Documentation

Pagination: follow the next-page link (PHP)

Read a catalog from its first page to its last without guessing the page count. The scenario follows links supplied by the source.

Choose PHP, paste the complete source from this article and set the run parameters below. The source for this collection is ScrapingCourse. This walkthrough applies to the specified demonstration page.

Example settings

{
  "path": "/pagination",
  "mode": "http",
  "expected": 147
}

path selects the page, mode selects an algorithm branch, and expected sets the control count for this example. It is not a plan limit. When the source dataset changes, check the expected count against it.

How the algorithm works

Open /pagination with mode: http. The url variable holds the page that should be processed next.
Check whether the URL is in visited, then mark it as visited. This tracks pages, independently of products.
Fetch the HTML and pass it to the collection function, which emits only products not encountered before.
Look for a[rel="next"] or a.next.page-numbers. If neither link is present, finish the loop rather than inventing another page number.
Resolve a relative next link to a complete URL. Both absolute links and short source links can then be followed.
Compare the final unique product count with expected to detect a missed page.

Products are processed by courseCollect($ctx, $html, $seen). Read the name first, skip empty names, and use the card link as the key, falling back to the name when necessary. seen prevents the same key being emitted twice. This matters when a later HTML read includes products already collected.

Details that matter

The algorithm keeps two separate collections: visited prevents page loops, while seen prevents duplicate product output.

PHP details

PHP calls network and browser methods sequentially with ->. courseCollect receives $seen and returns its updated array, so assign each result back. Close the page in finally; $ctx->fail() stops the run with a readable message.

Expected output

The configured demonstration dataset expects 147 unique records. The final check compares the actual unique key count with expected.

Field	Contents
`name`	Product name with leading and trailing whitespace removed.
`price`	Price converted from text to a number.
`image`	Image URL read from the card src attribute.

Complete scenario source

The source is shared by this collection. This example runs its http branch using the parameters above. Copy the complete block into the PHP editor; no fixed sign-in credentials or service keys need to be added.

<?php

function run(\Sdk\Context $ctx): void
{
    $origin = 'https://www.scrapingcourse.com';
    $path = (string) $ctx->param('path', '/pagination');
    $mode = (string) $ctx->param('mode', 'http');
    $auto = $ctx->param('auto_captcha', true) !== false;
    $seen = [];
    if ($mode === 'http') {
        $url = $origin.$path;
        $visited = [];
        while ($url !== null && count($visited) < 50) {
            if (isset($visited[$url])) {
                $ctx->fail('Pagination returned an already processed page');
            }
            $visited[$url] = true;
            $response = $ctx->http()->withoutCache()->get($url, $auto);
            if (! $response->ok()) {
                $ctx->fail('The source could not be opened: '.$response->status);
            }
            $html = $response->body;
            $seen = courseCollect($ctx, $html, $seen);
            $next = $ctx->dom($html)->attr('a[rel="next"], a.next.page-numbers', 'href');
            $url = $next ? $ctx->url()->absolutize($url, $next) : null;
        }
        if ($url !== null) {
            $ctx->fail('The pagination safety limit was reached');
        }
    } else {
        $page = $ctx->browser()->open($origin.$path, ['*/ajax/products*'], [], $auto);
        try {
            if ($mode === 'login') {
                $dom = $ctx->dom($page->content());
                $hint = '';
                foreach ($dom->qa('p') as $p) {
                    if (str_contains($p->text(), 'Demo Credentials:')) {
                        $hint = $p->text();
                    }
                }
                preg_match('/Password:\s*([^\s|]+)/i', $hint, $password);
                preg_match('/Email:\s*([^\s|]+@[^\s|]+)/i', $hint, $emailMatch);
                $email = $emailMatch[1] ?? '';
                if ($email === '' || ! isset($password[1])) {
                    $ctx->fail('The page does not contain demo credentials');
                }
                $page->type('#email', $email)->type('#password', $password[1])->click('button[type="submit"]');
            }
            if ($mode === 'challenge') {
                $text = preg_replace('/\s+/', ' ', $ctx->dom($page->content())->text('body') ?? '');
                if (! preg_match('/You (?:successfully )?bypassed|successfully bypassed|Congratulations/i', $text)) {
                    $ctx->fail('The expected page content was not received');
                }
                $ctx->emit(['name' => $path, 'passed' => true], $path);
            } else {
                $page->waitFor('.product-name:not(:empty)', 15000);
                if ($mode === 'button') {
                    $complete = false;
                    for ($i = 0; $i < 30; $i++) {
                        $html = $page->content();
                        $before = $ctx->dom($html);
                        $seen = courseCollect($ctx, $html, $seen);
                        $button = $before->q('#load-more-btn');
                        if ($button === null || preg_match('/display:\s*none/', $button->attr('style') ?? '')) {
                            $complete = true;
                            break;
                        }
                        $offset = $button->attr('data-offset');
                        $count = count($before->qa('.product-item'));
                        $page->click('#load-more-btn');
                        $response = $page->waitForResponse('*offset='.$offset, 15000);
                        if ($response === null || ($response['status'] < 200 || $response['status'] >= 300) || $response['truncated'] || $response['error']) {
                            $ctx->fail('The next batch could not be loaded');
                        }
                        if (trim($response['body'] ?? '') === '') {
                            $complete = true;
                            break;
                        }
                        $page->waitFor('.product-item:nth-child('.($count + 1).')');
                    }
                    if (! $complete) {
                        $ctx->fail('The batch loading safety limit was reached');
                    }
                }
                if ($mode === 'scroll') {
                    $stable = 0;
                    $previous = 0;
                    for ($i = 0; $i < 40 && $stable < 3; $i++) {
                        $page->scroll(3, 400);
                        $html = $page->content();
                        $seen = courseCollect($ctx, $html, $seen);
                        $count = count($ctx->dom($html)->qa('.product-item'));
                        $stable = $count === $previous ? $stable + 1 : 0;
                        $previous = $count;
                    }
                    if ($stable < 3) {
                        $ctx->fail('The feed is still loading: increase the scroll limit');
                    }
                }
                $seen = courseCollect($ctx, $page->content(), $seen);
            }
        } finally {
            $page->close();
        }
    }
    $expected = (int) $ctx->param('expected', 1);
    if ($mode !== 'challenge' && count($seen) !== $expected) {
        $ctx->fail('Incomplete result: '.count($seen).' instead of '.$expected);
    }
}

function courseCollect(\Sdk\Context $ctx, string $html, array $seen): array
{
    $dom = $ctx->dom($html);
    foreach ($dom->qa('.product-item, li.product') as $card) {
        $name = trim($card->q('.product-name, .woocommerce-loop-product__title')?->text() ?? '');
        $key = $card->q('a')?->attr('href') ?? $name;
        if ($name === '' || isset($seen[$key])) {
            continue;
        }
        $seen[$key] = true;
        $ctx->emit(['name' => $name, 'price' => $ctx->text()->money($card->q('.product-price, .price')?->text() ?? ''),
            'image' => $card->q('img')?->attr('src') ?? ''], $key);
    }

    return $seen;
}