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Full-Stack Reactive Website in Django (No JavaScript)

Modern websites that require complex user interaction are built using dedicated frontend frameworks like React, Vue.js among others. However, some complexities come with them. These include time, cost of hosting, SEO optimization, syntax differences, and in some cases having a duplicate business logic.  You can achieve the same reactive website with technologies like React without leaving your Django project or learning another language. It, therefore, is less complex, less code intensive and has a faster development time.

There are several technologies out there that can achieve these functionalities like Sockpuppet, reactor, and Unicorn. However, you could use Unicorn for this tutorial to achieve interactivity within our Django application without any custom JavaScript.

Note that there may be benefits to using a dedicated frontend; for instance, it can be helpful to have a dedicated team responsible for coding the frontend and backend of a piece of software.

Tutorial requirements

To follow along with this tutorial, the reader needs:

A basic understanding of the Django web framework.
A working knowledge of Docker.

Project setup and overview

Here is a quick look at the app you will be building:

Home Page

In this application, you can add and delete a new book without refreshing the page, and the same functionality is possible with Single Page Applications (SPAs).

To start, clone down the base branch from the django-reactive repo:

$ git clone https://github.com/Samuel-2626/django-reactive --branch base --single-branch
$ cd django-reactive

You will use Docker to simplify setting up and running Django with the dependencies. From the project root, create the images and spin up the Docker containers:

$ docker-compose up -d --build

Next, apply the migrations, create a superuser and run the development server:

$ docker-compose exec web python manage.py migrate
$ docker-compose exec web python manage.py createsuperuser
$ docker-compose exec web python manage.py run server

Take note of the Book model in books/models.py:

from django.db import models
class Book(models.Model):
    title = models.CharField(max_length=200)
    def __str__(self):
        return self.title

Working with Unicorn

Unicorn is a component framework that progressively enhances a standard Django view. It dynamically updates the DOM with AJAX calls in the background.

Add it to your installed application:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # Third-party
    "django_unicorn", # new
]

Update your project urls.py file like so:

from django.urls import path, include
path("unicorn/", include("django_unicorn.urls")), # new

How it works?

Unicorn is an open-source library that progressively enhances a standard Django view; therefore, the initial render of the component is quick and great for SEO.
Next, Unicorn binds to the elements stipulated and automatically performs AJAX calls when required.
Finally, the DOM is updated dynamically by Unicorn.

Project URLs, views & template

In this section, you will be setting up your project URLs, Views and Templates.

Update your project urls.py file like so:

path("", views.index), # new

Update your books' application views.py file like so:

def index(request):
    return render(request, "index.html", {})

Update your books' template index.html file like so:

{% load unicorn %}

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Django Books</title>

    <link
      href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css"
      rel="stylesheet"
      integrity="sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC"
      crossorigin="anonymous"
    />
    {% unicorn_scripts %}
  </head>
  <body>
    {% csrf_token %}
    <div class="container">
      <h2>Favourite Django Books</h2>

      {% unicorn 'book' %}
    </div>
  </body>
</html>

Explaining the logic

You created a basic Django template for your project while linking the views and URLs together.
Take note that you have to load unicorn at the top of the Django HTML template.
You also added the unicorn_scripts into the Django HTML template and added the crsf_token in the template as well.

According to Unicorn, the library follows the best practices of Django and therefore, it requires a CRSF token to be set on any page that is a component. This guarantees that no nefarious AJAX Posts can be done.

Additionally, according to Unicorn, it has the concept of component, to refer to a set of interactive functionality that can be put inside the template. So, for example, in the index.html file, you added a book component.

Furthermore, a component consists of: Django HTML template including particular tags. Python view class, which gives the backend logic for the template.

Adding and deleting books

In this section, you will be implementing the functionality to add and delete books without refreshing your browser using Unicorn.

Step 1

From your project root, create a new folder called unicorn, create a new folder called components, and finally, create a new file called book.py.

Step 2

From the unicorn folder you created earlier on, create another folder called templates, inside this folder create a new folder called unicorn and finally, inside this folder, create a new file called book.html.

Step 3

Inside the book.html, add the following code:

<div class="row">
  <div class="col-md-6">
    <section>
      <ul class="list-group">
        {% for book in books %}
        <li class="list-group-item">
          {{ book.title }}
          <button
            class="btn btn-outline-danger"
            style="float: right;"
            unicorn:click="delete_book('{{ book.id }}')"
          >
            Delete Book
          </button>
        </li>
        {% empty %}
        <p>Database Empty | Add your favourite Django book</p>
        {% endfor %}
      </ul>
    </section>
  </div>
  <div class="col-md-6">
    <form>
      <input
        type="text"
        class="form-control"
        placeholder="Enter title of the book..."
        unicorn:model.defer="title"
      />
      <br />
      <button
        class="btn btn-secondary"
        style="min-width: 100%;"
        unicorn:click.prevent="add_book"
      >
        Add Books
      </button>
    </form>
  </div>
</div>

What is Happening Here?

Inside the component, you have access to your normal Django syntax.
Note the input element; this is familiar except for the Unicorn: model attribute. This would specify what field in your backend component would be bound to this input. In this case, the field name would be title.

unicorn: model is the magic that ties the input to the backend component.

Notice the Add Books button with an attribute unicorn: click, which tells unicorn to bind the add_book backend method to the click browser event.
Likewise, the Delete Book button tells unicorn to bind the delete_book backend method. You also passed the book id to the delete_book function to uniquely identify each book.

To prevent updates from occurring on every input, you can add a lazy or defer modifier to the end of unicorn: model.

Attributes used in component templates habitually start with unicorn: but the shortcut u: is also supported. Note that properties of the component can be of many types, including str, int, list, dictionary, decimal, and Django Model.

Finally, Unicorn requires one root element that envelopes the component template.

Step 4

Inside the book.py, add the following code:

from django_unicorn.components import UnicornView
from books.models import Book
class BookView(UnicornView):
    title: str = ""
    books = Book.objects.none()
    def hydrate(self):
        self.books = Book.objects.all()
    def add_book(self):
        if self.title != "":
            book = Book(title=self.title)
            book.save()
        self.title = ""
    def delete_book(self, id):
        try:
            book = Book.objects.get(id=id)
            book.delete()
        except:
            pass

Explaining the code logic

You are importing the UnicornView, a subclass of TemplateView under the hood. Therefore, the process of switching from a standard class-based view should be straightforward.
The hydrate method is called when the component is instantiated to grab the latest books from the database so that the information is up-to-date.
The add_book method will create a new book model from the title, save it in the database, and then clear the title.
The delete_book method will delete a book that matches the id.

Once done, navigate to http://127.0.0.1:8080/ to ensure the app works as expected. You should see the following:

Home Page 2

Try adding and deleting some of your favourite Django books.

Conclusion

This tutorial introduced you on how to build a full-stack reactive web application in Django without any JavaScript. You built a simple application with unicorn that can add and delete a book without refreshing the page, hence, reactive.

You can download the complete code from here.

Happy coding!