daemon.js

'use strict'

var EventEmitter = require('events')
var electronEval = require('electron-eval')
var watt = require('watt')

class Daemon extends EventEmitter {
  constructor (opts) {
    super()
    this.daemon = electronEval(opts)
    watt.wrapAll(this, 'navigate', 'eval')

    var openDevTools = opts.showDevTools ? 'wv.openDevTools()' : ''

    this.daemon.eval(`
      var wv = window.webview = document.createElement('webview')
      wv.setAttribute('preload', '${require.resolve('./daemonPreload.js')}')
      wv.setAttribute('style', 'position: absolute; top: 0; right: 0; bottom: 0; left: 0;')
      wv.setAttribute('disablewebsecurity', '1')
      ${opts.userAgent ? `wv.setAttribute('useragent', '${opts.userAgent}')` : ''}
      document.body.appendChild(wv)
      wv.addEventListener('dom-ready', function () {
        ${openDevTools}
      })
      wv.addEventListener('did-finish-load', function () {
        window.send('did-finish-load')
      })
      window.webview.addEventListener('ipc-message', function (e) {
        window.send(e.channel, e.args[0])
      })
    `, this.error.bind(this))
  }

  error (err) {
    if (err) this.emit('error', err)
  }

  * navigate (url, next) {
    this.daemon.eval(`window.webview.setAttribute('src', '${url}')`)
    yield this.daemon.once('did-finish-load', next)
  }

  * eval (code, next) {
    var reqId = Math.random().toString(36)
    this.daemon.eval(`
      window.webview.send('eval', ${JSON.stringify(code)}, ${JSON.stringify(reqId)})
    `)
    var timeout = setTimeout(() => {
      this.eval(code, next)
    }, 5000)
    var res = yield this.daemon.once(reqId, next.arg(0))
    clearTimeout(timeout)
    if (res[0]) throw res[0]
    return res[1]
  }
}

module.exports = Daemon