CS165 Fall 2015

Introduction

This repository contains the distribution code for CS165 Fall 2017. We will continually update this repository throughout the semester, so it is recommended that you add

git://code.seas.harvard.edu/cs165-main/cs165-2017-base.git

as a new remote to your own local git repository. This will help you merge in any updates or bug fixes that we might release.

This repository is managed by the CS165 Staff, so please contact one of the TFs or Stratos if you have any questions at any time.

Getting Started

First, please add our distribution code repository as a new remote, you can do that with:

git remote add cs165 git://code.seas.harvard.edu/cs165-main/cs165-2017-base.git

This means in the future, you can pull from our repository using:

git pull cs165 master

Next, please make sure that your project/repo are set to private. You'll still need to share read access with the cs165-staff group.

We recommend that throughout the semester, you make git tags at each of the checkpoints so that it's easier to manage the progress of your project.

Client-Server code

We have included a simple unix socket implementation of an interactive client-server database implementation. You are recommended to use it as a foundation for your own database implementation. We have also provided a sample makefile that should be compatible with most machines. You are free to use your own makefile as well.

You can build both the client and server using:

make all

You should spin up the server first before trying to connect the client.

./server ./client

A high-level explanation of what happens is:

1. The server creates a socket to listen for an incoming connection.

2. The client attempts to connect to the server.

3. When the client has successfully connected, it waits for input from stdin. Once received, it will create a message struct containing the input and then send it to the server. It immediately waits for a response to determine if the server is willing to process the command.

4. When the server notices that a client has connected, it waits for a message from the client. When it receives the message from the client, it parses the input and decides whether it is a valid/invalid query. It immediately returns the response indicating whether it was valid or not.

5. Once the client receives the response, three things are possible:

1. if the query was invalid, then just go back to waiting for input from stdin.
2. if the query was valid and the server indicates that it will send back the result, then wait to receive another message from the server.
3. if the query was valid but the server indicates that it will not send back the result, then go back to waiting for input on stdin.

6. Back on the server side, if the query is a valid query then it should process it, and then send back the result if it was asked to.

Logging

We have included a couple useful logging functions in utils.c. These logging functions depend on #ifdef located within the code. There are multiple ways to enable logging. One way is by adding your own definition at the top of the file:

#define LOG 1

The other way is to add it during the compilation process. Instead of running just make, you can run:

`make CFLAGS+="-DLOG -DLOG_ERR -DLOG_INFO"