electrum-client-browser/src/socket/socket_client.js

Electrum protocol client for node.js and browser

const EventEmitter = require('events').EventEmitter
const util = require('./util')

const WebSocketClient = require('./socket_client_ws')

class SocketClient {
  constructor(host, port, protocol, options) {
    this.id = 0
    this.host = host
    this.port = port
    this.protocol = protocol
    this.options = options
    this.status = 0
    this.callback_message_queue = {}
    this.events = new EventEmitter()
    this.mp = new util.MessageParser((body, n) => {
      this.onMessage(body, n)
    })

    switch (protocol) {
      case 'ws':
      case 'wss':
        this.client = new WebSocketClient(this, host, port, protocol, options)
        break
      default:
        throw new Error(`invalid protocol: [${protocol}]`)
    }
  }

  async connect() {
    if (this.status === 1) {
      return Promise.resolve()
    }

    this.status = 1
    return this.client.connect()
  }

  close(cb = undefined) {
    if (cb) {
      cb(this.status)
    }
    if (this.status === 0) {
      return
    }

    this.client.close()
    this.status = 0
  }

  response(msg) {
    const callback = this.callback_message_queue[msg.id]

    if (callback) {
      delete this.callback_message_queue[msg.id]
      if (msg.error) {
        callback(msg.error.message)
      } else {
        callback(null, msg.result)
      }
    } else {
      console.log('Can\'t get callback')
    }
  }

  onMessage(body, n) {
    const msg = JSON.parse(body)
    if (msg instanceof Array) {
      // don't support batch request
    } else {
      if (msg.id !== void 0) {
        this.response(msg)
      } else {
        this.subscribe.emit(msg.method, msg.params)
      }
    }
  }

  onConnect() {}

  onClose(event) {
    this.status = 0
    Object.keys(this.callback_message_queue).forEach((key) => {
      this.callback_message_queue[key](new Error('close connect'))
      delete this.callback_message_queue[key]
    })
  }

  onRecv(chunk) {
    this.mp.run(chunk)
  }

  onEnd(error) {
    console.log(`onEnd: [${error}]`)
  }

  onError(error) {
    console.log(`onError: [${error}]`)
  }
}

module.exports = SocketClient