Usage

Paginating data collections

In order to paginate items into pages, Zend\Paginator must have a generic way of accessing that data. For that reason, all data access takes place through data source adapters. Several adapters ship with zend-paginator by default:

Database optimizations

Instead of selecting every matching row of a given query, the DbSelect adapter retrieves only the smallest amount of data necessary for displaying the current page. Because of this, a second query is dynamically generated to determine the total number of matching rows.

To create a paginator instance, you must supply an adapter to the constructor:

use Zend\Paginator\Adapter;
use Zend\Paginator\Paginator;

$paginator = new Paginator(new Adapter\ArrayAdapter($array));

In the case of the NullFill adapter, in lieu of a data collection you must supply an item count to its constructor.

Although the instance is technically usable in this state, in your controller action you'll need to tell the paginator what page number the user requested. This allows advancing through the paginated data.

$paginator->setCurrentPageNumber($page);

The simplest way to keep track of this value is through a URL parameter. The following is an example zend-router route configuration:

return [
    'routes' => [
        'paginator' => [
            'type' => 'segment',
            'options' => [
                'route' => '/list/[page/:page]',
                'defaults' => [
                    'page' => 1,
                ],
            ],
        ],
    ],
];

With the above route (and using zend-mvc controllers), you might set the current page number in your controller action like so:

$paginator->setCurrentPageNumber($this->params()->fromRoute('page'));

There are other options available; see the Configuration chapter for more on them.

Finally, you'll need to assign the paginator instance to your view. If you're using zend-mvc and zend-view, you can assign the paginator object to your view model:

$vm = new ViewModel();
$vm->setVariable('paginator', $paginator);
return $vm;

The DbSelect adapter

Installation Requirements

The DbSelect adapter depends on the zend-db component, so be sure to have it installed before getting started:

$ composer require zendframework/zend-db

Most adapters receive their datasets directly. However, the DbSelect adapter requires a more detailed explanation regarding the retrieval and count of the data from the database.

You do not have to retrieve data from the database prior to using the DbSelect adapter; the adapter will do the retrieval for you, as well as provide a count of total pages. If additional work has to be done on the database results which cannot be expressed via the provided Zend\Db\Sql\Select, object you must extend the adapter and override the getItems() method.

Additionally this adapter does not fetch all records from the database in order to count them. Instead, the adapter manipulates the original query to produce a corresponding COUNT query, and uses the new query to get the number of rows. While this approach requires an extra round-trip to the database, doing so is stillmany times faster than fetching an entire result set and using count(), especially with large collections of data.

The database adapter will try and build the most efficient query that will execute on pretty much any modern database. However, depending on your database or even your own schema setup, there might be more efficient ways to get a rowcount.

There are two approaches for doing this. The first is to extend the DbSelect adapter and override the count() method:

class MyDbSelect extends DbSelect
{
    public function count()
    {
        if ($this->rowCount) {
            return $this->rowCount;
        }

        $select = new Select();
        $select
          ->from('item_counts')
          ->columns(['c'=>'post_count']);

        $statement = $this->sql->prepareStatementForSqlObject($select);
        $result    = $statement->execute();
        $row       = $result->current();
        $this->rowCount = $row['c'];

        return $this->rowCount;
    }
}

$adapter = new MyDbSelect($query, $adapter);

Alternately, you can pass an additional Zend\Db\Sql\Select object as the fourth constructor argument to the DbSelect adapter to implement a custom count query.

For example, if you keep track of the count of blog posts in a separate table, you could achieve a faster count query with the following setup:

use Zend\Db\Sql\Select;
use Zend\Paginator\Adapter\DbSelect;
use Zend\Paginator\Paginator;

$countQuery = new Select();
$countQuery
    ->from('item_counts')
    ->columns([ DbSelect::ROW_COUNT_COLUMN_NAME => 'post_count' ]);

$adapter = new DbSelect($query, $dbAdapter, null, $countQuery);
$paginator = new Paginator($adapter);

Alternatively, the same can be achieved using the provided factory:

use Zend\Paginator\Adapter\DbSelect;
use Zend\Paginator\Factory as PaginatorFactory;

$countQuery = new Select();
$countQuery
    ->from('item_counts')
    ->columns([ DbSelect::ROW_COUNT_COLUMN_NAME => 'post_count' ]);

$paginator = PaginatorFactory::factory(
    [
        $query,
        $dbAdapter,
        null,
        $countQuery,
    ],
    DbSelect::class
);

This approach will probably not give you a huge performance gain on small collections and/or simple select queries. However, with complex queries and large collections, a similar approach could give you a significant performance boost.

The DbSelect adapter also supports returning of fetched records using the ResultSet subcomponent of zend-db. You can override the concrete ResultSet implementation by passing an object implementing Zend\Db\ResultSet\ResultSetInterface as the third constructor argument to the DbSelect adapter:

use Zend\Db\ResultSet\HydratingResultSet;
use Zend\Paginator\Adapter\DbSelect;
use Zend\Paginator\Paginator;

// $objectPrototype is an instance of our custom entity
// $hydrator is a custom hydrator for our entity
// (implementing Zend\Hydrator\HydratorInterface)
$resultSet = new HydratingResultSet($hydrator, $objectPrototype);

$adapter = new DbSelect($query, $dbAdapter, $resultSet)
$paginator = new Zend\Paginator\Paginator($adapter);

Now when we iterate over $paginator we will get instances of our custom entity instead of associative arrays.

