cakePHP : Pagination

If part of your application includes displaying lots of results, it's a good idea to give the user the possibility to view the results in digestable chunks and possibly to be able to sort the presented data. This tutorial will explain how, after copying a few files into your application, you can achieve this in very few lines of code.
You need almost no knowledge of cake to be able to make use of this tutorial :).

If you already have a table in mind that you want to add pagination to, read on; otherwise run through http://manual.cakephp.org/appendix/blog_tutorial to have some code to play with.

Setting Up

All of the files necessary are available here in the bakery.

Save this file http://bakery.cakephp.org/articles/view/67 as /app/controllers/components/pagination.php

Save this file http://bakery.cakephp.org/articles/view/68 as /app/views/helpers/pagination.php

Save this file http://bakery.cakephp.org/articles/view/69 as /app/views/elements/pagination.thtml


Create/modify the Controller

The only change necessary to use pagination is to include the component, the helper and call the component method "init" before the relavent find.
Controller Class:


class PostsController extends AppController
{
var $name = 'Posts'; // for PHP4 installs
var $components = array ('Pagination'); // Added
var $helpers = array('Pagination'); // Added

function index() {
$criteria=NULL;
list($order,$limit,$page) = $this->Pagination->init($criteria); // Added
$data = $this->Post->findAll($criteria, NULL, $order, $limit, $page); // Extra parameters added

$this->set('data',$data);
}
}
?>

Create/modify the View



To make use of pagination, include the element, and optionally modify your table headers to allow changing the sort order of results:
View Template:

Paginated Posts Index

$pagination->setPaging($paging); // Initialize the pagination variables
$th = array (
$pagination->sortBy('id'),
$pagination->sortBy('title'),
$pagination->sortBy('created')
); // Generate the pagination sort links
echo $html->tableHeaders($th); // Create the table headers with sort links if desired

foreach ($data as $output)
{
$tr = array (
$output['Post']['id'],
$html->link($output['Post']['title'], "/Posts/View/{$output['Post']['id']}"),
$output['Post']['created']
);
echo $html->tableCells($tr,array('class'=>'altRow'),array('class'=>'evenRow'));
}
?>

renderElement('pagination'); // Render the pagination element ?>


Adding Ajax updates


If you include the RequestHandler component, the AJAX helper in your controller and the prototype js file is loaded in your view - you get your updates by ajax. Yes, it's that simple. The div that will be updated by default is the "content" div, you can change this by specifying in the component (either directly, or at run time) which div to update. And yes, you can disable this automatic behaviour if required.
How to add Prototype

So how do you add the prototype library..? Well...
Modify your layout

PHP Snippet:

The Prototype JavaScript library is availble at http://prototype.conio.net/
put prototype.js in /app/webroot/js/
Add the JavaScript code inside the head tag

if(isset($javascript)):
echo $javascript->link('prototype.js');
endif;
?>