XMLReader & simpleXML 组合，带条件

Question

我使用 XMLReader 和 simpleXML 的组合来解析 WordPress 导出文件中的帖子。我意识到这有点不正常，但是，它更多的是备份项目，因此如果我们将来需要的话，我们可以轻松地找到其中一篇文章。他们所在的 WP 网站需要关闭。

我遇到的问题是 XML 文件中的某些节点为空或包含无用的值（即不是完整的帖子）。我需要添加一些字符串长度条件，但是，我不确定如何检查每个条件。

<?php 

$path_to_xml_file = 'compress.zlib://wordpress.2011.xml.gz';


$reader = new XMLReader();
                $reader->open($path_to_xml_file);
                while($reader->read())
                {
                        if($reader->nodeType == XMLReader::ELEMENT && $reader->name == 'item')
                        {
                                        $doc = new DOMDocument('1.0', 'UTF-8');
                                        $xml = simplexml_import_dom($doc->importNode($reader->expand(),true));
                                        //echo $xml->title; //or whatever

// Take care of the articles
$newcontent = $xml->children('http://purl.org/rss/1.0/modules/content/');
$contentString = $newcontent->encoded;
$titleString = $xml->title;

    echo '
    <div class="article-container" id="article-' .  $xml->title . '">
    <a href="#top" class="top-link">Back to the Top</a>
        <h2>' .  $xml->title . '</h2>
        <div class="articles">' . $newcontent->encoded . '</div>
    </div>';
                        }
                }

?>

我只用 simpleXML 就成功地检查了这一点，但是它本身就太占用内存了。 这是我的 simplexml 代码：

<?php 

    $url = 'wordpress.2011.xml.gz';
    $xml = new SimpleXMLElement("compress.zlib://$url", NULL, TRUE);

    foreach ($xml->item as $item) :

    $newcontent = $item->children('http://purl.org/rss/1.0/modules/content/');

    ?>

<?php
$contentString = $newcontent->encoded;
$titleString = $item->title;

if ((strlen($contentString) < 13) || (strlen($titleString) < 5))  {
    echo '';
} else {
    echo '
    <div class="article-container" id="article-' .  $item->title . '">
    <a href="#top" class="top-link">Back to the Top</a>
        <h2>' .  $item->title . '</h2>
        <div class="articles">' . $newcontent->encoded . '</div>
    </div>';
}
?>



 <?php endforeach; ?>

更新

在 Francis 的帮助下，它现在可以工作了。这是代码：

<?php 

$path_to_xml_file = 'compress.zlib://wordpress.2011.xml.gz';

$reader = new XMLReader();
$reader->open($path_to_xml_file);
$contentNS = 'http://purl.org/rss/1.0/modules/content/';
while($reader->read()) {
    if($reader->nodeType == XMLReader::ELEMENT and $reader->name == 'item') {
        $doc = new DOMDocument('1.0','UTF-8');
        $xml = simplexml_import_dom($doc->importNode($reader->expand(), true));
        $titleString = (string) $xml->title;
        $contentString = (string) $xml->children($contentNS)->encoded;
        if (strlen($contentString) > 12 and strlen($titleString) > 4)  {
            // Be careful with your output escaping!
            // This below looks like it might be wrong:
            // - $titleString for an ID (use slug)
            // - $titleString not escaped
            // - $contentString should be escaped? not sure here.
            // Have you considered using XMLWriter()?
            echo '
<div class="article-container" id="article-' .  $titleString . '">
    <a href="#top" class="top-link">Back to the Top</a>
    <h2>' .  $titleString . '</h2>
    <div class="articles">' . $contentString . '</div>
</div>';
        } else {

        echo'';

        }

        $reader->next(); //skip the subtrees, go to next item sibling
        // we already expand()ed this so we don't need to walk it.
    }
}

?>

Answer 1

当您说 $contentString = $newcontent->encoded 时，$contentString 的类型不是 string 而是 SimpleXMLElement >。因此，strlen() 返回了一些无意义的内容。

您需要将 SimpleXMLElement 显式转换为 string 才能获取元素的文本值：

$contentString = (string) $newcontent->encoded;

顺便说一句，您可以简化 DOM 扩展并通过使用 XMLReader::expand() 的可选参数转换为 SimpleXMLElement：

$sxe = simplexml_import_dom($reader->expand(new DOMDocument('1.0','UTF-8')));

EDIT 以及编写的第一个代码块的完整示例你想要什么（我认为？）可以看到我所做的就是从第二个代码示例中取出内部循环并将其放入第一个代码示例中的内部循环中。

$reader = new XMLReader();
$reader->open($path_to_xml_file);
$contentNS = 'http://purl.org/rss/1.0/modules/content/';
while($reader->read()) {
    if($reader->nodeType == XMLReader::ELEMENT and $reader->name == 'item') {
        $xml = simplexml_import_dom($reader->expand(new DOMDocument('1.0', 'UTF-8')));
        $titleString = (string) $xml->title;
        $contentString = (string) $xml->children($contentNS)->encoded;
        if (strlen($contentString) > 12 and strlen($titleString) > 4)  {
            // Be careful with your output escaping!
            // This below looks like it might be wrong:
            // - $titleString for an ID (use slug)
            // - $titleString not escaped
            // - $contentString should be escaped? not sure here.
            // Have you considered using XMLWriter()?
            echo '
<div class="article-container" id="article-' .  $titleString . '">
    <a href="#top" class="top-link">Back to the Top</a>
    <h2>' .  $titleString . '</h2>
    <div class="articles">' . $contentString . '</div>
</div>';
        }
        $reader->next(); //skip the subtrees, go to next item sibling
        // we already expand()ed this so we don't need to walk it.
    }
}