PHP "pretty print" HTML (not Tidy)

you're right, there seems to be no indentation for HTML (others are also confused). XML works, even with loaded code.

<?php
function tidyHTML($buffer) {
    // load our document into a DOM object
    $dom = new DOMDocument();
    // we want nice output
    $dom->preserveWhiteSpace = false;
    $dom->loadHTML($buffer);
    $dom->formatOutput = true;
    return($dom->saveHTML());
}

// start output buffering, using our nice
// callback function to format the output.
ob_start("tidyHTML");

?>
<html>
    <head>
    <title>foo bar</title><meta name="bar" value="foo"><body><h1>bar foo</h1><p>It's like comparing apples to oranges.</p></body></html>
<?php
// this will be called implicitly, but we'll
// call it manually to illustrate the point.
ob_end_flush();
?>

result:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html>
<head>
<title>foo bar</title>
<meta name="bar" value="foo">
</head>
<body>
<h1>bar foo</h1>
<p>It's like comparing apples to oranges.</p>
</body>
</html>

the same with saveXML() ...

<?xml version="1.0" standalone="yes"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html>
  <head>
    <title>foo bar</title>
    <meta name="bar" value="foo"/>
  </head>
  <body>
    <h1>bar foo</h1>
    <p>It's like comparing apples to oranges.</p>
  </body>
</html>

probably forgot to set preserveWhiteSpace=false before loadHTML?

disclaimer: i stole most of the demo code from tyson clugg/php manual comments. lazy me.


UPDATE: i now remember some years ago i tried the same thing and ran into the same problem. i fixed this by applying a dirty workaround (wasn't performance critical): i just somehow converted around between SimpleXML and DOM until the problem vanished. i suppose the conversion got rid of those nodes. maybe load with dom, import with simplexml_import_dom, then output the string, parse this with DOM again and then printed it pretty. as far as i remember this worked (but it was really slow).


The result:

<!DOCTYPE html>
<html>
    <head>
        <title>My website</title>
    </head>
</html>

Please consider:

function indentContent($content, $tab="\t"){
    $content = preg_replace('/(>)(<)(\/*)/', "$1\n$2$3", $content); // add marker linefeeds to aid the pretty-tokeniser (adds a linefeed between all tag-end boundaries)
    $token = strtok($content, "\n"); // now indent the tags
    $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 && strlen($token)>0){
        $padPrev = $padPrev ?: $pad; // previous padding //Artis
        $token = trim($token);
        // test for the various tag states
        if (preg_match('/.+<\/\w[^>]*>$/', $token, $matches)){// 1. open and closing tags on same line - no change
            $indent=0;
        }elseif(preg_match('/^<\/\w/', $token, $matches)){// 2. closing tag - outdent now
            $pad--;
            if($indent>0) $indent=0;
        }elseif(preg_match('/^<\w[^>]*[^\/]>.*$/', $token, $matches)){// 3. opening tag - don't pad this one, only subsequent tags (only if it isn't a void tag)
            foreach($matches as $m){
                if (preg_match('/^<(area|base|br|col|command|embed|hr|img|input|keygen|link|meta|param|source|track|wbr)/im', $m)){// Void elements according to http://www.htmlandcsswebdesign.com/articles/voidel.php
                    $voidTag=true;
                    break;
                }
            }
            $indent = 1;
        }else{// 4. no indentation needed
            $indent = 0;
        }

        if ($token == "<textarea>") {
            $line = str_pad($token, strlen($token) + $pad, $tab, STR_PAD_LEFT); // pad the line with the required number of leading spaces
            $result .= $line; // add to the cumulative result, with linefeed
            $token = strtok("\n"); // get the next token
            $pad += $indent; // update the pad size for subsequent lines
        } elseif ($token == "</textarea>") {
            $line = $token; // pad the line with the required number of leading spaces
            $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
        } else {
            $line = str_pad($token, strlen($token) + $pad, $tab, STR_PAD_LEFT); // pad the line with the required number of leading spaces
            $result .= $line . "\n"; // add to the cumulative result, with linefeed
            $token = strtok("\n"); // get the next token
            $pad += $indent; // update the pad size for subsequent lines
            if ($voidTag) {
                $voidTag = false;
                $pad--;
            }
        }           

    return $result;
}

//$htmldoc - DOMdocument Object!

$niceHTMLwithTABS = indentContent($htmldoc->saveHTML(), $tab="\t");

echo $niceHTMLwithTABS;

Will result in HTML that has:

  • Indentation based on "levels"
  • Line breaks after block level elements
  • While inline and self-closing elements are not affected

The function (which is a method for class I use) is largely based on: https://stackoverflow.com/a/7840997/7646824