Php:Proble when i convert in xml - php

Question

I want my arElemt(gurl and gname) put in . Example and problem2 = when i write g:url or g:name = Error... php7.2* and now example now now i have this construction
-rss
---title
---link
---description
---gurl
---gname
i want now i have this construction
-rss
---title
---link
---description
---gurl
---gname
---gurl
---gname
---gurl
---gname i want
-rss
---title
---link
---description
---item
-----gurl
-----gname
---item
-----gurl
-----gname
---item
-----gurl
-----gname
---item
-----gurl
-----gname
header("Content-type: text/xml; charset=utf-8");
$dom = new DOMDocument('1.0','utf-8');
$root = $dom->createElement('rss');
$dom->appendChild($root);
$title = $dom->createElement('title', 'test');
$root->appendChild($title );
$link = $dom->createElement('link', 'test');
$root->appendChild($link );
$description = $dom->createElement('description', 'test');
$root->appendChild($description );
$root = $item->createElement('item');
while($arElement = $rsElements->GetNext())
{
$url = $dom->createElement("gurl", $surl.$arElement[DETAIL_PAGE_URL]);
$item->appendChild($url );
$name = $dom->createElement("gname", $arElement[NAME]);
$root->appendChild($name );
}
echo $dom->saveXML();
$dom->save($file_name); // save as file

Answer 1

Here is a big difference between gurl and g:url. gurl is not an valid RSS tag afaik. g:url is an url element inside a defined namespace.
The g from g:url is a namespace prefix. It references a namespace definition. Look for a xmlns:g attribute in examples or for the namespace URI in the documentation of the format. The g is an alias for the value of that attribute. A parser resolves that to the URI internally. All the following nodes can be read as {urn:example:namespace}url.
<g:url xmlns:g="urn:example:namespace"/>
<g2:url xmlns:g2="urn:example:namespace"/>
<url xmlns="urn:example:namespace"/>
RSS itself is just wellformed XML, it uses no namespace. But it can contain other XML formats that use namespaces (MediaRSS, ...).
To create an element with a namespace use the method DOMDocument::createElementNS(). This will automatically add the namespace definition if needed. However if do not use the namespace for the document element it will be added multiple times. You can set the namespace definition as an attribute of the reserved XMLNS namespace.
$data = ['one', 'two'];
// the namespace for namespace definitions
const XMLNS_XMLNS = 'http://www.w3.org/2000/xmlns/';
// namespace referenced by prefix g?
const XMLNS_G = 'urn:example:namespace';
$document = new DOMDocument('1.0','utf-8');
$rss = $document->appendChild(
$document->createElement('rss')
);
// add the namespace definition to the document element
$rss->setAttributeNS(XMLNS_XMLNS, 'xmlns:g', XMLNS_G);
// create + append element node, set its text content
$rss->appendChild(
$document->createElement('title')
)->textContent = 'test';
foreach ($data as $value) {
$item = $rss->appendChild(
$document->createElement('item')
);
// create and append an element with the namespace
$item->appendChild(
$document->createElementNS(XMLNS_G, 'g:url')
)->textContent = 'http://example.com/page?'.$value;
}
$document->formatOutput = TRUE;
echo $document->saveXML();
Output:
<?xml version="1.0" encoding="utf-8"?>
<rss xmlns:g="urn:example:namespace">
<title>test</title>
<item>
<g:url>http://example.com/page?one</g:url>
</item>
<item>
<g:url>http://example.com/page?two</g:url>
</item>
</rss>
Hint 1: DOMNode::appendChild() returns the appended node. It is possible to nest the create call.
Hint 2: DOMNode::$textContent allows to read/write the text content of a node and escapes properly.

Answer 2

const XMLNS_XMLNS = 'http://www.w3.org/2000/xmlns/';
// namespace referenced by prefix g?
const XMLNS_G = 'urn:example:namespace';
$document = new DOMDocument('1.0','utf-8');
$rss = $document->appendChild(
$document->createElement('rss')
);
// add the namespace definition to the document element
$rss->setAttributeNS(XMLNS_XMLNS, 'xmlns:g', XMLNS_G);
// create + append element node, set its text content
$rss->appendChild(
$document->createElement('title')
)->textContent = 'test';
while($arElement = $rsElements->GetNext())
{
$item = $rss->appendChild(
$document->createElement('item')
);
$item->appendChild(
$document->createElementNS(XMLNS_G, 'g:url')
)->textContent = $surl.$arElement["DETAIL_PAGE_URL"];
$item->appendChild(
$document->createElementNS(XMLNS_G, 'g:name')
)->textContent = $arElement["NAME"];
}