Status Polling Queue

status_polling_queue.js.coffee

class @StatusPollingQueue
  constructor: () ->
    @queue = []
    @frequency = 3 * 1000 # 3 seconds
    @interval = undefined
    @failureLimit = 50

  add: (url, options = {}) ->
    return unless url

    request = {
      url: url,
      params: {},
      failures: 0
    }

    if options.params
      request.params = options.params

    if options.success
      request.success = options.success

    @queue.push(request)

  processQueue: () ->
    for request in @queue
      error = (xhr, status, error) =>
        request.failures += 1
        if request.failures == @failureLimit
          @queue.splice(@queue.indexOf(request), 1)
          return

      success = (response, status, xhr) =>
        request.success?.call(this, response)
        @queue.splice(@queue.indexOf(request), 1)
        return

      promise = $.ajax({
        url:     request.url,
        data:    request.params,
        error:   error,
        success: success,
      })

  polling: () ->
    @processQueue()

    unless @interval
      @interval = setInterval @polling.bind(@), @frequency

    if @queue.length == 0
      clearInterval @interval
      @interval = undefined