
 
 model_fields = {
-    "book": ["title", "description"],
+    "book": ["title", "description", "other_info"],
 }
 
 
@@ -41,5 +41,15 @@ class Migration(migrations.Migration):
                 help_text="The name for a book. (Multilingal field)",
             ),
         ),
+        migrations.AlterField(
+            model_name="book",
+            name="other_info",
+            field=garnett.fields.TranslatedField(
+                library_app.models.CustomTestingField(
+                    blank=True, default=''
+                ),
+                fallback=None,
+            ),
+        ),
         step_2_safe_prepare_translations("library_app", model_fields),
     ]

tests/library_app/models.py

@@ -7,6 +7,43 @@
 from garnett.utils import get_languages, get_current_language
 
 
+RANDOM_STR = "f6e56ce9-cc87-45ac-8a19-8c34136e6f52"
+BLEACH_STR = "string to be replace"
+
+
+class CustomTestingField(models.TextField):
+    def get_db_prep_save(self, value, connection):
+        """
+        Note: If there is data migration when migrating to TranslatedField, the manually added
+         step_1_safe_encode_content() function in the migration file will base64 encode the value in the field
+         before get_db_prep_save is called.
+
+         For example:
+            old value = "this is a book"
+            new value = '{"en": "dGhpcyBpcyBhIGJvb2s="}'
+
+        The new value is then parse to the get_db_prep_save() function.
+        If custom get_db_prep_save() function is used you will need to make sure that the custom get_db_prep_save() function is
+        not modifying the input value.
+
+        Some examples,
+            1. if the custom get_db_prep_save() function append a fix str to all input value:
+                    input value = '{"en": "dGhpcyBpcyBhIGJvb2s="}'
+                    return value = '{"en": "dGhpcyBpcyBhIGJvb2s="}1234567'
+               this would raise "django.db.utils.DataError: invalid input syntax for type json" because the return value
+               from the custom get_db_prep_save() function is not valid json
+
+            2. if the custom get_db_prep_save() function bleach certain substring (e.g dGhpcy) on the input value:
+                    input value = '{"en": "dGhpcyBpcyBhIGJvb2s="}'
+                    return value = '{"en": "BpcyBhIGJvb2s="}'
+               this would modify the base64 value and decoding the modfied base64 value would return unexpected result
+        """
+        if value is None:
+            return super().get_db_prep_save(value, connection)
+        bleached_value = value.replace(BLEACH_STR, RANDOM_STR)
+        return super().get_db_prep_save(bleached_value, connection)
+
+
 def validate_length(value):
     if len(value) < 3:
         raise ValidationError(_("Title is too short"))
@@ -70,6 +107,8 @@ class Book(models.Model):
 
     category = models.JSONField(blank=True, null=True)
 
+    other_info = fields.Translated(CustomTestingField(blank=True, default=""))
+
     def get_absolute_url(self):
         return f"/book/{self.pk}"
 

tests/tests/test_field.py

@@ -5,6 +5,7 @@
 import garnett.exceptions
 from garnett.context import set_field_language
 from garnett.fields import TranslatedField
+from library_app.models import Book, RANDOM_STR, BLEACH_STR
 
 book_data = dict(
     title={
@@ -50,3 +51,29 @@ def test_validate_bad_value_type(self):
         with set_field_language("fr"), self.assertRaises(ValidationError) as err:
             self.field.clean(value, None)
             self.assertEqual(err.exception, 'Invalid value for language "en"')
+
+    def test_trigger_get_db_prep_save(self):
+        content = "This is a book and this string to be replace"
+        Book.objects.create(
+            title={
+                "en": "A book",
+                "de": "Eine Gut Buch",
+            },
+            author="No one",
+            description="No description",
+            category={"dewey": 123},
+            number_of_pages=100,
+            other_info=content,
+        )
+        # Expect only one object is created
+        books = Book.objects.all()
+        self.assertEqual(len(books), 1)
+
+        # Expect CustomTestingField to be bleached
+        book = books[0]
+        self.assertEqual(book.other_info, content.replace(BLEACH_STR, RANDOM_STR))
+
+        # Expect other fields will not be bleached
+        self.assertNotIn(RANDOM_STR, book.title)
+        self.assertNotIn(RANDOM_STR, book.author)
+        self.assertNotIn(RANDOM_STR, book.description)

tox.ini

@@ -22,4 +22,4 @@ commands =
     poetry config virtualenvs.create false
     poetry install
     pip install "django~={env:DJANGO_VERSION}"
-    coverage run --append --source=. ./tests/manage.py test tests
+    coverage run --append --source=. ./tests/manage.py test tests -v 2