如何使正则表达式匹配全部或不匹配

Question

I want a RegEx to match the string that composes a valid IP, colon, and port. If the string contains a valid IP and invalid port # or vice-versa, I want it to match nothing at all. I'm implementing this in a C# app.

To do this, I'm trying to integrate the following from How to Find or Validate an IP Address

(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)

with the following from regex for port number

((6553[0-5])|(655[0-2][0-9])|(65[0-4][0-9]{2})|(6[0-4][0-9]{3})|([1-5][0-9]{4})|([0-5]{0,5})|([0-9]{1,4}))

Each of these work independently to match an IP address and port number just fine.

I combined them

(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\:((6553[0-5])|(655[0-2][0-9])|(65[0-4][0-9]{2})|(6[0-4][0-9]{3})|([1-5][0-9]{4})|([0-5]{0,5})|([0-9]{1,4}))

and the result is, for example:

256.250.139.193:1234  // bad IP, good port. The RegEx matches "56.250.139.193:1234". Fail. I want it to match nothing
1.1.1.1:65535         // good IP, good port #. The RegEx matches "1.1.1.1:65535". Pass. This is what I want it to do
1.1.1.1:65536         // good IP, bad port, matches "1.1.1.1:". Fail. I want it to match nothing

I can't figure out how to combine them to match all or nothing. I tried using repetition and grouping and it either didn't change what is matched or broke the RegEx entirely

Answer 1

Put word boundaries around the pattern.

Also, you had an error in your pattern for the port number. [0-5]{0,5} should be [0-5]{1,5} , otherwise it matches an empty port number.

\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?):((6553[0-5])|(655[0-2][0-9])|(65[0-4][0-9]{2})|(6[0-4][0-9]{3})|([1-5][0-9]{4})|([0-5]{1,5})|([0-9]{1,4}))\b

DEMO

Answer 2

One reliable and readable way, using a specific Perl parser Regexp::Common :

perl -MRegexp::Common -lne '
    my ($ip, $port) = /^($RE{net}{IPv4}):(\d+)$/;
    print "$ip:$port" if defined $ip and defined $port and $port  < 65536
' file