I wrote this small chat application for fun and practice. I had a time constraint, so unit testing and variable naming is not optimal.

Each client is a file, which is checked on each write. Any message in the format <sending user> <recipient> <message> is acknowledged and forwarded to the winforms GUI. There is a server channel which acts as a broadcast channel. Any message inserted here is forwarded to all clients (i.e. files) in the same directory. The server directory is given by .NET's System.IO.Path.GetTempPath().

Rather than communicating through windows forms, you can also use other utilities like touch fifo/username and echo "myusername #all Hello, World" >> fifo/otherusername

This program does not work well under Mono/Wine, since I have no special handling of UNIX filenames.

• Try not to use more than 5 hours (exceeded)
• Do not rely too heavily on existing libraries or other people's code

I chose unlicense, so you can basically use any code as you'd like.