htmlspecialchars_decode

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

htmlspecialchars_decode — Convierte entidades HTML especiales de nuevo en caracteres

Descripción

htmlspecialchars_decode(string $string, int $flags = ENT_COMPAT | ENT_HTML401): string

Esta función es la opuesta a htmlspecialchars(). Convierte entidades HTML especiales de nuevo en los caracteres.

Las entidades convertidas son: &, " (cuando ENT_NOQUOTES no se ha establecido), ' (cuando ENT_QUOTES se ha establecido), < y >.

Parámetros

string

El string a decodificar.

flags

Una máscara de bits de uno o más de los siguientes indicadores, que especifican cómo manejar las comillas y que tipo de documento utilizar. Por defecto es ENT_COMPAT | ENT_HTML401.

**Contantes disponibles para `flags`**
Nombre de la Constante	Descripción
`ENT_COMPAT`	Convertirá las comillas dobles y dejará solamente las comillas sencillas.
`ENT_QUOTES`	Convertirá tanto las comillas dobles como las sencillas.
`ENT_NOQUOTES`	Dejará tanto las comillas dobles como las sencillas sin convertir.
`ENT_HTML401`	Maneja el código como HTML 4.01.
`ENT_XML1`	Maneja el código como XML 1.
`ENT_XHTML`	Maneja el código como XHTML.
`ENT_HTML5`	Maneja el código como HTML 5.

Valores devueltos

Devuelve el string decodificado.

Historial de cambios

Versión	Descripción
5.4.0	Fueron agregadas las constantes `ENT_HTML401`, `ENT_XML1`, `ENT_XHTML` y `ENT_HTML5`.

Ejemplos

Ejemplo #1 Un ejemplo de htmlspecialchars_decode()

<?php
$str = "<p>this -&gt; &quot;</p>\n";

echo htmlspecialchars_decode($str);

// tenga en cuenta que aquí las comillas no se convierten
echo htmlspecialchars_decode($str, ENT_NOQUOTES);
?>

El resultado del ejemplo sería:

<p>this -> "</p>
<p>this -> &quot;</p>

Ver también

htmlspecialchars() - Convierte caracteres especiales en entidades HTML
html_entity_decode() - Convierte todas las entidades HTML a sus caracteres correspondientes
get_html_translation_table() - Devuelve la tabla de traducción utilizada por htmlspecialchars y htmlentities

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User Contributed Notes 8 notes

down

thomas at xci[ignore_this]teit dot commm ¶

16 years ago


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
  '"' => '&quot;'
  ''' => '&#39;'
  '<' => '&lt;'
  '>' => '&gt;'
  '&' => '&amp;'

'&#039;'
--------------------

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){ $translation['&#039;'] = '\''; }
        return strtr($string,$translation);
    }
?>

Br, Thomas

down

Anonymous ¶

18 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)));
    }
}

?>

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-2

or-k at or-k dot com ¶

19 years ago


that works also with &auml; and &quot; 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)));
}

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-6

pinkgothic at gmail dot com ¶

14 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 '&amp;<script>alert('XSS');</script>' to your PHP script:



<?php

$var = "&amp;<script>alert('XSS');</script>";

$var = (htmlspecialchars_decode($var) == $var) ? htmlspecialchars($var) : $var;

echo $var;

?>



Since '&amp;' 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.

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-10

geoffers@gmail ¶

19 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)));
}

?>

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-12

benharold at mac dot com ¶

15 years ago


If you use `htmlspecialchars()` to change things like the ampersand (&) into it's HTML equivalent (&amp;), 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; "&amp;". Clearly nobody want's "&amp;" 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.

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-12

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 &amp; 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 &amp; yellow make green.

?>

Put it in a function. Add it to the method of some abstract data class.

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-12

geoffers at gmail dot com ¶

19 years ago


For PHP4 Compatibility:

<?php

function htmlspecialchars_decode_php4 ($str) {
    return strtr($str, array_flip(get_html_translation_table(HTML_SPECIALCHARS)));
}

?>

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