One of the main obstacles of creating flexible and user-friendly web applications is designing an intuitive user interface. Many applications tend to grow in size and complexity quickly, and designers and programmers alike find they are unable to cope with displaying hundreds or thousands of records. Refactoring takes time, and performance and user satisfaction can suffer.
Displaying a reasonable number of records per page has always been a critical part of every application and used to cause many headaches for developers. CakePHP eases the burden on the developer by providing a terse way to paginate data.
Pagination in CakePHP controllers is done through the paginate() method. You
then use :php:class:`~Cake\\View\\Helper\\PaginatorHelper` in your view templates
to generate pagination controls.
You can call paginate() using an ORM table instance or Query object:
public function index()
{
// Paginate the ORM table.
$this->set('articles', $this->paginate($this->Articles));
// Paginate a partially completed query
$query = $this->Articles->find('published');
$this->set('articles', $this->paginate($query));
}
More complex use cases are supported by configuring the $paginate
controller property or as the $settings argument to paginate(). These
conditions serve as the basis for you pagination queries. They are augmented
by the sort, direction, limit, and page parameters passed in
from the URL:
class ArticlesController extends AppController
{
public $paginate = [
'limit' => 25,
'order' => [
'Articles.title' => 'asc'
]
];
}
Tip
Default order options must be defined as an array.
While you can include any of the options supported by
:php:meth:`~Cake\\ORM\\Table::find()` such as fields in your pagination
settings. It is cleaner and simpler to bundle your pagination options into
a :ref:`custom-find-methods`. You can use your finder in pagination by using the
finder option:
class ArticlesController extends AppController
{
public $paginate = [
'finder' => 'published',
];
}
If your finder method requires additional options you can pass those as values for the finder:
class ArticlesController extends AppController
{
// find articles by tag
public function tags()
{
$tags = $this->request->getParam('pass');
$customFinderOptions = [
'tags' => $tags
];
// We're using the $settings argument to paginate() here.
// But the same structure could be used in $this->paginate
//
// Our custom finder is called findTagged inside ArticlesTable.php
// which is why we're using `tagged` as the key.
// Our finder should look like:
// public function findTagged(Query $query, array $options) {
$settings = [
'finder' => [
'tagged' => $customFinderOptions
]
];
$articles = $this->paginate($this->Articles, $settings);
$this->set(compact('articles', 'tags'));
}
}
In addition to defining general pagination values, you can define more than one
set of pagination defaults in the controller. The name of each model can be used
as a key in the $paginate property:
class ArticlesController extends AppController
{
public $paginate = [
'Articles' => [],
'Authors' => [],
];
}
The values of the Articles and Authors keys could contain all the
properties that a basic $paginate array would.
Once you have used paginate() to create results. The controller's request
will be updated with paging parameters. You can access the pagination metadata
at $this->request->getAttribute('paging').
By default Controller::paginate() uses the Cake\Datasource\Paging\NumericPaginator
class which does a COUNT() query to calculate the size of the result set so
that page number links can be rendered. On very large datasets this count query
can be very expensive. In situations where you only want to show 'Next' and 'Previous'
links you can use the 'simple' paginator which does not do a count query:
class ArticlesController extends AppController
{
public $paginate = [
'className' => 'Simple', // Or use Cake\Datasource\Paging\SimplePaginator::class FQCN
];
}
When using the SimplePaginator you will not be able to generate page
numbers, counter data, links to the last page, or total record count controls.
You can paginate multiple models in a single controller action, using the
scope option both in the controller's $paginate property and in the
call to the paginate() method:
// Paginate property
public $paginate = [
'Articles' => ['scope' => 'article'],
'Tags' => ['scope' => 'tag']
];
// In a controller action
$articles = $this->paginate($this->Articles, ['scope' => 'article']);
$tags = $this->paginate($this->Tags, ['scope' => 'tag']);
$this->set(compact('articles', 'tags'));
The scope option will result in PaginatorComponent looking in
scoped query string parameters. For example, the following URL could be used to
paginate both tags and articles at the same time:
/dashboard?article[page]=1&tag[page]=3
See the :ref:`paginator-helper-multiple` section for how to generate scoped HTML elements and URLs for pagination.
To paginate the same model multiple times within a single controller action you need to define an alias for the model.:
// In a controller action
$this->paginate = [
'Articles' => [
'scope' => 'published_articles',
'limit' => 10,
'order' => [
'id' => 'desc',
],
],
'UnpublishedArticles' => [
'scope' => 'unpublished_articles',
'limit' => 10,
'order' => [
'id' => 'desc',
],
],
];
$publishedArticles = $this->paginate(
$this->Articles->find('all', [
'scope' => 'published_articles'
])->where(['published' => true])
);
// Load an additional table object to allow differentiating in paginator
$unpublishedArticlesTable = $this->fetchTable('UnpublishedArticles', [
'className' => 'App\Model\Table\ArticlesTable',
'table' => 'articles',
'entityClass' => 'App\Model\Entity\Article',
]);
$unpublishedArticles = $this->paginate(
$unpublishedArticlesTable->find('all', [
'scope' => 'unpublished_articles'
])->where(['published' => false])
);
By default sorting can be done on any non-virtual column a table has. This is
sometimes undesirable as it allows users to sort on un-indexed columns that can
be expensive to order by. You can set the allowed list of fields that can be sorted
using the sortableFields option. This option is required when you want to
sort on any associated data, or computed fields that may be part of your
pagination query:
public $paginate = [
'sortableFields' => [
'id', 'title', 'Users.username', 'created'
]
];
Any requests that attempt to sort on fields not in the allowed list will be ignored.
The number of results that are fetched per page is exposed to the user as the
limit parameter. It is generally undesirable to allow users to fetch all
rows in a paginated set. The maxLimit option asserts that no one can set
this limit too high from the outside. By default CakePHP limits the maximum
number of rows that can be fetched to 100. If this default is not appropriate
for your application, you can adjust it as part of the pagination options, for
example reducing it to 10:
public $paginate = [
// Other keys here.
'maxLimit' => 10
];
If the request's limit param is greater than this value, it will be reduced to
the maxLimit value.
Additional associations can be loaded to the paginated table by using the
contain parameter:
public function index()
{
$this->paginate = [
'contain' => ['Authors', 'Comments']
];
$this->set('articles', $this->paginate($this->Articles));
}
Controller::paginate() will throw a NotFoundException when trying to
access a non-existent page, i.e. page number requested is greater than total
page count.
So you could either let the normal error page be rendered or use a try catch
block and take appropriate action when a NotFoundException is caught:
use Cake\Http\Exception\NotFoundException;
public function index()
{
try {
$this->paginate();
} catch (NotFoundException $e) {
// Do something here like redirecting to first or last page.
// $this->request->getAttribute('paging') will give you required info.
}
}
Check the :php:class:`~Cake\\View\\Helper\\PaginatorHelper` documentation for how to create links for pagination navigation.