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mb_convert_case> <Multibyte String Funktionen
Last updated: Fri, 30 Oct 2009

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mb_check_encoding

(PHP 4 >= 4.4.3, PHP 5 >= 5.1.3)

mb_check_encodingCheck if the string is valid for the specified encoding

Beschreibung

bool mb_check_encoding ([ string $var = NULL [, string $encoding = mb_internal_encoding() ]] )

Checks if the specified byte stream is valid for the specified encoding. It is useful to prevent so-called "Invalid Encoding Attack".

Parameter-Liste

var

The byte stream to check. If it is omitted, this function checks all the input from the beginning of the request.

encoding

The expected encoding.

Rückgabewerte

Gibt bei Erfolg TRUE zurück, im Fehlerfall FALSE.



add a note add a note User Contributed Notes
mb_check_encoding
jbricci at ya-right dot com
02-Mar-2009 02:52
This function does not check for bad byte sequence(s), it only checks if the byte stream is valid. If you want to verify a encoded string is valid, (IE: does not contain any bad byte sequences do the following...

<?php

/* check a strings encoded value */

function checkEncoding ( $string, $string_encoding )
{
   
$fs = $string_encoding == 'UTF-8' ? 'UTF-32' : $string_encoding;

   
$ts = $string_encoding == 'UTF-32' ? 'UTF-8' : $string_encoding;

    return
$string === mb_convert_encoding ( mb_convert_encoding ( $string, $fs, $ts ), $ts, $fs );
}

/* test 1 variables */

$string = "\x00\x81";

$encoding = "Shift_JIS";

/* test 1 mb_check_encoding (test for bad byte stream) */

if ( true === mb_check_encoding ( $string, $encoding ) )
{
    echo
'valid (' . $encoding . ') encoded byte stream!<br />';
}
else
{
    echo
'invalid (' . $encoding . ') encoded byte stream!<br />';
}

/* test 1 checkEncoding (test for bad byte sequence(s)) */

if ( true === checkEncoding ( $string, $encoding ) )
{
    echo
'valid (' . $encoding . ') encoded byte sequence!<br />';
}
else
{
    echo
'invalid (' . $encoding . ') encoded byte sequence!<br />';
}

/* test 2 */

/* test 2 variables */

$string = "\x00\xE3";

$encoding = "UTF-8";

/* test 2 mb_check_encoding (test for bad byte stream) */

if ( true === mb_check_encoding ( $string, $encoding ) )
{
    echo
'valid (' . $encoding . ') encoded byte stream!<br />';
}
else
{
    echo
'invalid (' . $encoding . ') encoded byte stream!<br />';
}

/* test 2 checkEncoding (test for bad byte sequence(s)) */

if ( true === checkEncoding ( $string, $encoding ) )
{
    echo
'valid (' . $encoding . ') encoded byte sequence!<br />';
}
else
{
    echo
'invalid (' . $encoding . ') encoded byte sequence!<br />';
}

?>

mb_convert_case> <Multibyte String Funktionen
Last updated: Fri, 30 Oct 2009
 
 
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