notes.md

Demo 1.

In this example, we run a simple Express server which listens for a message. When it recieves this message, it publishes a message to MAM, and returns the root of the channel.

We then have a subscriber, which takes the root given to us from the output of the first message. We set it using a simple environment variable. The subscriber looks for a message, and when it finds the message, it recursively calls Mam.fetch on the next root. Since the next root doesn't change when there are no new messages, we can just keep calling this recursively until we get a new message.

This is some simply and kinda nasty programming, but it demonstrates a simple pub/sub with MAM.

Next up, I think we're going to look at applying some security to this, to make sure nobody looks in on our precious messages.

publisher.js

declare var require: any

const Mam = require('../lib/mam.node.js');
const IOTA = require('iota.lib.js');
const express = require('express');

var iota = new IOTA({ provider: `https://testnet140.tangle.works` })
const app = express();

// Initialise MAM State - PUBLIC
var mamState = Mam.init(iota)

// Publish to tangle
const publish = async (packet: any) => {
  // Create MAM Payload - STRING OF TRYTES
  var message = Mam.create(mamState, packet)
  // Save new mamState
  mamState = message.state
  // Attach the payload.
  console.log('Root: ', message.root)
  console.log('Address: ', message.address)
  await Mam.attach(message.payload, message.address)
  
  return message.root;
}

app.get('/', async (req: any, res: any) => {
  const { message } = req.query;
  console.log("publishing message:", message);
  const root = await publish(message);

  res.json({message, root});
});

app.listen(3000, () => console.log('Publisher listening on port 3000!'));

then, we curl curl "localhost:3000?message=hello"