yjs/src/Connector.js
2017-07-05 11:40:19 +02:00

494 lines
17 KiB
JavaScript

/* @flow */
'use strict'
function canRead (auth) { return auth === 'read' || auth === 'write' }
function canWrite (auth) { return auth === 'write' }
export default function extendConnector (Y/* :any */) {
class AbstractConnector {
/* ::
y: YConfig;
role: SyncRole;
connections: Object;
isSynced: boolean;
userEventListeners: Array<Function>;
whenSyncedListeners: Array<Function>;
currentSyncTarget: ?UserId;
syncingClients: Array<UserId>;
forwardToSyncingClients: boolean;
debug: boolean;
syncStep2: Promise;
userId: UserId;
send: Function;
broadcast: Function;
broadcastOpBuffer: Array<Operation>;
protocolVersion: number;
*/
/*
opts contains the following information:
role : String Role of this client ("master" or "slave")
userId : String Uniquely defines the user.
debug: Boolean Whether to print debug messages (optional)
*/
constructor (y, opts) {
this.y = y
if (opts == null) {
opts = {}
}
// Prefer to receive untransformed operations. This does only work if
// this client receives operations from only one other client.
// In particular, this does not work with y-webrtc.
// It will work with y-websockets-client
this.preferUntransformed = opts.preferUntransformed || false
if (opts.role == null || opts.role === 'master') {
this.role = 'master'
} else if (opts.role === 'slave') {
this.role = 'slave'
} else {
throw new Error("Role must be either 'master' or 'slave'!")
}
this.log = Y.debug('y:connector')
this.logMessage = Y.debug('y:connector-message')
this.y.db.forwardAppliedOperations = opts.forwardAppliedOperations || false
this.role = opts.role
this.connections = {}
this.isSynced = false
this.userEventListeners = []
this.whenSyncedListeners = []
this.currentSyncTarget = null
this.syncingClients = []
this.forwardToSyncingClients = opts.forwardToSyncingClients !== false
this.debug = opts.debug === true
this.broadcastOpBuffer = []
this.protocolVersion = 11
this.authInfo = opts.auth || null
this.checkAuth = opts.checkAuth || function () { return Promise.resolve('write') } // default is everyone has write access
if (opts.generateUserId !== false) {
this.setUserId(Y.utils.generateGuid())
}
}
resetAuth (auth) {
if (this.authInfo !== auth) {
this.authInfo = auth
this.broadcast({
type: 'auth',
auth: this.authInfo
})
}
}
reconnect () {
this.log('reconnecting..')
return this.y.db.startGarbageCollector()
}
disconnect () {
this.log('discronnecting..')
this.connections = {}
this.isSynced = false
this.currentSyncTarget = null
this.syncingClients = []
this.whenSyncedListeners = []
this.y.db.stopGarbageCollector()
return this.y.db.whenTransactionsFinished()
}
repair () {
this.log('Repairing the state of Yjs. This can happen if messages get lost, and Yjs detects that something is wrong. If this happens often, please report an issue here: https://github.com/y-js/yjs/issues')
for (var name in this.connections) {
this.connections[name].isSynced = false
}
this.isSynced = false
this.currentSyncTarget = null
this.findNextSyncTarget()
}
setUserId (userId) {
if (this.userId == null) {
this.log('Set userId to "%s"', userId)
this.userId = userId
return this.y.db.setUserId(userId)
} else {
return null
}
}
onUserEvent (f) {
this.userEventListeners.push(f)
}
removeUserEventListener (f) {
this.userEventListeners = this.userEventListeners.filter(g => f !== g)
}
userLeft (user) {
if (this.connections[user] != null) {
this.log('User left: %s', user)
delete this.connections[user]
if (user === this.currentSyncTarget) {
this.currentSyncTarget = null
this.findNextSyncTarget()
}
this.syncingClients = this.syncingClients.filter(function (cli) {
return cli !== user
})
for (var f of this.userEventListeners) {
f({
action: 'userLeft',
user: user
})
}
}
}
userJoined (user, role) {
if (role == null) {
throw new Error('You must specify the role of the joined user!')
}
if (this.connections[user] != null) {
throw new Error('This user already joined!')
}
this.log('User joined: %s', user)
this.connections[user] = {
isSynced: false,
role: role
}
let defer = {}
defer.promise = new Promise(function (resolve) { defer.resolve = resolve })
this.connections[user].syncStep2 = defer
for (var f of this.userEventListeners) {
f({
action: 'userJoined',
user: user,
role: role
})
}
if (this.currentSyncTarget == null) {
this.findNextSyncTarget()
}
}
// Execute a function _when_ we are connected.
