Description
Intro. to Network Programming
1. Introduction
In this part, you are going to implement the subscription features for the BBS service. The event will
be raised whenever the client creates a new post that title contains the keyword subscribed by any other
client.
2. Example Architecture using Apache Kafka
The middleware server will get a message/record from the producer when there has a new post and also
notify the client(s) who have subscribed to the specified topic.
A. BBS server is a producer, and each client is a consumer
B. Each client act as both a producer and a consumer
3. Requirements
The service can serve at least 10 clients. Your server and client program must be able to handle all
commands in the previous part (output results must be the same as the previous part). For some
commands such as whoami, exit, logout, create-board, list-board ##
result from the server. However, there are new commands that your client program will subscribe to the
new post. These commands are described as follows:
Command format Description Result
subscribe –board
–keyword
(command and arguments are in the
same line)
Subscribe the board with a keyword,
notify the client whenever the event be
raised.
Note [1]: Can subscribe the same
board multiple times with different
keywords. Notify user once someone
creates a new post with a specified
board and the title contains one of the
keywords
Note [2]: Subscribe objective (board)
can be nonexistent
Success Subscribe successfully
(The notify message should
at least include board, title,
and author)
Fail (1) Please login first
Fail (2) [Invalid option] usage:
subscribe –board
Fail (3) Already subscribed
subscribe –author
–keyword
(command and arguments are in the
same line)
Subscribe the author with a keyword,
notify the client whenever the event be
raised.
Both notes [1] and [2] are same as the
previous one (change objective to
author) ↑
Success same as the previous one
Fail (1) same as the previous one
Fail (2) [Invalid option] usage:
subscribe –author
Fail (3) same as the previous one
unsubscribe –board
(or middleware server) and remove all
the keywords associated with a specified
board.
Success Unsubscribe successfully
Fail (1) Please login first
Fail (2) You haven’t subscribed
unsubscribe –author
(or middleware server) and remove all
the keywords associated with a
specified author.
Success Unsubscribe successfully
Fail (1) Please login first
Fail (2) You haven’t subscribed
list-sub List the information about the
subscribed board(s) and author(s).
Success List all the subscribed info
Fail (1) Please login first
4. Scenario
Run your server first, and run your client program to connect to your server. The sample outputs of the
client program are listed as follows:
Client 1 Client 2 Client 3
bash$ ./client 127.0.0.1 7777
********************************
** Welcome to the BBS server. **
********************************
% register Paul paul@cs.nctu.edu.tw 12345
Register successfully.
bash$ ./client 127.0.0.1 7777
********************************
** Welcome to the BBS server. **
********************************
% register Brad brad@cs.nctu.edu.tw 12345
Register successfully.
bash$ ./client 127.0.0.1 7777
********************************
** Welcome to the BBS server. **
********************************
% register Gary gary@cs.nctu.edu.tw 12345
Register successfully.
% login Paul 12345
Welcome, Paul.
% login Brad 12345
Welcome, Brad.
% login Gary 12345
Welcome, Gary.
% subscribe –board HW4_Board
–keyword Project
Subscribe successfully
% subscribe –author Jason –keyword hw4
Subscribe successfully
% create-board HW4_Board
Create board successfully.
% subscribe –board HW4_Board
–keyword Project
Already subscribed
% subscribe –author Bryant
–keyword exam
Subscribe successfully
% subscribe –author Paul –keyword HW
Subscribe successfully
% subscribe –author Paul –keyword post
Subscribe successfully
% unsubscribe –author Brad
You haven’t subscribed Brad
% create-post HW4_Board
–title About Project –content HW4…
Create post successfully.
% *[HW4_Board] About Project – by Paul*
% list-board ##HW
Index Name Moderator
1 HW4_Board Paul
% create-post HW4_Board
–title About HW and Exam –content
blablabla
Create post successfully.
% unsubscribe –author Bryant
Unsubscribe successfully
% list-sub
Board: HW4_Board: Project
% *[HW4_Board] About HW and Exam –
by Paul*
% list-sub
Author: Jason: hw4; Paul: HW, post
5. Notes
1. About implementation:
• There is no limitation on your implementation. You can choose whatever which framework,
library, or even implement the logic by yourself, as long as it can achieve the goal of spec.
• The output message should show the information at least greater or equal to mentioned in
the requirements. In addition, it not restricted in any format.
2. About Kafka environment setup:
• Please refer to the slide in E3 – Apache Kafka Installation and Configuration.
3. About Kafka clients:
• C/C++
• https://github.com/edenhill/librdkafka
• Python
• https://github.com/dpkp/kafka-python
• https://github.com/confluentinc/confluent-kafka-python
• Node.js
• https://github.com/Blizzard/node-rdkafka
• https://github.com/tulios/kafkajs
• https://github.com/SOHU-Co/kafka-node
6. Grading Policy (100%)
• [20%] Commands from previous parts
• [30%] Subscribe part
• [30%] Unsubscribe part
• [20%] List-sub part
7. Submission
Please upload a zip file called “hw4_{$student_id}.zip” (e.g., hw4_0516000.zip) that includes your
source code. It must include at least your server source code and client source code. The
submission that doesn’t follow the rule will get 20% punishment on the grade.
You will get 0 points on this project for plagiarism.
