Recursively converts data (strings, arrays, objects) to UTF-8 encoding.

utf8ize.php

<?php

/**
 * Related with utf8 problems and based on differents answers from https://stackoverflow.com/a/19366999/3452348
 * This function is at the time of writing, for me, the best improved version existing actually.
 *
 * This function is designed to uniformly encode data as UTF-8. It handles strings by attempting
 * to detect the current encoding and converting it to UTF-8. For arrays and objects, it applies
 * the conversion recursively to each element or property. The function tries a predefined list
 * of common encodings if automatic detection fails. Note that only public properties of objects
 * are processed.
 *
 * @param mixed $d The data to be converted to UTF-8. Can be a string, an array, or an object.
 * @return mixed The converted data in UTF-8, maintaining the same type as the input (string,
 *               array, or object).
 */
public static function utf8ize($d)
{
    if (is_array($d)) {
        foreach ($d as $k => $v) {
            $d[$k] = self::utf8ize($v);
        }
    } elseif (is_object($d)) {
        // Recursively convert object properties
        $vars = get_object_vars($d);
        foreach ($vars as $k => $v) {
            $d->$k = self::utf8ize($v);
        }
    } elseif (is_string($d)) {
        // Try a list of common encodings before converting
        $encodings = ['UTF-8', 'ISO-8859-1', 'Windows-1251', 'Windows-1252', 'GB2312', 'BIG5'];
        foreach ($encodings as $encoding) {
            if (mb_check_encoding($d, $encoding)) {
                return mb_convert_encoding($d, 'UTF-8', $encoding);
            }
        }
        // Use 'auto' as a last resort
        return mb_convert_encoding($d, 'UTF-8', 'auto');
    }
    return $d;
}