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Описание

bool mb_check_encoding ( [string var [, string encoding]] )

mb_check_encoding() checks if the string is valid for the specified encoding. It is useful to prevent so-called "Invalid Encoding Attack".

Список параметров

var: String to check. If it is omitted, this function checks all the input from the beginning of the request.
encoding: Expected encoding.

Возвращаемые значения

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.

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mb_check_encoding

Olexa Riznyk
12-Jul-2007 11:53


This function returns true incorrectly sometimes (at least when internal encoding is UTF-8 and encoding being checked for is Windows-1251, and PHP version 4.4.4 on FreeBSD 6.2 STABLE). This bug was not answered in bug reporting yet, so here is a workaround:



Instead of checking for this:



<?php



mb_check_encoding($var, $destination_encoding)



?>



check for this:



<?php



mb_check_encoding($var, $destination_encoding) && mb_substr_count($var, '?', $source_encoding) == mb_substr_count(mb_convert_encoding($var, $destination_encoding, $source_encoding), '?', $destination_encoding)



?>



The idea is to count question mark characters ('?') in original value and converted value, because mb_convert_encoding function uses question marks to substitute characters that are not valid in destination encoding.

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