JavaScript library for the Metaverse Blockchain P2P network

Install

Install base package

npm install metaversejs-p2p

Install a transport plugin

npm install metaversejs-transport-tcpip

Usage

Please see the examples directory for more complete examples.

Pool

Create a pool

const { Pool } = require('metaversejs-p2p')
const { P2PTransporterTCPIP } = require('metaversejs-transport-tcpip')

const pool = new Pool({}, new P2PTransporterTCPIP()).connect()

Receive Messages

To access the incomming messages you can subscribe to $ingress

pool.$ingress.subscribe(message => {
    console.log('<<-- received from', message.peer.host, message.command, message.payload)
})

Get Pool Actions

Pool actions are available on the $egress subject

pool.$egress.subscribe(message=>{
    console.log('-->>', message.command)
})

Number Of Connected Peers

const q = pool.numberConnected()

Peer

Connect to peer

It will automatically send the version message and respond with verack if version messages are received.

const { Peer } = require('metaversejs-p2p')
const { P2PTransportTCPIP } = require('metaversejs-transport-tcpip')

const transport = new P2PTransportTCPIP({host: '198.199.84.199', port: 5251})
const peer = new Peer({
    transport,
    host: '198.199.84.199',
    port: 5251,
    relay: true,
}).connect()

Peer Status

The current status is avalable as a variable.

const status = peer.currentStatus

You can also subscibe to status changes on $status

peer.$status.subscribe(status=>console.log('peer status:', status))

Send Messages

The sendMessage function can send messages. The following example will send a Ping.

const { PingMessage } = require('metaversejs-p2p')

peer.sendMessage(new PingMessage())

You can access all outgoing messages by subscribing to $egress

peer.$egress.subscribe(message => {
    console.log('-->> egress to',peer.host, message.command, message.payload)
})

Receive

The received messages are available on the $ingress subject

peer.$ingress.subscribe(message => {
    console.log('<<-- ingress from', peer.host, message.command, message.payload)
})

Messages

Messages are transferred as binary data.

length	content
4 byte	NETWORK_MAGIC	mainnet value: 4d56534d
12 byte	COMMAND	ascii encoded command
4 byte	PAYLOAD LENGTH	Int32LE encoded
4 byte	PAYLOAD CHECKSUM	first 4 bytes of sha256sha256(payload)
rest	PAYLOAD

To make message handling easier there are classes for the supported messages.

Ping

To keep a connection open you should send ping messages to the other peer.

const { PingMessage } = require('metaversejs-p2p')
const message = new PingMessage({
  nonce?: Buffer // if not defined a random nonce will be generated
})

Pong

Send pong messages as a response of another peer's ping message.

const { PongMessage } = require('metaversejs-p2p')
const message = new PongMessage({
  nonce: Buffer // must be the nonce of the previous ping received from the peer
})

Verack

After receiving a version message from another peer you need to answer with a verack message.

const { VerackMessage } = require('metaversejs-p2p')
const message = new VerackMessage()

Version

The version message is the first message of a peer connecting to another peer. The version message contains information about both peers and the own services and state.

const { VersionkMessage } = require('metaversejs-p2p')
const message = new VersionMessage({
  relay: true, // receive unconfirmed transactions
  version: 70012, // version
  services: 1, // services your node provides
  startHeight: 3514519, // your current bestblockheight
  subversion: "/metaverse:0.9.0/", // subversion name
  nonce?: Buffer.from('fa4eba0d6e8b659e', 'hex'), // optional - default: random buffer
  timestamp: new Date("2020-03-29T19:11:25.000Z"), // optional - default: current timestamp
  addrMe: {
    ip: { // works without providing real ip but nodes should try to provide real ip
      v4: '95.116.169.107', // your ipv4 address
      v6: '0000:0000:0000:0000:0000:ffff:5f74:a96b' // your ipv6 address
    },
    port: 58616, // port number
    services: 1 // provided services
  },
  addrYou: { // similar to addMe
    ip: {
      v4: '198.199.84.199',
      v6: '0000:0000:0000:0000:0000:ffff:c6c7:54c7'
    },
    port: 5251,
    services: 0
  },
})

Inventory

Peers exchange information about each others transactions and blocks via inventory messages. The messages only contain the hashes of the transactions and blocks.

const { InventoryMessage, InventoryTx, InventoryBlock, } = require('metaversejs-p2p')

// can contain transactions
const message = new InventoryMessage([
    new InventoryTx('3550047ed23a5e68c5fca0f6cb1ddd0df69998c73e0318dc9c57adb376784849'),
    new InventoryTx('bfee531c274585ca3e222bc39e0fbad94b8e1a9b2cda09892d5e27d02caa3db9'),
])

// or blocks
const message = new InventoryMessage([
    new InventoryBlock('a2e5e162a0b6d0faeb71ced40836b6fdf3715e4950d7ac9dd02bd80daea33de7'),
    new InventoryBlock('8f3cc621407f2b749bb807d855db6c0787a543d6956148684c0804279c35e8ce'),
  ])

GetAddr

Ask the other peer for a list of other connected peers.

const { GetAddrMessage } = require('metaversejs-p2p')
const message = new GetAddrMessage()

MemPool

Ask the other peer to send the inventory of the mempool.

const { MemPoolMessage } = require('metaversejs-p2p')
const message = new MemPoolMessage()

Addr

Answer to the GetAddr message. It contains a list of addresses of the connected peers.

const { AddrMessage } = require('metaversejs-p2p')
const message = new AddrMessage({
  addresses: [
    {
      timestamp: new Date(),
      services: 1, // list of services that peer provides
      ip: {
        v6?: '0000:0000:0000:0000:0000:ffff:1b25:4427',
        v4?: '27.37.68.39',
      },
      port: 5251
    },
    // ... can and in most cases will contain more addresses
  ]
})

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.