Django Backend Developer Assignment

A Django REST API application with CRUD operations, background tasks using Celery, and comprehensive features.

Features

• Models: Orders, Customer, Seller, Product, PlatformApiCall
• Authentication: Token-based authentication
• CRUD Operations: Full CRUD for Orders and Products using Django REST Framework
• Permissions: Custom permissions and user restrictions
• API Logging: Automatic logging of all API calls via mixin
• Search & Filtering: Advanced search and filtering capabilities
• Background Tasks: Celery integration with scheduled tasks
• Excel Import: Management command to import products from Excel files
• Data Validation: Duplicate prevention and data validation

Models

Customer

• name, mobile, User (Foreign Key)

Seller

• name, mobile, User (Foreign Key)

Product

• name (unique), amount
• Validation for duplicate product creation

Order

• customer (FK), seller (FK), products (ManyToMany), amount

PlatformApiCall

• User (FK), requested_url, requested_data, response_data

API Endpoints

Authentication

• POST /api/auth/token/ - Get authentication token

Products

• GET /api/products/ - List products (with search, filter, sorting)
• POST /api/products/ - Create product
• GET /api/products/{id}/ - Retrieve product
• PUT /api/products/{id}/ - Update product
• DELETE /api/products/{id}/ - Delete product

Orders

• GET /api/orders/ - List orders (with product filter, search)
• POST /api/orders/ - Create order
• GET /api/orders/{id}/ - Retrieve order
• PUT /api/orders/{id}/ - Update order
• DELETE /api/orders/{id}/ - Delete order

Customer Orders (Restricted)

• GET /api/my-orders/ - List customer's own orders only

Customers

• GET /api/customers/ - List customers
• POST /api/customers/ - Create customer

Sellers

• GET /api/sellers/ - List sellers
• POST /api/sellers/ - Create seller

Query Parameters

Filtering & Search

• ?search=<term> - Search products by name in orders
• ?products=<id> - Filter orders by product
• ?ordering=asc|desc|top5 - Sort results

Examples

• /api/orders/?search=laptop - Search orders containing "laptop"
• /api/orders/?products=1 - Filter orders containing product ID 1
• /api/products/?ordering=top5 - Get top 5 products by amount

Setup Instructions

1. Install Dependencies

pip install djangorestframework celery redis pandas openpyxl django-cors-headers

2. Database Setup

python manage.py makemigrations
python manage.py migrate

3. Create Superuser

python manage.py createsuperuser

4. Start Redis Server (for Celery)

redis-server

5. Start Django Development Server

python manage.py runserver 0.0.0.0:3000

6. Start Celery Worker (in new terminal)

celery -A django_project worker --loglevel=info

7. Start Celery Beat (for scheduled tasks)

celery -A django_project beat --loglevel=info

Authentication

1. Create user account through Django admin or API
2. Get token: POST /api/auth/token/ with username/password
3. Include token in headers: Authorization: Token <your-token>

Import Products from Excel

Using Management Command

python manage.py import_products path/to/your/file.xlsx

Excel File Format

• Column A: name (Product name)
• Column B: amount (Product amount)

Using Celery Task

The system automatically runs import task daily at 2:30 PM. You can also trigger manually:

from api.tasks import import_products_task
import_products_task.delay('path/to/file.xlsx')

Features Implementation

1. Token Authentication

• Implemented using DRF TokenAuthentication
• Required for all API endpoints

2. CRUD Operations

• Full CRUD for Orders and Products
• Proper serializers with validation

3. PlatformApiCall Mixin

• Automatically logs all API calls
• Captures request data, response data, and metadata

4. Permissions

• Customer-only decorator for restricted endpoints
• Custom permissions for object-level access

5. Advanced Querying

• select_related: Used for Order list APIs to optimize user queries
• prefetch_related: Used for Product search in Order queries
• Search and filtering capabilities

6. Duplicate Prevention

• Product model validates unique names (case-insensitive)
• Excel import skips duplicates

7. Sorting Options

• Ascending/Descending order
• Top 5 results option

8. Customer Restrictions

• Customers can only view their own orders
• Decorator-based access control

Deployment on Replit

1. The application is configured to run on 0.0.0.0:3000
2. CORS is configured for cross-origin requests
3. Static and media files are properly configured
4. Database uses SQLite for simplicity

Celery Configuration

• Broker: Redis
• Scheduled Task: Daily at 2:30 PM for product import
• Tasks: Product import from Excel files

Testing

Access the API using tools like:

• Django admin panel: /admin/
• DRF browsable API: /api/
• Postman or curl for API testing

Security Features

• Token-based authentication
• CSRF protection
• User permission validation
• Input data validation
• SQL injection prevention through Django ORM

Performance Optimizations

• Database query optimization with select_related and prefetch_related
• Pagination for large datasets
• Efficient filtering and search implementation