Add FileField support

modeltrans/fields.py

@@ -13,7 +13,7 @@
     get_translated_field_label,
 )
 
-SUPPORTED_FIELDS = (fields.CharField, fields.TextField, JSONField)
+SUPPORTED_FIELDS = (fields.CharField, fields.TextField, JSONField, fields.files.FileField)
 
 DEFAULT_LANGUAGE = get_default_language()
 
@@ -108,6 +108,16 @@ def get_instance_fallback_chain(self, instance, language):
 
         return default
 
+    def get_localized_value(self, instance, field_name):
+        value = instance.i18n.get(field_name)
+
+        if isinstance(self.original_field, fields.files.FileField):
+            descriptor = self.descriptor_class(self)
+            descriptor.__set__(instance, value)
+            return descriptor.__get__(instance)
+
+        return value
+
     def __get__(self, instance, instance_type=None):
         # This method is apparently called with instance=None from django.
         # django-hstor raises AttributeError here, but that doesn't solve our problem.
@@ -132,7 +142,7 @@ def __get__(self, instance, instance_type=None):
 
         # Just return the value if this is an explicit field (<name>_<lang>)
         if self.language is not None:
-            return instance.i18n.get(field_name)
+            return self.get_localized_value(instance, field_name)
 
         # This is the _i18n version of the field, and the current language is not available,
         # so we walk the fallback chain:
@@ -145,7 +155,7 @@ def __get__(self, instance, instance_type=None):
 
             field_name = build_localized_fieldname(self.original_name, fallback_language)
             if field_name in instance.i18n and instance.i18n[field_name]:
-                return instance.i18n.get(field_name)
+                return self.get_localized_value(instance, field_name)
 
         # finally, return the original field if all else fails.
         return getattr(instance, self.original_name)
@@ -307,8 +317,43 @@ def get_translated_fields(self):
             if isinstance(field, TranslatedVirtualField):
                 yield field
 
+    def get_file_fields(self):
+        """Return a generator for all translated FileFields."""
+        for field in self.get_translated_fields():
+            if isinstance(field.original_field, fields.files.FileField):
+                yield field
+
     def contribute_to_class(self, cls, name):
         if name != "i18n":
             raise ImproperlyConfigured('{} must have name "i18n"'.format(self.__class__.__name__))
 
         super().contribute_to_class(cls, name)
+
+    def pre_save(self, model_instance, add):
+        """Ensure that translated field values are serializable before save"""
+        data = super().pre_save(model_instance, add)
+
+        if data is None:
+            return data
+
+        for field in self.get_file_fields():
+            localized_file_attname = field.attname
+            if localized_file_attname in data:
+                current_value = data[localized_file_attname]
+
+                # wrap the value in the descriptor class, which will set
+                # the value within the model instance, _NOT_ the i18n key
+                descriptor = field.descriptor_class(field)
+                descriptor.__set__(model_instance, current_value)
+
+                # retrieve the descriptor value, which will check to see if the
+                # file reference has been committed
+                file = descriptor.__get__(model_instance)
+                if file and not file._committed:
+                    # Commit the file to storage prior to saving the model
+                    file.save(file.name, file.file, save=False)
+
+                # finally, mimic how `get_prep_value` works
+                # for "concrete" FileField instances
+                data[localized_file_attname] = str(file)
+        return data

tests/app/models.py

@@ -234,3 +234,18 @@ class Comment(models.Model):
 
     def __str__(self):
         return self.text
+
+
+class Attachment(models.Model):
+    post = models.ForeignKey(
+        Post,
+        on_delete=models.CASCADE,
+        limit_choices_to={"is_published": True},
+        related_name="attachments",
+    )
+    file = models.FileField()
+
+    i18n = TranslationField(fields=("file",))
+
+    def __str__(self):
+        return self.file.name

tests/app/settings.py

@@ -103,3 +103,12 @@
 USE_TZ = True
 
 STATIC_URL = "/static/"
+
+STORAGES = {
+    "default": {
+        "BACKEND": "django.core.files.storage.InMemoryStorage",
+    },
+    "staticfiles": {
+        "BACKEND": "django.contrib.staticfiles.storage.StaticFilesStorage",
+    },
+}

tests/test_models.py

@@ -1,4 +1,6 @@
 from django.core.exceptions import ValidationError
+from django.core.files.base import ContentFile
+from django.core.files.storage.memory import InMemoryFileNode
 from django.db import DataError, models, transaction
 from django.test import TestCase, override_settings
 from django.utils.translation import override
@@ -7,11 +9,13 @@
 
 from .app.models import (
     Article,
+    Attachment,
     Blog,
     Challenge,
     ChallengeContent,
     ChildArticle,
     NullableTextModel,
+    Post,
     TaggedBlog,
     TextModel,
 )
@@ -137,6 +141,78 @@ def test_fallback_getting_JSONField(self):
             # an empty list)
             self.assertEqual(m.tags_i18n, [])
 
