Spring 2015 CSCI 373 Homework 5 Problems

Times

• Posted — 19 February
• First email — 1 March
• First submission — 7 March
• Second email — 11 March
• First question   16 March
• Second submission — 17 March
• Due date — 18 March

Submitted solutions

• Submitted — 17
• Working with the possible exception of port number handling — 4
• Not handling concurrent connections properly — 1
• Connecting but not following protocol (generally producing responses that are not given in the protocol specification) — 2
• Other problems
  • Bad python syntax
  • Using sys.argc as a string, not an array
  • Ignoring sys.argc port number argument
  • Binding to IP 120.0.0.1
  • Unneeded gethostname
  • Not using int on port argument
  • Trying to read anything from the standard input stream

Other stuff

A large number of the questions I received variations were “Do have have an example of a program that I can modify for the assignemnt?”

Testing is important. It can be tested using nc.

I did not see any functions to process the input line. I did see many an elif in the main loop. Write a command processing function and test it early!

Make your code “bullet proof.” This was hard for the first classes I taught, but now we have exceptions!

• The port argument may not be given.
• The port argument may not be a number.
• The port argument may be out-of-range.
• The port argument may already be in use.

Your program should check for all of these conditions.

The plan

What is submitted so far will be 50% of the 50 points. There will be a Homework 5bis to improve the overall grade. Start working on it.