Iterations

Iterations

This project involves writing a handful of small, independent servers. You can build them in any order, but we recommend building them in the order presented below.

To connect to a server, use the telnet command that comes with your computer.

Code Reviews & Feedback

Remember, the absolute, tip-top, #1 priority is asking for and receiving feedback on your code. It's better to "fall short" of an iteration and ask for feedback on an incomplete version than it is to get stuck. It's better to ask for feedback on a hacked-together-but-working version than worry about whether it's "polished enough."

Indeed, even if you know your code is unpolished or incomplete, you may as well ask for feedback so that we can be working on that feedback in parallel while you're polishing or completing your code. The worst that could possibly happen is that we give you feedback you are already aware of.

Time Server

We've built time_server.rb for you to show you what a basic network server looks like and to walk you through the process of connecting to one. To get started, run this command in your terminal:

ruby time_server.rb

You should see the text "Waiting for connections on port 2000...", like so:

To connect to this time server, open a new terminal window and run

telnet 127.0.0.1 2000

127.0.0.1 is a special IP address that always means "my own computer" and 2000 is the port on which our time server is running. Telnet should exit almost immediately, but not before receiving the current time from the server, like so:

Echo Server

An "echo server" reads a single line of input from any client that connects, echoes that same line back to the client, closes the connection, and then starts waiting again for the next client to connect.

You can run

ruby echo_server.rb

but it won't do anything yet. Open up echo_server.rb and take a stab at implementing the "echo" functionality.

To check whether your server is doing what you expect, connect to it using the telnet command and type a line of text. You should see something like this once its working correctly:

Feel free to change its behavior — the point is to understand what's going on and get feedback on your implementation!

Hot or Cold Server

Let's hook up the "hot or cold" kata from Week 1 to a server. If you don't remember, the "hot or cold" kata is a command-line guessing game that tells us whether our guess is too high, too low, or just right.

See hot_or_cold_server.rb for more details.

MOTD Server

"MOTD" stands for "message of the day." Starting from motd_server.rb, write a server that sends every client the contents of motd.txt.

Your Own Server

Write a server of your own! It can do anything you want, honestly. Some areas of investigation might be:

1. How do you write a server that can handle multiple clients simultaneously?
2. How do you write a server that allows clients to interact with each other, e.g., a chat server?
3. What issues would crop up if you started to allow clients to request arbitrary files from the server rather than a fixed file like motd.txt?