Testing out substack's "ACK' functionality for hypercore!

Readme.md

testing out ACKs in hypercore

Using substack's 'ack' branch of hypercore, you can set an 'ack' flag to 'true' when creating a hypercore replication feed, and you'll be able to tell, for any given hypercore log block you append to a hypercore feed, whether it has been received by a peer.

As a test, I ran "node testsend.js" below ... which generates a public key [KEY], and allows me to type messages into the terminal 'live'. In another directory, I ran "node testreceive.js [KEY]" in order receive those messages ...

Here's what it looked like on the 'send' side as I typed in new messages (I'm including a snippet after I'd already been testing a while) ...

2019-07-06T23:03:14.746Z> bubbles
2018-11-05T14:26:000Z> hello world
9
test another
2019-07-06T23:04:12.726Z> test another
10
hear hear!
2019-07-06T23:04:27.795Z> hear hear!
11
yay it's working!
2019-07-06T23:05:08.945Z> yay it's working!
12

You can see that the hyperlog replication feed block numbers ('9', '10', '11', '12') are being logged to the console as I send the messages, indicating that a peer has received those blocks as I append them.

COOL.

The code I used for 'testsend' and 'testreceive' are below.

testreceive.js

var discovery = require('discovery-swarm')
var hypercore = require('hypercore')
var pump = require('pump')

if( process.argv.length != 3 ) {
  console.log( "Usage" )
  console.log( "node dump.js cabalkey")
  process.exit(1)
 }

// Strip out the awesome
const key =  process.argv[2].replace('cabal://', '').replace('cbl://', '').replace('dat://', '').replace(/\//g, '')
//const key = 'c4a2a72e2df7867a4d9d0eeaf98e2930d6c3948f0c9087c34a09a2bcfbd69615';

console.log( "Connecting to", key)

// var feed = hypercore('./single-chat-feed-clone', '{paste the public key from the prev exercise}', {
var feed = hypercore('./received', key, {
  valueEncoding: 'json'
})

feed.createReadStream({ live: true})
  .on('data', function (data) {
    console.log(data)
  })
 
var swarm = discovery()

feed.ready(function () {
  // we use the discovery as the topic
  swarm.join(feed.discoveryKey)
  swarm.on('connection', function (connection) {
    console.log('(New peer connected!)')
    
    // We use the pump module instead of stream.pipe(otherStream)
    // as it does stream error handling, so we do not have to do that
    // manually.
    var stream=feed.replicate({ live:true,ack:true})
    // See below for more detail on how this work.
    pump(connection, stream, connection)
    
  })
})

testsend.js

var discovery = require('discovery-swarm')
var hypercore = require('hypercore')
var pump = require('pump')

var feed = hypercore('sending', {
  valueEncoding: 'json'
})

feed.append({ 
  type: 'chat-message',
  nickname: 'cat-lover',
  text: 'hello world', 
  timestamp: '2018-11-05T14:26:000Z' // new Date().toISOString()
}, function (err, seq) {
  if (err) throw err
  console.log('Data was appended as entry #' + seq)
})

// feed.get(0, function (err, msg) {
//   console.log('msg', msg)
// })

process.stdin.on('data', function (data) {
  feed.append({
    type: 'chat-message',
    nickname: 'cat-lover',
    text: data.toString(),
    timestamp: new Date().toISOString()
  })
})

feed.createReadStream({live:true})
  .on('data', function (data) {
    console.log(data.timestamp + '> ' + data.text.trim())
  })

var swarm = discovery()

feed.ready(function () {
  // we use the discovery as the topic
  swarm.join(feed.discoveryKey)
  swarm.on('connection', function (connection) {
    console.log('(New peer connected!)')
    
    // We use the pump module instead of stream.pipe(otherStream)
    // as it does stream error handling, so we do not have to do that
    // manually.
   var stream=feed.replicate({ live:true,ack:true})
    // See below for more detail on how this work.
   // pump(connection, feed.replicate({ live: true, ack:true}), connection)
    pump(connection, stream, connection)
    stream.on('ack', function (block) {
  console.log(block) // block is a sequence number
})

  })
  console.log('public key:', feed.key.toString('hex'))
})