Django Pagination

Django is an open-source free to use python based web framework. Django provides many inbuilt tools for web developers to provide rapid web development. One of these tools is pagination. Pagination is the technique to divide the content of one large page into many smaller pages. Pagination can be found in many web browsers, blogs, websites, etc.

Django provides some classes to support pagination. Paginator class provides the functioning of pagination in Django. We can pass QuerySet to the paginator class.

The paginator class resides in Django/core/paginator.py.  So if we want to use pagination in our project, we have to import it to our project.

From Django.core.paginator import Paginator

Paginator Class

The Paginator class takes the QuerySet as an input and then divides it into page objects displayed on different pages. The paginator class is connected to a view and then called inside a template.

Syntax:

class Paginator(object_list, per_page, orphans=0, allow_empty_first_page=True)

Arguments:

• Object_list: This is a required argument. It is a list of objects which we want to display on the page. We can also provide QuerySet, a tuple, or other sliceable objects with len() or count() method.
• Per_page: This is also a required argument. It represents the maximum number of objects we want to display on our page.
• Orphans: This is an optional argument. It is used to skip the last page if there are very few objects in it. If the number of items on the last page is less than or equal to the orphan, then those items will get shifted to the previous page.
• Allow_empty_first_page: This is also optional. It decides whether or not to keep the first page empty. If this is set to false and the object list is null, then an empty page error will be raised.

Methods:

• Get_page(number):It returns the page object with the index equals number starting from 1. If the given value is a negative number, it will return the first page, and if the value is greater than the page number, then the last page will be returned.
• Page(number): This returns a page object with an index range from 1. This will show an error if the value cannot be converted to an integer by calling int() or the page number does not exist.

Attributes:

• Count:Returns the total number of objects on all the pages.
• Num_pages:Returns the total number of pages.
• Page_range:It returns an index-1 based range iterator of page numbers.

Example:

Now we will use pagination in our project. In this project, we are rendering a list of books and their authors, and now we want to use pagination to divide the books across different pages. We have defined the Books model in models.py. To use the pagination, use the below code in the views.py file.

View.py:

fromdjango.shortcuts import render
fromdjango.core.paginator import Paginator 
from .models import Book


def index(request):
books = Book.objects.all()
book_paginator = Paginator(books, 20)
page_num = request.GET.get('page')
page = book_paginator.get_page(page_num)
context = {
        'count' : book_paginator.count,
        'page' : page
    }
return render(request, 'books/index.html', context)

In this code, first, we have imported the Paginator class.  Then the book's objects are divided into a total 20 number of different pages. Then we are fetching the page number from GET. After getting the page number, we can get the content of that page by the get_page() method.

Index.html:

<!DOCTYPE html>
<html lang="en">
……..
……..
<body>
<h2>Total Number of Books: {{ count }}</h2>
<h2>Page Number: {{ page.number }}</h2>


    {% for book in page.object_list %}
<div class="book-item">{{ book.title }} by {{ book.author}}</div><br>
    {% endfor %}


<div class="page-links">
        {% if page.has_previous %}
<a href="{% url 'index' %}?page={{ page.previous_page_number }}">Previous Page</a>
        {% endif %}
        {% if page.has_next %}
<a href="{% url 'index' %}?page={{ page.next_page_number }}">Next Page</a>
        {% endif %}
</div>


</body>
</html>

On this page, we have displayed the information, previous and next page links. We have skipped the styling for this file.

Class Page

The page object is generally not created manually. Rather, we use them by iterating through  Paginator or Paginator.page().

Syntax:

class Page(object_list, number, paginator)

Arguments:

• Object_list:It represents the list of objects.
• Number:Number represents the number of the page object.
• Paginator:It is the paginator object for which we are constructing this page.

Methods:

• has_next(): A Boolean argument returns True if there is a page next to this page.
• has_previous():A Boolean argument returns True if there is a page previous to this page.
• next_page_number():Returns the page number of the next page, raises an error if the next page does not exist.
• previous_page_numer():Returns the page number of the previous page, raises an error if the previous page does not exist.
• has_other_pages():A Boolean argument, returns True if previous or next page exists.