format xml string

Question

What is the best way to format XML within a PHP class.

$xml = "<element attribute=\"something\">...</element>";

$xml = '<element attribute="something">...</element>';

$xml = '<element attribute=\'something\'>...</element>';

$xml = <<<EOF
<element attribute="something">
</element>
EOF;

I'm pretty sure it is the last one!

i am not sure what you are asking. do you want to build xml using some php class? — Pramendra Gupta
– Pramendra Gupta, Commented Sep 1, 2010 at 9:18
It's a webservice call for a credit card payment, some of the parameters are XML for the amount/customer address, the amount can be hardcoded as it is constant, and it's that XML that I'll type in my php class — quj
– quj, Commented Sep 1, 2010 at 9:56
If it's a webservice, then you should not need to care about any formatting. Formatting is only useful if you need to provide the XML to humans to make it easier to read and author. Machines dont care. — Gordon
– Gordon, Commented Sep 1, 2010 at 10:41

Andrew · Accepted Answer · 2017-10-25 13:30:52Z

93

With DOM you can do

$dom = new DOMDocument;
$dom->preserveWhiteSpace = FALSE;
$dom->loadXML('<root><foo><bar>baz</bar></foo></root>');
$dom->formatOutput = TRUE;
echo $dom->saveXML();

gives (live demo)

<?xml version="1.0"?>
<root>
  <foo>
    <bar>baz</bar>
  </foo>
</root>

See DOMDocument::formatOutput and DOMDocument::preserveWhiteSpace properties description.

edited Oct 25, 2017 at 13:30

Andrew

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answered Sep 1, 2010 at 9:41

Gordon

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Comments

pravat231 · Accepted Answer · 2011-09-17 09:55:09Z

16

This function works perfectlly as you want you don't have to use any xml dom library or nething just pass the xml generated string into it and it will parse and generate the new one with tabs and line breaks.

function formatXmlString($xml){
    $xml = preg_replace('/(>)(<)(\/*)/', "$1\n$2$3", $xml);
    $token      = strtok($xml, "\n");
    $result     = '';
    $pad        = 0; 
    $matches    = array();
    while ($token !== false) : 
        if (preg_match('/.+<\/\w[^>]*>$/', $token, $matches)) : 
          $indent=0;
        elseif (preg_match('/^<\/\w/', $token, $matches)) :
          $pad--;
          $indent = 0;
        elseif (preg_match('/^<\w[^>]*[^\/]>.*$/', $token, $matches)) :
          $indent=1;
        else :
          $indent = 0; 
        endif;
        $line    = str_pad($token, strlen($token)+$pad, ' ', STR_PAD_LEFT);
        $result .= $line . "\n";
        $token   = strtok("\n");
        $pad    += $indent;
    endwhile; 
    return $result;
}

answered Sep 17, 2011 at 9:55

pravat231

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2 Comments

John Sheehan Over a year ago

You should attribute your sources: recursive-design.com/blog/2007/04/05/format-xml-with-php

Zsolti Over a year ago

Great script, just one thing to mention is, that if the xml has CDATA content, it will be also formatted, and in some cases it will break the good indentation of the whole xml.

Pramendra Gupta · Accepted Answer · 2010-09-01 09:33:41Z

6

//Here is example using XMLWriter

$w = new XMLWriter;
$w->openMemory();
$w->setIndent(true);
  $w->startElement('foo');
    $w->startElement('bar');
      $w->writeElement("key", "value");
    $w->endElement();
  $w->endElement();
echo $w->outputMemory();

//out put

<foo> 
 <bar> 
  <key>value</key> 
 </bar> 
</foo>

edited Sep 1, 2010 at 9:33

answered Sep 1, 2010 at 9:27

Pramendra Gupta

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1 Comment

fabrik Over a year ago

Btw, XMLWriter is better than the DOM functions? Looks nicer though.

Mark Brown · Accepted Answer · 2011-12-22 13:28:25Z

0

The first is better if you plan to embed values into the XML, The second is better for humans to read. Neither is good if you intend really work with XML.

However if you intend to perform a simple fire and forget function that takes XML as a input parameter, then I would say use the first method because you will need to embed parameters at some point.

I personally would use the PHP class simplexml, it's very easy to use and it's built in xpath support makes detailing the data returned in XML a dream.

answered Dec 22, 2011 at 13:28

Mark Brown

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Comments

Sandro Rosa · Accepted Answer · 2024-01-17 17:18:43Z

The above function formatXmlString is a great job ! Thanks! I updated it so one can use any symbol for indentation and also encode tags for displaying the code on a web page. Here's the new code and an example.

Just replace these lines into the above code

function formatXmlString( $xml = "", $indent_symbol = " ", $crlf = "\n", $bool_enc_tags = 0 )

$line = str_pad($token, strlen($token)+$pad * $indent_symbol_len, $indent_symbol, STR_PAD_LEFT);

After the while-loop, put the following

if ( $bool_enc_tags )
{
     $result = str_replace( "<", "&lt;", $result );
     $result = str_replace( ">", "&gt;", $result );
}

if ( $crlf != "\n" )
$result = preg_replace( "/\n/", $crlf, $result );

return $result;

Then test it as below

echo formatXmlString( '<root><foo><bar>baz</bar></foo></root>', str_repeat( "&nbsp;", 4 ), "<br/>", true );

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