backend-python

Instruction file imported from fao102/Style-Finder (.github/instructions/backend-python.instructions.md). Copyright stays with the author.

Backend Python Guidelines

Django / DRF Conventions

• Use python-decouple's config() for every environment variable read — never use os.environ.get directly in settings or views.
• All API logic lives in backend/app/api/views.py. Keep backend/app/views.py and backend/app/urls.py as legacy stubs; do not add new logic there.
• DRF viewsets are registered via DefaultRouter in backend/app/api/urls.py and aggregated in backend/core/api/urls.py. Follow this pattern for any new endpoints.
• After adding or modifying a model field, always generate a migration: python manage.py makemigrations app.
• The OutfitSearch model (backend/app/models.py) stores per-request Gemini analysis results. Add nullable fields (blank=True, null=True) for any new AI-extracted attributes.

Gemini Integration

• Model in use: gemini-2.5-flash. Do not change the model string without updating requirements.txt if the API version changes.
• Always request response_mime_type: "application/json" in generation_config to get structured output.
• Wrap Gemini and SerpAPI calls in try/except Exception and return a graceful error dict; never let an API failure cause an unhandled 500.

Image Handling

• Use resize_image() from backend/app/api/helper.py before passing images to Gemini. It caps dimensions at 720 px to control token cost.
• Uploaded images are stored at backend/media/uploads/ (controlled by MEDIA_ROOT). In production, consider cloud storage (S3/GCS) — placeholders are commented out in settings.py.

Settings

• Production settings: backend/core/settings.py — requires DATABASE_URL, SECRET_KEY, GEMINI_API_KEY, SERP_API_KEY, ALLOWED_HOSTS, CORS_ALLOWED_ORIGINS, CSRF_TRUSTED_ORIGINS.
• Dev settings: backend/core/dev_settings.py — uses SQLite and DEBUG=True. Select with DJANGO_SETTINGS_MODULE=core.dev_settings.
• CORS_ALLOWED_ORIGIN_REGEXES includes r"^https://.*\.vercel\.app$" to handle Vercel preview URLs automatically.

Testing

cd backend
python manage.py test          # runs Django test suite

There are no frontend-facing tests configured yet. Add tests under backend/app/tests/.