Regex for Localhost Detection

javascript

const regex = /^(?:https?:\\/\\/)?(?:localhost|127\.0\.0\.1|\[::1\])(?::\d+)?(?:\\/.*)?$/;
const isValid = regex.test(value);

python

import re
pattern = r'^(?:https?:\/\/)?(?:localhost|127\.0\.0\.1|\[::1\])(?::\d+)?(?:\/.*)?$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^(?:https?:\/\/)?(?:localhost|127\.0\.0\.1|\[::1\])(?::\d+)?(?:\/.*)?$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^(?:https?:\\/\\/)?(?:localhost|127\.0\.0\.1|\[::1\])(?::\d+)?(?:\\/.*)?$/', $value)) {
    echo "valid";
}

java

String pattern = "^(?:https?:\\/\\/)?(?:localhost|127\\.0\\.0\\.1|\\[::1\\])(?::\\d+)?(?:\\/.*)?$";
boolean isValid = value.matches(pattern);