// If not connected, wait until connected
whenSynced (f) {
if (this.isSynced) {
f()
} else {
this.whenSyncedListeners.push(f)
}
}
findNextSyncTarget () {
if (this.currentSyncTarget != null) {
return // "The current sync has not finished!"
}
var syncUser = null
for (var uid in this.connections) {
if (!this.connections[uid].isSynced) {
syncUser = uid
break
}
}
var conn = this
if (syncUser != null) {
this.currentSyncTarget = syncUser
this.y.db.requestTransaction(function * () {
var stateSet = yield * this.getStateSet()
// var deleteSet = yield * this.getDeleteSet()
var answer = {
type: 'sync step 1',
stateSet: stateSet,
// deleteSet: deleteSet,
protocolVersion: conn.protocolVersion,
auth: conn.authInfo
}
if (conn.preferUntransformed && Object.keys(stateSet).length === 0) {
answer.preferUntransformed = true
}
conn.send(syncUser, answer)
})
} else {
if (!conn.isSynced) {
this.y.db.requestTransaction(function * () {
if (!conn.isSynced) {
// it is crucial that isSynced is set at the time garbageCollectAfterSync is called
conn.isSynced = true
// It is safer to remove this!
// TODO: remove: yield * this.garbageCollectAfterSync()
// call whensynced listeners
for (var f of conn.whenSyncedListeners) {
f()
}
conn.whenSyncedListeners = []
}
})
}
}
}
send (uid, message) {
this.log('Send \'%s\' to %s', message.type, uid)
this.logMessage('Message: %j', message)
}
broadcast (message) {
this.log('Broadcast \'%s\'', message.type)
this.logMessage('Message: %j', message)
}
/*
Buffer operations, and broadcast them when ready.
*/
broadcastOps (ops) {
ops = ops.map(function (op) {
return Y.Struct[op.struct].encode(op)
})
var self = this
function broadcastOperations () {
if (self.broadcastOpBuffer.length > 0) {
self.broadcast({
type: 'update',
ops: self.broadcastOpBuffer
})
self.broadcastOpBuffer = []
}
}
if (this.broadcastOpBuffer.length === 0) {
this.broadcastOpBuffer = ops
this.y.db.whenTransactionsFinished().then(broadcastOperations)
} else {
this.broadcastOpBuffer = this.broadcastOpBuffer.concat(ops)
}
}
/*
You received a raw message, and you know that it is intended for Yjs. Then call this function.
*/
receiveMessage (sender/* :UserId */, message/* :Message */) {
if (sender === this.userId) {
return Promise.resolve()
}
this.log('Receive \'%s\' from %s', message.type, sender)
this.logMessage('Message: %j', message)
if (message.protocolVersion != null && message.protocolVersion !== this.protocolVersion) {
this.log(
`You tried to sync with a yjs instance that has a different protocol version
(You: ${this.protocolVersion}, Client: ${message.protocolVersion}).
The sync was stopped. You need to upgrade your dependencies (especially Yjs & the Connector)!
`)
this.send(sender, {
type: 'sync stop',
protocolVersion: this.protocolVersion
})
return Promise.reject(new Error('Incompatible protocol version'))
}
if (message.auth != null && this.connections[sender] != null) {
// authenticate using auth in message
var auth = this.checkAuth(message.auth, this.y)
this.connections[sender].auth = auth
auth.then(auth => {
for (var f of this.userEventListeners) {
f({
action: 'userAuthenticated',
user: sender,
auth: auth
})
}
})
} else if (this.connections[sender] != null && this.connections[sender].auth == null) {
// authenticate without otherwise
this.connections[sender].auth = this.checkAuth(null, this.y)
}
if (this.connections[sender] != null && this.connections[sender].auth != null) {
return this.connections[sender].auth.then((auth) => {
if (message.type === 'sync step 1' && canRead(auth)) {
let conn = this
let m = message
let wait // wait for sync step 2 to complete
if (this.role === 'slave') {
wait = Promise.all(Object.keys(this.connections)
.map(uid => this.connections[uid])
.filter(conn => conn.role === 'master')
.map(conn => conn.syncStep2.promise)
)
} else {
wait = Promise.resolve()
}
wait.then(() => {
this.y.db.requestTransaction(function * () {
var currentStateSet = yield * this.getStateSet()
// TODO: remove
// if (canWrite(auth)) {
// yield * this.applyDeleteSet(m.deleteSet)
// }
var ds = yield * this.getDeleteSet()
var answer = {
type: 'sync step 2',
stateSet: currentStateSet,
deleteSet: ds,
protocolVersion: this.protocolVersion,
auth: this.authInfo
}
