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Homework 4 -Message Broker
Description
In this assignment, you are going to extend your program in homework 2 and 3 in order to implement a Messenger-like function via message broker.
Example Architecture
NP-Client and NP-Server serve as project 2 & 3. Additionally, there are 6 commands added this time.
This is just an example architecture for your reference. If you have a better design, then you don’t have to follow this architecture.
Requirement
The server accept the following requests. For client side, like project 2 & 3, client program will help user to store their access token.
Therefore, users only need to type their username.
Request Format
Description
Request
Client Output ( usernames or groupnames are
Status
examples, please output the correct names)
login <id><password>
When user login, your client program
Success
Success!
should subscribe to all the related
channels, such as user’s personal
channel and the groups’ channels that
user has joined.
When request fail, your program
should have the same output message
as project 2 & 3.
send <token> <friend> <message>
Send message to your friend via
Success
Success!
message broker.
● <message> allow spaces
Fail-A
Not login yet
The request will success only when
passing the following rules: (A has the
highest priority, E has the lowest)
A. You cannot send message with
Fail-B
Usage: send <user> <friend> <message>
an invalid token
B. Correct request format
C. You cannot send to an user who
Fail-C
No such user exist
doesn’t exist.
D. You can only send to your
friend.
Fail-D
userA is not your friend
E. You can only send to online
user, which means that the user
already login, but not logout yet.
Fail-E
userA is not online
create-group <token> <group>
Create a group named <group>
Success
Success!
●
<group> is unique
Fail-A
Not login yet
●
<group> not allowed spaces
Fail-B
Usage: create-group <user> <group>
The request will success only when
Fail-C
EXAMPLE_GROUP already exist
passing the following rules: (A has the
highest priority, C has the lowest)
A. You cannot send message with
an invalid token
B. Correct request format
C. The group name must be
unique.
list-group <token>
List all the groups
Success
group_hello
The request will success only when
group_world
passing the following rules: (A has the
Success
No groups
highest priority, B has the lowest)
(No
groups
A. You cannot send message with
created)
an invalid token
Fail-A
Not login yet
B. Correct request format
Fail-B
Usage: list-group <user>
list-joined <token>
List the groups you already added
Success
group_hello
The request will success only when
group_world
Success (
No groups
passing the following rules: (A has the
No groups
highest priority, B has the lowest)
created)
A. You cannot send message with
Fail-A
Not login yet
an invalid token
Fail-B
Usage: list-joined <user>
B. Correct request format
join-group <token> <group>
Become the member of the group
Success
Success!
The request will success only when
Fail-A
Not login yet
passing the following rules: (A has the
Fail-B
Usage: join-group <user> <group>
highest priority, D has the lowest)
Fail-C
EXAMPLE_GROUP does not exist
A. You cannot send message with
Fail-D
Already a member of EXAMPLE_GROUP
an invalid token
B. Correct request format
C. You cannot join a non-exist
group
D. You cannot join the same group
multiple times
send-group <token> <group>
Send message to onlinegroup
Success
{
<message>
members, including yourself.
“status”: 0,
● <message> allow spaces
}
“message”:
“Success!”
The request will success only when
passing the following rules: (A has the
Fail-A
Not login yet
highest priority, D has the lowest)
A. You cannot send message with
Fail-B
Usage: send-group <user> <group> <message>
an invalid token
Fail-C
No such group exist
B. Correct request format
Fail-D
You are not the member of EXAMPLE_GROUP
C. You cannot send message to a
non-exist group
D. You cannot send message to a
group that you didn’t join
General
• All the commands in project 2 & 3 must work as before.
• You have to setup an ActiveMQ server to forward the messages.
• You may have to modify the login feature to integrate with the message broker. For the failing cases, output the same message as project 2 & 3.
• You need to implement the rest of the features,to handle all the successful request and failing request.
• Your client program must output the correct message according to different commands and different situations.
• You server should reply the correct message according to the priorities.
• Output format of receiving message from other users
◦ When USER_A send message “HELLO WORLD” to USER_B, your client program should show the message with following format to USER_B.
▪ <<<USER_A->USER_B: HELLO WORLD>>>
◦ When USER_A send message “HELLO WORLD” to GROUP_A, your client program should show the message with following format with all the group members, including USER_A.
▪ <<<USER_A->GROUP<GROUP_A>: HELLO WORLD>>>
Grade (100%)
• Receiving send message from other users - (20%)
• Receiving send-group message from groups - (20%)
• Every commands above except login10% - (60%)
Demo
It’s your responsibility to prepare the demo environment. TA will not help you prepare the environment, including the ActiveMQ. You can either bring your laptop, desktop, or using remote control to run the server.
When it’s your turn to demo, we will ask you to download the version you uploaded to new-e3.
1. Launch server (ip and port may change during demo): ./server 0.0.0.0 8888
2. Run with testcase: ./client TARGET_IP TARGET_PORT < testcase > output
Please learn how to run the above commands in your shell, no matter on Windows, Mac, or Linux.
Submit
Please upload a zip file called “hw4_{$student_id}.zip” that includes your source code. Submission that don’t follow the rule will get 20% punishment on the grade.
Demo time will be announced before the deadline. You are not allowed to modify your code after demo. Please submit your code on time.
If you have any questions, please ask your questions on course forum(https://e3new.nctu.edu.tw/)
Reference
1. JSON format (https://zh.wikipedia.org/wiki/JSON)
2. C socket (http://man7.org/linux/man-pages/man2/socket.2.html)
3. Python socket (https://docs.python.org/3/library/socket.html)
4. C JSON (https://github.com/json-c/json-c)
5. Python JSON (https://docs.python.org/3/library/json.html)
6. C++ ODB (https://www.codesynthesis.com/products/odb/)
7. Python peewee (http://docs.peewee-orm.com/en/latest/)
8. Activemq (http://activemq.apache.org/)
