使用 DomDocument 将实体添加到 DOCTYPE

我正在尝试创建一个类似于这样的 XML 文档...

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE stylesheet  [
    <!ENTITY nbsp   "&#160;">
    <!ENTITY copy   "&#169;">
    <!ENTITY reg    "&#174;">
    <!ENTITY trade  "&#8482;">
    <!ENTITY mdash  "&#8212;">
    <!ENTITY ldquo  "&#8220;">
    <!ENTITY rdquo  "&#8221;"> 
    <!ENTITY pound  "&#163;">
    <!ENTITY yen    "&#165;">
    <!ENTITY euro   "&#8364;">
]>
<NewsPost>
    <Post>
        <PermaLink>http://news.bradfordastronomy.co.uk/?p=92</PermaLink>
        <Title>Change of Venue for Monday Meetings until March 2015</Title>
        <Content>Due to building work at Eccleshill library, the Monday meetings will be held at     Upper Bolton Conservative Club, Idle Road, Bradford, BD2 4JN.&#13;
&#13;
&nbsp;&#13;
&#13;
&nbsp;&#13;
&#13;
&lt;span style="color: #ffff00"&gt;&lt;strong&gt;Update &lt;/strong&gt;&lt;/span&gt;&#13;
&#13;
The building work is taking longer than expected; however, we hope to be back at the Library by     the end of March 2015.</Content></Post></NewsPost>

我正在尝试使用 PHP 来做到这一点。到目前为止我拥有的当前代码是这样的......

    $imp = new DOMImplementation;

    $dtd = $imp->createDocumentType('stylesheet', '', '');

    $domDoc = new DOMDocument('1.0', 'utf-8');
    $domDoc->preserveWhiteSpace = false;

    require_once(newsFolder.'/wp-blog-header.php'); 
    //global $post;
    $args = array( 'posts_per_page' => 1 );
    $myposts = get_posts( $args );


    $rootElement = $domDoc->createElement('NewsPost');
    $domDoc->appendChild($rootElement); 

    foreach( $myposts as $post ) : setup_postdata($post);
        $postNode = $domDoc->createElement("Post");
        $rootElement->appendChild($postNode);

        $permaLinkNode = $domDoc->createElement("PermaLink",get_permalink());
        $postNode->appendChild($permaLinkNode);

        $titleNode = $domDoc->createElement("Title",get_the_title());
        $postNode->appendChild($titleNode);

        //$contentNode = $domDoc->createElement("Excerpt",get_the_excerpt());
        //$postNode->appendChild($contentNode);

        $contentNode = $domDoc->createElement("Content",get_the_content());
        $postNode->appendChild($contentNode);
    endforeach;

    $domDoc->save(cacheFolder.'LatestWordPressEntry.xml');

    unset($domDoc);

您会注意到没有代码将标签添加到 !DOCTYPE

我正在整个网络上查找，但看不到执行此操作的最佳实践方法。我真的不想将 XML 保存到字符串中，然后进行字符串替换（这总是一个巨大的麻烦）

对此的任何帮助将不胜感激。

基本上，我想改变

<!DOCTYPE stylesheet>

tag into

<!DOCTYPE stylesheet  [
    <!ENTITY nbsp   "&#160;">
    <!ENTITY copy   "&#169;">
    <!ENTITY reg    "&#174;">
    <!ENTITY trade  "&#8482;">
    <!ENTITY mdash  "&#8212;">
    <!ENTITY ldquo  "&#8220;">
    <!ENTITY rdquo  "&#8221;"> 
    <!ENTITY pound  "&#163;">
    <!ENTITY yen    "&#165;">
    <!ENTITY euro   "&#8364;">
]>

DOM 不是用于构建文档类型定义的接口，这就是为什么您找不到将实体声明等内容添加到内部子集的方法。如果您必须内联它而不是使用外部子集，则必须将其作为完整字符串提供并相应地加载它。

Example:

$xml = <<<'XML'
<!DOCTYPE stylesheet  [
    <!ENTITY nbsp   "&#160;">
    <!ENTITY copy   "&#169;">
    <!ENTITY reg    "&#174;">
    <!ENTITY trade  "&#8482;">
    <!ENTITY mdash  "&#8212;">
    <!ENTITY ldquo  "&#8220;">
    <!ENTITY rdquo  "&#8221;">
    <!ENTITY pound  "&#163;">
    <!ENTITY yen    "&#165;">
    <!ENTITY euro   "&#8364;">
]>
<NewsPost/>
XML;

$dom = new DOMDocument();
$dom->loadXML($xml);

echo $dom->saveXML();

Output:

<?xml version="1.0"?>
<!DOCTYPE stylesheet [
<!ENTITY nbsp "&#160;">
<!ENTITY copy "&#169;">
<!ENTITY reg "&#174;">
<!ENTITY trade "&#8482;">
<!ENTITY mdash "&#8212;">
<!ENTITY ldquo "&#8220;">
<!ENTITY rdquo "&#8221;">
<!ENTITY pound "&#163;">
<!ENTITY yen "&#165;">
<!ENTITY euro "&#8364;">
]>
<NewsPost/>