如何使用XPath和DOM替换PHP中的节点/元素？ [英] How can I use XPath and DOM to replace a node/element in php?

问题描述

说我有以下html

  $ html ='
< div class =website> ; 
< div> 
< div id =old_div> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< div class =a class> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< / div> 
< / div> 
< div id =another_div>< / div> 
< / div> 
< / div> 
'; 
  

而我想将 #old_div 替换为以下：

  $ replacement ='< div id =new_div>这是新的< / div>'; 
  

给出最终结果：

  $ html ='
< div class =website> 
< div> 
< div id =new_div>这是新的< / div> 
< div id =another_div>< / div> 
< / div> 
< / div> 
'; 
  

有没有一个简单的剪切和粘贴功能来做这个PHP？

---

由于所有Gordon的帮助，最终的工作代码：

 <？php 
 
 $ html =<<< HTML 
< div class =website> 
< div> 
< div id =old_div> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< div class =a class> 
< p>某些文字< / p> 
< p>某些文字< / p> 
< / div> 
< / div> 
< div id =another_div>< / div> 
< / div> 
< / div> 
 HTML; 
 
 $ dom = new DOMDocument; 
 $ dom-> loadXml（$ html）; //使用loadHTML，如果它是无效的XHTML 
 
 //创建替换
 $ replacement = $ dom-> createDocumentFragment（）; 
 $ replacement  - > appendXML（'< div id =new_div>这是新的< / div>'）; 
 
 // make replacement 
 $ xp = new DOMXPath（$ dom）; 
 $ oldNode = $ xp-> query（'// div [@ id =old_div]'） - > item（0）; 
 $ oldNode-> parentNode-> replaceChild（$ replacement，$ oldNode）; 
 //保存html输出
 $ new_html = $ dom-> saveXml（$ dom-> documentElement）; 
 
 echo $ new_html; 
 
？> 
  

解决方案

由于链接的副本中的答案不是全面的我举一个例子：

  $ dom = new DOMDocument; 
 $ dom-> loadXml（$ html）; //使用loadHTML如果它的无效（X）HTML 
 
 //创建新元素
 $ newNode = $ dom-> createElement（'div'，'this is new'）; 
 $ newNode-> setAttribute（'id'，'new_div'）; 
 
 //获取并替换旧元素
 $ oldNode = $ dom-> getElementById（'old_div'）; 
 $ oldNode-> parentNode-> replaceChild（$ newNode，$ oldNode）; 
 
 // print xml 
 echo $ dom-> saveXml（$ dom-> documentElement）; 
  

---

从技术上讲，您不需要XPath 。但是，您的libxml版本不能对未经验证的文档执行 getElementById （ id属性在XML中是特殊的）。在这种情况下，将呼叫替换为 getElementById 与

  $ xp =新的DOMXPath（$ dom）; 
 $ oldNode = $ xp-> query（'// div [@ id =old_div]'） - > item（0）; 
  

在键盘上演示

---

创建一个 $ newNode 与子节点，而不必逐个创建和追加元素，您可以执行

  $ newNode = $ dom-> ; createDocumentFragment（）; 
 $ newNode-> appendXML（'
< div id =new_div> 
< p>其他一些文本< / p> 
< p>其他文字< / p> 
< p>某些其他文字< / p> 
< p>其他文字< / p> 
< / div> 
' ）; 
  

Say I have the following html

$html = '
<div class="website">
    <div>
        <div id="old_div">
            <p>some text</p>
            <p>some text</p>
            <p>some text</p>
            <p>some text</p>
            <div class="a class">
                <p>some text</p>
                <p>some text</p>
            </div>
        </div>
        <div id="another_div"></div>
    </div>
</div>
';

And I want to replace #old_div with the following:

$replacement = '<div id="new_div">this is new</div>';

To give an end result of:

$html = '
<div class="website">
        <div>
            <div id="new_div">this is new</div>
            <div id="another_div"></div>
        </div>
    </div>
';

Is there an easy cut-and-paste function for doing this with PHP?

---

Final working code thanks to all Gordon's help:

<?php

$html = <<< HTML
<div class="website">
    <div>
        <div id="old_div">
            <p>some text</p>
            <p>some text</p>
            <p>some text</p>
            <p>some text</p>
            <div class="a class">
                <p>some text</p>
                <p>some text</p>
            </div>
        </div>
        <div id="another_div"></div>
    </div>
</div>
HTML;

$dom = new DOMDocument;
$dom->loadXml($html); // use loadHTML if it's invalid XHTML

//create replacement
$replacement  = $dom->createDocumentFragment();
$replacement  ->appendXML('<div id="new_div">this is new</div>');

//make replacement
$xp = new DOMXPath($dom);
$oldNode = $xp->query('//div[@id="old_div"]')->item(0);
$oldNode->parentNode->replaceChild($replacement  , $oldNode);
//save html output
$new_html = $dom->saveXml($dom->documentElement);

echo $new_html;

?>

解决方案

Since the answer in the linked duplicate is not that comprehensive, I'll give an example:

$dom = new DOMDocument;
$dom->loadXml($html); // use loadHTML if its invalid (X)HTML

// create the new element
$newNode = $dom->createElement('div', 'this is new');
$newNode->setAttribute('id', 'new_div');

// fetch and replace the old element
$oldNode = $dom->getElementById('old_div');
$oldNode->parentNode->replaceChild($newNode, $oldNode);

// print xml
echo $dom->saveXml($dom->documentElement);

---

Technically, you don't need XPath for this. However, it can happen that your version of libxml cannot do getElementById for non-validated documents (id attributes are special in XML). In that case, replace the call to getElementById with

$xp = new DOMXPath($dom);
$oldNode = $xp->query('//div[@id="old_div"]')->item(0);

Demo on codepad

---

To create a $newNode with child nodes without having to to create and append elements one by one, you can do

$newNode = $dom->createDocumentFragment();
$newNode->appendXML('
<div id="new_div">
    <p>some other text</p>
    <p>some other text</p>
    <p>some other text</p>
    <p>some other text</p>
</div>
');

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