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Django - Pagination

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• Django - Pagination
  • Paginator class
  • Page class
  • Exceptions
  • Using ListView
  • Using Paginator in a view function

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Paginator class

• Pagination use the Paginator class

• Constructor

Paginator(object_list, per_page, orphans=0, allow_empty_first_page=True)
# object_list: 

• Parameter:

Parameter	Description
ELLIPSIS	A translatable string used as a substitute for elided page numbers
count	The total number of objects, across all pages.
num_pages	The total number of pages.
page_range	A 1-based range iterator of page numbers,

• Attributes

Attribute	Description
object_list	Required. A list of sliceable object
per_page	Required. The maximum number of items to include on a page
orphans	The maximum number of items on last page
allow_empty_first_page	Whether the first page can to be empty

• Methods

Method	Description
get_page(number)	Returns a Page object with the given 1-based index
page(number)	Returns a Page object with the given 1-based index.
get_elided_page_range(number)	Returns a 1-based list of page numbers

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Page class

• Constructor

• A page acts like a sequence of Page.object_list when using len() or iterating it directly.

Page(object_list, number, paginator)
# object_list: 

• Methods:

Method	Description
has_next()	Returns True if there’s a next page.
has_previous()	Returns True if there’s a previous page.
has_other_pages()	Returns True if there’s a next or previous page.
next_page_number()	Returns the next page number.
previous_page_number()	Returns the previous page number.
start_index()	Returns the 1-based index of the first object on the page.
end_index()	Returns the 1-based index of the last object on the page.

• Attributes

Attribute	Description
object_list	The list of objects on this page.
number	The 1-based page number for this page.
paginator	The associated Paginator object.

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Exceptions

Exception	Description
InvalidPage	Raised when a paginator is passed an invalid page number.
PageNotAnInteger	Raised when page() is given a value that isn’t an integer.
EmptyPage	Raised when page() is given a valid value but no objects exist on that page.

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Using ListView

• Using the paginate_by attribute to define maximum items per page.

• Example:

# Blog/views.py
class ListBlog(ListView):
    # limits the number of objects per page, adds a paginator and page_obj to the context.
    paginate_by = 4
    model = Blog

<!-- display objects on current page -->
<ul class="list-group">
  // for blog in page_obj \\
  <li class="list-group-item">
    <a href="// url 'Blog:detail' blog.pk \\">__blog.title|upper__</a>
  </li>
  // endfor \\
</ul>
<!-- pagination -->
<nav aria-label="Page navigation d-flex">
  <ul class="pagination">
    <li class="page-item me-auto">
      <a class="nav-link disabled" aria-disabled="true">
        Page __ page_obj.number __ of __ page_obj.paginator.num_pages __
      </a>
    </li>
    // if page_obj.has_previous \\
    <li class="page-item">
      <a class="page-link" href="?page=1">&laquo; </a>
    </li>
    <li class="page-item">
      <a class="page-link" href="?page=__ page_obj.previous_page_number __"
        >Previous</a
      >
    </li>
    // endif \\

    <li class="page-item active" aria-current="page">
      <span class="page-link">__ page_obj.number __</span>
    </li>

    // if page_obj.has_next \\
    <li class="page-item">
      <a class="page-link" href="?page=__ page_obj.next_page_number __">Next</a>
    </li>
    <li class="page-item">
      <a class="page-link" href="?page=__ page_obj.paginator.num_pages __">
        &raquo;
      </a>
    </li>
    // endif \\
  </ul>
</nav>

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Using Paginator in a view function

• Example:

# Blog/views.py
from django.core.paginator import Paginator

def listing(request):
    contact_list = Blog.objects.all()
    paginator = Paginator(contact_list, 5)  # Creates a paginator

    page_number = request.GET.get("page")   # Get the page number from request
    page_obj = paginator.get_page(page_number)  # Creates a page object
    return render(request, "Blog/blog_list.html", {"page_obj": page_obj}) # return the page object

<!-- display objects on current page -->
<ul class="list-group">
  // for blog in page_obj \\
  <li class="list-group-item">
    <a href="// url 'Blog:detail' blog.pk \\">__blog.title|upper__</a>
  </li>
  // endfor \\
</ul>

<!-- pagination -->
<ul class="nav pagination d-flex justify-content-between">
  // if page_obj.has_previous \\
  <li class="page-item">
    <a class="nav-link" aria-current="page" href="?page=1">&laquo; first</a>
  </li>
  <li class="page-item">
    <a class="nav-link" href="?page=__ page_obj.previous_page_number __"
      >previous</a
    >
  </li>
  // endif \\
  <li class="nav-item mx-auto">
    <a class="nav-link disabled" aria-disabled="true">
      __ page_obj.number __ / __ page_obj.paginator.num_pages __
    </a>
  </li>
  // if page_obj.has_next \\
  <li class="nav-item">
    <a class="nav-link" href="?page=__ page_obj.next_page_number __"> next </a>
  </li>
  <li class="nav-item">
    <a class="nav-link" href="?page=__ page_obj.paginator.num_pages __">
      last &raquo;
    </a>
  </li>
  // endif \\
</ul>

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