I'm planning to create Yahoo Messenger bot using C#, but until now, I cant find a reliable Yahoo Messenger, except in PHP, Java and C++. Is there a library like this in C#?
Well, I just created a working YMSG library for a chat client (not a bot) in C#, so I can tell you there's nothing out there that works for YMSG version 16 for C#. (sorry it's for the company for which I work, I can't release any source)
But all is not lost. With the exception of the authentication procedure, the protocol is dirt simple to understand. Two good things:
The authentication procedure has been deciphered: http://www.carbonize.co.uk/ymsg16.html. It uses an HTTP call, but that's simple in C#. The only part you might struggle with is the hashing of challenge/response strings. Unfortunately there's no way to implement it in stages - it either works or it doesn't
WireShark has a dissector for YMSG that's pretty thorough. Helped me a lot.
(Note that this covers the IM portion of Yahoo YIM - I have no idea how the chat "rooms" work)
Good luck!
Eric