Php complex validation logic - php

Question

I need to validate an input from text area.
It is complex and i'm unable to figure out how i can do it best?
Can you guys help?
Input from the text area are basically host names or ips. The input can be of any of the following formats:
x.x.x.x (single IP)
x.x.x.x-x.x.x.x (range of IPs)
x.x.x.x/x.x.x.x (IP and mask)
x.x.x.x/xx (IP and CIDR)
URL (with or without http:// and https:// prefixes)
domain name in format: xxxxxxx.xxx
Also multiple values can be given, like:
192.168.1.1
192.168.1.2/192.168.1.4
I am able to get the lines of textbox using the following code:
$text = trim($targets);
$textAr = explode("\n", $text);
$textAr = array_filter($textAr, 'trim');
foreach ($textAr as $line) {
}
I am unable to proceed further. Please help.
Thanks,
Dave

Answer 1

If you don't mind being slightly loose on your validation, you can do something simple such as this:
function filter_fn($input)
{
$input = trim($input);
$regex_ip = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';
$regex_range = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})-([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';
$regex_cidr = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\/[0-9]{1,2})$/';
$regex_sub = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';
if (filter_var($input, FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => $regex_ip)))) {
return $input;
}
if (preg_match($regex_range, $input)) {
return $input;
}
if (preg_match($regex_cidr, $input)) {
return $input;
}
if (preg_match($regex_sub, $input)) {
return $input;
}
if (filter_var($input, FILTER_VALIDATE_URL)) {
return $input;
}
if (filter_var('http://'.$input, FILTER_VALIDATE_URL)) {
return $input;
}
return false;
}
$textAr = explode("\n", $text);
$textAr = array_filter($textAr, 'trim');
foreach ($textAr as $line) {
$success = filter_var($line, FILTER_CALLBACK, array('options' => 'filter_fn'));
if (!$success) {
// It failed.
} else {
// It worked.
}
}
Note that in my example, I used both preg_match and filter_var with FILTER_VALIDATE_REGEXP. Both are identical in this case, so that first filter_var could have just as easily been replaced with:
preg_match($regex_ip, $input)
Or, even:
filter_var($input, FILTER_VALIDATE_IP)