A cheat-sheet for creating web apps with the Django framework using the Python language. Most of the summaries and examples are based on the official documentation for Django v2.0.
- 🐍 Initializing pipenv (optional)
- 📘 Creating a project
- 📃 Creating an app
- 📺 Creating a view
- 🎨 Creating a template
- 🎫 Creating a model
- 📮 Creating model objects and queries
- 👨 Using the Admin page
- Make main folder with
$ mkdir <folder>and navigate to it with$ cd <folder> - Initialize pipenv with
$ pipenv install - Enter pipenv shell with
$ pipenv shell - Install django with
$ pipenv install django - Install other package dependencies with
$ pipenv install <package_name>
- Navigate to main folder with
$ cd <folder> - Create project with
$ django-admin startproject <project_name>
The project directory should look like this:
project/
manage.py
project/
__init__.py
settings.py
urls.py
wsgi.py
- Run the development server with
$ python manage.py runserverwithin the project directory - If you want your
SECRET_KEYto be more secure, you can set it to reference an environment variable - In the
settings.pyfile within the project directory change theSECRET_KEYline to the following:
SECRET_KEY = os.environ.get('SECRET_KEY')- To quickly generate a random hex for your secret key:
>>> import secrets
>>> secrets.token_hex()- You can set this environment variable in your shell with
export SECRET_KEY=<secret_key>
- Navigate to the outer project folder
$ cd <outer_project_folder> - Create app with
$ python manage.py startapp <app_name> - Inside the
appfolder, create a file calledurls.py
The project directory should now look like this:
project/
manage.py
db.sqlite3
project/
__init__.py
settings.py
urls.py
wsgi.py
app/
migrations/
__init__.py
__init__.py
admin.py
apps.py
models.py
tests.py
urls.py
views.py
- To include this app in your project, add your app to the project's
settings.pyfile by adding its name to theINSTALLED_APPSlist:
INSTALLED_APPS = [
'app',
# ...
]- To migrate changes over:
$ python manage.py migrate- Within the app directory, open
views.pyand add the following:
from django.http import HttpResponse
def index(request):
return HttpResponse("Hello, World!")- Still within the app directory, open (or create)
urls.py
from django.urls import path
from . import views
urlpatterns = [
path('', views.index, name='index'),
]- Now within the project directory, edit
urls.pyto include the following
from django.contrib import admin
from django.urls import include, path
urlpatterns = [
path('app/', include('app.urls')),
path('admin/', admin.site.urls),
]- To create a url pattern to the index of the site, use the following urlpattern:
urlpatterns = [
path("", include('app.urls')),
]- Remember: there are multiple files named
urls.py - The
urls.pyfile within app directories are organized by theurls.pyfound in the project folder.
- Within the app directory, HTML, CSS, and JavaScript files are located within the following locations:
app/
templates/
index.html
static/
style.css
script.js
- To add a template to views, open
views.pywithin the app directory and include the following:
from django.shortcuts import render
def index(request):
return render(request,'index.html')- To include context to the template:
def index(request):
context = {"context_variable": context_variable}
return render(request,'index.html', context)- Within the HTML file, you can reference static files by adding the following:
{% load static %}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="{% static 'styles.css' %}">
</head>
</html>- To make sure to include the following in your
settings.py:
STATIC_URL = '/static/'
STATICFILES_DIRS = [
os.path.join(BASE_DIR, "static")
]- To add an
extends:
{% extends 'base.html'%}
{% block content %}
Hello, World!
{% endblock %}- And then in
base.htmladd:
<body>
{% block content %}{% endblock %}
</body>- Within the app's
models.pyfile, an example of a simple model can be added with the following:
from django.db import models
class Person(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)Note that you don't need to create a primary key, Django automatically adds an IntegerField.
- To perform changes in your models, use the following commands in your shell:
$ python manage.py makemigrations <app_name>
$ python manage.py migrate
Note: including <app_name> is optional.
- A one-to-many relationship can be made with a
ForeignKey:
class Musician(models.Model):
first_name = models.CharField(max_length=50)
last_name = models.CharField(max_length=50)
instrument = models.CharField(max_length=100)
class Album(models.Model):
artist = models.ForeignKey(Musician, on_delete=models.CASCADE)
name = models.CharField(max_length=100)
release_date = models.DateField()
num_stars = models.IntegerField()- In this example, to query for the set of albums of a musician:
>>> m = Musician.objects.get(pk=1)
>>> a = m.album_set.get()- A many-to-many relationship can be made with a
ManyToManyField:
class Topping(models.Model):
# ...
pass
class Pizza(models.Model):
# ...
toppings = models.ManyToManyField(Topping)Note that the ManyToManyField is only defined in one model. It doesn't matter which model has the field, but if in doubt, it should be in the model that will be interacted with in a form.
- Although Django provides a
OneToOneFieldrelation, a one-to-one relationship can also be defined by adding the kwarg ofunique = Trueto a model'sForeignKey:
ForeignKey(SomeModel, unique=True)- For more detail, the official documentation for database models provides a lot of useful information and examples.
- Example
models.pyfile:
from django.db import models
class Blog(models.Model):
name = models.CharField(max_length=100)
tagline = models.TextField()
def __str__(self):
return self.name
class Author(models.Model):
name = models.CharField(max_length=200)
email = models.EmailField()
def __str__(self):
return self.name
class Entry(models.Model):
blog = models.ForeignKey(Blog, on_delete=models.CASCADE)
headline = models.CharField(max_length=255)
body_text = models.TextField()
pub_date = models.DateField()
mod_date = models.DateField()
authors = models.ManyToManyField(Author)
n_comments = models.IntegerField()
n_pingbacks = models.IntegerField()
rating = models.IntegerField()
def __str__(self):
return self.headline- To create an object within the shell:
$ python manage.py shell
>>> from blog.models import Blog
>>> b = Blog(name='Beatles Blog', tagline='All the latest Beatles news.')
>>> b.save()- To save a change in an object:
>>> b.name = 'The Best Beatles Blog'
>>> b.save()- To retrieve objects:
>>> all_entries = Entry.objects.all()
>>> indexed_entry = Entry.objects.get(pk=1)
>>> find_entry = Entry.objects.filter(name='Beatles Blog')- To create a
superuser:
$ python manage.py createsuperuser- To add a model to the Admin page include the following in
admin.py:
from django.contrib import admin
from .models import Author, Book
admin.site.register(Author)
admin.site.register(Book)