489 lines
14 KiB
JavaScript
489 lines
14 KiB
JavaScript
/**
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* @module provider/websocket
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*/
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/* eslint-env browser */
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import * as Y from 'yjs' // eslint-disable-line
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import * as bc from 'lib0/broadcastchannel'
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import * as time from 'lib0/time'
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import * as encoding from 'lib0/encoding'
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import * as decoding from 'lib0/decoding'
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import * as syncProtocol from 'y-protocols/sync'
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import * as authProtocol from 'y-protocols/auth'
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import * as awarenessProtocol from 'y-protocols/awareness'
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import { Observable } from 'lib0/observable'
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import * as math from 'lib0/math'
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import * as url from 'lib0/url'
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export const messageSync = 0
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export const messageQueryAwareness = 3
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export const messageAwareness = 1
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export const messageAuth = 2
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/**
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* encoder, decoder, provider, emitSynced, messageType
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* @type {Array<function(encoding.Encoder, decoding.Decoder, WebsocketProvider, boolean, number):void>}
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*/
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const messageHandlers = []
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messageHandlers[messageSync] = (
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encoder,
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decoder,
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provider,
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emitSynced,
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_messageType
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) => {
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encoding.writeVarUint(encoder, messageSync)
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const syncMessageType = syncProtocol.readSyncMessage(
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decoder,
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encoder,
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provider.doc,
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provider
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)
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if (
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emitSynced && syncMessageType === syncProtocol.messageYjsSyncStep2 &&
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!provider.synced
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) {
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provider.synced = true
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}
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}
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messageHandlers[messageQueryAwareness] = (
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encoder,
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_decoder,
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provider,
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_emitSynced,
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_messageType
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) => {
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encoding.writeVarUint(encoder, messageAwareness)
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encoding.writeVarUint8Array(
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encoder,
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awarenessProtocol.encodeAwarenessUpdate(
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provider.awareness,
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Array.from(provider.awareness.getStates().keys())
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)
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)
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}
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messageHandlers[messageAwareness] = (
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_encoder,
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decoder,
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provider,
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_emitSynced,
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_messageType
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) => {
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awarenessProtocol.applyAwarenessUpdate(
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provider.awareness,
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decoding.readVarUint8Array(decoder),
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provider
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)
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}
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messageHandlers[messageAuth] = (
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_encoder,
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decoder,
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provider,
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_emitSynced,
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_messageType
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) => {
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authProtocol.readAuthMessage(
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decoder,
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provider.doc,
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(_ydoc, reason) => permissionDeniedHandler(provider, reason)
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)
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}
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// @todo - this should depend on awareness.outdatedTime
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const messageReconnectTimeout = 30000
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/**
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* @param {WebsocketProvider} provider
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* @param {string} reason
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*/
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const permissionDeniedHandler = (provider, reason) =>
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console.warn(`Permission denied to access ${provider.url}.\n${reason}`)
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/**
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* @param {WebsocketProvider} provider
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* @param {Uint8Array} buf
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* @param {boolean} emitSynced
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* @return {encoding.Encoder}
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*/
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const readMessage = (provider, buf, emitSynced) => {
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const decoder = decoding.createDecoder(buf)
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const encoder = encoding.createEncoder()
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const messageType = decoding.readVarUint(decoder)
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const messageHandler = provider.messageHandlers[messageType]
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if (/** @type {any} */ (messageHandler)) {
