Механизм пагинации в веб-приложениях на PHP через индекс p

Расширенные примеры пагинации

Полноценный класс Pagination с поддержкой всех параметров

<?php
class Pagination {
    private $total;
    private $perPage;
    private $currentPage;
    private $urlPattern;

    public function __construct($total, $perPage = 10, $currentPage = 1, $urlPattern = '?p=(:num)') {
        $this->total = $total;
        $this->perPage = $perPage;
        $this->currentPage = max(1, $currentPage);
        $this->urlPattern = $urlPattern;
    }

    public function getTotalPages() {
        return ceil($this->total / $this->perPage);
    }

    public function getOffset() {
        return ($this->currentPage - 1) * $this->perPage;
    }

    public function getLimit() {
        return $this->perPage;
    }

    public function buildUrl($page) {
        return str_replace('(:num)', $page, $this->urlPattern);
    }

    public function render($range = 2) {
        $totalPages = $this->getTotalPages();
        if ($totalPages <= 1) return '';

        $html = '<div class="pagination">';
        $html .= $this->renderArrow($this->currentPage - 1, '«');

        $start = max(1, $this->currentPage - $range);
        $end = min($totalPages, $this->currentPage + $range);

        if ($start > 1) {
            $html .= '<a href="'.$this->buildUrl(1).'">1</a>';
            if ($start > 2) $html .= '<span class="dots">…</span>';
        }
        for ($i = $start; $i <= $end; $i++) {
            $active = ($i == $this->currentPage) ? ' class="active"' : '';
            $html .= '<a href="'.$this->buildUrl($i).'"'.$active.'>'.$i.'</a>';
        }
        if ($end < $totalPages) {
            if ($end < $totalPages - 1) $html .= '<span class="dots">…</span>';
            $html .= '<a href="'.$this->buildUrl($totalPages).'">'.$totalPages.'</a>';
        }

        $html .= $this->renderArrow($this->currentPage + 1, '»');
        $html .= '</div>';
        return $html;
    }

    private function renderArrow($page, $label) {
        $totalPages = $this->getTotalPages();
        if ($page < 1 || $page > $totalPages) {
            return '<span class="disabled">'.$label.'</span>';
        }
        return '<a href="'.$this->buildUrl($page).'">'.$label.'</a>';
    }
}
?>

Пример использования класса:
<?php
$pdo = new PDO(/* ... */);
$total = $pdo->query("SELECT COUNT(*) FROM articles")->fetchColumn();
$currentPage = isset($_GET['p']) ? (int)$_GET['p'] : 1;

$pagination = new Pagination($total, 10, $currentPage, '?p=(:num)&sort=date');
$offset = $pagination->getOffset();
$limit = $pagination->getLimit();

$stmt = $pdo->prepare("SELECT * FROM articles ORDER BY created_at DESC LIMIT :limit OFFSET :offset");
$stmt->bindValue(':limit', $limit, PDO::PARAM_INT);
$stmt->bindValue(':offset', $offset, PDO::PARAM_INT);
$stmt->execute();
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

// Вывод данных...
foreach ($rows as $row) { /* ... */ }

// Вывод пагинации
echo $pagination->render(3);
?>

Результат (пример HTML):

<div class="pagination">
    <a href="?p=1&sort=date">«</a>
    <span class="dots">…</span>
    <a href="?p=4&sort=date">4</a>
    <a href="?p=5&sort=date" class="active">5</a>
    <a href="?p=6&sort=date">6</a>
    <span class="dots">…</span>
    <a href="?p=20&sort=date">»</a>
</div>

Пагинация с сохранением порядка сортировки (несколько сортирующих параметров)

<?php
$allowedSorts = ['title', 'created_at', 'views'];
$sort = isset($_GET['sort']) && in_array($_GET['sort'], $allowedSorts) ? $_GET['sort'] : 'created_at';
$order = isset($_GET['order']) && $_GET['order'] === 'asc' ? 'ASC' : 'DESC';

$queryParams = $_GET;
unset($queryParams['p']);

for ($i = 1; $i <= $totalPages; $i++) {
    $queryParams['p'] = $i;
    $url = '?' . http_build_query($queryParams);
    // ... вывод ссылок
}
?>

Результат: ссылки вида ?sort=created_at&order=DESC&p=2.