How do I remove a specific node using its attribute value in PHP XML Dom?

问题

My question is best phrase as: Remove a child with a specific attribute, in SimpleXML for PHP

except I'm not using simpleXML.

I'm new to XML for PHP so I may not be doing the best way

I have a xml created using the $dom->save($xml) for each individual user. (not placing all in one xml due to undisclosed reasons)

It gives me that xml declaration <?xml version="1.0"?> (no idea how to make it to others, but that's not the point, hopefully)

<?xml version="1.0"?>
<details>
 <person>name</person>
 <data1>some data</data1>
 <data2>some data</data2>
 <data3>some data</data3>
 <category id="0">
  <categoryName>Cat 1</categoryName>
  <categorydata1>some data</categorydata1>
 </category>
 <category id="1">
  <categoryName>Cat 2</categoryName>
  <categorydata1>some data</categorydata1>
  <categorydata2>some data</categorydata2>
  <categorydata3>some data</categorydata3>
  <categorydata4>some data</categorydata4>
 </category>
</details>

And I want to remove a category that has a specific attribute named id with the DOM class in php when i run a function activated from using a remove button.

the following is the debug of the function im trying to get to work. Can i know what I'm doing wrong?

function CatRemove($myXML){
        $xmlDoc = new DOMDocument();
        $xmlDoc->load( $myXML );
        $categoryArray = array();

        $main = $xmlDoc->getElementsByTagName( "details" )->item(0);

        $mainElement = $xmlDoc->getElementsByTagName( "details" );
        foreach($mainElement as $details){
            $currentCategory = $details->getElementsByTagName( "category" );
            foreach($currentCategory as $category){
                $categoryID = $category->getAttribute('id');
                array_push($categoryArray, $categoryID);
                if($categoryID == $_POST['categorytoremoveValue']) {
                    return $categoryArray;
                }
            }
        }


        $xmlDoc->save( $myXML );
    }

Well the above prints me an array of [0]->0 all the time when i slot the return outside the if. is there a better way? I've tried using getElementbyId as well but I've no idea how to work that.

I would prefer not to use an attribute though if that would make things easier.

回答1:

Ok, let’s try this complete example of use:

function CatRemove($myXML, $id) {
    $xmlDoc = new DOMDocument();
    $xmlDoc->load($myXML);
    $xpath = new DOMXpath($xmlDoc);
    $nodeList = $xpath->query('//category[@id="'.(int)$id.'"]');
    if ($nodeList->length) {
        $node = $nodeList->item(0);
        $node->parentNode->removeChild($node);
    }
    $xmlDoc->save($myXML);
}

// test data
$xml = <<<XML
<?xml version="1.0"?>
<details>
 <person>name</person>
 <data1>some data</data1>
 <data2>some data</data2>
 <data3>some data</data3>
 <category id="0">
  <categoryName>Cat 1</categoryName>
  <categorydata1>some data</categorydata1>
 </category>
 <category id="1">
  <categoryName>Cat 2</categoryName>
  <categorydata1>some data</categorydata1>
  <categorydata2>some data</categorydata2>
  <categorydata3>some data</categorydata3>
  <categorydata4>some data</categorydata4>
 </category>
</details>
XML;
// write test data into file
file_put_contents('untitled.xml', $xml);
// remove category node with the id=1
CatRemove('untitled.xml', 1);
// dump file content
echo '<pre>', htmlspecialchars(file_get_contents('untitled.xml')), '</pre>';

回答2:

So you want to remove the category node with a specific id?

$node = $xmlDoc->getElementById("12345");
if ($node) {
    $node->parentNode->removeChild($node);
}

You could also use XPath to get the node, for example:

$xpath = new DOMXpath($xmlDoc);
$nodeList = $xpath->query('//category[@id="12345"]');
if ($nodeList->length) {
    $node = $nodeList->item(0);
    $node->parentNode->removeChild($node);
}

I haven’t tested it but it should work.

回答3:

Can you try with this modified version:

function CatRemove($myXML, $id){
    $doc = new DOMDocument();
    $doc->loadXML($myXML);
    $xpath = new DOMXpath($doc);
    $nodeList = $xpath->query("//category[@id='$id']");
    foreach ($nodeList as $element) {
        $element->parentNode->removeChild($element);
    }

    echo htmlentities($doc->saveXML());
}

It's working for me. Just adapt it to your needs. It's not intended to use as-is, but just a proof of concept. You also have to remove the xml declaration from the string.

回答4:

the above funciton modified to remove an email from a mailing list

function CatRemove($myXML, $id) {
    $xmlDoc = new DOMDocument();
    $xmlDoc->load($myXML);
    $xpath = new DOMXpath($xmlDoc);
    $nodeList = $xpath->query('//subscriber[@email="'.$id.'"]');
    if ($nodeList->length) {
        $node = $nodeList->item(0);
        $node->parentNode->removeChild($node);
    }
    $xmlDoc->save($myXML);
}
$xml = 'list.xml';
$to = $_POST['email'];//user already submitted they email using a form 
CatRemove($xml,$to);

来源：https://stackoverflow.com/questions/457153/how-do-i-remove-a-specific-node-using-its-attribute-value-in-php-xml-dom