PHP修改ZendPDF元数据

Question

我正在使用ZendPDF在Symfony中创建一个PDF/A-1b

为此，我必须在PDF的XML结构中设置一些元数据。但我不知道该怎么做。

我试图通过DOMDocument修改XML，但是当我尝试添加DOMNode时，它说它不能写入属性

$node = new DOMNode();
$node->nodeName = "part";

但是我不能写属性异常

我只需要在DOMDocument上附加一个孩子

完整代码

$metadata = $this->pdf->getMetadata();

    $metadataDOM = new DOMDocument();
    $metadataDOM->loadXML($metadata);

    $xpath = new DOMXPath($metadataDOM);
    $xpath->registerNamespace('x', 'adobe:ns:meta/');
    $xpath->registerNamespace('rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#');
    $xpath->registerNamespace('xmp', 'http://ns.adobe.com/xap/1.0/');
    $xpath->registerNamespace('xmpGImg', 'http://ns.adobe.com/xap/1.0/g/img/');
    $xpath->registerNamespace('xmpTPg', 'http://ns.adobe.com/xap/1.0/t/pg/');
    $xpath->registerNamespace('stDim', 'http://ns.adobe.com/xap/1.0/sType/Dimensions#');
    $xpath->registerNamespace('xmpG', 'http://ns.adobe.com/xap/1.0/g/');
    $xpath->registerNamespace('dc', 'http://purl.org/dc/elements/1.1/');
    $xpath->registerNamespace('xmpMM', 'http://ns.adobe.com/xap/1.0/mm/');
    $xpath->registerNamespace('pdf', 'http://ns.adobe.com/pdf/1.3/');
    $xpath->registerNamespace('pdfaid', 'http://www.aiim.org/pdfa/ns/id');

    $data = $xpath->query('//rdf:Description')->item(0);

    $node = new DOMNode();
    $node->nodeName = "asdf";
    $data->appendChild($node);

    dump($data);
    dump($metadataDOM->saveXML());
    die;

Answer 1

您的问题是nodeName属性是只读的--请参阅：http://php.net/manual/en/class.domnode.php

在这里定义在domNode类中：public readonly string $nodeName;

在下面的链接中，还有一个其他元素的解决方案，即只读"textContent“。

http://php.net/manual/en/class.domnode.php#95545

来自php.net的的解决方案的副本：

您不能像缺少的只读标志所建议的那样，简单地覆盖$textContent来替换DOMNode的文本内容。相反，你必须这样做：

<?php

$node->removeChild($node->firstChild);
$node->appendChild(new DOMText('new text content'));

?>

This example shows what happens:

<?php

$doc = DOMDocument::loadXML('<node>old content</node>');
$node = $doc->getElementsByTagName('node')->item(0);
echo "Content 1: ".$node->textContent."\n";

$node->textContent = 'new content';
echo "Content 2: ".$node->textContent."\n";

$newText = new DOMText('new content');

$node->appendChild($newText);
echo "Content 3: ".$node->textContent."\n";

$node->removeChild($node->firstChild);
$node->appendChild($newText);
echo "Content 4: ".$node->textContent."\n";

?>

The output is:

Content 1: old content // starting content
Content 2: old content // trying to replace overwriting $node->textContent
Content 3: old contentnew content // simply appending the new text node
Content 4: new content // removing firstchild before appending the new text node

If you want to have a CDATA section, use this:

<?php
$doc = DOMDocument::loadXML('<node>old content</node>');
$node = $doc->getElementsByTagName('node')->item(0);
$node->removeChild($node->firstChild);
$newText = $doc->createCDATASection('new cdata content');
$node->appendChild($newText);
echo "Content withCDATA: ".$doc->saveXML($node)."\n";
?>

顺便说一下。这个问题与symfony毫无关系。

Answer 2

问题解决

我创建了基本的PDF/A-1b格式，不再需要修改元数据了。