django-nublado-translation 0.2.2

A Django app for simple model-field translations.

django-nublado-translation

A minimal, explicit model-field translation system for Django.

Translations are implemented via a strict two-model contract:

• a source model
• a translation model

No GenericForeignKeys.
No automatic field injection on the source model.
Source model remains unchanged.

---

Features

• Abstract base models:
  • TranslationSourceModel:
  • TranslationModel:
• Manager:
  • TranslationSourceManager: Manager for TranslationSourceManager
• Guarantees:
  • One translation per (source, language).
  • Source-model unique fields are unique per language in the translation model.
• Base-language fallback support (e.g., es-ar → es).

---

Installation

pip install django-nublado-translation

INSTALLED_APPS = [
    ...,
    "django_nublado_translation",
]

---

Abstract models

TranslationSourceModel

Base model for translatable objects.

• Translations are stored and cached in a language-code-indexed dictionary translations_dict for convenience.

from django.db import models

from django_nublado_translation.models import TranslationSourceModel
from django_nublado_translation.managers import TranslationSourceManager


class Article(TranslationSourceModel):
    title = models.CharField(max_length=250)
    slug = models.SlugField(max_length=250, unique=True)
    content = models.TextField()

    translated_fields = [
        "title",
        "slug",
        "content",
    ]

    objects = TranslationSourceManager()

Notes

• translated_fields is required for translations, and is the single source of truth for translated fields.
• TranslationSourceManager is optional, but recommended, to take advantage of its translation-filtering capability.

---

TranslationModel

Base model for translations of a TranslationSourceModel subclass.

• A foreign key to the source model is generated automatically.
• Default foreign key name: source.
• Default reverse relation name: translations.
• Fields are derived from translated_fields in related source model.
• Constraint naming is derived from the translation model name.

Subclasses must define:

• source_model
• No translated field declarations are allowed on the translation model.

from django_nublado_translation.models import TranslationModel


class ArticleTranslation(TranslationModel):
    source_model = Article


# Source object
article = Article.objects.create(
    title="Hello everybody",
    slug="hello-everybody",
    content="Hello, everybody.",
)

# Translation object
ArticleTranslation.objects.create(
    source=article,
    language="es",
    title="Hola a todos",
    slug="hola-a-todos",
    content="Hola a todos.",
)

Notes

• source_name may be overridden before migrations.
• Translated fields are copied from TranslationSourceModel.translated_fields.

---

Working with translations

Using a subclass of TranslationSource

Getting translations:

# Assume the default language is "en", available translation languages are
# "es" and "de", and the object has a translation for "es".

# Fetching a translation.
article.get_translation("es")
article.get_translation("es-ar")   # Falls back to "es" if no translation found for "es-ar".
article.get_current_translation()  # Uses active Django language

• Returns None if no translation exists.

Getting translation information:

# Find out if an object has a translation in a given language.
article.has_translation("es") # True
article.has_translation("de") # False

# Get translation-languages object doesn't have a translation for.
article.get_available_translation_languages() # ["de"]

Cache management for translation_dict.

article.clear_translations_dict_cache()

• Invalidates the internal translation cache.
• Required when translations are modified outside the instance lifecycle.

---

Using TranslationSourceManager

Prefetching translations

Article.objects.prefetch_translations()

Article.objects.prefetch_translations().filter(slug="source-article-slug")

# Prefetch filtered translations.
translation_qs = ArticleTranslation.objects.filter(language="es", published_status="published")

Article.objects.prefetch_translations(queryset=translation_qs)

---

App settings

from django_nublado_translation.conf.app_settings import app_settings

app_settings.SOURCE_LANGUAGE

Available settings

Setting	Default
SOURCE_LANGUAGE	django.conf.settings.LANGUAGE_CODE

Override

DJANGO_NUBLADO_TRANSLATION = {
    "SOURCE_LANGUAGE": "en",
}

---

Testing

pytest

Requires pytest-django.