Rendering pages with view scripts

Installation Requirements

The rendering with view scripts depends on the zend-view component, so be sure to have it installed before getting started:

$ composer require zendframework/zend-view

The view script is used to render the page items (if you're using zend-paginator to do so) and display the pagination control.

Because Zend\Paginator\Paginator implements the SPL interface IteratorAggregate, you can loop over an instance using foreach:

<html>
<body>
<h1>Example</h1>
<?php if (count($this->paginator)): ?>
<ul>
<?php foreach ($this->paginator as $item): ?>
  <li><?= $item; ?></li>
<?php endforeach; ?>
</ul>
<?php endif; ?>

<?= $this->paginationControl(
    $this->paginator,
    'Sliding',
    'my_pagination_control',
    ['route' => 'application/paginator']
) ?>
</body>
</html>

Notice the view helper call near the end. PaginationControl accepts up to four parameters: the paginator instance, a scrolling style, a view script name, and an array of additional parameters.

The second and third parameters are very important. Whereas the view script name is used to determine how the pagination control should look, the scrolling style is used to control how it should behave. Say the view script is in the style of a search pagination control, like the one below:

What happens when the user clicks the "next" link a few times? Well, any number of things could happen:

• The current page number could stay in the middle as you click through (as it does on Yahoo!)
• It could advance to the end of the page range and then appear again on the left when the user clicks "next" one more time.
• The page numbers might even expand and contract as the user advances (or "scrolls") through them (as they do on Google).

There are four scrolling styles packaged with Zend Framework:

The fourth and final parameter is reserved for an optional associative array of variables that you want available in your view (available via $this). For instance, these values could include extra URL parameters for pagination links.

By setting the default view script name, default scrolling style, and view instance, you can eliminate the calls to PaginationControl completely:

use Zend\Paginator\Paginator;
use Zend\View\Helper\PaginationControl;

Paginator::setDefaultScrollingStyle('Sliding');
PaginationControl::setDefaultViewPartial('my_pagination_control');

When all of these values are set, you can render the pagination control inside your view script by echoing the paginator instance:

<?= $this->paginator ?>

Using other template engines

Of course, it's possible to use zend-paginator with other template engines. For example, with Smarty you might do the following:

$smarty-assign('pages', $paginator->getPages());

You could then access paginator values from a template like so:

{$pages.pageCount}

Example pagination controls

The following example pagination controls will help you get started with zend-view:

Search pagination:

<!--
See http://developer.yahoo.com/ypatterns/pattern.php?pattern=searchpagination
-->

<?php if ($this->pageCount): ?>
<div class="paginationControl">
<!-- Previous page link -->
<?php if (isset($this->previous)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->previous]); ?>">
    &lt; Previous
  </a> |
<?php else: ?>
  <span class="disabled">&lt; Previous</span> |
<?php endif; ?>

<!-- Numbered page links -->
<?php foreach ($this->pagesInRange as $page): ?>
  <?php if ($page != $this->current): ?>
    <a href="<?= $this->url($this->route, ['page' => $page]); ?>">
        <?= $page; ?>
    </a> |
  <?php else: ?>
    <?= $page; ?> |
  <?php endif; ?>
<?php endforeach; ?>

<!-- Next page link -->
<?php if (isset($this->next)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->next]); ?>">
    Next &gt;
  </a>
<?php else: ?>
  <span class="disabled">Next &gt;</span>
<?php endif; ?>
</div>
<?php endif; ?>

Item pagination:

<!--
See http://developer.yahoo.com/ypatterns/pattern.php?pattern=itempagination
-->

<?php if ($this->pageCount): ?>
<div class="paginationControl">
<?= $this->firstItemNumber; ?> - <?= $this->lastItemNumber; ?>
of <?= $this->totalItemCount; ?>

<!-- First page link -->
<?php if (isset($this->previous)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->first]); ?>">
    First
  </a> |
<?php else: ?>
  <span class="disabled">First</span> |
<?php endif; ?>

<!-- Previous page link -->
<?php if (isset($this->previous)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->previous]); ?>">
    &lt; Previous
  </a> |
<?php else: ?>
  <span class="disabled">&lt; Previous</span> |
<?php endif; ?>

<!-- Next page link -->
<?php if (isset($this->next)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->next]); ?>">
    Next &gt;
  </a> |
<?php else: ?>
  <span class="disabled">Next &gt;</span> |
<?php endif; ?>

<!-- Last page link -->
<?php if (isset($this->next)): ?>
  <a href="<?= $this->url($this->route, ['page' => $this->last]); ?>">
    Last
  </a>
<?php else: ?>
  <span class="disabled">Last</span>
<?php endif; ?>

</div>
<?php endif; ?>

Dropdown pagination:

<?php if ($this->pageCount): ?>
<select id="paginationControl" size="1">
<?php foreach ($this->pagesInRange as $page): ?>
  <?php $selected = ($page == $this->current) ? ' selected="selected"' : ''; ?>
  <option value="<?= $this->url($this->route, ['page' => $page]);?>"<?= $selected ?>>
    <?= $page; ?>
  </option>
<?php endforeach; ?>
</select>
<?php endif; ?>

<script type="text/javascript"
     src="http://ajax.googleapis.com/ajax/libs/prototype/1.6.0.2/prototype.js">
</script>
<script type="text/javascript">
$('paginationControl').observe('change', function() {
    window.location = this.options[this.selectedIndex].value;
})
</script>

Listing of properties

The following options are available to pagination control view scripts: