Writing a library in your language of choice is not very hard but here are a few guidelines to help you produce a library that will be as complete as possible:
- Read the API documentation carefully.
- Make sure you normalize emails and OpenID URLs according to the rules.
- Email hashes should default to MD5 (for the Gravatar redirection to work) while SHA256 is the only hash allowed for OpenID hashes.
- The base URL should be looked up in DNS to ensure that federation is possible.
- SRV weight and priority handling is tricky. Have a look at srv_hostname() to see how it's done in the CPAN module.
If you have any questions or run into any problems, come talk to us.