Getting SimpleXMLElement to include the encoding in output - php

Question

This:
$XML = new SimpleXMLElement("<foo />");
echo($XML->asXML());
...outputs this:
<?xml version="1.0"?>
<foo/>
But I want it to output the encoding, too:
<?xml version="1.0" encoding="UTF-8"?>
<foo/>
Is there some way to tell SimpleXMLElement to include the encoding attribute of the <?xml?> tag? Aside from doing this:
$XML = new SimpleXMLElement("<?xml version='1.0' encoding='utf-8'?><foo />");
echo($XML->asXML());
Which works, but it's annoying to have to manually specify the version and encoding.
Assume for the purposes of this question that I cannot use DOMDocument instead.

Answer 1

You can try this, but you must use simplexml_load_string for $xml
$xml // Your main SimpleXMLElement
$xml->addAttribute('encoding', 'UTF-8');
Or you can still use other means to add the encoding to your output.
Simple Replacement
$outputXML=str_replace('<?xml version="1.0"?>', '<?xml version="1.0" encoding="UTF-8"?>', $outputXML);
Regular Expressions
$outputXML=preg_replace('/<\?\s*xml([^\s]*)\?>/' '<?xml $1 encoding="UTF-8"?>', $outputXML);
DOMDocument - I know you said you don't want to use DOMDocument, but here is an example
$xml = dom_import_simplexml($simpleXML);
$xml->xmlEncoding = 'UTF-8';
$outputXML = $xml->saveXML();
You can wrap this code into a function that receives a parameter $encoding and adds it to the

Answer 2

Simple and clear only do this
$XMLRoot = new SimpleXMLElement('<?xml version="1.0" encoding="utf-8"?><element></element>');
OutPut
<?xml version="1.0" encoding="UTF-8"?>
<element></element>
to add attributes in element only use
$XMLRoot->addAttribute('name','juan');
to add child use
$childElement = $XMLRoot->addChild('elementChild');
$childElement->addAttribute('attribName','somthing');

Answer 3

The DOMDoc proposal of Cristian Toma seems a good approach if the document isn't too heavy. You could wrap it up in something like this:
private function changeEncoding(string $xml, string $encoding) {
$dom = new \DOMDocument();
$dom->loadXML($xml);
$dom->encoding = $encoding;
return $dom->saveXML();
}
Comes in useful when you don't have access to the serializer producing the xml.

Answer 4

I would say you will need to do this on creation of each XML object. Even if SimpleXMLElement had a way of setting it you would still need to set it as I guess it would be possible for the object to pick a valid default.
Maybe create a constant and Create objects like this
$XML = new SimpleXMLElement($XMLNamespace . "<foo />");
echo($XML->asXML());

Answer 5

If you don't specify an encoding, SimpleXML cannot (sanely) guess which one you intended.