Views In Django | Python

Django Views are one of the vital participants of MVT Structure of Django. A View is the user interface — what you see in your browser when you render a website. It is represented by HTML/CSS/Javascript and Jinja files. 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.

Illustration of How to create and use a Django view using an Example. Consider a project named mcatutorialshaving an app namedmcatutorials.

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 mcatutorials/views.py,

# import Http Response from django 
from django.http import HttpResponse 
# get datetime 
import datetime 
  
# create a function 
def mcatutorials_view(request): 
    # fetch date and time 
    now = datetime.datetime.now() 
    # convert to string 
    html = "Time is {}".format(now) 
    # return response 
    return HttpResponse(html) 

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 mcatutorials_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 mcatutorials/urls.py,

from django.urls import path 
  
# importing views from views..py 
from .views import mcatutorials_view 
  
urlpatterns = [ 
    path('', mcatutorials_view), 
] 

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.

Django views are divided into two major categories :-

• Function Based Views
• Class Based Views

Function based views are writter using a function in python which recieves 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.

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 mcatutorials/models.py,

# import the standard Django Model 
# from built-in library 
from django.db import models 
   
# declare a new model with a name "McatutorialsModel" 
class McatutorialsModel(models.Model): 
  
    # fields of the model 
    title = models.CharField(max_length = 200) 
    description = models.TextField() 
  
    # renames the instances of the model 
    # with their title name 
    def __str__(self): 
        return self.title 

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 mcatutorials.models import McatutorialsModel
>>> McatutorialsModel.objects.create(
                       title="title1",
                       description="description1").save()
>>> McatutorialsModel.objects.create(
                       title="title2",
                       description="description2").save()
>>> McatutorialsModel.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 Mcatutorials/admin.py,

from django.contrib import admin 
from .models import McatutorialsModel 
# Register your models here. 
admin.site.register(McatutorialsModel) 

Now we have everything ready for back end. Verify that instnaces have been created from http://localhost:8000/admin/mcatutorials/mcatutorialsmodel/

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

from django.shortcuts import render 
  
# relative import of forms 
from .models import McatutorialsModel 
  
  
def list_view(request): 
    # dictionary for initial data with  
    # field names as keys 
    context ={} 
  
    # add the dictionary during initialization 
    context["dataset"] = McatutorialsModel.objects.all() 
          
    return render(request, "list_view.html", context)

Create a template in templates/list_view.html,

< div class="main"> 
  
    {% for data in dataset %}. 
  
    {{ data.title }}< br/> 
    {{ data.description }}< br/> 
    < hr/> 
  
    {% endfor %} 
  
< /div>

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.

Create View – Function based Views Django

Detail View – Function based Views Django

Update View – Function based Views Django

Delete View – Function based Views Django

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 a class-based views with few lines only. This is where Object-Oriented Programming comes into impact.

from django.views.generic.list import ListView 
from .models import McatutorialsModel 
  
class McatutorialsList(ListView): 
  
    # specify the model for list view 
    model = McatutorialsModel 

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

from django.urls import path 
  
# importing views from views..py 
from .views import McatutorialsList 
urlpatterns = [ 
    path('', McatutorialsList.as_view()), 
] 

Create a template in templates/mcatutorials/mcatutorialsmodel_list.html,

< ul> 
    < !-- Iterate over object_list -->
    {% for object in object_list %} 
    < !-- Display Objects -->
    < li>{{ object.title }}< /li> 
    < li>{{ object.description }}< /li> 
  
    < hr/> 
    < !-- If objet_list is empty  -->
    {% empty %} 
    < li>No objects yet.< /li> 
    {% endfor %} 
< /ul> 

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

• 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