django

Django Framework Skill

progressive_disclosure: entry_point: summary: "Full-featured Python web framework with batteries included (ORM, admin, auth)" when_to_use: - "When building content-heavy web applications" - "When needing built-in admin interface" - "When using Django ORM and migrations" - "When building REST APIs with Django REST Framework" quick_start: - "pip install django" - "django-admin startproject myproject" - "python manage.py runserver" token_estimate: entry: 75-90 full: 4500-5500

Overview

Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. Built by experienced developers, it takes care of much of the hassle of web development, enabling focus on writing applications without reinventing the wheel.

Key Philosophy: "Batteries included" - Django comes with extensive built-in features including ORM, authentication, admin interface, forms, and security features.

Core Concepts

MVT Architecture (Model-View-Template)

Django follows the MVT pattern:

• Model: Data layer (ORM models, database schema)
• View: Business logic (handles requests, returns responses)
• Template: Presentation layer (HTML with Django template language)

Project vs Apps

• Project: The entire Django application (settings, URLs, WSGI config)
• Apps: Modular components (blog, auth, API) that can be reused across projects

# Create project
django-admin startproject myproject
cd myproject

# Create app
python manage.py startapp blog

# Register app in settings.py
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    # ...
    'blog',
]

Models and ORM

Model Definition

# models.py
from django.db import models
from django.contrib.auth.models import User

class Category(models.Model):
    name = models.CharField(max_length=100, unique=True)
    slug = models.SlugField(unique=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = "categories"
        ordering = ['name']

    def __str__(self):
        return self.name

class Post(models.Model):
    STATUS_CHOICES = [
        ('draft', 'Draft'),
        ('published', 'Published'),
    ]

    title = models.CharField(max_length=200)
    slug = models.SlugField(unique=True)
    author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='posts')
    category = models.ForeignKey(Category, on_delete=models.SET_NULL, null=True)
    content = models.TextField()
    status = models.CharField(max_length=10, choices=STATUS_CHOICES, default='draft')
    published_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-published_at']
        indexes = [
            models.Index(fields=['-published_at']),
            models.Index(fields=['slug']),
        ]

    def __str__(self):
        return self.title