CommonView#

A minimal peer-to-peer web app. Everyone who opens the page becomes a peer in a single shared network. Peers discover each other over nostr relays and communicate over WebRTC (full mesh). It borrows the discovery/signaling approach from trystero's nostr strategy, but only the parts needed here.

For now the shared state is just a counter — a stand-in for the richer state (including binary blobs) planned later.

How it works#

• Identity (src/p2p/identity.ts) — each peer has a secp256k1 / BIP340 (schnorr) keypair, persisted in localStorage. The x-only public key is the peer ID. The same key signs every nostr event and every application message.
• Discovery/signaling (src/p2p/nostr.ts) — peers announce on a hashed "root topic" and listen there to find each other. WebRTC offers/answers/ICE are delivered to a per-peer topic. Only ephemeral nostr event kinds are used, so nothing is stored on relays.
• WebRTC (src/p2p/peer.ts) — a trimmed data-channel wrapper. Glare is avoided by letting only the peer with the smaller ID make the offer.
• Mesh + state (src/p2p/network.ts) — every peer connects to every other peer. On connect, peers exchange a self-reported timestamp of when they joined. The oldest peer (earliest timestamp, ties broken by ID) is the central peer and holds the authoritative state.
  • Commands (+/−) are sent to the central peer, which applies them and broadcasts the new state to everyone.
  • Every message is a signed envelope ({data, from, sig}) and is verified on receipt.
  • If the central peer leaves, the next-oldest peer becomes central and its last-known state becomes the source of truth.
  • A page reload, or losing and regaining the network, is a reconnect (new timestamp). State is never persisted, so once all peers leave it resets.

Run#

npm install
npm run dev

Open the printed URL in two different browsers or profiles (two tabs in the same profile share the same localStorage key, so they'd be the same peer). Watch the roster populate and the counter stay in sync.