django

---

1. CRUD Operations with Django Models

# Create a new model instance
product = Product(name="Apple", price=10.0)
product.save()

# Retrieve a model instance
product = Product.objects.get(id=1)

# Update a model instance
product.price = 12.0
product.save()

# Delete a model instance
product.delete()

2. Querying Objects with Django ORM

# Get all products with price greater than 10
products = Product.objects.filter(price__gt=10.0)

# Get the first product with name "Apple"
product = Product.objects.get(name="Apple")

# Order products by price in descending order
products = Product.objects.order_by('-price')

3. Creating Django Forms

class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = ['name', 'price']

4. Handling User Authentication with Django

from django.contrib.auth.models import User

# Create a new user
user = User.objects.create_user('username', '[e-mail]', 'password')

# Authenticate a user
user = authenticate(username='username', password='password')

5. Django Model Inheritance

class Product(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=6, decimal_places=2)

class Book(Product):
    author = models.CharField(max_length=100)

6. Django Middleware

class MyMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        # Do something before the view is called
        response = self.get_response(request)
        # Do something after the view is called
        return response

7. Django Template Filters

from django import template

register = template.Library()

@register.filter
def currency(value):
    return f"${value:.2f}"

8. Django Custom Manager

from django.db import models

class MyManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(is_active=True)

9. Django REST Framework

from rest_framework import serializers, viewsets, routers

class ProductSerializer(serializers.ModelSerializer):
    class Meta:
        model = Product
        fields = ['id', 'name', 'price']

class ProductViewSet(viewsets.ModelViewSet):
    queryset = Product.objects.all()
    serializer_class = ProductSerializer

router = routers.DefaultRouter()
router.register('products', ProductViewSet)

10. Django Channels

import channels

@channels.routing.route("websocket.connect")
def connect(message):
    message.reply_channel.send({"accept": True})

@channels.routing.route("websocket.receive")
def receive(message):
    print(message.text)

@channels.routing.route("websocket.disconnect")
def disconnect(message):
    pass

11. Django Internationalization (i18n)

from django.utils.translation import gettext as _

# Define translation in settings.py
LANGUAGE_CODE = 'en-us'

# Translate in template
<h1>{_('Welcome to Django')}</h1>

12. Django Password Reset

from django.contrib.auth.forms import PasswordResetForm

# Reset password form
form = PasswordResetForm(data={'email': '[e-mail]'})
if form.is_valid():
    form.save()

13. Django Admin

from django.contrib import admin

# Register model in admin interface
admin.site.register(Product)

14. Django Mail

from django.core.mail import send_mail

send_mail(
    'Subject',
    'Message',
    '[e-mail]',
    ['[e-mail]'],
    fail_silently=False
)

15. Django Caching

from django.core.cache import cache

# Set cache value
cache.set('foo', 'bar')

# Retrieve cache value
value = cache.get('foo')

16. Django File Uploads

from django.core.files.storage import FileSystemStorage

# File storage
fs = FileSystemStorage()
fs.save('my_file.txt', File(open('myfile.txt', 'rb')))

17. Django Signal Processing

from django.db.models.signals import post_save

# Signal handler
def my_handler(sender, **kwargs):
    # Do something when a model is saved
    pass

# Connect signal handler
post_save.connect(my_handler, sender=Product)

18. Django Haystack Search

from haystack import indexes

class ProductIndex(indexes.SearchIndex, indexes.Indexable):
    text = indexes.CharField(document=True, use_template=True)

# Rebuild search index
ProductIndex().reindex()

19. Django Cart

from django.contrib.sessions.models import Session

# Retrieve cart from session
session = Session.objects.get(session_key='...')
cart = session.get('cart', {})

20. Django Celery Task Scheduling

from celery import task

@task
def my_task():
    # Perform task asynchronously
    pass

21. Django HTML Purifier

from django.contrib.admin import SimpleListFilter

class MyFilter(SimpleListFilter):
    title = 'Title'
    parameter_name = 'title'

    def lookups(self, request, model_admin):
        # Define filter options
        return [('option1', 'Option 1'), ('option2', 'Option 2')]

    def queryset(self, request, queryset):
        # Filter queryset based on selected option
        if self.value() == 'option1':
            return queryset.filter(...)
        elif self.value() == 'option2':
            return queryset.filter(...)
        else:
            return queryset

