Filter Функции
Содержание
- filter_has_var — Checks if variable of specified type exists
- filter_id — Returns the filter ID belonging to a named filter
- filter_input_array — Gets multiple variables from outside PHP and optionally filters them
- filter_input — Gets variable from outside PHP and optionally filters it
- filter_list — Returns a list of all supported filters
- filter_var_array — Gets multiple variables and optionally filters them
- filter_var — Filters a variable with a specified filter
Коментарии
Just to note that "server and env support may not work in all sapi, for filter 0.11.0 or php 5.2.0" as mentioned in Filter tutorial bellow.
The workaround is obvious:
Instead of
<?php
$var = filter_input(INPUT_SERVER, 'SERVER_NAME', FILTER_DEFAULT);
?>
use
<?php
$var = filter_var(isset($_SERVER['SERVER_NAME']) ? $_SERVER['SERVER_NAME'] : NULL, FILTER_DEFAULT);
?>
Also notice that filter functions are using only the original variable values passed to the script even if you change the value in super global variable ($_GET, $_POST, ...) later in the script.
<?php
echo filter_input(INPUT_GET, 'var'); // print 'something'
echo $_GET['var']; // print 'something'
$_GET['var'] = 'changed';
echo filter_input(INPUT_GET, 'var'); // print 'something'
echo $_GET['var']; // print 'changed'
?>
In fact, external data are duplicated in SAPI before the script is processed and filter functions don't use super globals anymore (as explained in Filter tutorial bellow, section 'How does it work?').
There is an undocumented filter flag for FILTER_VALIDATE_BOOLEAN. The documentation implies that it will return NULL if the value doesn't match the allowed true/false values. However this doesn't happen unless you give it the FILTER_NULL_ON_FAILURE flag like this:
<?php
$value = 'car';
$result = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
?>
In the above $result will equal NULL. Without the extra flag it would equal FALSE, which isn't usually a desired result for this specific filter.
I recommend you to use the FILTER_REQUIRE_SCALAR (or FILTER_REQUIRE_ARRAY) flags, since you can use array-brackets both to access string offsets and array-element -- however, not only this can lead to unexpected behaviour. Look at this example:
<?php
$image = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_FLAG_STRIP_LOW));
// further checks
?>
/script.php?src[0]=foobar will cause a warning. :-(
Hence my recommendation:
<?php
$image = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_REQUIRE_SCALAR | FILTER_FLAG_STRIP_LOW));
// further checks
?>