Regex for X-Forwarded-For Header

javascript

const regex = /^(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:,\s*)?)+$/;
const isValid = regex.test(value);

python

import re
pattern = r'^(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:,\s*)?)+$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:,\s*)?)+$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:,\s*)?)+$/', $value)) {
    echo "valid";
}

java

String pattern = "^(?:\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}(?:,\\s*)?)+$";
boolean isValid = value.matches(pattern);