Format XML with PHP

Published 1 year, 8 months ago in PHP, Programming, Web

function formatXmlString($xml) {  
  
  // add marker linefeeds to aid the pretty-tokeniser (adds a linefeed between all tag-end boundaries)
  $xml = preg_replace('/(>)(<)(\/*)/', "$1\n$2$3", $xml);
  
  // now indent the tags
  $token      = strtok($xml, "\n");
  $result     = ''; // holds formatted version as it is built
  $pad        = 0; // initial indent
  $matches    = array(); // returns from preg_matches()
  
  // scan each line and adjust indent based on opening/closing tags
  while ($token !== false) : 
  
    // test for the various tag states
    
    // 1. open and closing tags on same line - no change
    if (preg_match('/.+<\/\w[^>]*>$/', $token, $matches)) : 
      $indent=0;
    // 2. closing tag - outdent now
    elseif (preg_match('/^<\/\w/', $token, $matches)) :
      $pad--;
    // 3. opening tag - don't pad this one, only subsequent tags
    elseif (preg_match('/^<\w[^>]*[^\/]>.*$/', $token, $matches)) :
      $indent=1;
    // 4. no indentation needed
    else :
      $indent = 0; 
    endif;
    
    // pad the line with the required number of leading spaces
    $line    = str_pad($token, strlen($token)+$pad, ' ', STR_PAD_LEFT);
    $result .= $line . "\n"; // add to the cumulative result, with linefeed
    $token   = strtok("\n"); // get the next token
    $pad    += $indent; // update the pad size for subsequent lines    
  endwhile; 
  
  return $result;
}

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14 Responses to “Format XML with PHP”

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1 Matt 2008/01/23 06:46

Hi,

I just wanted to say that that is a fantastic bit of code. Great stuff
2 Matt 2008/01/23 06:49

Also, would there be a way to exclude certain tags such as and tags from creating a line break and formatting.
3 dave 2008/01/25 07:37

Thanks for the feedback matt – unfortunately there’s currently no way to selectively exclude tags from being formatted and indented… out of interest, what kind of tags did you have in mind? I could possibly put exceptions in if there was a need for them.
4 tomh 2008/02/06 00:40

Thanks! Exactlyl I was looking for.
Simple and powerful. Tom
5 Rolf 2008/02/16 10:43

Very nice code here!
6 Enrico 2008/05/18 22:50

Nice stuff! Would be great to have tabs instead of spaces. Something like “formatXmlString($xml, $indent = ”\t”)”.

Cheers
Enrico
7 Zapalenie Åojotokowe 2008/06/27 00:39

Doesn’t work for empty tags like – you need to remove the newline between them afterwards:

// add marker linefeeds to aid the pretty-tokeniser (adds a linefeed between all tag-end boundaries)
$xml = preg_replace(’/(>)(< )(\/*)/’, ”$1\n$2$3”, $xml);

// remove lines between an empty tag
$xml = preg_replace(”|/ ] )(\s([^>] ))?>\n
8 Zapalenie Åojotokowe 2008/06/27 00:40

Seems my comment got cut off:

// remove lines between an empty tag
$xml = preg_replace(”|/ ] )(\s([^>] ))?>\n
9 zaker 2008/06/30 23:34

Custom padding
1. Modify function declaration this way: function formatXmlString($xml, $padstr = ” ”);

2. change $line declaration this way:
$line = str_repeat($padstr, $pad).$token;
10 kg23 2008/09/18 15:31

You can also use the linux xmllint command as so…

public static function formatXmlString($xml) {
$xml = escapeshellarg($xml);
$result = array();
exec(‘echo ’.$xml.’ | xmllint—format -’,$result);
$result = join(”\n”,$result);
return $result;
}
11 emzet 2008/09/18 23:19

very nice, thanks!
12 gg2laba 2008/09/21 08:36

good one, some little problems for me :
– i added \s* to get reed of existing whitespaces :

// add marker linefeeds to aid the pretty-tokeniser (adds a linefeed between all tag-end boundaries)
$xml = preg_replace(’/(>)\s*(< )(\/*)/’, ”$1\n$2$3”, $xml);
– i added $indent=0; too because the indent fail sometime for me ! :

// 2. closing tag – outdent now
elseif (preg_match(’/^< \/\w/’, $token, $matches)) :
$pad—;$indent=0;

thanks for this, made me win a lot of time.
13 Jamie 2008/11/14 03:44

Thanks! Just added as a handy php macro for use in EditPlus text editor.
14 David 2008/11/25 12:44

Really great function you wrote here.

recurser

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14 Responses to “Format XML with PHP”

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