php - 如何通过 symfony 爬虫获取当前父节点之后的下一个节点？

Question

用于解析的 HTML 5 示例:

<div id="orderDetails">
    <div> ... any number of blocks with unnecessary stuff ... </div>
    <div>Label for important info</div>
    <table> ... some other block type ... </table>
    <div>Some very important info here</div>
    <div> ... any number of blocks with unnecessary stuff ... </div>
</div>

我的 PHP 代码如下所示:

$crawler = new \Symfony\Component\DomCrawler\Crawler($html);
$label = $crawler->filter('#orderDetails div:contains("Label for important info")');
$info = $label->parent()->next('div');
assert('Some very important info here' === $info->text(), 'Important info must be grabbed from HTML');

但不幸的是，爬虫没有方法parent 和next。但是..它有 parents 给我所有父节点==所有我不能不同的div。

所以在这种情况下我有两个问题:

1. 如何获取当前节点的父节点？不是所有节点，而是“实际”节点!
2. 如何使用 next/prev 的类比水平遍历 dom？

谢谢。

Answer 1

故事

在深入研究源代码之后，我发现方法 nextAll() 返回的不是“全部”，而是“一个”节点 ($node = $this->getNode( 0);).

这意味着如果我需要“当前节点之后的两个节点”，那么我必须编写 $node->nextAll()->nextAll()->nextAll()。

WTF？这是 super 奇怪的命名约定 (0_0)。

答案

1. How to get parent of current node? Not all nodes but "actual" one!

// This is only one parent node
$parent = $node->parents();

2. How to traverse dom horizontally with some analogue of next/prev?

// This is only one node – next after current
$next = $node->nextAll();
// This is only one node – previous before current
$prev = $node->nextAll();
// This is only one node – next after two from current
$nextAfterTwo = $node->nextAll()->nextAll()->nextAll();

具体代码解决方案

因此，根据需要的实现确实存在，问题的功能解决方案如下所示:

/**
 * Returns sibling node that is after current and filtered with selector
 *
 * @param Crawler $start    Node from which start traverse
 * @param string  $selector CSS/XPath selector like in `Crawler::filter($selector)`
 *
 * @return Crawler Found node wrapped with Crawler
 *
 * @throws \InvalidArgumentException When node not found
 */
function getNextFiltered(Crawler $start, string $selector) : Crawler
{
    $count = $start->parents()->count();
    $next  = $start->nextAll();
    while ($count --> 0) {
        $filtered = $next->filter($selector);
        if ($filtered->count()) return $filtered;
        $next = $next->nextAll();
    }

    throw new \InvalidArgumentException('No node found');
}

在我的例子中:

$crawler = new Crawler($html);
$label   = $crawler->filter('#orderDetails div:contains("Label for important info")');
$info    = getNextFiltered($label, 'div');
assert('Some very important info here' === $info->text(), 'Important info must be grabbed from HTML');