Django Request Object

Learn how to read and manage the information provided by an HTTP request in Django

This page explains the request object provided by Django as the default argument in views. For those unfamiliar with Django, this web framework is written in Python by experienced developers using a batteries-included concept. For more information regarding this amazing web framework please access:

• How to install Django - simple, tested steps to install Django

• Django for beginners - a comprehensive tutorial that covers the basics

Let's create a Django project and code our first view where the request object is exposed:

Create and activate a virtual environment

$ # Linux-based systems
$ virtualenv env
$ source env/bin/activate  

For Windows-based systems, the syntax is slightly different:

$ virtualenv env
$ .\env\Scripts\activate

Install Django - using PIP

$ pip install django

The above command will install the latest stable version of Django.

Build a Django Project

A new project can be generated with ease in Django by using django-admin that provides a collection of settings for the database, Django, and security layer.

Create the project folder

$ mkdir my-django-project
$ cd my-django-project

Inside the directory, we will generate the core of our project using django-admin tool :

$ django-admin startproject config .

Note: Take into account that . at the end of the command.

Create the database and the app tables

$ python manage.py makemigrations # generate SQL
$ python manage.py migrate        # Apply changes on database   

Start the application

$ python manage.py runserver 
$
$ # Access the web app in browser: http://127.0.0.1:8000/

At this point we should see the default Django page in the browser:

Django - Default Project Page.

Create New Application

In the previous section, we've generated the core of the project that handles the configuration and now we will create the first Django application to serve a simple page to the users.

$ python manage.py startapp app

Update settings to include the new app - config/settings.py

# File: config/settings.py (partial content)
...
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app'                           # <-- NEW
]
...

Update routing - config/urls.py

# File: config/urls.py (partial content)
...
from django.contrib import admin
from django.urls import path
from django.conf.urls import include, url   # <-- NEW
from app.views import hello                 # <-- NEW

urlpatterns = [
    path('admin/', admin.site.urls),
    url('', hello),                         # <-- NEW
]

Code out first route and get access to the request object

from django.shortcuts import render
from django.http import HttpResponse     # <-- NEW

def hello(request):                      # <-- NEW    
    return HttpResponse("Hello Django")  # <-- NEW   

Request Object Properties

The request object in Django comes with a few interesting properties:

Item / Helper	Sample Value	Short Information
REMOTE_ADDR	12.245.68.71	IP of the client
HTTP_USER_AGENT	Mozilla/5.0	User Browser Information
request.path	/admin/	The URL without domain
request.is_secure()	True / False	True if the request was made over HTTPS
request.method	POST / GET	The Request Method

How to check the request type in view.

A widely user code chunk is when we test the type of the request and manage the submitted data on POST (when we send information to the server, login action for instance):

from django.shortcuts import render
from django.http import HttpResponse     

def hello(request):

    if request.method == 'GET':    
        return HttpResponse("Received a GET request")
        
    elif request.method == 'POST':    
        return HttpResponse("Received a POST request")

For newcomers, GET is used to pull information from the server without altering anything. Search is a good example of a GET request when we try to locate information on Google or Wikipedia.

POST is used to update the information on the server like change the title for a book or register a new item in our service.

Another difference between GET and POST is the location of the submitted information.

• GET submits data in URL: http://myservice.com?search=all_books

• POST submits data in the request body (not visible in the URL)

List all request headers

This subsection contains a code sample that prints all headers and request objects provided by Django:

def headers(request): 
    values = request.META.items() 
    
    rows = ''
    for key, val in values:
        rows += '<tr><td>%s</td><td>%s</td></tr>' % (key, val)

    return HttpResponse( '<table>' + rows + '</table>' )

Here is the script output executed using a local development server:

Django Request Object - Provided Information.

Read Request Variables

Django provides dictionaries for GET and POST requests populated with all variables sent by the client. We can access the variables by key or using get() helper for both cases.

Read GET variables

def parse_get(request):
    
    var1 = request.GET['my_var']       # this might throw KeyError exception
    
    var2 = request.GET.get('var_2')    # Soft read on variable
    
    var3 = request.GET.get('var_3', 1) # Soft Read with Default value     

For POST, the process is identical.

def parse_post(request):
    
    post_var1 = request.POST['my_var']       # this might throw KeyError exception
    
    post_var2 = request.POST.get('var_2')    # Soft read on variable
    
    post_var3 = request.POST.get('var_3', 9) # Soft Read with Default value     

Thanks for reading! For more topics, feel free to contact Appseed.

Resources

• Read more about Django (official docs)

• Start fast a new project using development-ready Django Starters