Patching

1) addslashes — Quote string with slashes

Description

string addslashes ( string $str )

Returns a string with backslashes before characters that need to be quoted in database queries etc. These characters are single quote ('), double quote ("), backslash (\) and NUL (the NULL byte).

An example use of addslashes() is when you're entering data into a database. For example, to insert the name O'reilly into a database, you will need to escape it. Most databases do this with a \ which would mean O\'reilly. This would only be to get the data into the database, the extra \ will not be inserted. Having the PHP directive magic_quotes_sybase set to on will mean ' is instead escaped with another '.

The PHP directive magic_quotes_gpc is on by default, and it essentially runs addslashes() on all GET, POST, and COOKIE data. Do not use addslashes() on strings that have already been escaped with magic_quotes_gpc as you'll then do double escaping. The function get_magic_quotes_gpc() may come in handy for checking this.

Example 2305. An addslashes() example

$str = "Is your name O'reilly?";

// Outputs: Is your name O\'reilly?
echo addslashes($str);
?>

2) stripslashes — Un-quote string quoted with addslashes()

Description

string stripslashes ( string $str )

Returns a string with backslashes stripped off. (\' becomes ' and so on.) Double backslashes (\\) are made into a single backslash (\).

Note: If magic_quotes_sybase is on, no backslashes are stripped off but two apostrophes are replaced by one instead.

An example use of stripslashes() is when the PHP directive magic_quotes_gpc is on (it's on by default), and you aren't inserting this data into a place (such as a database) that requires escaping. For example, if you're simply outputting data straight from an HTML form.

Example 2363. A stripslashes() example

$str = "Is your name O\'reilly?";

// Outputs: Is your name O'reilly?
echo stripslashes($str);
?>

3) htmlspecialchars — Convert special characters to HTML entities

Description

string htmlspecialchars ( string $string [, int $quote_style [, string $charset]] )

Certain characters have special significance in HTML, and should be represented by HTML entities if they are to preserve their meanings. This function returns a string with some of these conversions made; the translations made are those most useful for everyday web programming. If you require all HTML character entities to be translated, use htmlentities() instead.

This function is useful in preventing user-supplied text from containing HTML markup, such as in a message board or guest book application. The optional second argument, quote_style, tells the function what to do with single and double quote characters. The default mode, ENT_COMPAT, is the backwards compatible mode which only translates the double-quote character and leaves the single-quote untranslated. If ENT_QUOTES is set, both single and double quotes are translated and if ENT_NOQUOTES is set neither single nor double quotes are translated.

The translations performed are:

• '&' (ampersand) becomes '&'
• '"' (double quote) becomes '"' when ENT_NOQUOTES is not set.
• ''' (single quote) becomes ''' only when ENT_QUOTES is set.
• '<' (less than) becomes '<'
• '>' (greater than) becomes '>'

Example 2324. htmlspecialchars() example

$new = htmlspecialchars("Test", ENT_QUOTES);
echo $new; // <a href='test'>Test</a>
?>

4) get_magic_quotes_gpc — Gets the current configuration setting of magic quotes gpc

Description

int get_magic_quotes_gpc ( void )

Returns the current configuration setting of magic_quotes_gpc

Keep in mind that the setting magic_quotes_gpc will not work at runtime.

For more information about magic_quotes, see this security section.

Return Values

Returns 0 if magic quotes gpc are off, 1 otherwise.

Examples

Example 1775. get_magic_quotes_gpc() example

echo get_magic_quotes_gpc(); // 1
echo $_POST['lastname']; // O\'reilly
echo addslashes($_POST['lastname']); // O\\\'reilly

if (!get_magic_quotes_gpc()) {
$lastname = addslashes($_POST['lastname']);
} else {
$lastname = $_POST['lastname'];
}

echo $lastname; // O\'reilly
$sql = "INSERT INTO lastnames (lastname) VALUES ('$lastname')";
?>

Notes

Note: If the directive magic_quotes_sybase is ON it will completely override magic_quotes_gpc. So even when get_magic_quotes_gpc() returns TRUE neither double quotes, backslashes or NUL's will be escaped. Only single quotes will be escaped. In this case they'll look like: ''