正则表达式确定，如果给出IPv6或IPv4以及端口

Question

I'm searching for a regular expression that can determine, if the given IP address is IPv4 or IPv6 and (most important for me) if a port number is attached, or not.

I tried a few regular expressions, but none of them worked as expected.

Answer 1

If I can assume that the input will be a simple valid IP address and you simply want to know whether you have a port or not, you could do the following:

if (preg_match("/^(?:[0-9.]+|(?:\[[0-9a-fA-F:]+\]))(:[0-9]+)$/", $ip)) 
{
    echo "A port was found.";
} 
else 
{
    echo "A port was not found.";
}

This will match an IP adress like

• [2001:0db8:85a3:08d3:1319:8a2e:0370:7344]:8080 or
• 127.0.0.1:8080

but it will not match

• 2001:0db8:85a3:08d3:1319:8a2e:0370:7344 or
• 127.0.0.1

Keep in mind that the standard defines an IPv6 host to be distinguished by enclosing the IP literal within square brackets.