Regex for Matching IPv6 Addresses - Confusion with Embedded IPv4 Formats
I'm migrating some code and I've searched everywhere and can't find a clear answer..... I'm trying to construct a regex pattern to match IPv6 addresses, but I'm working with a scenario with the different formats, especially when it comes to embedded IPv4 addresses. My goal is to capture both the full IPv6 representation and the hybrid format where the last 32 bits are represented in IPv4 notation. I've written the following regex: ```python import re ipv6_pattern = r'([0-9a-fA-F]{1,4}:){7}([0-9a-fA-F]{1,4}|:)|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|([0-9a-fA-F]{1,4}:){1}(:[0-9a-fA-F]{1,4}){1,6}|:((:[0-9a-fA-F]{1,4}){1,7}|:)|([0-9a-fA-F]{1,4}:){1,6}:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$' # Testing the regex with some example addresses addresses = [ '2001:0db8:85a3:0000:0000:8a2e:0370:7334', '2001:db8::ff00:42:8329', '::1', '2001:db8:0:0:0:0:0:2', '::ffff:192.168.1.1' ] for address in addresses: match = re.match(ipv6_pattern, address) print(f'{address}: {match is not None}') ``` However, when I run this code, it seems to unexpected result for the last address `::ffff:192.168.1.1`, returning `False` when it should match. I also want to ensure that I properly validate the range of the IPv4 part (0-255). Can anyone guide to refine this regex to make it work for embedded IPv4 formats? I'm using Python 3.10 and the `re` library, and I've read through several resources but need to seem to find a solution that covers all edge cases. Any insights would be greatly appreciated! I'm on Ubuntu 22.04 using the latest version of Python. The project is a microservice built with Python. Am I approaching this the right way?