Simple protocol for exchanging JSON commands.

Each message transferred by a web socket is a JSON with two attributes

 {command: {string}, params: {*}}

Inside WebSocket threads, the class can be used to subscribe to messages arrived from clients and assign handlers to it (if you need to receive web socket messages in server):

  const WebSockets = require('@unitybase/ub/modules/web-sockets')
  var wsNotifier = WebSockets.getWSNotifier()
  if (wsNotifier) {
    console.debug('Start subscribing to wsNotifier tsts_* events')
    wsNotifier.on('tst_echo', function (connection, params) {
      connection.send({
        command: 'tst_message',
        params: {from: connection.session.userID, message: params}
      })
    })
  }

Inside http threads can be used as follows:

  const WebSockets = require('@unitybase/ub/modules/web-sockets')
  function notifyAboutNewRecord(rowID){
    let notifier = WebSockets.getWSNotifier()
    if (notifier) {
      //send message to ALL connected sessions
      notifier.broadcast('ub_entityModification', {action: 'insert', ID: rowID})

      //Send to specific user
      var userSessions = notifier.getUserSessions(Session.userID)
      userSessions.forEach(function(sessionID){
          notifier.sendCommand('test_command', sessionID, {action: 'inserted', ID: rowID})
      })
    }
  }

If WebSocket support are enabled in server config then instance of this protocol is accessible via UB.wsNotifier

# new JsonMessagesProtocol (namedAs:  string)

# broadcast (command:  string, params:  *) instance

# getUserSessions (userID:  number) → Array.<number> instance

# sendCommand (command:  string, recipient:  number, params:  *) → boolean instance