PHP:Variable in function not working

Question

I'm trying to get dns records of a domain through dns_get_record() but the function doesn't seem to work when a variable is inserted..here's my code

<form action="" method="post">
 <input type="text" name="host" placeholder="Enter IP or Domain"/>
 <select name="dns">
 <option value="DNS_A" selected="selected">A</option>
 ....
 <option value="DNS_ANY">ANY</option>
 </select>
</form>
<?php
$host=$_POST['host'];
$dns=$_POST['dns'];
$type=end(explode('_',$dns));
if ($host==""){
 exit();
}
echo "Results for $host $type record<br />";
$result = dns_get_record($host, $dns);
echo "Result = ";
print_r($result);
?>

but if i put

$result = dns_get_record($host, DNS_A);

instead of

$result = dns_get_record($host, $dns);

it works..help!

• deceze: Learn what a constant is: php.net/constants
• deceze: @ppeterka That is a constant for once, not a string! Don't quote it.
• ppeterka: @deceze I didn't even think of that - I blindly (and dumbly) defaulted to the usual "not escaped string" issue I saw too many times...

Answer 1

DNS_A is a constant of value 1, while you are passing string "DNS_A", try by passing value of constant, using $result = dns_get_record($host, constant($dns));

• nitish: it worked..but $host works even without passing a value of constant?

Answer 2

This is because your POST returns a literal string: "DNS_A", if you prefer. This is NOT the same as DNS_A, which is a constant and most likely contains an integer.

You'll need a mapping table for this one. Or just pass the integer value straight off.