PeerConnectFS

PeerConnectFS is a permissioned, peer-to-peer file sharing system built on a hybrid client-server and P2P architecture, featuring authentication, file publishing, and real-time transfers over UDP and TCP. The system mirrors practical peer-based networks, simulating decentralized file exchanges with a centralized indexing server.

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Technologies Used

• Python 3
• socket module (UDP & TCP)
• threading for concurrent execution
• Custom application-layer protocol

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Key Features

• 🔐 User Authentication
  Authenticated users via a secure UDP channel using a centralized credentials.txt file.

• 🧭 Central Indexing Server
  Tracks active users and their published files. Clients query the server to locate files.

• 🫀 Heartbeat Mechanism
  Clients send heartbeat signals every 2 seconds to maintain active status. Server removes inactive users after 3 seconds of silence.

• 📂 File Publishing & Sharing

  • pub <filename> to publish a file
  • get <filename> downloads directly from another peer using TCP
  • unp <filename> unpublishes a file

• 🔍 Search & Discovery

  • lap: List all active peers
  • lpf: List your published files
  • sch <substring>: Search for files shared by others

• 🔄 Multithreaded Architecture
  Separate threads manage:

  • User interaction
  • Heartbeat messages
  • Incoming TCP file requests
  • File transfers (upload/download)

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Commands (Client)

get <filename>   # Download file from another peer
pub <filename>   # Publish a file to the network
unp <filename>   # Unpublish a file
lap              # List active peers
lpf              # List your published files
sch <substring>  # Search shared files
xit              # Exit the network

📸 Example Usage

Let's walk through a simple example using three sample users: hans, vader, and yoda.

1. Start the server

python3 server.py 50000

2. Start each client in a separate terminal

python3 client.py 50000

Each client will be prompted to authenticate with a username and password from credentials.txt.

3. Sample interaction

Hans (Uploader)

$ python3 client.py 50000
Username: hans
Password: hanspass
> pub BitTrickle.mp4
> lpf
BitTrickle.mp4

Vader (Downloader)

$ python3 client.py 50000
Username: vader
Password: vaderpass
> sch BitTrickle
BitTrickle.mp4
> get BitTrickle.mp4
Download successful: BitTrickle.mp4

Yoda (Peer Discovery)

$ python3 client.py 50000
Username: yoda
Password: yodapass
> lap
hans
vader

4. Exit the network

> xit

This demonstrates core features: publishing, searching, downloading, peer discovery, and session management—all within a decentralized file sharing system.