overleaf/services/web/frontend/js/ide/connection/SocketIoShim.js

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/* global io */
class SocketShimBase {
static connect(url, options) {
return new SocketShimBase()
}
constructor(socket) {
this._socket = socket
}
}
const transparentMethods = [
'connect',
'disconnect',
'emit',
'on',
'removeListener',
]
for (const method of transparentMethods) {
SocketShimBase.prototype[method] = function () {
this._socket[method].apply(this._socket, arguments)
}
}
class SocketShimNoop extends SocketShimBase {
static connect() {
return new SocketShimNoop()
}
constructor(socket) {
super(socket)
this.socket = {
get connected() {
return false
},
get sessionid() {
return undefined
},
get transport() {
return {}
},
connect() {},
disconnect(reason) {},
}
}
connect() {}
disconnect(reason) {}
emit() {}
on() {}
removeListener() {}
}
class SocketShimV0 extends SocketShimBase {
static connect(url, options) {
return new SocketShimV0(io.connect(url, options))
}
constructor(socket) {
super(socket)
this.socket = this._socket.socket
}
}
class SocketShimV2 extends SocketShimBase {
static connect(url, options) {
options.forceNew = options['force new connection']
// .resource has no leading slash, path wants to see one.
options.path = '/' + options.resource
options.reconnection = options.reconnect
options.timeout = options['connect timeout']
return new SocketShimV2(url, options)
}
static get EVENT_MAP() {
// Use the v2 event names transparently to the frontend.
const connectionFailureEvents = [
'connect_error',
'connect_timeout',
'error',
]
return new Map([
['connect_failed', connectionFailureEvents],
['error', connectionFailureEvents],
])
}
_on(event, handler) {
// Keep track of our event listeners.
// We move them to a new socket in ._replaceSocketWithNewInstance()
if (!this._events.has(event)) {
this._events.set(event, [handler])
} else {
this._events.get(event).push(handler)
}
this._socket.on(event, handler)
}
on(event, handler) {
if (SocketShimV2.EVENT_MAP.has(event)) {
for (const v2Event of SocketShimV2.EVENT_MAP.get(event)) {
this._on(v2Event, handler)
}
} else {
this._on(event, handler)
}
}
_removeListener(event, handler) {
// Keep track of our event listeners.
// We move them to a new socket in ._replaceSocketWithNewInstance()
if (this._events.has(event)) {
const listeners = this._events.get(event)
const pos = listeners.indexOf(handler)
if (pos !== -1) {
listeners.splice(pos, 1)
}
}
this._socket.removeListener(event, handler)
}
removeListener(event, handler) {
if (SocketShimV2.EVENT_MAP.has(event)) {
for (const v2Event of SocketShimV2.EVENT_MAP.get(event)) {
this._removeListener(v2Event, handler)
}
} else {
this._removeListener(event, handler)
}
}
static createNewSocket(url, options) {
// open a brand new connection for the default namespace '/'
// The old socket can still leak 'disconnect' events from the teardown
// of the old transport. The leaking 'disconnect' events interfere with
// the _new_ connection and cancel the new connect attempt.
// Also skip the caching in these locations:
// - `io.connect()` caches `io.Manager`s in `io.managers`
// - `io.Manager().socket()` caches `io.Socket`s in its `this.nsps`
return io.Manager(url, options).socket('/', options)
}
_replaceSocketWithNewInstance() {
const oldSocket = this._socket
const newSocket = SocketShimV2.createNewSocket(this._url, this._options)
// move our existing event handlers to the new socket
this._events.forEach((listeners, event) => {
for (const listener of listeners) {
oldSocket.removeListener(event, listener)
newSocket.on(event, listener)
}
})
if (oldSocket.connected) {
// We overwrite the reference to oldSocket soon.
// Make sure we are disconnected.
oldSocket.disconnect()
}
this._socket = newSocket
}
connect() {
// have the same logic behind socket.connect and socket.socket.connect
this._replaceSocketWithNewInstance()
}
constructor(url, options) {
super(SocketShimV2.createNewSocket(url, options))
this._url = url
this._options = options
this._events = new Map()
const self = this
function _getEngine() {
return (self._socket.io && self._socket.io.engine) || {}
}
this.socket = {
get connected() {
return self._socket.connected
},
get sessionid() {
if (self._socket.id) {
return self._socket.id
}
// socket.id is discarded upon disconnect
// the id is still available in the internal state
return _getEngine().id
},
get transport() {
return _getEngine().transport
},
connect() {
self._replaceSocketWithNewInstance()
},
disconnect(reason) {
return self._socket.disconnect(reason)
},
}
}
}
let current
if (typeof io === 'undefined' || !io) {
sl_console.log('[socket.io] Shim: socket.io is not loaded, returning noop')
current = SocketShimNoop
} else if (typeof io.version === 'string' && io.version.slice(0, 1) === '0') {
sl_console.log('[socket.io] Shim: detected v0')
current = SocketShimV0
} else {
// socket.io v2 does not have a global io.version attribute.
sl_console.log('[socket.io] Shim: detected v2')
current = SocketShimV2
}
export default {
SocketShimNoop,
SocketShimV0,
SocketShimV2,
current,
connect: current.connect,
stub: () => new SocketShimNoop(),
}