Filter Fonctions

Sommaire

filter_has_var — Vérifie si une variable d'un type spécifique existe
filter_id — Retourne l'identifiant d'un filtre nommé
filter_input — Récupère une variable externe et la filtre
filter_input_array — Récupère plusieurs valeurs externes et les filtre
filter_list — Retourne une liste de tous les filtres supportés
filter_var — Filtre une variable avec un filtre spécifique
filter_var_array — Récupère plusieurs variables et les filtre

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User Contributed Notes 2 notes

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vojtech at x dot cz ¶

18 years ago

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?').

down

fumble1 at web dot de ¶

17 years ago

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
?>

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