Easy Pagination In Perl

Introduction

Pagination is a very basic requirement of a web application, in this article we'll see how to implement pagination easily using the Perl module Data::Pageset.

Basically there are two types of pagination, Jumping and Sliding. In the jumping type the current page jumps from the starting position in a frame till the end and goes till the get before moving on to the next frame. Whereas, in the sliding type the current page remains in the center of the frame (of course except the current page is not in the starting or ennding half of the pageset), here is an illustration of the jumping and sliding pagination types which will help you understand the logic better.

Jumping

Code:

   [1] 2  3  4  5  =>   # first frame: [1-5]
<=  1 [2] 3  4  5  =>
<=  1  2 [3] 4  5  =>
<=  1  2  3 [4] 5  =>
<=  1  2  3  4 [5] =>   # current page jumps to the next frame
<= [6] 7  8  9 10  =>   # second frame: [6-10]
<=  6 [7] 8  9 10  =>
<=  6  7 [8] 9 10  =>

Sliding

Code:

  [1] 2  3  4  5  => 
<= 1 [2] 3  4  5  => 
<= 1  2 [3] 4  5  =>   # from here onwards current page remaing in the center
<= 2  3 [4] 5  6  =>   # current page
<= 3  4 [5] 6  7  =>   # and it stays there...
<= 4  5 [6] 7  8  => 
<= 5  6 [7] 8  9  => 
<= 6  7 [8] 9 10  => 

The Code

Code:

## the default is Jumping
use Data::Pageset;

my $total_entries = 500;
my $entries_per_page = 10;
my $current_page = 30;
my $pages_per_set = 11;

my $paging_jump = Data::Pageset->new({
    'total_entries'       => $total_entries, 
    'entries_per_page'    => $entries_per_page, 
    # Optional, will use defaults otherwise.
    'current_page'        => $current_page,
    'pages_per_set'       => $pages_per_set
});

my $paging_slide = Data::Pageset->new({
    'total_entries'       => $total_entries, 
    'entries_per_page'    => $entries_per_page, 
    # Optional, will use defaults otherwise.
    'current_page'        => $current_page,
    'pages_per_set'       => $pages_per_set,
    'mode'                => 'slide'
});

# Print the page numbers of the current set : Jumping
foreach my $page (@{$paging->pages_in_set()}) 
{
	if($page == $paging_jump->current_page()) 
	{
		print "[$page] ";
	} 
	else 
	{
		print "$page ";
	}
}

print "\n\n";

# Print the page numbers of the current set : Jumping
foreach my $page (@{$paging_slide->pages_in_set()}) 
{
	if($page == $paging->current_page()) 
	{
		print "[$page] ";
	} 
	else 
	{
		print "$page ";
	}
}

Hope you liked the article and find it useful, you can check more about the module at http://search.cpan.org/~llap/Data-Pageset-1.05/lib/Data/Pageset.pm