Socket programming

this is socket programming projects for isfahan university of technology network course.

How to run

in each project first run server by command python server.py in windows cmd (or python3 server.py in mac/linux)
then run client by command python client.py in windows cmd (or python3 client.py in mac/linux)

Note: Project1 can have multiple clients running

Project 1

It's simple client server model that each clinet send two numbers to server and receives sum of those as a result.

options:

there is configs dictionary in server.py and client.py that give you below options:

• you can change IP address that server is listening on by changing value of IP_Address in both client and server files.
• Protocol of network layer can be IPv4 or IPv6 by defining it in IP_version in both files.
• PORT defiens port number that server is listening and client is sending data (it should be greater than 1023 because numbers less than 1023 are reserved).
• Transport_type can be either TCP or UDP.
• Clients_limit defines how many clients can simultaneously be connected to the server.
• timeout defines maximum time that server keep connection to each clients open, without sending any data.

Project 2

In this project client can send two types of queries to the server (UDP is used as transport layer):

• GET : then server send all saved data back to client
• POST "something": then server saves "something"

questions:

• why UDP does not have close() method?
  • because it's not connection-oriented. there is no connection that needs to be closed.
• TCP is good, so why UDP exists?!
  • TCP brings more overhead.
  • establishing connection in TCP takes some times.
  • when netowrk is broken, TCP is not a good option.
  • UDP use cases (when a bit of loss dosn't matter):
    • Voice over IP (VoIP)
    • Streaming
    • Domain Name Systems (DNS)
    • Online multiplayer games
    • ...

Project 3

client and server can send unlimited number of messages to each others (one message client then one message server). then each one can terminate connection by sending Good Bye.

messages are encrypted using RSA method.

how to run

because of encryption, you require pycryptodome module to run server and client. you can install it using:

pip install pycryptodome

or install it from pipfile with pipenv virtual enviroment.

pipenv install

then in two separate terminals

pipenv run python server.py

pipenv run python client.py