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messageHandler(encoder, decoder, provider, emitSynced, messageType)
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} else {
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console.error('Unable to compute message')
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}
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return encoder
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}
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/**
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* @param {WebsocketProvider} provider
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*/
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const setupWS = (provider) => {
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if (provider.shouldConnect && provider.ws === null) {
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const websocket = new provider._WS(provider.url)
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websocket.binaryType = 'arraybuffer'
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provider.ws = websocket
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provider.wsconnecting = true
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provider.wsconnected = false
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provider.synced = false
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websocket.onmessage = (event) => {
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provider.wsLastMessageReceived = time.getUnixTime()
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const encoder = readMessage(provider, new Uint8Array(event.data), true)
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if (encoding.length(encoder) > 1) {
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websocket.send(encoding.toUint8Array(encoder))
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}
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}
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websocket.onerror = (event) => {
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provider.emit('connection-error', [event, provider])
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}
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websocket.onclose = (event) => {
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provider.emit('connection-close', [event, provider])
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provider.ws = null
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provider.wsconnecting = false
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if (provider.wsconnected) {
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provider.wsconnected = false
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provider.synced = false
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// update awareness (all users except local left)
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awarenessProtocol.removeAwarenessStates(
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provider.awareness,
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Array.from(provider.awareness.getStates().keys()).filter((client) =>
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client !== provider.doc.clientID
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),
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provider
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)
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provider.emit('status', [{
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status: 'disconnected'
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}])
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} else {
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provider.wsUnsuccessfulReconnects++
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}
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// Start with no reconnect timeout and increase timeout by
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// using exponential backoff starting with 100ms
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setTimeout(
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setupWS,
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math.min(
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math.pow(2, provider.wsUnsuccessfulReconnects) * 100,
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provider.maxBackoffTime
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),
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provider
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)
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}
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websocket.onopen = () => {
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provider.wsLastMessageReceived = time.getUnixTime()
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provider.wsconnecting = false
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provider.wsconnected = true
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provider.wsUnsuccessfulReconnects = 0
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provider.emit('status', [{
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status: 'connected'
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}])
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// always send sync step 1 when connected
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const encoder = encoding.createEncoder()
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encoding.writeVarUint(encoder, messageSync)
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syncProtocol.writeSyncStep1(encoder, provider.doc)
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websocket.send(encoding.toUint8Array(encoder))
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// broadcast local awareness state
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if (provider.awareness.getLocalState() !== null) {
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const encoderAwarenessState = encoding.createEncoder()
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encoding.writeVarUint(encoderAwarenessState, messageAwareness)
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encoding.writeVarUint8Array(
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encoderAwarenessState,
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awarenessProtocol.encodeAwarenessUpdate(provider.awareness, [
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provider.doc.clientID
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])
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)
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websocket.send(encoding.toUint8Array(encoderAwarenessState))
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}
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}
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provider.emit('status', [{
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status: 'connecting'
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}])
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}
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}
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/**
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* @param {WebsocketProvider} provider
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* @param {ArrayBuffer} buf
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*/
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const broadcastMessage = (provider, buf) => {
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if (provider.wsconnected && provider.ws && provider.ws.readyState === provider.ws.OPEN) {
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/** @type {WebSocket} */ (provider.ws).send(buf)
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}
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if (provider.bcconnected) {
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bc.publish(provider.bcChannel, buf, provider)
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}
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}
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/**
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* Websocket Provider for Yjs. Creates a websocket connection to sync the shared document.
