PHP invalid character error - php

Question

I'm getting this error when running this code:
Fatal error: Uncaught exception 'DOMException' with message 'Invalid Character Error' in test.php:29 Stack trace: #0 test.php(29): DOMDocument->createElement('1OhmStable', 'a') #1 {main} thrown in test.php on line 29
The nodes that from the original XML file do contain invalid characters, but as I am stripping the invalid characters away from the nodes, the nodes should be created. What type of encoding do I need to do on the original XML document? Do I need to decode the saveXML?
function __cleanData($c)
{
return preg_replace("/[^A-Za-z0-9]/", "",$c);
}
$xml = new DOMDocument('1.0', 'UTF-8');
$xml->load('test.xml');
$xml->formatOutput = true;
$append = array();
foreach ($xml->getElementsByTagName('product') as $product )
{
foreach($product->getElementsByTagName('name') as $name )
{
$append[] = $name;
}
foreach ($append as $a)
{
$nodeName = __cleanData($a->textContent);
$element = $xml->createElement(htmlentities($nodeName) , 'a');
}
$product->removeChild($xml->getElementsByTagName('details')->item(0));
$product->appendChild($element);
}
$result = $xml->saveXML();
$file = "data.xml";
file_put_contents($file,$result);
This is what the original XML looks like:
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href="/v1/xsl/xml_pretty_printer.xsl" type="text/xsl"?>
<products>
<product>
<modelNumber>M100</modelNumber>
<itemId>1553725</itemId>
<details>
<detail>
<name>1 Ohm Stable</name>
<value>600 x 1</value>
</detail>
</details>
</product>
</products>
The new document is supposed to look like this:
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href="/v1/xsl/xml_pretty_printer.xsl" type="text/xsl"?>
<products>
<product>
<modelNumber>M100</modelNumber>
<itemId>1553725</itemId>
<1 Ohm Stable>
</1 Ohm Stable>
</product>
</products>

Answer 1

Simply you can not use an element name start with number
1OhmStable <-- rename this
_1OhmStable <-- this is fine
php parse xml - error: StartTag: invalid element name
A nice article :- http://www.xml.com/pub/a/2001/07/25/namingparts.html
A Name is a token beginning with a letter or one of a few punctuation characters, and continuing with letters, digits, hyphens, underscores, colons, or full stops, together known as name characters.

Answer 2

You have not written where you get that error. In case it's after you cleaned the value, this is my guess:
preg_replace("/[^A-Za-z0-9]/", "",$c);
This replacement is not written for UTF-8 encoded strings (which are used by DOMDocument). You can make it UTF-8 compatible by using the u-modifier (PCRE8)­Docs:
preg_replace("/[^A-Za-z0-9]/u", "",$c);
^
It's just a guess, I suggest you make it more precise in your question which part of your code triggers the error.

Answer 3

Even if __cleandata() will remove all other characters than latin alphabets a-z and numbers, it doesn't necessarily guarantee that the result is a valid XML name. Your function can return strings that begin with a number but numbers are illegal name start characters in XML, they can only appear in a name after the first name character. Also spaces are forbidden in names, so that is another point where your expected XML output would fail.

Answer 4

Make sure scripts have same encoding: if it's UTF make sure they are without Byte Order Mark (BOM) at very begin of file.
To do that open your XML file with a text editor like Notepad++ and convert your file in "UTF-8 without BOM".
I had a similar error, but with a json file