htmlspecialchars_decode

(PHP 5 >= 5.1.0)

htmlspecialchars_decode Преобразует специальные HTML-сущности обратно в соответствующие символы

Описание

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

Эта функция является антиподом htmlspecialchars(). Она преобразует специальные HTML-сущности обратно в соответствующие символы.

Конвертируемые сущности : &, " (когда ENT_NOQUOTES не установлена), ' (когда ENT_QUOTES установлена), < и >.

Список параметров

string

Строка, которую надо преобразовать.

flags

Битовая маска из одного или нескольких следующих флагов, которые указывают как обрабатывать кавычки и какие типы документов использовать. Значением по умолчанию является ENT_COMPAT | ENT_HTML401.

Доступные константы, используемые в качестве параметра flags
Имя константы Описание
ENT_COMPAT Преобразует двойные кавычки и пропускает одинарные.
ENT_QUOTES Преобразует и двойные, и одинарные кавычки.
ENT_NOQUOTES Не преобразует ни двойные, ни одинарные кавычки.
ENT_HTML401 Обрабатывать код как HTML 4.01.
ENT_XML1 Обрабатывать код как XML 1.
ENT_XHTML Обрабатывать код как XHTML.
ENT_HTML5 Обрабатывать код как HTML 5.

Возвращаемые значения

Возвращает преобразованную строку.

Список изменений

Версия Описание
5.4.0 Добавлены константы ENT_HTML401, ENT_XML1, ENT_XHTML и ENT_HTML5.

Примеры

Пример #1 Пример использования функции htmlspecialchars_decode()

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

echo 
htmlspecialchars_decode($str);

// обратите внимание, что в данном случае кавычки не будут преобразованы
echo htmlspecialchars_decode($strENT_NOQUOTES);
?>

Результат выполнения данного примера:

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

Смотрите также

  • htmlspecialchars() - Преобразует специальные символы в HTML-сущности
  • html_entity_decode() - Преобразует все HTML-сущности в соответствующие символы
  • get_html_translation_table() - Возвращает таблицу преобразований, используемую функциями htmlspecialchars и htmlentities

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User Contributed Notes 9 notes

up
6
Anonymous
7 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
6 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
1
benharold at mac dot com
5 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
0
benharold at mac dot com
5 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
0
geoffers@gmail
9 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
0
geoffers at gmail dot com
9 years ago
For PHP4 Compatibility:

<?php

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

?>
up
-1
or-k at or-k dot com
8 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
-1
pinkgothic at gmail dot com
4 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
-5
Wout
6 years ago
The following replacement for PHP 4 is a little more complete, as the quote_style is taken into account as well:

if (!function_exists("htmlspecialchars_decode")) {
    function htmlspecialchars_decode($string, $quote_style = ENT_COMPAT) {
        return strtr($string, array_flip(get_html_translation_table(HTML_SPECIALCHARS, $quote_style)));
    }
}
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