Files
ms/packages/websocket/src/socket.io-adapter/index.ts
2023-02-09 13:49:48 +08:00

508 lines
13 KiB
TypeScript

import { EventEmitter } from "events";
import { yeast } from "./contrib/yeast";
// import WebSocket = require("ws");
// const canPreComputeFrame = typeof WebSocket?.Sender?.frame === "function";
/**
* A public ID, sent by the server at the beginning of the Socket.IO session and which can be used for private messaging
*/
export type SocketId = string;
/**
* A private ID, sent by the server at the beginning of the Socket.IO session and used for connection state recovery
* upon reconnection
*/
export type PrivateSessionId = string;
// we could extend the Room type to "string | number", but that would be a breaking change
// related: https://github.com/socketio/socket.io-redis-adapter/issues/418
export type Room = string;
export interface BroadcastFlags {
volatile?: boolean;
compress?: boolean;
local?: boolean;
broadcast?: boolean;
binary?: boolean;
timeout?: number;
}
export interface BroadcastOptions {
rooms: Set<Room>;
except?: Set<Room>;
flags?: BroadcastFlags;
}
interface SessionToPersist {
sid: SocketId;
pid: PrivateSessionId;
rooms: Room[];
data: unknown;
}
export type Session = SessionToPersist & { missedPackets: unknown[][] };
export class Adapter extends EventEmitter {
public rooms: Map<Room, Set<SocketId>> = new Map();
public sids: Map<SocketId, Set<Room>> = new Map();
private readonly encoder;
/**
* In-memory adapter constructor.
*
* @param {Namespace} nsp
*/
constructor(readonly nsp: any) {
super();
this.encoder = nsp.server.encoder;
}
/**
* To be overridden
*/
public init(): Promise<void> | void {}
/**
* To be overridden
*/
public close(): Promise<void> | void {}
/**
* Returns the number of Socket.IO servers in the cluster
*
* @public
*/
public serverCount(): Promise<number> {
return Promise.resolve(1);
}
/**
* Adds a socket to a list of room.
*
* @param {SocketId} id the socket id
* @param {Set<Room>} rooms a set of rooms
* @public
*/
public addAll(id: SocketId, rooms: Set<Room>): Promise<void> | void {
if (!this.sids.has(id)) {
this.sids.set(id, new Set());
}
for (const room of rooms) {
this.sids.get(id).add(room);
if (!this.rooms.has(room)) {
this.rooms.set(room, new Set());
this.emit("create-room", room);
}
if (!this.rooms.get(room).has(id)) {
this.rooms.get(room).add(id);
this.emit("join-room", room, id);
}
}
}
/**
* Removes a socket from a room.
*
* @param {SocketId} id the socket id
* @param {Room} room the room name
*/
public del(id: SocketId, room: Room): Promise<void> | void {
if (this.sids.has(id)) {
this.sids.get(id).delete(room);
}
this._del(room, id);
}
private _del(room: Room, id: SocketId) {
const _room = this.rooms.get(room);
if (_room != null) {
const deleted = _room.delete(id);
if (deleted) {
this.emit("leave-room", room, id);
}
if (_room.size === 0 && this.rooms.delete(room)) {
this.emit("delete-room", room);
}
}
}
/**
* Removes a socket from all rooms it's joined.
*
* @param {SocketId} id the socket id
*/
public delAll(id: SocketId): void {
if (!this.sids.has(id)) {
return;
}
for (const room of this.sids.get(id)) {
this._del(room, id);
}
this.sids.delete(id);
}
/**
* Broadcasts a packet.
*
* Options:
* - `flags` {Object} flags for this packet
* - `except` {Array} sids that should be excluded
* - `rooms` {Array} list of rooms to broadcast to
*
* @param {Object} packet the packet object
* @param {Object} opts the options
* @public
*/
public broadcast(packet: any, opts: BroadcastOptions): void {
const flags = opts.flags || {};
const packetOpts = {
preEncoded: true,
volatile: flags.volatile,
compress: flags.compress,
};
packet.nsp = this.nsp.name;
const encodedPackets = this._encode(packet, packetOpts);
this.apply(opts, (socket) => {
if (typeof socket.notifyOutgoingListeners === "function") {
socket.notifyOutgoingListeners(packet);
}
socket.client.writeToEngine(encodedPackets, packetOpts);
});
}
/**
* Broadcasts a packet and expects multiple acknowledgements.