if (message.preferUntransformed === true && Object.keys(m.stateSet).length === 0) {
answer.osUntransformed = yield * this.getOperationsUntransformed()
} else {
answer.os = yield * this.getOperations(m.stateSet)
}
conn.send(sender, answer)
if (this.forwardToSyncingClients) {
conn.syncingClients.push(sender)
setTimeout(function () {
conn.syncingClients = conn.syncingClients.filter(function (cli) {
return cli !== sender
})
conn.send(sender, {
type: 'sync done'
})
}, 5000) // TODO: conn.syncingClientDuration)
} else {
conn.send(sender, {
type: 'sync done'
})
}
})
})
} else if (message.type === 'sync step 2' && canWrite(auth)) {
var db = this.y.db
let defer = this.connections[sender].syncStep2
let m = message
// apply operations first
db.requestTransaction(function * () {
// yield * this.applyDeleteSet(m.deleteSet)
if (m.osUntransformed != null) {
yield * this.applyOperationsUntransformed(m.osUntransformed, m.stateSet)
} else {
this.store.apply(m.os)
}
// defer.resolve()
})
// then apply ds
db.whenTransactionsFinished().then(() => {
db.requestTransaction(function * () {
yield * this.applyDeleteSet(m.deleteSet)
})
defer.resolve()
})
return defer.promise
} else if (message.type === 'sync done') {
var self = this
this.connections[sender].syncStep2.promise.then(function () {
self._setSyncedWith(sender)
})
} else if (message.type === 'update' && canWrite(auth)) {
if (this.forwardToSyncingClients) {
for (var client of this.syncingClients) {
this.send(client, message)
}
}
if (this.y.db.forwardAppliedOperations) {
var delops = message.ops.filter(function (o) {
return o.struct === 'Delete'
})
if (delops.length > 0) {
this.broadcastOps(delops)
}
}
this.y.db.apply(message.ops)
}
})
} else {
return Promise.reject(new Error('Unable to deliver message'))
}
}
_setSyncedWith (user) {
var conn = this.connections[user]
if (conn != null) {
conn.isSynced = true
}
if (user === this.currentSyncTarget) {
this.currentSyncTarget = null
this.findNextSyncTarget()
}
}
/*
Currently, the HB encodes operations as JSON. For the moment I want to keep it
that way. Maybe we support encoding in the HB as XML in the future, but for now I don't want
too much overhead. Y is very likely to get changed a lot in the future
Because we don't want to encode JSON as string (with character escaping, wich makes it pretty much unreadable)
we encode the JSON as XML.
When the HB support encoding as XML, the format should look pretty much like this.
does not support primitive values as array elements
expects an ltx (less than xml) object
*/
parseMessageFromXml (m/* :any */) {
function parseArray (node) {
for (var n of node.children) {
if (n.getAttribute('isArray') === 'true') {
return parseArray(n)
} else {
return parseObject(n)
}
}
}
function parseObject (node/* :any */) {
var json = {}
for (var attrName in node.attrs) {
var value = node.attrs[attrName]
var int = parseInt(value, 10)
if (isNaN(int) || ('' + int) !== value) {
json[attrName] = value
} else {
json[attrName] = int
}
}
for (var n/* :any */ in node.children) {
var name = n.name
if (n.getAttribute('isArray') === 'true') {
json[name] = parseArray(n)
} else {
json[name] = parseObject(n)
}
}
return json
}
parseObject(m)
}
/*
encode message in xml
we use string because Strophe only accepts an "xml-string"..
So {a:4,b:{c:5}} will look like
<y a="4">
<b c="5"></b>
</y>
m - ltx element
json - Object
*/
encodeMessageToXml (msg, obj) {
// attributes is optional
function encodeObject (m, json) {
for (var name in json) {
var value = json[name]
if (name == null) {
// nop
} else if (value.constructor === Object) {
encodeObject(m.c(name), value)
} else if (value.constructor === Array) {
encodeArray(m.c(name), value)
} else {
m.setAttribute(name, value)
}
}
}
function encodeArray (m, array) {
m.setAttribute('isArray', 'true')
for (var e of array) {
if (e.constructor === Object) {
encodeObject(m.c('array-element'), e)
} else {
encodeArray(m.c('array-element'), e)
}
}
}
if (obj.constructor === Object) {
encodeObject(msg.c('y', { xmlns: 'http://y.ninja/connector-stanza' }), obj)
} else if (obj.constructor === Array) {
encodeArray(msg.c('y', { xmlns: 'http://y.ninja/connector-stanza' }), obj)
} else {
throw new Error("I can't encode this json!")
}
}
}
Y.AbstractConnector = AbstractConnector
}