web-udp

web-udp is a library used to establish UDP connections in Node/browser environments. The key goal of this project to provide a small, stable API that anyone can use to work with real-time data on the Web.

The library is currently implemented as an abstraction on top of unreliable RTCDataChannels. Since WebRTC is a dependency, a signaling server is included with the package to facilitate connections between clients. Client/server connections are available with the help of the wrtc package.

API

Signal<T>#subscribe(subscriber: (data: *) => *)
Signal<T>#unsubscribe(subscriber: (data: *) => *)
 
Client(options?: { url?: string })
Client#connect(to?: string = "__MASTER__", options?: { binaryType?: "arraybuffer" | "blob" }): Promise<Connection>
Client#route(): Promise<string>
Client#connections: Signal<Connection>
 
Connection#send(message: *): void
Connection#close(): void
Connection#closed: Signal<>
Connection#errors: Signal<{ err: string }>
Connection#messages: Signal<*>
 
// Node
Server({ server: http.Server })
Server#client(): Client
Server#connections: Signal<Connection>

Examples

Client/Server

// client.js
 
import { Client } from "web-udp";
 
async function main() {
  const client = new Client();
  const { send, messages } = await client.connect();
 
  send("ping");
  messages.subscribe(console.log);
}

// server.js
 
const server = require("http").createServer();
const { Server } = require("web-udp");
 
const udp = new Server({ server });
 
udp.connections.subscribe(
  connection => {
    const { send, messages, errors, closed } = connection;
 
    messages.subscribe(
      message => {
        if (message === "ping") {
          send("pong");
        }
      }
    );
 
    closed.subscribe(
      () => console.log("A connection closed.")
    );
 
    errors.subscribe(
      err => console.log(err)
    );
  }
);
 
server.listen(8000);

P2P

// client.js
 
async function main() {
  const left = new Client();
  const right = new Client();
  const route = await left.route();
  const connection = await right.connect(route);
 
  left.connections.subscribe(
    ({ messages }) => messages.subscribe(console.log)
  );
 
  connection.send("HELLO");
}

// server.js
 
const server = require("http").createServer();
const { Server } = require("web-udp");
 
Server({ server });
 
server.listen(8000);