Client-Server Program Using Domain Sockets

This program establishes a client-server system that communicates through UNIX domain sockets. The client sends files to the server, which in turn saves these received files into a specific directory.

Table of Contents

• Features
• Design
  • Server (server.py)
  • Client (client.py)
• Setup
• Usage
• Test Plan
• Screenshots
• Notes

Features

• Client communicates file details (name, size, content) to the server.
• Server saves received files to a specified directory.
• Graceful shutdown on both client and server with proper resource cleanup.
• Error handling for scenarios like missing files or server not running.

Design

Server (server.py)

Functions:

1. __init__ (in File class) - Initializes a File object with a name and content.
2. save (in File class) - Saves the content of the file to a specified directory.
3. signal_handler - Handles the SIGINT signal for graceful shutdown.
4. clearSocket - Removes the domain socket file if it exists to ensure a clean startup.

Client (client.py)

Function:

1. signal_handler - Handles the SIGINT signal, informs the server about the client's exit and ensures graceful shutdown.

Setup

1. Clone this repository.
2. Navigate to the directory containing the program files.
3. You will need 2 terminals at this directory one to run the server and one client

Usage

Server: python3 server.py <directory_to_save_files>

Client: python3 client.py <name of 1 or more files>

Test Plan

1. Server's ability to receive and save files:

   • Input: python3 server.py ./test_directory and python3 client.py test.txt

   • Expected Output: The content of test.txt is saved in ./test_directory/test.txt.

   • Input: python3 client.py mountain.jpeg

   • Expected Output: The image mountain.jpeg is saved in ./test_directory/mountain.jpeg.

   • Input: python3 client.py paint.jpg client.py

   • Expected Output: The content of paint.jpg and client.py is saved in ./test_directory/paint.jpg and ./test_directory/client.py.

2. Client's ability to handle non-existent files:

   • Input: python3 client.py nonexistent.txt
   • Expected Output: "File nonexistent.txt not found." and the server will look for the next client

3. Client shutdown using ctrl-c:

   • Input: python3 client.py without arguments
   • control-c
   • Expected Output: "stopping client."

4. Server shutdown using ctrl-c:

   • Expected Output: "Shutting Down Server...

   Bye."

5. Client handling a non-running server:

   • Input: python3 client.py test.txt (without starting the server)
   • Expected Output: "Server is not running."

Notes

• Server runs continuously, accepting file transmissions until interrupted by the user.
• Client can send multiple files in a single run.
• Client provides informative feedback for errors such as missing files or server not running.
• If the client is give no files in the argument, the client will ask the user once for files to input
• Files that already exist in the directory will be overwritten