PHP XML how to output nice format

Here are the codes:

$doc = new DomDocument('1.0');
// create root node
$root = $doc->createElement('root');
$root = $doc->appendChild($root);
$signed_values = array('a' => 'eee', 'b' => 'sd', 'c' => 'df');
// process one row at a time
foreach ($signed_values as $key => $val) {
    // add node for each row
    $occ = $doc->createElement('error');
    $occ = $root->appendChild($occ);
    // add a child node for each field
    foreach ($signed_values as $fieldname => $fieldvalue) {
        $child = $doc->createElement($fieldname);
        $child = $occ->appendChild($child);
        $value = $doc->createTextNode($fieldvalue);
        $value = $child->appendChild($value);
    }
}
// get completed xml document
$xml_string = $doc->saveXML() ;
echo $xml_string;

If I print it in the browser I don't get nice XML structure like

<xml> \n tab <child> etc.

I just get

<xml><child>ee</child></xml>

And I want to be utf-8 How is this all possible to do?

You can try to do this:

...
// get completed xml document
$doc->preserveWhiteSpace = false;
$doc->formatOutput = true;
$xml_string = $doc->saveXML();
echo $xml_string;

You can make set these parameter right after you've created the DOMDocument as well:

$doc = new DomDocument('1.0');
$doc->preserveWhiteSpace = false;
$doc->formatOutput = true;

That's probably more concise. Output in both cases is (Demo):

<?xml version="1.0"?>
<root>
  <error>
    <a>eee</a>
    <b>sd</b>
    <c>df</c>
  </error>
  <error>
    <a>eee</a>
    <b>sd</b>
    <c>df</c>
  </error>
  <error>
    <a>eee</a>
    <b>sd</b>
    <c>df</c>
  </error>
</root>

I'm not aware how to change the indentation character(s) with DOMDocument. You could post-process the XML with a line-by-line regular-expression based replacing (e.g. with preg_replace):

$xml_string = preg_replace('/(?:^|\G)  /um', "\t", $xml_string);

Alternatively, there is the tidy extension with tidy_repair_string which can pretty print XML data as well. It's possible to specify indentation levels with it, however tidy will never output tabs.

tidy_repair_string($xml_string, ['input-xml'=> 1, 'indent' => 1, 'wrap' => 0]);

With a SimpleXml object, you can simply

$domxml = new DOMDocument('1.0');
$domxml->preserveWhiteSpace = false;
$domxml->formatOutput = true;
/* @var $xml SimpleXMLElement */
$domxml->loadXML($xml->asXML());
$domxml->save($newfile);

$xml is your simplexml object

So then you simpleXml can be saved as a new file specified by $newfile

<?php

$xml = $argv[1];

$dom = new DOMDocument();

// Initial block (must before load xml string)
$dom->preserveWhiteSpace = false;
$dom->formatOutput = true;
// End initial block

$dom->loadXML($xml);
$out = $dom->saveXML();

print_R($out);

Tried all the answers but none worked. Maybe it's because I'm appending and removing childs before saving the XML. After a lot of googling found this comment in the php documentation. I only had to reload the resulting XML to make it work.

$outXML = $xml->saveXML(); 
$xml = new DOMDocument(); 
$xml->preserveWhiteSpace = false; 
$xml->formatOutput = true; 
$xml->loadXML($outXML); 
$outXML = $xml->saveXML(); 

// ##### IN SUMMARY #####

$xmlFilepath = 'test.xml';
echoFormattedXML($xmlFilepath);

/*
 * echo xml in source format
 */
function echoFormattedXML($xmlFilepath) {
	header('Content-Type: text/xml'); // to show source, not execute the xml
	echo formatXML($xmlFilepath); // format the xml to make it readable
} // echoFormattedXML

/*
 * format xml so it can be easily read but will use more disk space
 */
function formatXML($xmlFilepath) {
	$loadxml = simplexml_load_file($xmlFilepath);
	
	$dom = new DOMDocument('1.0');
	$dom->preserveWhiteSpace = false;
	$dom->formatOutput = true;
	$dom->loadXML($loadxml->asXML());
	$formatxml = new SimpleXMLElement($dom->saveXML());
	//$formatxml->saveXML("testF.xml"); // save as file

	return $formatxml->saveXML();
} // formatXML

Two different issues here:

• Set the formatOutput and preserveWhiteSpace attributes to TRUE to generate formatted XML:

    $doc->formatOutput = TRUE;
    $doc->preserveWhiteSpace = TRUE;
  

• Many web browsers (namely Internet Explorer and Firefox) format XML when they display it. Use either the View Source feature or a regular text editor to inspect the output.

---

See also xmlEncoding and encoding.

This is a slight variation of the above theme but I'm putting here in case others hit this and cannot make sense of it ...as I did.

When using saveXML(), preserveWhiteSpace in the target DOMdocument does not apply to imported nodes (as at PHP 5.6).

Consider the following code:

$dom = new DOMDocument();                               //create a document
$dom->preserveWhiteSpace = false;                       //disable whitespace preservation
$dom->formatOutput = true;                              //pretty print output
$documentElement = $dom->createElement("Entry");        //create a node
$dom->appendChild ($documentElement);                   //append it 
$message = new DOMDocument();                           //create another document
$message->loadXML($messageXMLtext);                     //populate the new document from XML text
$node=$dom->importNode($message->documentElement,true); //import the new document content to a new node in the original document
$documentElement->appendChild($node);                   //append the new node to the document Element
$dom->saveXML($dom->documentElement);                   //print the original document

In this context, the $dom->saveXML(); statement will NOT pretty print the content imported from $message, but content originally in $dom will be pretty printed.

In order to achieve pretty printing for the entire $dom document, the line:

$message->preserveWhiteSpace = false; 

must be included after the $message = new DOMDocument(); line - ie. the document/s from which the nodes are imported must also have preserveWhiteSpace = false.

based on the answer by @heavenevil This function pretty prints using the browser

function prettyPrintXmlToBrowser(SimpleXMLElement $xml)
{
    $domXml = new DOMDocument('1.0');
    $domXml->preserveWhiteSpace = false;
    $domXml->formatOutput = true;
    $domXml->loadXML($xml->asXML());
    $xmlString = $domXml->saveXML();
    echo nl2br(str_replace(' ', ' ', htmlspecialchars($xmlString)));
}