Replaces 'ill-formed' byte sequences with '?'.
See: https://github.com/php/php-src/pull/1099
(PHP 7 >= 7.2.0, PHP 8)
mb_scrub — Replace ill-formed byte sequences with the substitute character
Perform a character set conversion from the specified encoding, or the default encoding if no encoding was specified, to the same encoding. This has the effect of replacing any invalid byte sequences with the substitute character.
stringThe input string.
encoding
The encoding used to interpret string.
If it is omitted or null, the
mbstring.internal_encoding setting
will be used if set, otherwise the default_charset setting
will be used.
The string result with invalid byte sequences replaced.
As of PHP 8.0.0, a ValueError is thrown if
encoding is an invalid encoding.
Prior to PHP 8.0.0, an E_WARNING was emitted instead.
| Version | Description |
|---|---|
| 8.0.0 |
encoding is nullable now.
|
| 8.0.0 |
Now throws a ValueError if
encoding is an invalid encoding.
Previously, an E_WARNING was emitted
and false was returned.
|
Example #1 Byte-level replacement performed by mb_scrub()
bin2hex() is used here because terminals, browsers and fonts may render an ill-formed byte sequence with a replacement character of their own, which hides what the string actually contains.
<?php
// The byte 0xFF cannot appear in a valid UTF-8 string.
$input = "A\xFFB";
echo bin2hex($input), "\n";
// The default substitute character is "?" (0x3F).
echo bin2hex(mb_scrub($input, 'UTF-8')), "\n";
// U+FFFD REPLACEMENT CHARACTER is encoded as EF BF BD in UTF-8.
mb_substitute_character(0xFFFD);
echo bin2hex(mb_scrub($input, 'UTF-8')), "\n";
?>The above example will output:
41ff42 413f42 41efbfbd42
Example #2 Using mb_scrub() before UTF-8 aware processing
PCRE patterns using the u modifier reject subjects that
are not well-formed UTF-8. Scrubbing the input first makes it acceptable.
<?php
$input = "A\xFFB";
var_dump(preg_match_all('/./us', $input));
echo preg_last_error_msg(), "\n";
$clean = mb_scrub($input, 'UTF-8');
var_dump(preg_match_all('/./us', $clean));
?>The above example will output:
bool(false) Malformed UTF-8 characters, possibly incorrectly encoded int(3)
Replaces 'ill-formed' byte sequences with '?'.
See: https://github.com/php/php-src/pull/1099