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* The document name is attached to the provided url. I.e. the following example
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* creates a websocket connection to http://localhost:1234/my-document-name
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*
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* @example
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* import * as Y from 'yjs'
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* import { WebsocketProvider } from 'y-websocket'
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* const doc = new Y.Doc()
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* const provider = new WebsocketProvider('http://localhost:1234', 'my-document-name', doc)
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*
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* @extends {Observable<string>}
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*/
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export class WebsocketProvider extends Observable {
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/**
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* @param {string} serverUrl
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* @param {string} roomname
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* @param {Y.Doc} doc
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* @param {object} [opts]
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* @param {boolean} [opts.connect]
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* @param {awarenessProtocol.Awareness} [opts.awareness]
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* @param {Object<string,string>} [opts.params]
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* @param {typeof WebSocket} [opts.WebSocketPolyfill] Optionall provide a WebSocket polyfill
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* @param {number} [opts.resyncInterval] Request server state every `resyncInterval` milliseconds
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* @param {number} [opts.maxBackoffTime] Maximum amount of time to wait before trying to reconnect (we try to reconnect using exponential backoff)
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* @param {boolean} [opts.disableBc] Disable cross-tab BroadcastChannel communication
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*/
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constructor (serverUrl, roomname, doc, {
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connect = true,
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awareness = new awarenessProtocol.Awareness(doc),
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params = {},
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WebSocketPolyfill = WebSocket,
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resyncInterval = -1,
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maxBackoffTime = 2500,
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disableBc = false
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} = {}) {
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super()
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// ensure that url is always ends with /
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while (serverUrl[serverUrl.length - 1] === '/') {
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serverUrl = serverUrl.slice(0, serverUrl.length - 1)
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}
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const encodedParams = url.encodeQueryParams(params)
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this.maxBackoffTime = maxBackoffTime
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this.bcChannel = serverUrl + '/' + roomname
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this.url = serverUrl + '/' + roomname +
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(encodedParams.length === 0 ? '' : '?' + encodedParams)
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this.roomname = roomname
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this.doc = doc
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this._WS = WebSocketPolyfill
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this.awareness = awareness
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this.wsconnected = false
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this.wsconnecting = false
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this.bcconnected = false
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this.disableBc = disableBc
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this.wsUnsuccessfulReconnects = 0
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this.messageHandlers = messageHandlers.slice()
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/**
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* @type {boolean}
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*/
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this._synced = false
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/**
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* @type {WebSocket?}
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*/
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this.ws = null
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this.wsLastMessageReceived = 0
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/**
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* Whether to connect to other peers or not
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* @type {boolean}
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*/
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this.shouldConnect = connect
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/**
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* @type {number}
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*/
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this._resyncInterval = 0
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if (resyncInterval > 0) {
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this._resyncInterval = /** @type {any} */ (setInterval(() => {
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if (this.ws && this.ws.readyState === WebSocket.OPEN) {
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// resend sync step 1
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const encoder = encoding.createEncoder()
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encoding.writeVarUint(encoder, messageSync)
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syncProtocol.writeSyncStep1(encoder, doc)
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this.ws.send(encoding.toUint8Array(encoder))
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}
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}, resyncInterval))
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}
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/**
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* @param {ArrayBuffer} data
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* @param {any} origin
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*/
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this._bcSubscriber = (data, origin) => {
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if (origin !== this) {
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const encoder = readMessage(this, new Uint8Array(data), false)
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if (encoding.length(encoder) > 1) {
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bc.publish(this.bcChannel, encoding.toUint8Array(encoder), this)
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}
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}
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}
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/**
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* Listens to Yjs updates and sends them to remote peers (ws and broadcastchannel)
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* @param {Uint8Array} update
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* @param {any} origin
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*/
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this._updateHandler = (update, origin) => {
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if (origin !== this) {
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const encoder = encoding.createEncoder()
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encoding.writeVarUint(encoder, messageSync)
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syncProtocol.writeUpdate(encoder, update)
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broadcastMessage(this, encoding.toUint8Array(encoder))
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}
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}
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this.doc.on('update', this._updateHandler)
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/**
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* @param {any} changed
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* @param {any} _origin
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*/
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this._awarenessUpdateHandler = ({ added, updated, removed }, _origin) => {
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const changedClients = added.concat(updated).concat(removed)
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const encoder = encoding.createEncoder()
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encoding.writeVarUint(encoder, messageAwareness)
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encoding.writeVarUint8Array(
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encoder,
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awarenessProtocol.encodeAwarenessUpdate(awareness, changedClients)
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)
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broadcastMessage(this, encoding.toUint8Array(encoder))
