为什么count（DOMNode-> childNodes）返回不正确的子数？ （PHP和XML） [英] Why does count(DOMNode->childNodes) return an incorrect number of children? (PHP and XML)

问题描述

我有一个名为processDeleteForm（）的PHP函数，旨在从名为struct.xml的xml文档中删除指定的节点。到目前为止，我遇到的唯一问题是在processDeleteForm（）中，它通过循环遍历父节点的每个子节点来搜索要删除的节点，并通过name属性进行匹配，但是我避开没有能够得到正确数量的子节点的循环，所以它在到达正确的节点之前停止。相关代码：

I have a PHP function called processDeleteForm() designed to remove a specified node from an xml document named structure.xml. The only problem I'm having with it so far is that in processDeleteForm(), it searches for the node to be removed by looping through each child node of the parent node, and matches it by the "name" attribute, but I haven't been able to get the correct number of child nodes for the loop, so it stops before it reaches the correct node. Relevant code:

function processDeleteForm($dir, $filename)
{
  echo "Processing delete request.<br/>";
  echo "Request to delete ".$filename." from ".$dir.".<br/>";
  $xmlDoc = new DOMDocument();

  $xmlDoc->load("structure.xml");
  $node = dirDOMNodeWritable($dir, $xmlDoc);

  $target;
  echo "Working directory has ".count($node->childNodes)." child(ren).<br/>";
  for($x = 0; $x < count($node->childNodes); $x++)
  {
    if($node->childNodes->item($x)->getAttribute("name") == $filename)
    {
      $target = $node->childNodes->item($x);
      echo "Target found.<br/>";
    }
    else
    {
      echo "Searching for target...<br/>";
    }
  }

  if($target->getAttribute("type") != "directory")
  {
    $fstored = "uploads/".$target->childNodes->item(0)->wholeText;
    unlink($fstored);
  }

  $node->removeChild($target);

  $file = fopen("structure.xml", "w");
  fwrite($file, $xmlDoc->saveXML());

}

structure.xml：

structure.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
<directory name="root" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
  <directory name="music" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
    <directory name="She" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
      <directory name="Chiptek" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
        <directory name="mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
          <file name="intro.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">intro.mp3</file>
          <file name="music.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">music.mp3</file>
          <file name="supersonic.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">supersonic.mp3</file>
          <file name="memories.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">memories.mp3</file>
          <file name="chiptek.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">chiptek.mp3</file>
          <file name="intermission.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">intermission.mp3</file>
          <file name="kicks.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">kicks.mp3</file>
          <file name="1997.mp3" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/mpeg">1997.mp3</file>
        </directory>
        <directory name="ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="directory">
          <file name="intro.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">intro.ogg</file>
          <file name="music.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">music.ogg</file>
          <file name="supersonic.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">supersonic.ogg</file>
          <file name="memories.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">memories.ogg</file>
          <file name="chiptek.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">chiptek.ogg</file>
          <file name="intermission.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">intermission.ogg</file>
          <file name="kicks.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">kicks.ogg</file>
          <file name="1997.ogg" owner="elarsen" read="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" write="aclum,ahoffman,apavlowski,bvollmer,dpotts,drichardson,epiatt,jcantrell,jreeve,kdouglas,kjab,lbrewer,lholliday,mfriedman,norty,pmoore,rlongwell,scatlett,sketcherside,tperkins" type="audio/ogg">1997.ogg</file>
        </directory>
      </directory>
    </directory>
  </directory>
  <directory name="test01" owner="elarsen" read="0" write="0" type="directory"/>
  <directory name="test02" owner="elarsen" read="0" write="0" type="directory"/>
  <directory name="test03" owner="elarsen" read="0" write="0" type="directory"/>
</directory>

*以上内容应该是xml文件的内容，但我无法弄清楚如何显示它。如果有更多关于在stackoverflow上格式化xml的知识的人可以修复它，我将非常有责任。

*The above is supposed to be the contents of an xml file, but I can't figure out how to display it as such. If somebody with more knowledge about formatting xml on stackoverflow could fix it, I would be much obliged.

看到代码负责创建名为test01，test02和test03的目录：

It might also be useful to see the code responsible for the creation of the directories named "test01", "test02", and "test03":

function processNewForm($dir, $dirName, $readPrivs, $writePrivs)
{
  $readString = "";
  $writeString = "";
  $dirOwner = $_SESSION["user"];

  for($x = 0; $x < count($readPrivs); $x++)
  {
    $readString += $readPrivs[$x].",";
  }
  for($x = 0; $x < count($writePrivs); $x++)
  {
    $writeString += $writePrivs[$x].",";
  }

  $xmlDoc = new DOMDocument();

  $xmlDoc->load("structure.xml");
  $node = dirDOMNodeWritable($dir, $xmlDoc);

  $newDir = $xmlDoc->createElement("directory");
  $newDir->setAttribute("name", $dirName);
  $newDir->setAttribute("owner", $dirOwner);
  $newDir->setAttribute("read", $readString);
  $newDir->setAttribute("write", $writeString);
  $newDir->setAttribute("type", "directory");

  $node->appendChild($newDir);

  $file = fopen("structure.xml", "w");
  fwrite($file, $xmlDoc->saveXML());

}

当前输出如下所示：

Received delete request.
Validating delete request... Request is valid.
Processing delete request.
Request to delete test03/ from /.
Working directory has 1 child(ren).
Searching for target...

Notice: Undefined variable: target in E:\aepi\dev\fileshare.php on line 540

Fatal error: Call to a member function getAttribute() on a non-object in E:\aepi\dev\fileshare.php on line 540

推荐答案

从 PHP手册（count） ：

返回var中的元素数。如果var不是一个数组或一个实现了Countable接口的对象，则返回1。

Returns the number of elements in var. If var is not an array or an object with implemented Countable interface, 1 will be returned.

DOMNode :: $ childNodes 是 DOMNodeList 对象。不是 可数 。它总是返回一个（即使是空的）。使用其 长度 属性：

DOMNode::$childNodes is a DOMNodeList object. It is not Countable. It will always return one (even if empty). Use its length property instead:

$count = $element->childNodes->length;

这篇关于为什么count（DOMNode-> childNodes）返回不正确的子数？ （PHP和XML）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！