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Hello World Basic Django App

Hello World Basic Django App

PURPOSE

To create a Web App that focuses on scalabality & securtiy, "Django" is the go to framework in Python. It's a feature rich solution that enforces best practices from the ground up.

The Author assumes that you have some basic understanding of working with Python 3.

Step 0: [Optional] Creating a virtual environment and activating it.

If you're on Windows, open command prompt and type:

py -m venv django_env
cd django_env/Scripts
./activate

Step 1. Initial Setup:

Installing Django framework using pip

# inside the venv
pip install django
# if you have skipped the step of creating a virtual environment
py -m pip install django

Creating a new project

md Hello-World-Django
cd Hello-World-Django
djangoadmin startproject learning_django
py manage.py runserver
  • Take a look at your project directory. Why so many files, I wonder?
  • Visit localhost:8000 on your browser. Oh look, it's Django, saying hello to you!

Creating an app inside the project

djangoadmin startapp first_app
  • Take a look at your directory structure again. Wonderful, isn't it? Confusing, but wonderful!

Step 2: Let's some write code:

Open your project in your favorite text editor Vim!

gvim .

Inside your first_app folder, you will see a views.py file

Hello-World-Django
│
└───learning_django
    │
    └───learning_django
    └───first_app
    │   admin.py
    │   models.py
    │   views.py <- Open this file.

Open it, and modify the code so it looks like this:

from django.http import HttpResponse # simple html response. no templates.

# in flask, you would use @app.route decorator here.
# in django, we keep the route/url path in a separate file called "urls.py"
def index(request): # our first view/function that will have some logic.
    # this is where you would write some operational logic like
    # split_text = some_text_to_split.split(',')
    # for now, we will just return Hello World, without any additional processing.

    return HttpResponse("Hello, world. You're at the first_app index.")
  • The comments can be ommited, they are for explanatory purposes only.

Create & Open first_app\urls.py

Hello-World-Django
│
└───learning_django
    │
    └───learning_django
    └───first_app
    │   admin.py
    │   models.py
    │   views.py
    │   urls.py <- create this file and open it.

Add the following to it:

from django.urls import path # standard django function for defining url paths

from . import views # importing the views.py file that we just modified.

urlpatterns = [
    path('', views.index, name='index'),
    # !IMPORTANT: We are importing and serving the index function at /first_app endpoint.
    # in flask, you would just add the path like @app.route('/first_app') in your function.
    # to replicate the same behavior.
]

We must add first_app app's urls to our learning_django app's urls.py file

Open learning_django\urls.py:

Hello-World-Django
│
└───learning_django
    │
    └───learning_django
    │   asgi.py
    │   settings.py
    │   urls.py <- Open this file.
    └───first_app

Modify it to:

from django.contrib import admin # for the admin routes
from django.urls import include, path # include is used to include paths from other apps.

urlpatterns = [
    path('first_app/', include('first_app.urls')),
    # we are serving this app's endpoints at /first_app
    path('admin/', admin.site.urls),
]
  • A separate urls file for each app adds clarity.
  • We can scan through all the urls files to know what all endpoints are there
  • To understand the routes, we don't need to view the internal logic (i.e. views) and vice-versa.
  • It is also easier to mantain and update paths this way.

Open learning_django\settings.py

Hello-World-Django
│
└───learning_django
    │
    └───learning_django
    │   asgi.py
    │   settings.py <- Open this file.
    │   urls.py
    └───first_app

Add first_app to your installed apps:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'first_app' # Add your app name here.
]

Step 3: Now, run the server again and visit localhost:8000\first_app

py manage.py runserver
  • You would be greeted with the Hello World message that you wrote in your views.

Voila! You have successfully hosted a Django Web App on your local machine and served your own response on an endpoint!


Tagged in django