125 lines
3.5 KiB
JavaScript
125 lines
3.5 KiB
JavaScript
import logger from "./logger"
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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
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// revival reconnections if things go astray. Internal class, not intended for direct user manipulation.
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const now = () => new Date().getTime()
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const secondsSince = time => (now() - time) / 1000
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class ConnectionMonitor {
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constructor(connection) {
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this.visibilityDidChange = this.visibilityDidChange.bind(this)
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this.connection = connection
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this.reconnectAttempts = 0
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}
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start() {
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if (!this.isRunning()) {
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this.startedAt = now()
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delete this.stoppedAt
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this.startPolling()
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addEventListener("visibilitychange", this.visibilityDidChange)
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logger.log(`ConnectionMonitor started. stale threshold = ${this.constructor.staleThreshold} s`)
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}
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}
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stop() {
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if (this.isRunning()) {
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this.stoppedAt = now()
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this.stopPolling()
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removeEventListener("visibilitychange", this.visibilityDidChange)
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logger.log("ConnectionMonitor stopped")
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}
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}
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isRunning() {
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return this.startedAt && !this.stoppedAt
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}
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recordMessage() {
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this.pingedAt = now()
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}
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recordConnect() {
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this.reconnectAttempts = 0
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delete this.disconnectedAt
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logger.log("ConnectionMonitor recorded connect")
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}
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recordDisconnect() {
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this.disconnectedAt = now()
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logger.log("ConnectionMonitor recorded disconnect")
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}
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// Private
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startPolling() {
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this.stopPolling()
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this.poll()
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}
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stopPolling() {
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clearTimeout(this.pollTimeout)
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}
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poll() {
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this.pollTimeout = setTimeout(() => {
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this.reconnectIfStale()
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this.poll()
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}
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, this.getPollInterval())
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}
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getPollInterval() {
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const { staleThreshold, reconnectionBackoffRate } = this.constructor
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const backoff = Math.pow(1 + reconnectionBackoffRate, Math.min(this.reconnectAttempts, 10))
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const jitterMax = this.reconnectAttempts === 0 ? 1.0 : reconnectionBackoffRate
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const jitter = jitterMax * Math.random()
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return staleThreshold * 1000 * backoff * (1 + jitter)
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}
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reconnectIfStale() {
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if (this.connectionIsStale()) {
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logger.log(`ConnectionMonitor detected stale connection. reconnectAttempts = ${this.reconnectAttempts}, time stale = ${secondsSince(this.refreshedAt)} s, stale threshold = ${this.constructor.staleThreshold} s`)
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this.reconnectAttempts++
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if (this.disconnectedRecently()) {
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logger.log(`ConnectionMonitor skipping reopening recent disconnect. time disconnected = ${secondsSince(this.disconnectedAt)} s`)
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} else {
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logger.log("ConnectionMonitor reopening")
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this.connection.reopen()
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}
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}
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}
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get refreshedAt() {
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return this.pingedAt ? this.pingedAt : this.startedAt
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}
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connectionIsStale() {
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return secondsSince(this.refreshedAt) > this.constructor.staleThreshold
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}
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disconnectedRecently() {
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return this.disconnectedAt && (secondsSince(this.disconnectedAt) < this.constructor.staleThreshold)
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}
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visibilityDidChange() {
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if (document.visibilityState === "visible") {
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setTimeout(() => {
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if (this.connectionIsStale() || !this.connection.isOpen()) {
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logger.log(`ConnectionMonitor reopening stale connection on visibilitychange. visibilityState = ${document.visibilityState}`)
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this.connection.reopen()
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}
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}
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, 200)
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}
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}
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}
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ConnectionMonitor.staleThreshold = 6 // Server::Connections::BEAT_INTERVAL * 2 (missed two pings)
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ConnectionMonitor.reconnectionBackoffRate = 0.15
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export default ConnectionMonitor
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