add WebSocket reconnection logic
This commit is contained in:
Nick Krecklow
191
assets/js/socket.js
Normal file
191
assets/js/socket.js
Normal file
@ -0,0 +1,191 @@
|
||||
export class SocketManager {
|
||||
constructor (app) {
|
||||
this._app = app
|
||||
this._hasRequestedHistoryGraph = false
|
||||
this._reconnectDelayBase = 0
|
||||
}
|
||||
|
||||
reset () {
|
||||
this._hasRequestedHistoryGraph = false
|
||||
}
|
||||
|
||||
createWebSocket () {
|
||||
this._webSocket = new WebSocket('ws://' + location.host)
|
||||
|
||||
// The backend will automatically push data once connected
|
||||
this._webSocket.onopen = () => {
|
||||
this._app.caption.set('Loading...')
|
||||
|
||||
// Reset reconnection scheduling since the WebSocket has been established
|
||||
this._reconnectDelayBase = 0
|
||||
}
|
||||
|
||||
this._webSocket.onclose = (event) => {
|
||||
this._app.handleDisconnect()
|
||||
|
||||
// Modify page state to display loading overlay
|
||||
// Code 1006 denotes "Abnormal closure", most likely from the server or client losing connection
|
||||
// See https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent
|
||||
// Treat other codes as active errors (besides connectivity errors) when displaying the message
|
||||
if (event.code === 1006) {
|
||||
this._app.caption.set('Lost connection!')
|
||||
} else {
|
||||
this._app.caption.set('Disconnected due to error.')
|
||||
}
|
||||
|
||||
// Reset modified DOM structures
|
||||
document.getElementById('big-graph-mobile-load-request').style.display = 'none'
|
||||
|
||||
// Schedule socket reconnection attempt
|
||||
this.scheduleReconnect()
|
||||
}
|
||||
|
||||
this._webSocket.onmessage = (message) => {
|
||||
const payload = JSON.parse(message.data)
|
||||
|
||||
switch (payload.message) {
|
||||
case 'init':
|
||||
this._app.setPublicConfig(payload.config)
|
||||
|
||||
// Display the main page component
|
||||
// Called here instead of syncComplete so the DOM can be drawn prior to the graphs being drawn
|
||||
// Otherwise flot.js will cause visual alignment bugs
|
||||
this._app.setPageReady(true)
|
||||
|
||||
// Allow the graphDisplayManager to control whether or not the historical graph is loaded
|
||||
// Defer to isGraphVisible from the publicConfig to understand if the frontend will ever receive a graph payload
|
||||
if (this._app.publicConfig.isGraphVisible) {
|
||||
if (this._app.graphDisplayManager.isVisible) {
|
||||
this.sendHistoryGraphRequest()
|
||||
} else {
|
||||
document.getElementById('big-graph-mobile-load-request').style.display = 'block'
|
||||
}
|
||||
}
|
||||
|
||||
payload.servers.forEach(this._app.addServer)
|
||||
|
||||
if (payload.mojangServices) {
|
||||
this._app.mojangUpdater.updateStatus(payload.mojangServices)
|
||||
}
|
||||
|
||||
// Init payload contains all data needed to render the page
|
||||
// Alert the app it is ready
|
||||
this._app.handleSyncComplete()
|
||||
|
||||
break
|
||||
|
||||
case 'updateServer': {
|
||||
// The backend may send "update" events prior to receiving all "add" events
|
||||
// A server has only been added once it's ServerRegistration is defined
|
||||
// Checking undefined protects from this race condition
|
||||
const serverRegistration = this._app.serverRegistry.getServerRegistration(payload.serverId)
|
||||
|
||||
if (serverRegistration) {
|
||||
serverRegistration.updateServerStatus(payload, false, this._app.publicConfig.minecraftVersions)
|
||||
}
|
||||
|
||||
// Use update payloads to conditionally append data to graph
|
||||
// Skip any incoming updates if the graph is disabled
|
||||
if (payload.updateHistoryGraph && this._app.graphDisplayManager.isVisible) {
|
||||
