Assignment 1: Basic Message Processing

This first assignment is meant as a warm-up exercise to get reacquainted with socket programming. You must implement an IRC server that implements the NICK and USER messages only well enough to perform a single user registration as shown in Example IRC Communications. Take into account that a barely minimal server that meets these requirements, and passes most of the automated tests for this assignment, can be written in roughly 50 lines of C code (in fact, we will give you those 50 lines of code). However, although this kludgy solution will get you some number of points on the tests, it will earn you a zero on the design grade.

So, you should start implementing your solution with the requirements of the rest of the project in mind. More specifically, your solution to this assignment should meet the following requirements:

  • (A) You must send the RPL_WELCOME only after the NICK and USER messages have been received.
  • (B) You must take into account that you may get more or less than one full message when you read from a socket. You may not solve this problem by reading one character at a time from the socket.
  • (C) Your solution must parse the nick and username from the NICK and USER messages, and compose the correct RPL_WELCOME reply.

Although not required for this assignment, you should take into account that the remaining two parts of the project will involve adding support for additional messages and replies. Any time you spend writing a message parser and constructor (that works with more than just NICK and USER) will be time well spent. However, if your solution to this assignment takes some shortcuts by assuming that you will only be dealing with the NICK and USER messages and the RPL_WELCOME reply, you will not be penalized for it.

Your server must be implemented in C, and must use sockets. There should be no need for you to use pthreads at this point.