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htmlspecialchars_decode

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

htmlspecialchars_decode Converte entidades especiais HTML de volta para caracteres

Descrição

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

Esta função é oposta a htmlspecialchars(). Ela converte de volta entidade especiais HTML em caracteres.

As entidades convertidas são: &, " (quando ENT_NOQUOTES não estiver definida), ' (quando ENT_QUOTES estiver definida), < e >.

Parâmetros

string

A string a ser decodificada.

flags

Uma máscara de bits de uma ou mais das opções a seguir, que especificam como lidar com aspas e que tipos de documentos são usados. O padrão é ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401.

Constantes disponíveis para flags
Nome da Constante Descrição
ENT_COMPAT Converte aspas duplas e não converte aspas simples.
ENT_QUOTES Converte tanto aspas duplas quanto simples.
ENT_NOQUOTES Não converte aspas duplas ou simples.
ENT_SUBSTITUTE Substitui sequências de unidade de código inválidas com um Caractere de Substituição Unicode U+FFFD (UTF-8) ou � ao invés de retornar uma string vazia.
ENT_HTML401 Lida com o código como HTML 4.01.
ENT_XML1 Lida com o código como XML 1.
ENT_XHTML Lida com o código como XHTML.
ENT_HTML5 Lida com o código como HTML 5.

Valor Retornado

Retorna a string decodificada.

Registro de Alterações

Versão Descrição
8.1.0 O padrão de flags mudou de ENT_COMPAT para ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401.

Exemplos

Exemplo #1 Um exemplo de htmlspecialchars_decode()

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

echo
htmlspecialchars_decode($str);

// observe que aqui as aspas não são convertidas
echo htmlspecialchars_decode($str, ENT_NOQUOTES);
?>

O exemplo acima produzirá:

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

Veja Também

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User Contributed Notes 8 notes

up
2
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)));
}
}

?>
up
1
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
up
-2
or-k at or-k dot com
18 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)));
}
up
-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.
up
-10
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)));
}

?>
up
-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.
up
-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.
up
-12
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)));
}

?>
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