Question 172264 in PHP Question posted in
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Can I use XPath & SimpleXML to access embedded nodes in PHP?

I’m trying to access all the text within the Text node of the following XML document:

<Section>
 <Subsection lims:inforce-start-date="2003-07-01" lims:fid="182941" lims:id="182941">
  <Label>(2)</Label>
  <Text>
   In subsection (1),
    <DefinedTermEn>beer</DefinedTermEn>
   and
    <DefinedTermEn>malt liquor</DefinedTermEn>
   have the meaning assigned by section 4.
   </Text>
 </Subsection>
</Section>

With Xpath, using $xml->xpath("Body/Section/Subsection") will return the following:

object(SimpleXMLElement)#7 (3) {
    
    ["Label"]=>
    string(3) "(2)"
    ["Text"]=>
    string(64) "In subsection (1),  and  have the meaning assigned by section 4."

Which makes the inner node disappear. Is there a way to "flatten" all the content of all the subnodes within a node so that I can get a continuous piece of text?
e. g. In subsection (1), beer and malt liquor have the meaning assigned by section 4.

Tags:

2

Answers


  1. 0

    Mixed nodes are to complex for SimpleXML – use DOM. The DOMNode::$textContent property will return the text content of any node. For element nodes this includes the text content of any descendant node. Also DOMXpath::evaluate() supports expression that return scalar values. If you cast a node list into a string it will return the text content of the first node in the list.

    // bootstrap DOM
$document = new DOMDocument();
$document->loadXML(getXML());
$xpath = new DOMXpath($document);

// iterate the subsection element nodes
foreach ($xpath->evaluate('//Subsection') as $subsection) {
    var_dump(
        [
            // text content of the "Label" child element
            'label' => $xpath->evaluate('string(Label)', $subsection),
            // text content of the "Text" child element
            'text' => $xpath->evaluate('string(Text)', $subsection),
        ]
    );
}

function getXML() {
  return <<<'XML'
<Section xmlns:lims="urn:lims">
 <Subsection lims:inforce-start-date="2003-07-01" lims:fid="182941" lims:id="182941">
  <Label>(2)</Label>
  <Text>
   In subsection (1),
    <DefinedTermEn>beer</DefinedTermEn>
   and
    <DefinedTermEn>malt liquor</DefinedTermEn>
   have the meaning assigned by section 4.
   </Text>
 </Subsection>
</Section>
XML;
}

    Output:

    array(2) {
  ["label"]=>
  string(3) "(2)"
  ["text"]=>
  string(101) "
   In subsection (1),
    beer
   and
    malt liquor
   have the meaning assigned by section 4.
   "
}
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  2. 0

    The answer @ThW posted explains how DOM is a better fit for this, however that approach may leave you with a whitespace problem. You may want to think about writing a function to recurse the node tree within your Text element and build a string that trims the whitespace from each text node, leaving you with a single line.

    <?php

$input = <<<END
<Body>
<Section>
 <Subsection lims:inforce-start-date="2003-07-01" lims:fid="182941" lims:id="182941">
  <Label>(2)</Label>
  <Text>
   In subsection (1),
    <DefinedTermEn>beer</DefinedTermEn>
   and
    <DefinedTermEn>malt liquor</DefinedTermEn>
   have the meaning assigned by section 4.
   </Text>
 </Subsection>
</Section>
</Body>
END;

// Create DOMDocument instance and load XML
$dom = new DOMDocument();
$dom->loadXML($input);

// Instantiate XPath with our document
$xpath = new DOMXPath($dom);

// Get the Text elements
$textElements = $xpath->query("/Body/Section/Subsection/Text");

/**
 * Recursive function to build a string from the text content within
 * a DOMNode and its children. Whitespace is trimmed.
 *
 * @param DOMNode $node
 * @return string
 */
function getBranchText(DOMNode $node ) : string
{
    $buffer = [];

    if($node->nodeType == XML_TEXT_NODE || $node->nodeType == XML_CDATA_SECTION_NODE)
    {
        $buffer[] = trim($node->nodeValue);
    }
    elseif ($node->nodeType == XML_ELEMENT_NODE)
    {
        foreach($node->childNodes as $currChild)
        {
            $buffer[] = getBranchText($currChild);
        }
    }

    return implode(' ', $buffer);
}

$output = getBranchText($textElements[0]);

echo $output.PHP_EOL;

    Output:

    In subsection (1), beer and malt liquor have the meaning assigned by section 4.
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