PHP DOMDocument Japanese Character encoding issue

Question

I have a file called: ニューヨーク・ヤンキース-チケット-200x225.jpg

I am able to successfully do this with my PHP code:

    if (file_exists(ABSPATH . 'ニューヨーク・ヤンキース-チケット-200x225.jpg')) {
    echo 'yes';
}

However, when I parse my content using DOMDocument, that same string is returned as: ãã¥ã¼ã¨ã¼ã¯ã»ã¤ã³ã­ã¼ã¹-ãã±ãã-200x225.jpg

How do I prevent this happening with the following code? Our application is internationalised so we need to accomodate all utf-8 characters:

$dom = new DOMDocument();
$dom->encoding = 'utf-8';
$dom->loadHTML($content);
$images = $dom->getElementsByTagName('img');

foreach ($images as $image) {
    if( $image->hasAttribute('srcset') ) continue;
    echo $initImgSrc = $image->getAttribute('src');
    if (!preg_match('/[_-]\d+x\d+(?=\.[a-z]{3,4}$)/', $initImgSrc)) continue;

    $newImgSrc = preg_replace('/[_-]\d+x\d+(?=\.[a-z]{3,4}$)/', '', $initImgSrc);
    if (strpos($newImgSrc, '/') === 0) {
        $newImgPath = str_replace( '/wp-content', ABSPATH . 'wp-content', $newImgSrc);
    } else {
        $newImgPath = str_replace( get_home_url(), ABSPATH, $newImgSrc);
    }
    if (!file_exists($newImgPath)) continue;
    echo 'yes';
    $dom->saveXML($image);

    $oldSrc = 'src="' . $initImgSrc . '"';
    $newDataSrcSet = $initImgSrc . ' 1x, ' . $newImgSrc . ' 2x';
    $newSrcWithSrcSet = $oldSrc . ' srcset="' . $newDataSrcSet .'"';
    $content  = str_replace( $oldSrc, $newSrcWithSrcSet, $content );
}
return $content;

This code works normally, just not with the Japanese characters. Any help would be immensely appreciated

Answer 1

DOMDocument::loadHTML will treat your string as being in ISO-8859-1 unless you tell it otherwise. This results in UTF-8 strings being interpreted incorrectly.

If your string doesn't contain an XML encoding declaration, you can prepend one to cause the string to be treated as UTF-8:

$profile = '<p>イリノイ州シカゴにて、アイルランド系の家庭に、9</p>';
$dom = new DOMDocument();
$dom->loadHTML('<?xml encoding="utf-8" ?>' . $profile);
echo $dom->saveHTML();

If you cannot know if the string will contain such a declaration already, there's a workaround in SmartDOMDocument which should help you:

$profile = '<p>イリノイ州シカゴにて、アイルランド系の家庭に、9</p>';
$dom = new DOMDocument();
$dom->loadHTML(mb_convert_encoding($profile, 'HTML-ENTITIES', 'UTF-8'));
echo $dom->saveHTML();

This is not a great workaround, but since not all characters can be represented in ISO-8859-1 (like these katana), it's the safest alternative.

Answer copied from here: PHP DOMDocument loadHTML not encoding UTF-8 correctly