如何在 XPath 中注册 PHP 函数? [英] How to register PHP function in XPath?

问题描述

如何在XPATH 中注册 PHP 函数?因为 XPATH 不允许我使用 ends-with()

How can I register PHP function in XPATH? Because XPATH does not allows me to use ends-with()

这是一位成员提供的一种解决方案，但它不适用.

Here is one solutions given by one member but it does not works with.

他使用的代码是:

$xpath = new DOMXPath($document);
$xpath->registerNamespace("php", "http://php.net/xpath");
$xpath->registerPHPFunctions("ends_with");
$nodes = $x->query("//tr[/td/a/img[php:function('ends-with',@id,'_imgProductImage')]"

function ends_with($node, $value){
    return substr($node[0]->nodeValue,-strlen($value))==$value;
}

我使用的是 PHP 5.3.9.

I am using PHP 5.3.9.

推荐答案

在您的问题中，它看起来像是一个错字，没有名为 ends-with 的函数，因此我希望它不起作用:

In your question it looks like a typo, there is no function named ends-with therefore I would expect it not to work:

//tr[/td/a/img[php:function('ends-with',@id,'_imgProductImage')]
                             ^^^^^^^^^

改为使用正确的语法，例如正确的函数名:

Instead use the right syntax, e.g. the correct function name:

//tr[/td/a/img[php:function('ends_with',@id,'_imgProductImage')]
                             ^^^^^^^^^

或者例如像下面的例子:

Or for example like with the following example:

book.xml:

<?xml version="1.0" encoding="UTF-8"?>
<books>
 <book>
  <title>PHP Basics</title>
  <author>Jim Smith</author>
  <author>Jane Smith</author>
 </book>
 <book>
  <title>PHP Secrets</title>
  <author>Jenny Smythe</author>
 </book>
 <book>
  <title>XML basics</title>
  <author>Joe Black</author>
 </book>
</books>

PHP:

<?php
$doc = new DOMDocument;
$doc->load('book.xml');

$xpath = new DOMXPath($doc);

// Register the php: namespace (required)
$xpath->registerNamespace("php", "http://php.net/xpath");

// Register PHP functions (no restrictions)
$xpath->registerPHPFunctions();

// Call substr function on the book title
$nodes = $xpath->query('//book[php:functionString("substr", title, 0, 3) = "PHP"]');

echo "Found {$nodes->length} books starting with 'PHP':\n";
foreach ($nodes as $node) {
    $title  = $node->getElementsByTagName("title")->item(0)->nodeValue;
    $author = $node->getElementsByTagName("author")->item(0)->nodeValue;
    echo "$title by $author\n";
}

如您所见，此示例注册了所有 PHP 函数，包括现有 substr() 函数.

As you can see, this example registers all PHP functions including the existing substr() function.

查看 DOMXPath::registerPHPFunctions 了解更多信息，这也是代码示例的来源.

See DOMXPath::registerPHPFunctions for more information, that is also where the code example has been taken from.

希望对您有所帮助，如果您对此仍有疑问，请告诉我.

I hope this is helpful, let me know if you still have a question about this.

另见:

• 如何在 php 中使用 preg 添加 html 属性(2010 年 8 月)
• 在 PHP XPath 中使用正则表达式->评估(2011 年 11 月)
• 在 Xpath (PHP) 中获取以大写开头的标签(2012 年 7 月)；在特定的这个答案中.
• 从一堆 xml 文件中特定正则表达式模式的搜索结果中获取 xpath(2013 年 3 月)；在特定的这个答案中.

• How to use preg in php to add html properties (Aug 2010)
• Using Regex in PHP XPath->evaluate (Nov 2011)
• Get tags that start with uppercase in Xpath (PHP) (Jul 2012); in specific this answer.
• Get xpath from search result of a specific regex pattern in a bunch of xml files (Mar 2013); in specific this answer.

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