PHP DOMXPath-> query（）/-> evaluate（）不匹配内部文本

Question

我目前正在尝试创建一个纯PHP菜单遍历系统-这是因为我正在为某些人做一个即兴项目，但是他们想要尽可能少的JS（即：无）和理想的纯PHP。

我有一个看起来像这样的菜单：

 ul { list-style-type: none; } nav > ul.sidebar-list ul.sub { display: none; } nav > ul.sidebar-list ul.sub.active { display: block; } 

 <nav class="sidebar" aria-labelledby="primary-navigation"> <ul class="sidebar-list"> <!--each element has a sub-menu which is initially hidden by css when the page is loaded. Via php the appropriate path the current page and top-level links will be visible only--> <a href="#"><li>Home</li></a> <!--sub-items--> <ul class="sub active"> <a href="#"><li>Barn</li></a> <a href="#"><li>Activities</li></a> <ul class="sub active"> <a href="#"><li>News</li></a> <a href="#"><li>Movements</li></a> <a href="#"><li>Reviews</li></a> <a href="#"><li>About Us</li></a> <a href="#"><li>Terms of Use</li></a> </ul> </ul> <a href="#"><li>Events</li></a> <ul class="sub"> <a href="#"><li>Overview</li></a> <a href="#"><li>Farming</li></a> <a href="#"><li>Practises</li></a> <a href="#"><li>Links</li></a> <ul class="sub"> <a href="#"><li>Another Farm</li></a> <a href="#"><li>24m</li></a> </ul> </ul> </ul> </nav> 

为了尝试将页面的标题内文与菜单项内文匹配（可能不是最好的处理方式，但我仍在学习php），我运行：

$menu = new DOMDocument();
assert($menu->loadHTMLFile($menu_path), "Loading nav.html (menu file) failed");
//show content to log of the html document
error_log("HTML file: \n\n".$menu->textContent);

//set up a query to find an element matching the title string found
$xpath = new DOMXPath($menu);

$menu_query = "//a/li[matches(text(), '$title_text', 'i')]";
$elements = $xpath->query($menu_query);
error_log($elements ? ("Result of xpath query is: ".print_r($elements, TRUE)): "The xpath query for searching the menu is incorrect and will not find you anything!\ntype of return: ".gettype($elements));

我在以下网址获得了正确的回报： https : //www.freeformatter.com/xpath-tester.html，但是在脚本中却没有。 我已经尝试了文本匹配的许多不同组合，例如： //x:a/x:li[lower-case(text())='$title_text']但始终为空节点列表。

Answer 1

PHP使用XPath 1.0。 matches是XPath 2.0的功能，因此如果您要查找警告，则会在错误日志中看到警告。

PHP Warning:  DOMXPath::query(): xmlXPathCompOpEval: function matches not found in php shell code on line 1
PHP Stack trace:
PHP   1. {main}() php shell code:0
PHP   2. DOMXPath->query() php shell code:1

一个简单的区分大小写的匹配可以通过相等检查来完成。

$title_text = "Farming";
$menu_query = "//a/li[. = '$title_text']";

但是不区分大小写的搜索涉及将字符从大写转换为小写：

$title_text = "FaRmInG";
$title_text = strtolower($title_text);
$menu_query = "//a/li[translate(., 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz') = '$title_text']";

无论哪种情况，我们最终都可以通过以下方式迭代NodeList：

$html = <<< HTML
<nav class="sidebar" aria-labelledby="primary-navigation">
  <ul class="sidebar-list">

    <!--each element has a sub-menu which is initially hidden by css when the page is loaded. Via php the appropriate path the current page and top-level links will be visible only-->
    <a href="#"><li>Home</li></a>
    <!--sub-items-->
    <ul class="sub active">
      <a href="#"><li>Barn</li></a>
      <a href="#"><li>Activities</li></a>
      <ul class="sub active">
        <a href="#"><li>News</li></a>
        <a href="#"><li>Movements</li></a>
        <a href="#"><li>Reviews</li></a>
        <a href="#"><li>About Us</li></a>
        <a href="#"><li>Terms of Use</li></a>
      </ul>
    </ul>
    <a href="#"><li>Events</li></a>
    <ul class="sub">
      <a href="#"><li>Overview</li></a>
      <a href="#"><li>Farming</li></a>
      <a href="#"><li>Practises</li></a>
      <a href="#"><li>Links</li></a>
      <ul class="sub">
        <a href="#"><li>Another Farm</li></a>
        <a href="#"><li>24m</li></a>
      </ul>
    </ul>
  </ul>
</nav>
HTML;
$menu = new DOMDocument();
$menu->loadHTML($html);
$xpath = new DOMXPath($menu);
$elements = $xpath->query($menu_query);
foreach ($elements as $element) {
    print_r($element);
}