bcevents

Sends and listens to events broadcasted on bitcoin transactions. Events can be used to trigger remote actions or send payloads to listeners.

Install

npm install bcevents datapay bsv

Get Started

var Emitter = require('bcevents')
var emitter = new Emitter({ pkey: 'private key for tx fees' })
 
emitter.on('my-event', console.log) // prints { ..., payload: 1234 }
emitter.emit('my-event', 1234, console.log) // prints tx hash

Protocol

Everytime emit() is called, a new transaction is broadcasted with the event and payload inside the OP_RETURN:

• OP_RETURN
  • protocol_id
  • event
  • payload (optional)

The protocol Id should be set when creating emitters otherwise the events will be listened by any agent using the default protocol id.

emitter = new Emitter({ protocol: 'my-unique-protocol-id' })

Encryption

To Encrypt both event and payload on transactions, use the enkKey field. When set, transaction data will be encrypted and decrypted using AES.

var emitter = new Emitter({ encKey: 'my-password' })

To use a different encryption, both encrypt and decrypt function can be set:

var emitter = new Emitter({
  encrypt: (data) => myEncrypt(data),
  decrypt: (data) => myDecrypt(data)
})

Examples

Ping-Pong

// endless ping-pong between two agents
// oracle.js
var emitter = new Emitter({ pkey: 'oracle pkey', protocol: 'pingpongtest' })
emitter.on('ping' () => {
  emitter.emit('pong')
})
 
// client.js
var emitter = new Emitter({ pkey: 'client pkey', protocol: 'pingpongtest' })
emitter.on('pong', () => {
  emitter.emit('ping')
})
emitter.emit('ping').then(console.log)

Whitelisting

var whitelist = [addr1, addr2, ...] // addresses whitelist
 
emitter.on('some-event', (e) {
  if (!whitelist.includes(e.from)) {
    return
  }
  // ...
})