Reactive interface

[jcheng5]

ws <- reactiveWebsocket("ws://echo.websockets.org")
observe({
  print(ws()) # Reactive read
})

[avsdev-cw]

For those interested, an anti-pattern for this is:

  newWSMessage <- reactiveVal()

  observeEvent(newWSMessage(), {
    msg <- newWSMessage()$msg
    # handle message in a reactive way
  }, ignoreInit = TRUE)

  ws$onMessage(function(event) {
    newWSMessage(list(
      msg = jsonlite::fromJSON(event$data),
      random = stats::runif(1)
    ))
  })

Notes:

• I'm using JSON frames for my socket data, you may wish to change the jsonlite::fromJSON() call to something else
• I'm using stats::runif() to generate a unique value in order to ensure repeated messages are handled and not filtered by shiny
• This assumes that only 1 message is read from the websocket per reactive event cycle (I do not know if this is always the case... I suspect not)