Hypercore-substream NPM

hypercore-substream

A hypercore extension that allows you to create and tunnel virtual streams over a replication channel.

Usage

const hypercore = require('hypercore')
const SubstreamRouter = require('hypercore-substream')

// Setup two feeds and two vnets
const localFeed = hypercore(RAM)
const vnetA = localFeed.registerExtension(new SubstreamRouter())


const remoteFeed = hypercore(RAM, localFeed.key)
const vnetB = remoteFeed.registerExtension(new SubstreamRouter())

// Start replication
const replicationStream = localFeed.replicate(true, { live: true })
replicationStream
  .pipe(remoteFeed.replicate(false, { live: true }))
  .pipe(replicationStream)


// Open a substream by specifying identical namespace
const localSub = vnetA.open('nameofsub')
const remoteSub = vnetB.open('nameofsub')

remoteSub.on('data', chunk => console.log('Recv data:', chunk.toString())

// Connect event signals that both ends are ready
virtual.once('connect', () => {
  localSub.write('Hello Underworld!')
})

Should print

> Recv data: Hello Underworld

API

class: `SubstreamRouter`

const vnet = core.registerExtension(new SubstreamRouter(opts = {}))

The router is responsible for creating new and multiplexing existing substreams.

In order to be usable it needs to be passed through a registerExtension() method by something that supports hypercore extensions.

Handlers

when initializing a new SubstreamRouter you can optionally pass the following handlers:

opts.onsubdiscovery: function (namespace, peer) Listen for new substreams
opts.onsubconnect: function(sub) When a substream becomes established
opts.onsubclose: function(sub) When a substream is closed

`vnet.open(namespace, opts = {}, callback)`

Creates new substreams

Arguments

namespace a string or buffer identifying the channel.
opts Object
- opts.timeout Number signifying time to wait before HandshakeTimeoutError' is emitted
callback optional function (error, virtualStream) If provided, will be called when stream becomes either active or fails to initialize.

Returns

a full-duplex node stream.

`Substream` event `connected`

Emitted when a connection has been established on both peer's ends. Note: the sub stream is initialized in corked and paused state. It is resumed and uncorked after the connected event has been fired.