Updating XML node with PHP

Question

I've an XML file test.xml

<?xml version="1.0"?>
<info>
  <user>
    <name>
      <firstname>FirstName</firstname>
      <lastname>Last Name</lastname>
      <nameCoordinate>
        <xName>125</xName>
        <yName>20</yName>
      </nameCoordinate>
    </name>
  </user>
</info>

I'm trying to update the node xName & yName using PHP on a form submission. So, I've loaded the file using simplexml_load_file(). The PHP form action code is below

<?php 
    $xPostName = $_POST['xName'];
    $yPostName = $_POST['yName'];

    //load xml file to edit
        $xml = simplexml_load_file('test.xml');

    $xml->info->user->name->nameCoordinate->xName = $xPostName;
    $xml->info->user->name->nameCoordinate->yName = $yPostName;
    echo "done";
?>

I want to update the node values but the above code seems to be incorrect. Can anyone help me rectify it??

UPDATE: My question is somewhat similar to this Updating a XML file using PHP but here, I'm loading the XML from an external file and also I'm updating an element, not an attribute. That's where my confusion lies.

what is not working as expected? you don't have an error explained. — Samuel Herzog, Jan 20 '11 at 14:02

score 37 · Accepted Answer · answered Jan 20 '11 at 14:29

37

You're not accessing the right node. In your example, $xml holds the root node <info/>. Here's a great tip: always name the variable that holds your XML document after its root node, it will prevent such confusion.

Also, as Ward Muylaert pointed out, you need to save the file.

Here's the corrected example:

// load the document
// the root node is <info/> so we load it into $info
$info = simplexml_load_file('test.xml');

// update
$info->user->name->nameCoordinate->xName = $xPostName;
$info->user->name->nameCoordinate->yName = $yPostName;

// save the updated document
$info->asXML('test.xml');

answered Jan 20 '11 at 14:29

Josh Davis

28,400
5
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What will happen if the xName or yName node doesn't already exist? – swl1020 Mar 25 '13 at 14:15
What if you have several users with several yName and want to edit all of them at once? Any thoughts? – user906379 Jul 08 '15 at 21:10

Ward Muylaert · Answer 2 · 2011-01-20T14:32:11.530

3

You have to write the changes back to the file, use the asXML method of the SimpleXMLElement.

edited Jan 20 '11 at 14:32

answered Jan 20 '11 at 14:07

Ward Muylaert

545
4
27

I believe that rewrites the whole tags. I want to update only specific nodes. – ptamzz Jan 20 '11 at 14:13
1

It does, but short of writing half the XML interpreting logic in your own code to only write specific nodes, I believe that is as far as you'll get with SimpleXML. – Ward Muylaert Jan 20 '11 at 14:17

score 2 · Answer 3 · answered Dec 27 '19 at 12:47

try like this.

$xmlDoc = new \DOMDocument;
$xmlDoc->load('Books.xml');
$response = $xmlDoc->getElementsByTagName('Text');

foreach ($response as $node){
        $node->nodeValue = 'test';
    }
$xmlDoc->saveXML();

this might not the best answer but it worked for me.

Updating XML node with PHP

3 Answers3

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