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(PHP 4 >= 4.1.0, PHP 5)
import_request_variables — Import GET/POST/Cookie variables into the global scope
Imports GET/POST/Cookie variables into the global scope. It is useful if you disabled register_globals, but would like to see some variables in the global scope.
If you're interested in importing other variables into the global scope, such as $_SERVER, consider using extract().
Using the types parameter, you can specify which request variables to import. You can use 'G', 'P' and 'C' characters respectively for GET, POST and Cookie. These characters are not case sensitive, so you can also use any combination of 'g', 'p' and 'c'. POST includes the POST uploaded file information.
Hinweis:
Note that the order of the letters matters, as when using "GP", the POST variables will overwrite GET variables with the same name. Any other letters than GPC are discarded.
Variable name prefix, prepended before all variable's name imported into the global scope. So if you have a GET value named "userid", and provide a prefix "pref_", then you'll get a global variable named $pref_userid.
Hinweis:
Although the prefix parameter is optional, you will get an E_NOTICE level error if you specify no prefix, or specify an empty string as a prefix. This is a possible security hazard. Notice level errors are not displayed using the default error reporting level.
Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.
Beispiel #1 import_request_variables() example
<?php
// This will import GET and POST vars
// with an "rvar_" prefix
import_request_variables("gp", "rvar_");
echo $rvar_foo;
?>
Regarding the last post:
When $_GET[$k] is compared against NULL or '' (empty string) inside the foreach loop, it should be compared only against one of the expressions or strict equality operator should be used.
In this case, second part of expression ($_GET[$k] == NULL) will be *never* executed, because of NULL gets converted to empty string.
Also be aware that zero is equal (==) to empty string, so if passing zeroes through the $_GET, use strict comparsion to check whether variable exist or not.
Next notice: when nothing will be set into $_GET array, all comparsions will generate lot of E_NOTICE errors, because you are accessing unassigned variable.
<?
// Slightly modified previous example
$input = array('name' => null, 'age' => 26) ;
// 26 is the default age, if $_GET['age'] is empty or not set
/**
* Extracts $_GET variables to global scope by the definition from the $input array
* @return void
*/
function extract_get() {
global $input;
if (isset($input) && is_array($input)) foreach ($input as $k => $v) {
if (!isset($_GET[$k])) {
$GLOBALS[$k] = $v;
continue;
}
$getval = $_GET[$k];
if ($getval === null || $getval === '') {
$getval = $v;
} elseif (is_numeric($v)) {
$getval = (int) $getval;
} elseif (get_magic_quotes_gpc() == 1) {
$getval = stripslashes_deep($getval);
}
$GLOBALS[$k] = $getval;
unset($getval);
}
}
/**
* Performs stripslashes function recursively on the array or on the single variable
* @param mixed $var Variable - can be scalar variable or the array
* @return mixed Variable with slashes stripped with function stripslashes()
*/
function stripslashes_deep($var) {
if (!is_array($var))
return stripslashes($var);
foreach($var as $k => $v) {
$var[$k] = stripslashes_deep($v);
}
return $var;
}
?>
What i do is have a small script in my header file that takes an array called $input, and loops through the array to extract variables. that way the security hole can be closed, as you specify what variables you would like extracted
$input = array('name' => null, 'age' => 26) ;
// 26 is the default age, if $_GET['age'] is empty or not set
function extract_get()
{
global $input ;
if ($input)
{
foreach ($input as $k => $v)
{
if ($_GET[$k] == '' or $_GET[$k] == NULL)
{
$GLOBALS[$k] = $v ;
}
else
{
$GLOBALS = $_GET[$k] ;
}
}
}
}
reply to ceo AT l-i-e DOT com:
I don't think it's a risk, as all of your request variables will be tagged with the prefix. As long as you don't prefix any of your internal variables with the same, you should be fine.
If someone tries to access an uninitiated security-related variable like $admin_level through request data, it will get imported as $RV_admin_level.
PHP5 seems to have fixed that, in the sense that import_request_variables("g") works like extract($_GET). It doesn't seem to be passing a reference to the global, but instead creating a copy of it as expected
oops, a typo in my comment:
The last line in the second example (the on using the extract() function) should read:
echo $_GET['var']; # prints 1, so $_GET has been unchanged
Beware:
import_request_variables() does not copy the request variables into local scope variables. Instead, it copies the *reference* to the request variable content to local variables Important implication: any change to the local variable means a changes to the respective request variable, too!
This is a clear difference to extract($_GET) which copies the content of the request variables into local variables.
To shed some light on the implication, consider this (assuming the query string "...&var=1"):
echo $_GET['var']; # prints: 1
import_request_variables();
echo $var; # prints 1
$var = 2;
echo $_GET['var']; # prints 2 !!!!
So, $_GET has changed as well!
On the other hand:
echo $_GET['var']; # prints: 1
extract($_GET);
echo $var; # prints 1
$var = 2;
echo $_GET['var']; # prints 2 !!!!
Because of this, I recommend NOT using import_request_variables(), but extract($_GET); extract($_POST); extract($_COOKIE); instead, since this combination bears not these unexspected side effects.
PS: not to mention that you have to reconsider your coding style if any need to import_request_variables arises at all!
Call me crazy, but it seems to me that if you use this function, even WITH the prefix, then you might as well just turn register_globals back on...
Sooner or later, somebody will find a "hole" with your prefixed variables in an un-initialized variable.
Better to import precisely the variables you need, and initialize anything else properly.
import_request_variables does *not* read from the $_GET, $_POST, or $_COOKIE arrays - it reads the data directly from what was submitted. This is an important distinction if, for example, the server has magic_quotes turned on and you massage the data to run stripslashes on it; if you then use import_request_variables, your variables will still have slashes in them.
In other words: even if you say $_GET=""; $_POST=""; then use import_request_variables, it'll still get all the request data.
If you change the contents of $_GET and you then want to bring this data into global variables, use extract($_GET, EXTR_PREFIX_ALL, "myprefix") instead.
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