The example for "htmlspecialchars_decode()" below sadly does not work for all PHP4 versions.
Quote from the PHP manual:
"get_html_translation_table() will return the translation table that is used internally for htmlspecialchars() and htmlentities()."
But it does NOT! At least not for PHP version 4.4.2.
This was already reported in a bug report (http://bugs.php.net/bug.php?id=25927), but it was marked as BOGUS.
Proof:
Code:
--------------------
<?php
var_dump(get_html_translation_table(HTML_SPECIALCHARS,ENT_QUOTES));
var_dump(htmlspecialchars('\'',ENT_QUOTES));
?>
--------------------
Output:
--------------------
array
'"' => '"'
''' => '''
'<' => '<'
'>' => '>'
'&' => '&'
'''
--------------------
This comment now is not to report this bug again (though I really believe it is one), but to complete the example and warn people of this pitfall.
To make sure your htmlspecialchars_decode fake for PHP4 works, you should do something like this:
<?php
function htmlspecialchars_decode($string,$style=ENT_COMPAT)
{
$translation = array_flip(get_html_translation_table(HTML_SPECIALCHARS,$style));
if($style === ENT_QUOTES){ $translation['''] = '\''; }
return strtr($string,$translation);
}
?>
Br, Thomas
htmlspecialchars_decode
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
htmlspecialchars_decode — Converte especiais entidades HTML para caracteres
Descrição
htmlspecialchars_decode
( string
$string
, int $quote_style = ?
) : stringEsta função é o oposto da htmlspecialchars(). Ela converte especiais entidades HTML para caracteres.
As entidades convertidas são: &,
" (quando ENT_NOQUOTES não é usado),
' (quando ENT_QUOTES é usado),
< e >.
Parâmetros
-
string -
A string para decodificar
-
quote_style -
O tipo de aspa. Uma das seguintes constantes:
Constantes do quote_style Nome da constante Descrição ENT_COMPATConverterá aspas dupla e deixará aspas simples (default) ENT_QUOTESConverterá ambas as aspas ENT_NOQUOTESDeixará ambas as aspas
Valor Retornado
Retorna a string decodificada.
Exemplos
Exemplo #1 Um exemplo da htmlspecialchars_decode()
<?php
$str = '<p>this -> "</p>';
echo htmlspecialchars_decode($str);
// note that here the quotes aren't converted
echo htmlspecialchars_decode($str, ENT_NOQUOTES);
?>
O exemplo acima irá imprimir:
<p>this -> "</p> <p>this -> "</p>
Veja Também
- htmlspecialchars() - Converte caracteres especiais para a realidade HTML
- html_entity_decode() - Converte todas as entidades HTML para os seus caracteres
- get_html_translation_table() - Retorna a tabela de tradução usada por htmlspecialchars e htmlentities
add a note
User Contributed Notes 8 notes
thomas at xci[ignore_this]teit dot commm ¶
16 years ago
Anonymous ¶
17 years ago
This should be the best way to do it.
(Reposted because the other one seems a bit slower and because those who used the code under called it htmlspecialchars_decode_php4)
<?php
if ( !function_exists('htmlspecialchars_decode') )
{
function htmlspecialchars_decode($text)
{
return strtr($text, array_flip(get_html_translation_table(HTML_SPECIALCHARS)));
}
}
?>
or-k at or-k dot com ¶
18 years ago
that works also with ä and " and so on.
get_html_translation_table(HTML_ENTITIES) => offers more characters than HTML_SPECIALCHARS
function htmlspecialchars_decode_PHP4($uSTR)
{
return strtr($uSTR, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));
}
pinkgothic at gmail dot com ¶
13 years ago
Keep in mind that you should never trust user input - particularly for "mixed-bag" input containing a combination of plain text and markup or scripting code.
Why?
Well, consider someone sending '&<script>alert('XSS');</script>' to your PHP script:
<?php
$var = "&<script>alert('XSS');</script>";
$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
echo $var;
?>
Since '&' decodes into '&', (htmlspecialchars_decode($var) == $var) will be -false-, thus returning $var without that it's escaped. In consequence, the script-tags are untouched, and you've just opened yourself to XSS.
There is, unfortunately, no reliable way to determine whether HTML is escaped or not that does not come with this caveat that I know of. Rather than try and catch the case 'I've already encoded this', you are better off avoiding double-escaping by simply escaping the HTML as close to the actual output as you can muster, e.g. in the view in an MVC development structure.
benharold at mac dot com ¶
15 years ago
If you use `htmlspecialchars()` to change things like the ampersand (&) into it's HTML equivalent (&), you might run into a situation where you mistakenly pass the same string to the function twice, resulting in things appearing on your website like, as I call it, the ampersanded amp; "&". Clearly nobody want's "&" on his or her web page where there is supposed to be just an ampersand. Here's a quick and easy trick to make sure this doesn't happen:
<?php
$var = "This is a string that could be passed to htmlspecialchars multiple times.";
if (htmlspecialchars_decode($var) == $var) {
$var = htmlspecialchars($var);
}
echo $var;
?>
Now, if your dealing with text that is a mixed bag (has HTML entities and non-HTML entities) you're on your own.
geoffers@gmail ¶
18 years ago
[Update of previous note, having noticed I forgot to put in quote style]
PHP4 Compatible function:
<?php
function htmlspecialchars_decode_php4 ($str, $quote_style = ENT_COMPAT) {
return strtr($str, array_flip(get_html_translation_table(HTML_SPECIALCHARS, $quote_style)));
}
?>
benharold at mac dot com ¶
15 years ago
or of course:
<?php
$var = "Blue & yellow make green.";
$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
echo $var; // outputs Blue & yellow make green.
// you can do it a bunch of times, it still won't screw you!
$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;
echo $var; // still outputs Blue & yellow make green.
?>
Put it in a function. Add it to the method of some abstract data class.
geoffers at gmail dot com ¶
18 years ago
For PHP4 Compatibility:
<?php
function htmlspecialchars_decode_php4 ($str) {
return strtr($str, array_flip(get_html_translation_table(HTML_SPECIALCHARS)));
}
?>
