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@xeoncross
Last active July 8, 2023 14:46
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Fix HTML encoding errors with PHP DOMDocument
<?php
// Ignore errors
libxml_use_internal_errors(true) AND libxml_clear_errors();
// http://stackoverflow.com/q/10237238/99923
// http://stackoverflow.com/q/12034235/99923
// http://stackoverflow.com/q/8218230/99923
// original input (unknown encoding)
$html = 'hi</b><p>سلام<div>の家庭に、9 ☆';
print $html . PHP_EOL;
$doc = new DOMDocument();
$doc->preserveWhiteSpace = false;
$doc->loadHTML($html);
print $doc->saveHTML($doc->documentElement) . PHP_EOL . PHP_EOL;
$doc = new DOMDocument('1.0', 'UTF-8');
$doc->loadHTML($html);
$doc->encoding = 'utf-8';
print $doc->saveHTML($doc->documentElement) . PHP_EOL . PHP_EOL;
$doc = new DOMDocument();
$doc->loadHTML('<?xml encoding="utf-8"?>' . $html);
$doc->encoding = 'utf-8';
print $doc->saveHTML($doc->documentElement) . PHP_EOL . PHP_EOL;
$doc = new DOMDocument('1.0', 'UTF-8');
$doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
print $doc->saveHTML($doc->documentElement) . PHP_EOL . PHP_EOL;
// Benchmark
print "Testing XML encoding spec" . PHP_EOL;
$time = microtime(TRUE);
for ($i=0; $i < 10000; $i++) {
$doc = new DOMDocument();
$doc->loadHTML('<?xml encoding="utf-8"?>' . $html);
foreach ($doc->childNodes as $item)
if ($item->nodeType == XML_PI_NODE)
$doc->removeChild($item); // remove hack
$doc->encoding = 'utf-8';
$doc->saveHTML();
unset($doc);
}
print (microtime(TRUE) - $time) . " seconds" . PHP_EOL . PHP_EOL;
print "Testing mb_convert_encoding" . PHP_EOL;
$time = microtime(TRUE);
for ($i=0; $i < 10000; $i++) {
$doc = new DOMDocument();
$doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
$doc->saveHTML();
unset($doc);
}
print (microtime(TRUE) - $time) . " seconds" . PHP_EOL . PHP_EOL;
hi</b><p>سلام<div>の家庭に、9 ☆
<html><body>
<p>hi</p>
<p>سلام</p>
<div>の家庭に、9 ☆</div>
</body></html>
<html><body>
<p>hi</p>
<p>سلام</p>
<div>の家庭に、9 ☆</div>
</body></html>
<html><body>
<p>hi</p>
<p>سلام</p>
<div>の家庭に、9 ☆</div>
</body></html>
<html><body>
<p>hi</p>
<p>سلام</p>
<div>の家庭に、9 ☆</div>
</body></html>
Testing XML encoding spec
0.45506000518799 seconds
Testing mb_convert_encoding
0.47111082077026 seconds
@mmaldonadoemergya
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Nice, that work for me.

@adrianbj
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adrianbj commented Jul 7, 2023

In the age of PHP 8.2 deprecations, I am finding that adding <?xml encoding="utf-8" ?> seems to be the best option. The only other thing that seems to work is mb_encode_numericentity($str, [0x80, 0x10FFFF, 0, ~0], 'UTF-8') but I think I prefer the readability of the former and it also makes sense in that it is forcing domdocument to use UTF-8 when it seems to ignore other attempts to do so.

@xeoncross
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Author

In the age of PHP 8.2 I would really recommend you all leave PHP for Go or Rust. They are an order of magnitude faster. Designed from the ground-up for multiple CPU cores. Better error handling. No goofy work-arounds for utf8, rock-solid standard libraries, best-in-class community libraries, dead-simple deployments, and the list goes on-and-on.

I maintained a PHP framework. After forcing PHP to do so many things it did poorly (NLP, Encryption, HTML parsing, etc...) Go and Rust are a breath of fresh air. PHP offers nothing at this point they don't have and do better.

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