PHP Manual: Validation

Validation

Example #1 Validating email addresses with filter_var


<?php
$email_a = 'joe@example.com';
$email_b = 'bogus';

if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo "This ($email_a) email address is considered valid.";
}
if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
    echo "This ($email_b) email address is considered valid.";
}
?>

The above example will output:

This (joe@example.com) email address is considered valid.

Example #2 Validating IP addresses with filter_var


<?php
$ip_a = '127.0.0.1';
$ip_b = '42.42';

if (filter_var($ip_a, FILTER_VALIDATE_IP)) {
    echo "This (ip_a) IP address is considered valid.";
}
if (filter_var($ip_b, FILTER_VALIDATE_IP)) {
    echo "This (ip_b) IP address is considered valid.";
}
?>

The above example will output:

This (ip_a) IP address is considered valid.

Example #3 Passing options to filter_var


<?php
$int_a = '1';
$int_b = '-1';
$int_c = '4';
$options = array(
    'options' => array(
                      'min_range' => 0,
                      'max_range' => 3,
                      )
);
if (filter_var($int_a, FILTER_VALIDATE_INT, $options) !== FALSE) {
    echo "This (int_a) integer is considered valid (between 0 and 3).\n";
}
if (filter_var($int_b, FILTER_VALIDATE_INT, $options) !== FALSE) {
    echo "This (int_b) integer is considered valid (between 0 and 3).\n";
}
if (filter_var($int_c, FILTER_VALIDATE_INT, $options) !== FALSE) {
    echo "This (int_c) integer is considered valid (between 0 and 3).\n";
}

$options['options']['default'] = 1;
if (($int_c = filter_var($int_c, FILTER_VALIDATE_INT, $options)) !== FALSE) {
    echo "This (int_c) integer is considered valid (between 0 and 3) and is $int_c.";
}
?>

The above example will output:

This (int_a) integer is considered valid (between 0 and 3).
This (int_c) integer is considered valid (between 0 and 3) and is 1.