Fix character decoding regression when title precedes meta[charset]

Because of PHP 8.2 deprecation, in f14428e4c0, we stopped converting non-ASCII characters to HTML entities. Instead, we started to explicitly insert `meta[charset]` tag at the start of the document.

Later, we discovered that was breaking `html[lang]` so, in efbbc86df9, we made the insertion smarter. One of the improvements was that it would not insert the `meta[charset]` tag when it was already present.

That, however, broke websites that had `title` tag before `meta[charset]`. On those, libxml2 would decode the `title` contents as ISO-8859-1.

We could improve the logic (e.g. check that there is not text content before `meta[charset]`) or insert the tag unconditionally but it will probably be simplest to just go back to converting the non-ASCII characters to entities, just using non-deprecated function variant.
This commit is contained in:
Jan Tojnar
2025-05-28 01:10:59 +02:00
parent 3e9b15db46
commit 8b89d70b1a
2 changed files with 21 additions and 31 deletions
+7 -31
View File
@@ -1422,7 +1422,7 @@ class Readability implements LoggerAwareInterface
unset($tidy);
}
$this->html = self::ensureMetaCharset((string) $this->html);
$this->html = self::entitizeNonAscii((string) $this->html);
if ('html5lib' === $this->parser || 'html5' === $this->parser) {
$this->dom = (new HTML5())->loadHTML($this->html);
@@ -1512,43 +1512,19 @@ class Readability implements LoggerAwareInterface
}
/**
* Tries to insert `meta[charset]` tag into the proper place in the passed HTML document.
* Converts non-ASCII UTF-8 characters to numeric HTML entities.
*
* `DOMDocument::loadHTML` will parse HTML documents as ISO-8859-1 if there is no `meta[charset]` tag.
* This means that UTF-8-encoded HTML fragments such as those coming from JSON-LD `articleBody` field would be parsed with incorrect encoding.
* Unfortunately, we cannot just put the tag at the start of the HTML fragment, since that would cause parser to auto-insert a `html` element, losing the attributes of the original `html` tag.
*
* @param string $html UTF-8 encoded document
*/
private static function ensureMetaCharset(string $html): string
private static function entitizeNonAscii(string $html): string
{
$charsetTag = '<meta charset="utf-8">';
$convmap = [
0x80, 0x1FFFFF, 0, 0x10FFFF,
];
// Only look at first 1024 bytes since, according to HTML5 specification,
// that’s where <meta> elements declaring a character encoding must be located.
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/meta#charset
$start = substr($html, 0, 1000);
if (1 === preg_match('/<meta[^>]+charset/i', $start)) {
// <meta> tag is already present, no need for modification.
return $html;
}
if (1 === preg_match('/<head[^>]*>/i', $start)) {
// <head> tag was located, <meta> tags go there.
$html = preg_replace('/<head[^>]*>/i', '$0' . $charsetTag, $html, 1);
return $html;
}
if (1 === preg_match('/<html[^>]*>/i', $start)) {
// <html> tag was located, let’s put it inside and have parser create <head>.
$html = preg_replace('/<html[^>]*>/i', '$0' . $charsetTag, $html, 1);
return $html;
}
// Fallback – just plop the <meta> at the start of the fragment.
return $charsetTag . $html;
return mb_encode_numericentity($html, $convmap, 'utf8', true);
}
}