String Functions
addcslashes() treats NUL as a string terminator:
assert("any" === addcslashes("any\0body", "-"));
unless you order it backslashified:
assert("any\\000body" === addcslashes("any\0body", "\0"));
(Uncertain whether this should be declared a bug or simply that addcslashes() is not binary-safe, whatever that means.)
addcslashes
(PHP 4, PHP 5)
addcslashes — Escapa una cadena de la misma forma que lo hace C
Descripción
string addcslashes
( string $cadena
, string $lista_caracteres
)
Devuelve una cadena con barras invertidas antes de los caracteres definidos en el parámetro lista_caracteres . Si lista_caracteres contiene caracteres como \n, \r, etc. también se convierten de la misma forma, mientras que los caracteres con códico ASCII inferior a 32 y superior a 126 son convertidos a representación octal.
Se debe tener en cuenta que si se marcan para escapar los caracteres 0, a, b, f, n, r, t y v, se transforman en los caracteres especiales \0, \a, \b, \f, \n, \r, \t y \v. En PHP \0 (NULL), \r (retorno de carro), \n (nueva línea) y \t (tabulador) son secuencias de escape predefinidas, mientras que en C todos los caracteres especiales mencionados anteriormente son secuencias de escape predefinidas.
El parámetro lista_caracteres puede indicar rangos como por ejemplo "\0..\37", que escaparía todos los caracteres con código ASCII entre 0 y 31.
Example #1 Ejemplo de addcslashes()
<?php
$escapado = addcslashes($no_escapado, "\0..\37!@\177..\377");
?>
Al definir secuencias de caracteres en el parámetro lista_caracteres se debe asegurar que se quieren escapar todos los caracteres incluidos en el rango.
<?php
echo addcslashes('prueba[ ]', 'A..z');
// La salida seria: \p\r\u\e\b\a\[ \]
// Se escapan todos los caracteres en mayusculas y minusculas
// ... pero tambien los caracteres [\]^_` , los tabuladores, los retornos
// de carro, las nuevas lineas, etc.
?>
<?php
echo addcslashes("zoo['.']", 'z..A');
// La salida seria: \zoo['\.']
?>
Vea también stripcslashes(), stripslashes(), htmlspecialchars() y quotemeta().
add a note
User Contributed Notesaddcslashes
stein at visibone dot com
13-Nov-2007 12:16
13-Nov-2007 12:16
Johannes
27-Oct-2007 02:34
27-Oct-2007 02:34
Be carefull with adding the \ to the list of encoded characters. When you add it at the last position it encodes all encoding slashes. I got a lot of \\\ by this mistake.
So always encode \ at first.
phpcoder at cyberpimp dot pimpdomain dot com
20-Jan-2005 09:35
20-Jan-2005 09:35
Forgot to add something:
The only time you would likely use addcslashes() without specifying the backslash (\) character in charlist is when you are VALIDATING (not encoding!) a data string.
(Validation ensures that all control characters and other unsafe characters are correctly encoded / escaped, but does not alter any pre-existing escape sequences.)
You can validate a data string multiple times without fear of "double encoding". A single decoding pass will return the original data, regardless of how many times it was validated.)
phpcoder at cyberpimp dot pimpdomain dot com
20-Jan-2005 08:02
20-Jan-2005 08:02
If you are using addcslashes() to encode text which is to later be decoded back to it's original form, you MUST specify the backslash (\) character in charlist!
Example:
<?php
$originaltext = 'This text does NOT contain \\n a new-line!';
$encoded = addcslashes($originaltext, '\\');
$decoded = stripcslashes($encoded);
//$decoded now contains a copy of $originaltext with perfect integrity
echo $decoded; //Display the sentence with it's literal \n intact
?>
If the '\\' was not specified in addcslashes(), any literal \n (or other C-style special character) sequences in $originaltext would pass through un-encoded, but then be decoded into control characters by stripcslashes() and the data would lose it's integrity through the encode-decode transaction.
ruben at intesys dot it
31-May-2004 06:51
31-May-2004 06:51
jsAddSlashes for XHTML documents:
<?php
header("Content-type: text/xml");
print <<<EOF
<?xml version="1.0"?>
<html>
<head>
<script type="text/javascript">
EOF;
function jsAddSlashes($str) {
$pattern = array(
"/\\\\/" , "/\n/" , "/\r/" , "/\"/" ,
"/\'/" , "/&/" , "/</" , "/>/"
);
$replace = array(
"\\\\\\\\", "\\n" , "\\r" , "\\\"" ,
"\\'" , "\\x26" , "\\x3C" , "\\x3E"
);
return preg_replace($pattern, $replace, $str);
}
$message = jsAddSlashes("\"<Hello>\",\r\n'&World'\\!");
print <<<EOF
alert("$message");
</script>
</head>
<body>
<h1>Hello, World!</h1>
</body>
</html>
EOF;
?>
21-Sep-2003 08:44
<?
function jsaddslashes($s)
{
$o="";
$l=strlen($s);
for($i=0;$i<$l;$i++)
{
$c=$s[$i];
switch($c)
{
case '<': $o.='\\x3C'; break;
case '>': $o.='\\x3E'; break;
case '\'': $o.='\\\''; break;
case '\\': $o.='\\\\'; break;
case '"': $o.='\\"'; break;
case "\n": $o.='\\n'; break;
case "\r": $o.='\\r'; break;
default:
$o.=$c;
}
}
return $o;
}
?>
<script language="javascript">
document.write("<? echo jsaddslashes('<h1 style="color:red">hello</h1>'); ?>");
</script>
output :
<script language="javascript">
document.write("\x3Ch1 style=\"color:red\"\x3Ehello\x3C/h1\x3E");
</script>
natNOSPAM at noworrie dot NO_SPAM dot com
18-May-2002 01:22
18-May-2002 01:22
I have found the following to be much more appropriate code example:
<?php
$escaped = addcslashes($not_escaped, "\0..\37!@\@\177..\377");
?>
This will protect original, innocent backslashes from stripcslashes.