22. Django Google Auth

from django.contrib.auth.backends import ModelBackend

class GoogleAuthBackend(ModelBackend):
    def authenticate(self, request, **kwargs):
        # Authenticate user using Google OAuth token
        pass

23. Django Stripe Payment

import stripe

# Create a Stripe charge
stripe.Charge.create(
    amount=1000,
    currency="usd",
    source="tok_...
)

24. Django PayPal Payment

from paypal.standard.models import ST_PP_COMPLETED

# PayPal payment processing
if request.method == 'POST' and request.POST.get('txn_type') == 'web_accept':
    order = Order.objects.get(id=request.POST.get('custom'))
    if request.POST.get('payment_status') == ST_PP_COMPLETED:
        """
        Payment processing logic
        """

25. Django REST Framework JWT Authentication

from rest_framework_jwt.authentication import JSONWebTokenAuthentication

# JWT authentication
authentication_classes = [JSONWebTokenAuthentication]

26. Django User Permissions

from django.contrib.auth.models import Permission

# Create a new permission
permission = Permission.objects.create(codename='can_edit_product', name='Can edit product')

# Assign permission to a user
user.user_permissions.add(permission)

27. Django Group Permissions

from django.contrib.auth.models import Group

# Create a new group
group = Group.objects.create(name='Editors')

# Assign permission to a group
group.permissions.add(permission)

# Add user to group
user.groups.add(group)

28. Django Crispy Forms

from crispy_forms.helper import FormHelper
from crispy_forms.layout import Submit

# Crispy form helper
helper = FormHelper()
helper.add_input(Submit('submit', 'Save'))

29. Django Extensions

from django_extensions.management.commands.runserver_plus import Command as RunserverPlusCommand

# Run Django development server with debug toolbar
python manage.py runserver_plus

30. Django debug_toolbar

# Install debug_toolbar
pip install django-debug-toolbar

# Add debug toolbar to INSTALLED_APPS
INSTALLED_APPS = [
    ...
    'debug_toolbar',
]

# Add debug toolbar middleware
MIDDLEWARE = [
    ...
    'debug_toolbar.middleware.DebugToolbarMiddleware',
]

# Enable debug toolbar in settings.py
DEBUG_TOOLBAR_CONFIG = {
    'INTERCEPT_REDIRECTS': False,
}

31. Django htmx

pip install django-htmx

# Add htmx to INSTALLED_APPS
INSTALLED_APPS = [
    ...
    'htmx.apps.HtmxConfig',
]

32. Django livewire

pip install django-livewire

# Add livewire to INSTALLED_APPS
INSTALLED_APPS = [
    ...
    'livewire',
]

# Configure livewire
LIVEWIRE_CONFIG = {
    'dom_id_prefix': 'lw',
}

33. Django query count

from django.db import connection

# Display number of queries executed
print(len(connection.queries))

34. Django benchmark

from django.core.cache import CacheKeyWarning
from django.db.models.query import QuerySet

# Display benchmark results for a queryset
qs = QuerySet().all()
with CacheKeyWarning(warnings.catch_warnings()):
    warnings.simplefilter('ignore')
    results = qs.explain(analyze=True)

# Print benchmark results
for row in results:
    print(row)

35. Django inspectdb

python manage.py inspectdb > models.py

36. Django loaddata

python manage.py loaddata initial_data.json

37. Django dumpdata

python manage.py dumpdata > data.json

38. Django migrate

python manage.py migrate

39. Django runserver

python manage.py runserver

40. Django shell

python manage.py shell

41. Django createsuperuser

python manage.py createsuperuser

42. Django startapp

python manage.py startapp myapp

43. Django startapp

python manage.py startapp myapp

44. Django startproject

python manage.py startproject myproject

45. Django collectstatic

python manage.py collectstatic

46. Django test

python manage.py test

47. Django coverage

python manage.py coverage

48. Django freezegun

from freezegun import freeze_time

@freeze_time("2023-01-01")
def my_test():
    pass

49. Django pytest

import pytest

@pytest.mark.django_db
def test_my_model():
    pass

50. Django factory_boy

from factory import Faker, SubFactory
from factory.django import DjangoModelFactory

class UserFactory(DjangoModelFactory):
    class Meta:
        model = User
    username = Faker('user_name')
    email = Faker('email')

51. Django model_mommy