Homework 1 - Bulletin Board System: Part 1 Solution

Description

In this project, you are asked to design Bulletin Board System (BBS) server. Your program should be able to handle multiple connections and receive user command from standard input. After receiving command, the server send the corresponding message back.
Requirement

The service accepts the following commands and at least 10 clients:

When client enter command incompletely E.g., missing parameters, the server should show command format for client.


Command format
Description

Result
register <username> <email> <password>
Register with username, email
Success
Register successfully.

and password.







<username> must be unique.



<email> and <password>
Fail
Username is already used.

have no limitation.



If username is already used,



show failed message,



otherwise it is success.


login <username> <password>
Login with username and
Success
Welcome, <username>.

password.




Fail (1)
Please logout first.

Fail(1): User already login.







Fail(2): Username or
Fail (2)
Login failed.

password is incorrect.


logout
Logout account.
Success
Bye, <username>.

If login not yet, show failed
Fail
Please login first.

message, otherwise logout



successfully.


whoami
Show your username.
Success
<username>.

If login not yet, show failed
Fail
Please login first.

message, otherwise show



username.


exit
Close connection.



General

Please make sure you develop your program on Linux. For development environment, you can just apply NCTU CSCC account to use Linux workstation. If you don’t want to apply anything, you can use VM for develop.

Use ‘’% “ as the command line prompt. Notice that there is only one space after the prompt.

The server close connection if client use exit command, but server still running and client can connect again.

For manage user information, storing data in your server is necessary. Therefore, you must have some methods to handle this, like manage a simple database e.g. SQLite and then design tables by yourself or only use data structure to store data.

To run your server, you must to provide port number for your program. E.g., bash$ ./server 7890

Now, you can use telnet or other client program to connect your server, when client connect to server, the server print message “New connection.”

Assume your server is running on localhost and listening at port 7890. E.g., bash$ telnet 127.0.0.1 7890
Scenario


bash$ telnet 127.0.0.1 7890

********************************

** Welcome to the BBS server. **

********************************

    • register

Usage: register <username> <email> <password>

    • register Bob bob@qwer.asdf 123456 Register successfully.

    • register Bob asdf@asdf.asdf 123456 Username is already used.

    • login

Usage: login <username> <password>

    • login Bob


    • login Bob 654321 Login failed.

    • login Tom 654321 Login failed.

    • login Bob 123456 Welcome, Bob.
    • login Bob 123456

Please logout first.

    • whoami

Bob

    • logout Bye, Bob.
    • logout


    • whoami

Please login first.

    • exit





Grade (100%)

Socket connection and print welcome message to client. - (30%) register command. - (30%)

login / logout command. - (20%) whoami command. - (10%)

exit command. - (10%)
Submission

Please upload a zip file called “hw1_{$student_id}.zip” that includes your source code. Submission that don’t follow the rule will get 20% punishment on the grade.

You will get 0 points on this project for plagiarism. Please don’t copy-paste any code!

Note


You will be asked to use AWS resources in projects 3 and 4, so we suggest you use AWS SDK supported languages to im-plement this project.

Reference

    1. C/C++ Socket

    2. SQLite C/C++ Interface

    3. Linux socket SELECT

    4. Database table example


CREATE TABLE USERS(

UID INTEGER PRIMARY KEY AUTOINCREMENT,

Username TEXT NOT NULL UNIQUE,

Email TEXT NOT NULL,

Password TEXT NOT NULL

);


    5. AWS SDK supported languages