*
* Options:
* - `flags` {Object} flags for this packet
* - `except` {Array} sids that should be excluded
* - `rooms` {Array} list of rooms to broadcast to
*
* @param {Object} packet the packet object
* @param {Object} opts the options
* @param clientCountCallback - the number of clients that received the packet
* @param ack - the callback that will be called for each client response
*
* @public
*/
public broadcastWithAck(
packet: any,
opts: BroadcastOptions,
clientCountCallback: (clientCount: number) => void,
ack: (...args: any[]) => void
) {
const flags = opts.flags || {};
const packetOpts = {
preEncoded: true,
volatile: flags.volatile,
compress: flags.compress,
};
packet.nsp = this.nsp.name;
// we can use the same id for each packet, since the _ids counter is common (no duplicate)
packet.id = this.nsp._ids++;
const encodedPackets = this._encode(packet, packetOpts);
let clientCount = 0;
this.apply(opts, (socket) => {
// track the total number of acknowledgements that are expected
clientCount++;
// call the ack callback for each client response
socket.acks.set(packet.id, ack);
if (typeof socket.notifyOutgoingListeners === "function") {
socket.notifyOutgoingListeners(packet);
}
socket.client.writeToEngine(encodedPackets, packetOpts);
});
clientCountCallback(clientCount);
}
private _encode(packet: unknown, packetOpts: Record<string, unknown>) {
const encodedPackets = this.encoder.encode(packet);
// if (
// canPreComputeFrame &&
// encodedPackets.length === 1 &&
// typeof encodedPackets[0] === "string"
// ) {
// // "4" being the "message" packet type in the Engine.IO protocol
// const data = Buffer.from("4" + encodedPackets[0]);
// // see https://github.com/websockets/ws/issues/617#issuecomment-283002469
// packetOpts.wsPreEncodedFrame = WebSocket.Sender.frame(data, {
// readOnly: false,
// mask: false,
// rsv1: false,
// opcode: 1,
// fin: true,
// });
// }
return encodedPackets;
}
/**
* Gets a list of sockets by sid.
*
* @param {Set<Room>} rooms the explicit set of rooms to check.
*/
public sockets(rooms: Set<Room>): Promise<Set<SocketId>> {
const sids = new Set<SocketId>();
this.apply({ rooms }, (socket) => {
sids.add(socket.id);
});
return Promise.resolve(sids);
}
/**
* Gets the list of rooms a given socket has joined.
*
* @param {SocketId} id the socket id
*/
public socketRooms(id: SocketId): Set<Room> | undefined {
return this.sids.get(id);
}
/**
* Returns the matching socket instances
*
* @param opts - the filters to apply
*/
public fetchSockets(opts: BroadcastOptions): Promise<any[]> {
const sockets = [];
this.apply(opts, (socket) => {
sockets.push(socket);
});
return Promise.resolve(sockets);
}
/**
* Makes the matching socket instances join the specified rooms
*
* @param opts - the filters to apply
* @param rooms - the rooms to join
*/
public addSockets(opts: BroadcastOptions, rooms: Room[]): void {
this.apply(opts, (socket) => {
socket.join(rooms);
});
}
/**
* Makes the matching socket instances leave the specified rooms
*
* @param opts - the filters to apply
* @param rooms - the rooms to leave
*/
public delSockets(opts: BroadcastOptions, rooms: Room[]): void {
this.apply(opts, (socket) => {
rooms.forEach((room) => socket.leave(room));
});
}
/**
* Makes the matching socket instances disconnect
*
* @param opts - the filters to apply
* @param close - whether to close the underlying connection
*/
public disconnectSockets(opts: BroadcastOptions, close: boolean): void {
this.apply(opts, (socket) => {
socket.disconnect(close);
});
}
private apply(opts: BroadcastOptions, callback: (socket) => void): void {
const rooms = opts.rooms;
const except = this.computeExceptSids(opts.except);
if (rooms.size) {
const ids = new Set();
for (const room of rooms) {
if (!this.rooms.has(room)) continue;
for (const id of this.rooms.get(room)) {
if (ids.has(id) || except.has(id)) continue;
const socket = this.nsp.sockets.get(id);
if (socket) {
callback(socket);
ids.add(id);
}
}
}
} else {
for (const [id] of this.sids) {
if (except.has(id)) continue;
const socket = this.nsp.sockets.get(id);
if (socket) callback(socket);
}
}
}
private computeExceptSids(exceptRooms?: Set<Room>) {
const exceptSids = new Set();
if (exceptRooms && exceptRooms.size > 0) {
for (const room of exceptRooms) {
if (this.rooms.has(room)) {
this.rooms.get(room).forEach((sid) => exceptSids.add(sid));
}
}
}
return exceptSids;
}
/**
* Send a packet to the other Socket.IO servers in the cluster
* @param packet - an array of arguments, which may include an acknowledgement callback at the end
*/
public serverSideEmit(packet: any[]): void {
console.warn(
"this adapter does not support the serverSideEmit() functionality"
);
}
/**
* Save the client session in order to restore it upon reconnection.