// Update may not be successful, safely append 0 points
|
||||
const playerCount = payload.result ? payload.result.players.online : 0
|
||||
|
||||
this._app.graphDisplayManager.addGraphPoint(serverRegistration.serverId, payload.timestamp, playerCount)
|
||||
|
||||
// Only redraw the graph if not mutating hidden data
|
||||
if (serverRegistration.isVisible) {
|
||||
this._app.graphDisplayManager.requestRedraw()
|
||||
}
|
||||
}
|
||||
break
|
||||
}
|
||||
|
||||
case 'updateMojangServices': {
|
||||
this._app.mojangUpdater.updateStatus(payload)
|
||||
break
|
||||
}
|
||||
|
||||
case 'historyGraph': {
|
||||
// Consider the graph visible since a payload has been received
|
||||
// This is used for the manual graph load request behavior
|
||||
this._app.graphDisplayManager.isVisible = true
|
||||
|
||||
this._app.graphDisplayManager.buildPlotInstance(payload.graphData)
|
||||
|
||||
// Build checkbox elements for graph controls
|
||||
let lastRowCounter = 0
|
||||
let controlsHTML = ''
|
||||
|
||||
this._app.serverRegistry.getServerRegistrations()
|
||||
.map(serverRegistration => serverRegistration.data.name)
|
||||
.sort()
|
||||
.forEach(serverName => {
|
||||
const serverRegistration = this._app.serverRegistry.getServerRegistration(serverName)
|
||||
|
||||
controlsHTML += '<td>' +
|
||||
'<input type="checkbox" class="graph-control" minetrack-server-id="' + serverRegistration.serverId + '" ' + (serverRegistration.isVisible ? 'checked' : '') + '>' +
|
||||
' ' + serverName +
|
||||
'</input></td>'
|
||||
|
||||
// Occasionally break table rows using a magic number
|
||||
if (++lastRowCounter % 6 === 0) {
|
||||
controlsHTML += '</tr><tr>'
|
||||
}
|
||||
})
|
||||
|
||||
// Apply generated HTML and show controls
|
||||
document.getElementById('big-graph-checkboxes').innerHTML = '<table><tr>' +
|
||||
controlsHTML +
|
||||
'</tr></table>'
|
||||
|
||||
document.getElementById('big-graph-controls').style.display = 'block'
|
||||
|
||||
// Bind click event for updating graph data
|
||||
this._app.graphDisplayManager.initEventListeners()
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
scheduleReconnect () {
|
||||
// Release any active WebSocket references
|
||||
this._webSocket = undefined
|
||||
|
||||
this._reconnectDelayBase++
|
||||
|
||||
// Exponential backoff for reconnection attempts
|
||||
// Clamp ceiling value to 30 seconds
|
||||
this._reconnectDelaySeconds = Math.min((this._reconnectDelayBase * this._reconnectDelayBase), 30)
|
||||
|
||||
const reconnectInterval = setInterval(() => {
|
||||
this._reconnectDelaySeconds--
|
||||
|
||||
if (this._reconnectDelaySeconds === 0) {
|
||||
// Explicitly clear interval, this avoids race conditions
|
||||
// #clearInterval first to avoid potential errors causing pre-mature returns
|
||||
clearInterval(reconnectInterval)
|
||||
|
||||
// Update displayed text
|
||||
this._app.caption.set('Reconnecting...')
|
||||
|
||||
// Attempt reconnection
|
||||
// Only attempt when reconnectDelaySeconds === 0 and not <= 0, otherwise multiple attempts may be started
|
||||
this.createWebSocket()
|
||||
} else if (this._reconnectDelaySeconds > 0) {
|
||||
// Update displayed text
|
||||
this._app.caption.set('Reconnecting in ' + this._reconnectDelaySeconds + 's...')
|
||||
}
|
||||
}, 1000)
|
||||
}
|
||||
|
||||
sendHistoryGraphRequest () {
|
||||
if (!this._hasRequestedHistoryGraph) {
|
||||
this._hasRequestedHistoryGraph = true
|
||||
|
||||
// Send request as a plain text string to avoid the server needing to parse JSON
|
||||
// This is mostly to simplify the backend server's need for error handling
|
||||
this._webSocket.send('requestHistoryGraph')
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user