P2P Relay Server

Host-Client Connections Through Relays

Traditional peer-to-peer (P2P) gaming can run into hurdles with NAT traversal, firewalls, and devices lacking public IP addresses. A small relay service helps these peers discover one another and connect in real time. We can combine this with a host-client architecture such that the server host then simply pipes messages between participants, making it easy to build real-time game lobbies or collaborative apps.

Forking Local First Relay

We start with an open-source relay repository, Local First Relay, that already performs discovery and connection requests. We adapt the code for a host to open a game session or "channel," and for peers (clients) to join that same channel. Once a matching pair of connection requests is received, the relay server simply pairs the sockets and carries data from one peer to the other, letting them communicate directly via WebSockets. The server keeps overhead low by avoiding heavy data persistence, storing only ephemeral user and channel details.

Example

Below is a snapshot of how you might integrate the server with your own game logic:

// Host perspective
import { Client } from '@localfirst/relay-client'
// ...
const host = new Client({ userName: 'host-uuid', url: 'wss://myrelay.example.com' })
host.join('spaceRacer-lobby') // open the 'spaceRacer-lobby' channel

// Client perspective
const client = new Client({ userName: 'playerJoe', url: 'wss://myrelay.example.com' })
client.join('spaceRacer-lobby') // also joins the same channel

Once both are connected, each receives an introduction message about the other. Then they each open a direct "connection" endpoint, piping the data so that the host and client can exchange game events in real time. For encryption or authentication—you can verify the identities of connecting peers and encrypting the data they send via your own hashing or encryption methods.

Future

Although the relay server is only a message-forwarder, it's possible to integrate a plugin layer to handle ephemeral session states or server-side analytics, which lets us keep track of how many lobbies and what metadata (game type, player nicknames, etc.) are most popular. We may also add minimal security upgrades like verifying channel ownership or restricting the creation of new channels to certain users.