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# Responsible for ensuring the cable connection is in good health by validating the heartbeat pings sent from the server, and attempting
# revival reconnections if things go astray. Internal class, not intended for direct user manipulation.
class ActionCable.ConnectionMonitor
@pollInterval:
min: 3
max: 30
@staleThreshold: 6 # Server::Connections::BEAT_INTERVAL * 2 (missed two pings)
identifier: ActionCable.INTERNAL.identifiers.ping
constructor: (@consumer) ->
@consumer.subscriptions.add(this)
@start()
connected: ->
@reset()
@pingedAt = now()
delete @disconnectedAt
ActionCable.log("ConnectionMonitor connected")
disconnected: ->
@disconnectedAt = now()
received: ->
@pingedAt = now()
reset: ->
@reconnectAttempts = 0
start: ->
@reset()
delete @stoppedAt
@startedAt = now()
@poll()
document.addEventListener("visibilitychange", @visibilityDidChange)
ActionCable.log("ConnectionMonitor started, pollInterval is #{@getInterval()}ms")
stop: ->
@stoppedAt = now()
document.removeEventListener("visibilitychange", @visibilityDidChange)
ActionCable.log("ConnectionMonitor stopped")
poll: ->
setTimeout =>
unless @stoppedAt
@reconnectIfStale()
@poll()
, @getInterval()
getInterval: ->
{min, max} = @constructor.pollInterval
interval = 5 * Math.log(@reconnectAttempts + 1)
clamp(interval, min, max) * 1000
reconnectIfStale: ->
if @connectionIsStale()
ActionCable.log("ConnectionMonitor detected stale connection, reconnectAttempts = #{@reconnectAttempts}")
@reconnectAttempts++
if @disconnectedRecently()
ActionCable.log("ConnectionMonitor skipping reopen because recently disconnected at #{@disconnectedAt}")
else
ActionCable.log("ConnectionMonitor reopening")
@consumer.connection.reopen()
connectionIsStale: ->
secondsSince(@pingedAt ? @startedAt) > @constructor.staleThreshold
disconnectedRecently: ->
@disconnectedAt and secondsSince(@disconnectedAt) < @constructor.staleThreshold
visibilityDidChange: =>
if document.visibilityState is "visible"
setTimeout =>
if @connectionIsStale() or not @consumer.connection.isOpen()
ActionCable.log("ConnectionMonitor reopening stale connection after visibilitychange to #{document.visibilityState}")
@consumer.connection.reopen()
, 200
now = ->
new Date().getTime()
secondsSince = (time) ->
(now() - time) / 1000
clamp = (number, min, max) ->
Math.max(min, Math.min(max, number))
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