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}
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this._unloadHandler = () => {
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awarenessProtocol.removeAwarenessStates(
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this.awareness,
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[doc.clientID],
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'window unload'
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)
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}
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if (typeof window !== 'undefined') {
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window.addEventListener('unload', this._unloadHandler)
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} else if (typeof process !== 'undefined') {
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process.on('exit', this._unloadHandler)
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}
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awareness.on('update', this._awarenessUpdateHandler)
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this._checkInterval = /** @type {any} */ (setInterval(() => {
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if (
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this.wsconnected &&
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messageReconnectTimeout <
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time.getUnixTime() - this.wsLastMessageReceived
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) {
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// no message received in a long time - not even your own awareness
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// updates (which are updated every 15 seconds)
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/** @type {WebSocket} */ (this.ws).close()
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}
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}, messageReconnectTimeout / 10))
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if (connect) {
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this.connect()
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}
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}
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/**
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* @type {boolean}
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*/
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get synced () {
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return this._synced
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}
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set synced (state) {
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if (this._synced !== state) {
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this._synced = state
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this.emit('synced', [state])
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this.emit('sync', [state])
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}
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}
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destroy () {
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if (this._resyncInterval !== 0) {
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clearInterval(this._resyncInterval)
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}
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clearInterval(this._checkInterval)
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this.disconnect()
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if (typeof window !== 'undefined') {
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window.removeEventListener('unload', this._unloadHandler)
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} else if (typeof process !== 'undefined') {
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process.off('exit', this._unloadHandler)
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}
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this.awareness.off('update', this._awarenessUpdateHandler)
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this.doc.off('update', this._updateHandler)
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super.destroy()
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}
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connectBc () {
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if (this.disableBc) {
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return
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}
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if (!this.bcconnected) {
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bc.subscribe(this.bcChannel, this._bcSubscriber)
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this.bcconnected = true
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}
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// send sync step1 to bc
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// write sync step 1
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const encoderSync = encoding.createEncoder()
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encoding.writeVarUint(encoderSync, messageSync)
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syncProtocol.writeSyncStep1(encoderSync, this.doc)
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bc.publish(this.bcChannel, encoding.toUint8Array(encoderSync), this)
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// broadcast local state
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const encoderState = encoding.createEncoder()
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encoding.writeVarUint(encoderState, messageSync)
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syncProtocol.writeSyncStep2(encoderState, this.doc)
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bc.publish(this.bcChannel, encoding.toUint8Array(encoderState), this)
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// write queryAwareness
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const encoderAwarenessQuery = encoding.createEncoder()
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encoding.writeVarUint(encoderAwarenessQuery, messageQueryAwareness)
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bc.publish(
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this.bcChannel,
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encoding.toUint8Array(encoderAwarenessQuery),
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this
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)
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// broadcast local awareness state
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const encoderAwarenessState = encoding.createEncoder()
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encoding.writeVarUint(encoderAwarenessState, messageAwareness)
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encoding.writeVarUint8Array(
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encoderAwarenessState,
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awarenessProtocol.encodeAwarenessUpdate(this.awareness, [
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this.doc.clientID
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])
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)
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bc.publish(
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this.bcChannel,
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encoding.toUint8Array(encoderAwarenessState),
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this
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)
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}
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disconnectBc () {
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// broadcast message with local awareness state set to null (indicating disconnect)
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const encoder = encoding.createEncoder()
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encoding.writeVarUint(encoder, messageAwareness)
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encoding.writeVarUint8Array(
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encoder,
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awarenessProtocol.encodeAwarenessUpdate(this.awareness, [
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this.doc.clientID
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], new Map())
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)
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broadcastMessage(this, encoding.toUint8Array(encoder))
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if (this.bcconnected) {
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bc.unsubscribe(this.bcChannel, this._bcSubscriber)
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this.bcconnected = false
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}
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}
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disconnect () {
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this.shouldConnect = false
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this.disconnectBc()
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if (this.ws !== null) {
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this.ws.close()
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}
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}
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connect () {
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this.shouldConnect = true
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if (!this.wsconnected && this.ws === null) {
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setupWS(this)
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this.connectBc()
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}
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}
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}
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