如何在PHP中实现Web scraper？

$url = "https://example.com";
$html = file_get_contents($url);
$dom = new DOMDocument();
@$dom->loadHTML($html);

$xpath = new DOMXPath($dom);
$elements = $xpath->query("//div[@class='example']");

foreach ($elements as $element) {
    echo $element->nodeValue . PHP_EOL;
}

$url = "https://example.com";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$html = curl_exec($ch);
curl_close($ch);

// 使用DOM解析器库解析HTML
$dom = new DOMDocument();
@$dom->loadHTML($html);

$xpath = new DOMXPath($dom);
$elements = $xpath->query("//div[@class='example']");

foreach ($elements as $element) {
    echo $element->nodeValue . PHP_EOL;
}

require 'vendor/autoload.php';

use GuzzleHttp\Client;
use Symfony\Component\DomCrawler\Crawler;

$client = new Client();
$response = $client->get('https://example.com');

$html = (string) $response->getBody();
$crawler = new Crawler($html);

$elements = $crawler->filter('div.example');

foreach ($elements as $element) {
    echo $element->nodeValue . PHP_EOL;
}