15 Prompts for Django: From Models to REST API — A Developer’s Battle-Tested Toolkit

Act as a senior Django developer. Write a Django model `Order` with fields:
- `id` (AutoField, primary key)
- `user` (ForeignKey to User, CASCADE)
- `total` (DecimalField, max_digits=10, decimal_places=2)
- `status` (CharField, choices: PENDING, PAID, SHIPPED, CANCELLED, default=PENDING)
- `created_at`, `updated_at` (auto_now_add / auto_now)

Add model-level validation: `total` must be > 0. Override `save()` to call `full_clean()`. Include `__str__`, `Meta` with ordering by `-created_at`, and a custom manager method `paid_orders()`.

Output only the code, no explanation.

You are a Django REST Framework expert. Given these models:

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
    price = models.DecimalField(max_digits=6, decimal_places=2)

Write a `BookSerializer` that:
- Includes nested `AuthorSerializer` (read-only for create/update)
- Validates that `price` is not negative
- Has a custom `create()` that accepts `author_id` as a write-only field

Use ModelSerializer. Output only the serializers.py code.

Senior Django dev needed. Write a class-based view `OrderDetailView` that:
- Uses `LoginRequiredMixin`, `UserPassesTestMixin`
- Only allows the order owner or staff to view
- Fetches order by UUID (slug field) from URL
- Returns a 404 if not found
- Renders `orders/detail.html` with context `{'order': order}`
- Handles POST to cancel order (change status to CANCELLED)

Write the view, URL pattern (path), and test that a non-owner gets 403.

Act as Django admin expert. Customise the admin for `Product` model with:
- `list_display`: name, category, price, stock, is_active
- `list_filter`: category, is_active, created_at
- `search_fields`: name, description
- `ordering`: -created_at
- `readonly_fields`: created_at, updated_at
- `fieldsets`: separate basic info, pricing, metadata
- Inline for `ProductImage` model (stacked inline)
- Custom action `make_active` that sets is_active=True for selected products

Write the complete admin.py.

You are a Django developer. Write a management command `export_orders` that:
- Takes a required argument `--start-date` and `--end-date` (date format YYYY-MM-DD)
- Exports orders in that range as CSV to stdout
- Columns: id, user_email, total, status, created_at
- Uses `csv.writer` with proper quoting
- Handles empty results gracefully (print "No orders found" to stderr)
- Uses `BaseCommand` style

Output only the command code.

Senior Django backend dev. Write a `post_save` signal for `Order` model that:
- When an order status changes to PAID, send a confirmation email (use `send_mail` from django.core.mail)
- Log the action to a custom `OrderLog` model (fields: order, action, timestamp)
- Disconnect the signal during fixture loading (use `raw=True` check)
- Use `@receiver` decorator

Write the signals.py and the connection in apps.py.

Django REST Framework pro. Create a `ModelViewSet` for `Article` model:
- Uses `ArticleSerializer`
- Permission classes: `IsAuthenticatedOrReadOnly` for list/retrieve, `IsAdminUser` for create/update/destroy
- Override `get_queryset` to return only published articles for unauthenticated users
- Add a custom action `@action(detail=True, methods=['post'])` called `publish` that sets `is_published=True`
- Use `DefaultRouter` in urls.py

Write views.py, serializers.py, urls.py.

Act as Django ORM optimisation specialist. Given this slow view:

class OrderListView(ListView):
    model = Order
    queryset = Order.objects.all()

Optimise it to:
- Use `select_related('user')` and `prefetch_related('items__product')`
- Add pagination (20 per page)
- Add a filter by status via GET parameter
- Annotate total count of items per order
- Write a test that checks the number of SQL queries (using `assertNumQueries`)

Output the optimised view and test.

Django middleware expert. Write a middleware `RequestTimingMiddleware` that:
- Records the time of each request (using `time.perf_counter`)
- Adds a header `X-Request-Time` with the duration in milliseconds to the response
- Logs requests that take longer than 1 second to `django.request` logger
- Is compatible with Django 5.0+

Write the middleware class and how to add it to settings.MIDDLEWARE.

You are a TDD advocate. Write a test for `Order.cancel()` method that:
- Uses `factory_boy` to create a User and Order
- Calls `order.cancel()`
- Asserts status becomes CANCELLED
- Asserts a `OrderLog` entry was created with action 'cancelled'
- Uses `pytest-django` with `@pytest.mark.django_db`
- Also test that cancelling an already-shipped order raises `ValidationError`

Write the factories.py and test_models.py.

Senior Django + Celery developer. Write a Celery task `send_order_confirmation` that:
- Takes `order_id` as argument
- Fetches the Order (with select_related user)
- Renders an HTML email template `emails/order_confirmation.html`
- Sends via `send_mail` with `html_message`
- Retries up to 3 times on `smtplib.SMTPException` with exponential backoff
- Logs success/failure
- Uses `@shared_task` decorator

Write tasks.py and the task call from the signal (from prompt #6).

Act as a performance consultant. Write a `settings/local.py` configuration for `django-debug-toolbar` that:
- Shows only in DEBUG=True
- Includes panels: SQL, Request, Templates, Cache, Signals
- Configures INTERNAL_IPS for Docker (use `show_toolbar_callback` to always show if DEBUG)
- Sets `SHOW_COLLAPSED = True`
- Adds jQuery CDN for toolbar UI

Write the settings snippet and the URL configuration in urls.py.

Django REST API architect. Implement throttling for a public API:
- `AnonRateThrottle`: 100 requests/hour
- `UserRateThrottle`: 1000 requests/hour
- Custom throttle `BurstRateThrottle` that allows 10 requests/minute, then blocks for 60 seconds
- Apply `BurstRateThrottle` globally, others per viewset
- Add `X-RateLimit-Remaining` header to responses via custom exception handler

Write throttles.py, settings, and the custom exception handler.

Django ORM expert. Write queries that:
1. Annotate each category with total revenue from paid orders (sum of order totals)
2. Annotate each user with their last order date
3. Filter users who have placed more than 5 orders
4. Get the top 10 products by quantity sold

Use `aggregate`, `annotate`, `FilteredAggregation` (for conditional sums). Output only the ORM code.

Django model design expert. Explain with code examples:
1. Multi-table inheritance: `Student` and `Teacher` inheriting from `Person`
2. Proxy model: `Organizer` as proxy of `User` with custom manager `organizers = Organizer.objects.all()`
3. Abstract base class: `TimestampedModel` with created_at/updated_at

For each, write the models, show the database tables created, and discuss when to use which.