Sahara is an offline-first, peer-to-peer communication system for situations where internet access is unavailable. Devices communicate over the same Wi-Fi, hotspot, or local network.

Each node discovers nearby peers, joins a shared room, and exchanges messages through either the terminal or the React interface.

Internet and mobile networks often fail during natural disasters. Sahara provides a simple way for civilians and rescue teams on the same local network to exchange messages without relying on a remote server.

Sahara uses go-libp2p to connect peers and GossipSub to distribute chat messages. Peers use a shared room name:

roomFlag := flag.String("room", "chat-room", "name of chat room to join")

Pass the same room name to every peer that should join the conversation.

Sahara uses multicast DNS (mDNS) to discover other peers on the same local network. Peers must use the same same_string value to find one another.

• cmd/Sahara/main.go - runs the chat node, HTTP API, and terminal client.
• cmd/Sahara/logs.txt - stores received messages.
• internal/p2p/host.go - creates the libp2p host.
• internal/p2p/mdns.go - discovers peers with mDNS.
• internal/p2p/pubsub.go - implements chat rooms with GossipSub.
• cmd/node/main.go - connects directly to a known peer for testing.

The frontend is built with React and provides a basic interface for sending and receiving messages.

From cmd/Sahara:

go run . --port 9000 --same_string xyz --room myroom --nick Avi --enable-http=true

Start another peer in a second terminal:

go run . --port 9001 --same_string xyz --room myroom --nick Friend

Both peers must use the same same_string and room. Only one peer should enable the HTTP server.

From frontend:

npm install
npm run dev

Open the local URL printed by Vite.

Created by Avinash.