*/
public persistSession(session: SessionToPersist) {}
/**
* Restore the session and find the packets that were missed by the client.
* @param pid
* @param offset
*/
public restoreSession(
pid: PrivateSessionId,
offset: string
): Session {
return null;
}
}
interface PersistedPacket {
id: string;
emittedAt: number;
data: unknown[];
opts: BroadcastOptions;
}
type SessionWithTimestamp = SessionToPersist & { disconnectedAt: number };
export class SessionAwareAdapter extends Adapter {
private readonly maxDisconnectionDuration: number;
private sessions: Map<PrivateSessionId, SessionWithTimestamp> = new Map();
private packets: PersistedPacket[] = [];
constructor(readonly nsp: any) {
super(nsp);
this.maxDisconnectionDuration =
nsp.server.opts.connectionStateRecovery.maxDisconnectionDuration;
const timer = setInterval(() => {
const threshold = Date.now() - this.maxDisconnectionDuration;
this.sessions.forEach((session, sessionId) => {
const hasExpired = session.disconnectedAt < threshold;
if (hasExpired) {
this.sessions.delete(sessionId);
}
});
for (let i = this.packets.length - 1; i >= 0; i--) {
const hasExpired = this.packets[i].emittedAt < threshold;
if (hasExpired) {
this.packets.splice(0, i + 1);
break;
}
}
}, 60 * 1000);
// prevents the timer from keeping the process alive
timer.unref();
}
override persistSession(session: SessionToPersist) {
(session as SessionWithTimestamp).disconnectedAt = Date.now();
this.sessions.set(session.pid, session as SessionWithTimestamp);
}
override restoreSession(
pid: PrivateSessionId,
offset: string
): Session {
const session = this.sessions.get(pid);
if (!session) {
// the session may have expired
return null;
}
const hasExpired =
session.disconnectedAt + this.maxDisconnectionDuration < Date.now();
if (hasExpired) {
// the session has expired
this.sessions.delete(pid);
return null;
}
const index = this.packets.findIndex((packet) => packet.id === offset);
if (index === -1) {
// the offset may be too old
return null;
}
const missedPackets = [];
for (let i = index + 1; i < this.packets.length; i++) {
const packet = this.packets[i];
if (shouldIncludePacket(session.rooms, packet.opts)) {
missedPackets.push(packet.data);
}
}
return {
...session,
missedPackets,
};
}
override broadcast(packet: any, opts: BroadcastOptions) {
const isEventPacket = packet.type === 2;
// packets with acknowledgement are not stored because the acknowledgement function cannot be serialized and
// restored on another server upon reconnection
const withoutAcknowledgement = packet.id === undefined;
const notVolatile = opts.flags?.volatile === undefined;
if (isEventPacket && withoutAcknowledgement && notVolatile) {
const id = yeast();
// the offset is stored at the end of the data array, so the client knows the ID of the last packet it has
// processed (and the format is backward-compatible)
packet.data.push(id);
this.packets.push({
id,
opts,
data: packet.data,
emittedAt: Date.now(),
});
}
super.broadcast(packet, opts);
}
}
function shouldIncludePacket(
sessionRooms: Room[],
opts: BroadcastOptions
): boolean {
const included =
opts.rooms.size === 0 || sessionRooms.some((room) => opts.rooms.has(room));
const notExcluded = sessionRooms.every((room) => !opts.except.has(room));
return included && notExcluded;
}