@ndn/node-transport

@ndn/node-transport

This package is part of NDNts, Named Data Networking libraries for the modern web.

This package implements socket transports for Node.js environment.

import { TcpTransport, UdpTransport } from "@ndn/node-transport";

// other imports for examples
import { L3Face, Transport } from "@ndn/l3face";
import { Data, Interest } from "@ndn/packet";
(async () => {
if (process.env.CI) { return; }

Transport Types

There are three transport types:

• UnixTransport: Unix socket, or Windows named pipe.
• TcpTransport: TCP tunnel.
• UdpTransport: UDP tunnel.

// TcpTransport.connect() establishes a TCP tunnel.
// It accepts either host+port or an options object for net.createConnection().
const tcp = await TcpTransport.connect("hobo.cs.arizona.edu", 6363);
await useInL3Face(tcp);

// UdpTransport.connect() establishes a UDP tunnel.
// It supports IPv4 only.
const udp = await UdpTransport.connect({ host: "hobo.cs.arizona.edu" });
await useInL3Face(udp);

})();

How to Use a Transport

Transports are normally used to construct L3Face objects (from @ndn/l3face package). L3Face allows sending and receiving layer-3 packets on a transport. L3Face does not provide Interest-Data matching logic, timeout scheduler, etc. It is more like a forwarder's face.

This section presents the low-level details of how to use a "raw" transport with L3Face class.

async function useInL3Face(transport: Transport) {

// Transports are normally used in a network layer face.
const face = new L3Face(transport);

// We want to know if something goes wrong.
face.on("rxerror", (err) => console.warn(err));
face.on("txerror", (err) => console.warn(err));

await Promise.all([
  face.tx({ async *[Symbol.asyncIterator]() {
    // Send five Interests.
    let seq = Math.floor(Math.random() * 99999999);
    for (let i = 0; i < 5; ++i) {
      await new Promise((r) => setTimeout(r, 50));
      const interest = new Interest(`/ndn/edu/arizona/ping/NDNts/${seq++}`);
      console.log(`${transport} <I ${interest.name}`);
      yield interest;
    }
    await new Promise((r) => setTimeout(r, 200));
  } }),
  (async () => {
    let nData = 0;
    for await (const pkt of face.rx) {
      if (!(pkt instanceof Data)) {
        continue;
      }
      // Print incoming Data name.
      const data: Data = pkt;
      console.log(`${transport} >D ${data.name}`);
      if (++nData >= 5) {
        return;
      }
    }
  })(),
]);

// L3Face and Transport are automatically closed when TX iterable is exhausted.
}