Guestbook Backend API

A Django REST Framework based guestbook application with optimized database queries and caching system.

Features

• Create entries with user name, subject and message
• Automatic user creation for new names
• Paginated entry list (3 per page)
• User statistics
• Database query optimization
• Built-in caching system
• PostgreSQL database support

Installation

1. Install requirements:

pip install -r requirements.txt

2. Create .env file:

DJANGO_SECRET_KEY=your-secret-key
DJANGO_DEBUG=True
DB_NAME=guestbook_db
DB_USER=your_db_user
DB_PASSWORD=your_db_password
DB_HOST=localhost
DB_PORT=5432

3. Run migrations:

python manage.py migrate

4. Start development server:

python manage.py runserver

API Documentation

1. Create Entry

• URL: /api/entries/
• Method: POST
• Content-Type: application/json
• Request Body:

{
    "name": "user_name",
    "subject": "entry_subject",
    "message": "entry_message"
}

2. List Entries

• URL: /api/entries/
• Method: GET
• Query Parameters: page (optional)
• Response Format:

{
    "count": 10,
    "page_size": 3,
    "total_pages": 4,
    "current_page_number": 1,
    "links": {
        "next": "http://api/entries/?page=2",
        "previous": null
    },
    "entries": [
        {
            "user": "user_name",
            "subject": "entry_subject",
            "message": "entry_message"
        }
    ]
}

3. Get Users Data

• URL: /api/users-data/
• Method: GET
• Response Format:

{
    "users": [
        {
            "username": "user_name",
            "last_entry": "subject | message"
        }
    ]
}

Validation Rules

• Name:
  • Minimum length: 2 characters
  • Maximum length: 255 characters
  • Only letters, spaces, and hyphens allowed
  • Cannot contain numbers
• Subject:
  • Minimum length: 3 characters
  • Maximum length: 255 characters
  • Cannot contain inappropriate content
• Message:
  • Minimum length: 10 characters
• General Rules:
  • Message cannot be identical to subject
  • Same message cannot be posted within 5 minutes

Postman Collection

A ready-to-use Postman collection is available for testing the API. To use it:

1. Open Postman application
2. Click on "Import" button
3. Select the file from postman/Guestbook_API.postman_collection.json
4. The collection includes pre-configured requests for all endpoints

Technical Details

Database Optimizations

• Indexes on foreign keys
• Composite indexes (user + created_at)
• select_related usage
• Database-level aggregation

Security

• CORS protection
• Environment variables
• Debug mode disabled in production

Caching

• 5 minute cache duration
• LocMemCache implementation