Views In Django | Python

Django Views are one of the vital participants of MVT Structure of Django. As per Django Documentation, A view function is a Python function that takes a Web request and returns a Web response. This response can be the HTML contents of a Web page, or a redirect, or a 404 error, or an XML document, or an image, anything that a web browser can display. 

Django views are part of the user interface — they usually render the HTML/CSS/Javascript in your Template files into what you see in your browser when you render a web page. (Note that if you’ve used other frameworks based on the MVC (Model-View-Controller), do not get confused between Django views and views in the MVC paradigm. Django views roughly correspond to controllers in MVC, and Django templates to views in MVC.)

Django View Example

Illustration of How to create and use a Django view using an Example. Consider a project named neveropen having an app named Lazyroar. 

Refer to the following articles to check how to create a project and an app in Django.
 

• How to Create a Basic Project using MVT in Django?
• How to Create an App in Django ?

After you have a project ready, we can create a view in Lazyroar/views.py,

Let’s step through this code one line at a time: 

• First, we import the class HttpResponse from the django.http module, along with Python’s datetime library.
• Next, we define a function called Lazyroar_view. This is the view function. Each view function takes an HttpRequest object as its first parameter, which is typically named request.
• The view returns an HttpResponse object that contains the generated response. Each view function is responsible for returning an HttpResponse object.

For more info on HttpRequest and HttpResponse visit – Django Request and Response cycle – HttpRequest and HttpResponse Objects
Let’s get this view to working, in Lazyroar/urls.py,

Now, visit http://127.0.0.1:8000/,

To check how to make a basic project using MVT (Model, View, Template) structure of Django, visit Creating a Project Django.

Types of Views

Django views are divided into two major categories:-

• Function-Based Views
• Class-Based Views

Function Based Views

Function based views are written using a function in python which receives as an argument HttpRequest object and returns an HttpResponse Object. Function based views are generally divided into 4 basic strategies, i.e., CRUD (Create, Retrieve, Update, Delete). CRUD is the base of any framework one is using for development. 
 

Function based view Example –

Let’s Create a function-based view list view to display instances of a model. Let’s create a model of which we will be creating instances through our view. In Lazyroar/models.py,

After creating this model, we need to run two commands in order to create Database for the same.

Python manage.py makemigrations
Python manage.py migrate

Now let’s create some instances of this model using shell, run form bash,

Python manage.py shell

Enter following commands

>>> from Lazyroar.models import GeeksModel
>>> GeeksModel.objects.create(
                       title="title1",
                       description="description1").save()
>>> GeeksModel.objects.create(
                       title="title2",
                       description="description2").save()
>>> GeeksModel.objects.create(
                       title="title2",
                       description="description2").save()

Now if you want to see your model and its data in the admin panel, then you need to register your model.
Let’s register this model. In Lazyroar/admin.py,

Now we have everything ready for the back end. Verify that instances have been created from http://localhost:8000/admin/Lazyroar/Lazyroarmodel/ 

Let’s create a view and template for the same. In Lazyroar/views.py,

Create a template in templates/list_view.html,

Let’s check what is there on http://localhost:8000/

Similarly, function based views can be implemented with logics for create, update, retrieve and delete views.
Django CRUD (Create, Retrieve, Update, Delete) Function Based Views :-
 

Class Based Views

Class-based views provide an alternative way to implement views as Python objects instead of functions. They do not replace function-based views, but have certain differences and advantages when compared to function-based views: 

• Organization of code related to specific HTTP methods (GET, POST, etc.) can be addressed by separate methods instead of conditional branching.
• Object oriented techniques such as mixins (multiple inheritance) can be used to factor code into reusable components.

Class-based views are simpler and efficient to manage than function-based views. A function-based view with tons of lines of code can be converted into class-based views with few lines only. This is where Object-Oriented Programming comes into impact.  

Class based view Example –

In Lazyroar/views.py,

Now create a URL path to map the view. In Lazyroar/urls.py,

Create a template in templates/Lazyroar/Lazyroarmodel_list.html,

Let’s check what is there on http://localhost:8000/
 

Django CRUD (Create, Retrieve, Update, Delete) Class Based Generic Views :-

• CreateView – Class based Views Django
• DetailView – Class based Views Django
• UpdateView – Class based Views Django
• DeleteView – Class based Views Django
• FormView – Class Based Views Django