django-expert

Django Expert

Expert guidance for Django - high-level Python web framework for building secure, scalable web applications with batteries included.

Core Concepts

Django Architecture

• MVT (Model-View-Template) pattern
• ORM (Object-Relational Mapping)
• Admin interface
• Authentication system
• URL routing
• Template engine
• Forms and validation

Key Components

• Models (database tables)
• Views (business logic)
• Templates (presentation)
• URLs (routing)
• Forms (user input)
• Middleware (request/response processing)

Project Setup

# Install Django
pip install django

# Create project
django-admin startproject myproject
cd myproject

# Create app
python manage.py startapp myapp

# Run migrations
python manage.py migrate

# Create superuser
python manage.py createsuperuser

# Run server
python manage.py runserver

Models

# myapp/models.py
from django.db import models
from django.contrib.auth.models import User
from django.utils import timezone

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

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

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

    def __str__(self):
        return self.title

    def save(self, *args, **kwargs):
        if self.status == 'published' and not self.published_at:
            self.published_at = timezone.now()
        super().save(*args, **kwargs)

class Comment(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE, related_name='comments')
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    content = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['created_at']

    def __str__(self):
        return f'Comment by {self.author} on {self.post}'