+    def test_fallback_getting_FileField(self):
+        post = Post.objects.create(title="Test Post", is_published=True)
+        sample_file = ContentFile("sample content", name="sample-en.txt")
+        attachment = Attachment.objects.create(post=post, file=sample_file)
+
+        with override("fr"):
+            self.assertIsInstance(attachment.file_i18n, models.fields.files.FieldFile)
+            self.assertIsInstance(attachment.file_i18n.file, InMemoryFileNode)
+
+    def test_set_FileField(self):
+        post = Post.objects.create(title="Test Post", is_published=True)
+
+        en_content = "sample content"
+        fr_content = "exemple de contenu"
+        sample_file_en = ContentFile(en_content, name="sample-en.txt")
+        sample_file_fr = ContentFile(fr_content, name="sample-fr.txt")
+
+        attachment = Attachment.objects.create(
+            post=post, file=sample_file_en, file_fr=sample_file_fr
+        )
+        self.assertIsInstance(attachment.file_fr, models.fields.files.FieldFile)
+
+        self.assertIsInstance(attachment.file.file, InMemoryFileNode)
+        self.assertIsInstance(attachment.file_fr.file, InMemoryFileNode)
+
+        saved_fr_content = attachment.file_fr.read().decode("utf-8")
+        self.assertEqual(saved_fr_content, fr_content)
+
+        with override("fr"):
+            self.assertEqual(attachment.file_i18n, attachment.file_fr)
+
+    def test_FileField_getter(self):
+        post = Post.objects.create(title="Test Post", is_published=True)
+
+        fr_content = "exemple de contenu 2"
+        sample_file_fr = ContentFile(fr_content, name="sample-fr-2.txt")
+
+        attachment = Attachment(post=post, file_fr=sample_file_fr)
+        # prior to invoking save, the file_fr should be an instance of FieldFile
+        self.assertIsInstance(attachment.file_fr, models.fields.files.FieldFile)
+        # but the file object should be an instance of ContentFile
+        self.assertIsInstance(attachment.file_fr.file, ContentFile)
+        attachment.save()
+
+        # After saving, the file object should be the default storage class
+        self.assertIsInstance(attachment.file_fr.file, InMemoryFileNode)
+
+        # Retreiving the instance from the database, file and file_fr
+        # should return the same kind of interface (a FieldFile instance)
+        attachment = Attachment.objects.get(pk=attachment.pk)
+        self.assertIsInstance(attachment.file, models.fields.files.FieldFile)
+        self.assertIsInstance(attachment.file_fr, models.fields.files.FieldFile)
+
+        # Test that we can overwrite those with new content
+        new_content = "new content"
+        new_fr_content = "new French content"
+        attachment.file = ContentFile(new_content, name="content-new.txt")
+        attachment.file_fr = ContentFile(new_fr_content, name="content-new-fr.txt")
+        self.assertIsInstance(attachment.file, models.fields.files.FieldFile)
+        self.assertIsInstance(attachment.file_fr, models.fields.files.FieldFile)
+
+        attachment.save()
+
+        self.assertIsInstance(attachment.file_fr, models.fields.files.FieldFile)
+        self.assertIsInstance(attachment.file, models.fields.files.FieldFile)
+
+        with attachment.file.open() as f:
+            self.assertEqual(f.read().decode("utf-8"), new_content)
+
+        with attachment.file_fr.open() as f:
+            self.assertEqual(f.read().decode("utf-8"), new_fr_content)
+
     def test_creating_using_virtual_default_language_field(self):
         m = Blog.objects.create(title_en="Falcon")
 

tests/test_querysets.py

@@ -4,6 +4,7 @@
 import django
 from django.db import models
 from django.db.models import F, Q
+from django.db.models.functions import Collate
 from django.test import TestCase, override_settings
 from django.utils.translation import override
 
@@ -489,9 +490,9 @@ def test_order_by_lower(self):
 
         filtered = Blog.objects.filter(category=c)
 
-        # order by title should result in aA because it is case sensitive.
-        qs = filtered.order_by("title", "title_nl")
-        self.assertEqual(key(qs, "title"), "a A")
+        # order by title should result in Aa because it is case sensitive.
+        qs = filtered.order_by(Collate("title", "C"), Collate("title_nl", "C"))
+        self.assertEqual(key(qs, "title"), "A a")
 
         # order by Lower('title') should result in Aa because lower('A') == lower('A')
         # so the title_nl field should determine the sorting

tests/test_translating.py

@@ -45,6 +45,7 @@ def test_get_translated_models(self):
             app_models.Challenge,
             app_models.ChallengeContent,
             app_models.Post,
+            app_models.Attachment,
             app_models.Comment,
         }
         self.assertEqual(set(get_translated_models("app")), expected)