Files
socket.io/lib/socket.ts

526 lines
12 KiB
TypeScript

import { Packet, PacketType } from "socket.io-parser";
import Emitter = require("component-emitter");
import { on } from "./on";
import { Manager } from "./manager";
const debug = require("debug")("socket.io-client:socket");
export interface SocketOptions {
/**
* the authentication payload sent when connecting to the Namespace
*/
auth: object | ((cb: (data: object) => void) => void);
}
/**
* Internal events.
* These events can't be emitted by the user.
*/
const RESERVED_EVENTS = Object.freeze({
connect: 1,
connect_error: 1,
disconnect: 1,
disconnecting: 1,
// EventEmitter reserved events: https://nodejs.org/api/events.html#events_event_newlistener
newListener: 1,
removeListener: 1,
});
interface Flags {
compress?: boolean;
volatile?: boolean;
}
export class Socket extends Emitter {
public readonly io: Manager;
public id: string;
public connected: boolean;
public disconnected: boolean;
public receiveBuffer: Array<ReadonlyArray<any>> = [];
public sendBuffer: Array<Packet> = [];
private readonly nsp: string;
private readonly auth: object | ((cb: (data: object) => void) => void);
private ids: number = 0;
private acks: object = {};
private flags: Flags = {};
private subs?: Array<VoidFunction>;
private _anyListeners: Array<(...args: any[]) => void>;
/**
* `Socket` constructor.
*
* @public
*/
constructor(io: Manager, nsp: string, opts?: Partial<SocketOptions>) {
super();
this.io = io;
this.nsp = nsp;
this.ids = 0;
this.acks = {};
this.receiveBuffer = [];
this.sendBuffer = [];
this.connected = false;
this.disconnected = true;
this.flags = {};
if (opts && opts.auth) {
this.auth = opts.auth;
}
if (this.io._autoConnect) this.open();
}
/**
* Subscribe to open, close and packet events
*
* @private
*/
private subEvents() {
if (this.subs) return;
const io = this.io;
this.subs = [
on(io, "open", this.onopen.bind(this)),
on(io, "packet", this.onpacket.bind(this)),
on(io, "close", this.onclose.bind(this)),
];
}
/**
* Whether the Socket will try to reconnect when its Manager connects or reconnects
*/
public get active(): boolean {
return !!this.subs;
}
/**
* "Opens" the socket.
*
* @public
*/
public connect(): Socket {
if (this.connected) return this;
this.subEvents();
if (!this.io["_reconnecting"]) this.io.open(); // ensure open
if ("open" === this.io._readyState) this.onopen();
return this;
}
/**
* Alias for connect()
*/
public open(): Socket {
return this.connect();
}
/**
* Sends a `message` event.
*
* @return self
* @public
*/
public send(...args: any[]): Socket {
args.unshift("message");
this.emit.apply(this, args);
return this;
}
/**
* Override `emit`.
* If the event is in `events`, it's emitted normally.
*
* @param ev - event name
* @return self
* @public
*/
public emit(ev: string, ...args: any[]): Socket {
if (RESERVED_EVENTS.hasOwnProperty(ev)) {
throw new Error('"' + ev + '" is a reserved event name');
}
args.unshift(ev);
const packet: any = {
type: PacketType.EVENT,
data: args,
};
packet.options = {};
packet.options.compress = this.flags.compress !== false;
// event ack callback
if ("function" === typeof args[args.length - 1]) {
debug("emitting packet with ack id %d", this.ids);
this.acks[this.ids] = args.pop();
packet.id = this.ids++;
}
const isTransportWritable =
this.io.engine &&
this.io.engine.transport &&
this.io.engine.transport.writable;
const discardPacket =
this.flags.volatile && (!isTransportWritable || !this.connected);
if (discardPacket) {
debug("discard packet as the transport is not currently writable");
} else if (this.connected) {
this.packet(packet);
} else {
this.sendBuffer.push(packet);
}
this.flags = {};
return this;
}
/**
* Sends a packet.
*
* @param packet
* @private
*/
private packet(packet: Partial<Packet>) {
packet.nsp = this.nsp;
this.io._packet(packet);
}
/**
* Called upon engine `open`.
*
* @private
*/
private onopen() {
debug("transport is open - connecting");
if (typeof this.auth == "function") {
this.auth((data) => {
this.packet({ type: PacketType.CONNECT, data });
});
} else {
this.packet({ type: PacketType.CONNECT, data: this.auth });
}
}
/**
* Called upon engine `close`.
*
* @param reason
* @private
*/
private onclose(reason: Socket.DisconnectReason) {
debug("close (%s)", reason);
this.connected = false;
this.disconnected = true;
delete this.id;
super.emit("disconnect", reason);
}
/**
* Called with socket packet.
*
* @param packet
* @private
*/
private onpacket(packet: Packet) {
const sameNamespace = packet.nsp === this.nsp;
if (!sameNamespace) return;
switch (packet.type) {
case PacketType.CONNECT:
if (packet.data && packet.data.sid) {
const id = packet.data.sid;
this.onconnect(id);
} else {
super.emit(
"connect_error",
new Error(
"It seems you are trying to reach a Socket.IO server in v2.x with a v3.x client, but they are not compatible (more information here: https://socket.io/docs/v3/migrating-from-2-x-to-3-0/)"
)
);
}
break;
case PacketType.EVENT:
this.onevent(packet);
break;
case PacketType.BINARY_EVENT:
this.onevent(packet);
break;
case PacketType.ACK:
this.onack(packet);
break;
case PacketType.BINARY_ACK:
this.onack(packet);
break;
case PacketType.DISCONNECT:
this.ondisconnect();
break;
case PacketType.CONNECT_ERROR:
const err = new Error(packet.data.message);
// @ts-ignore
err.data = packet.data.data;
super.emit("connect_error", err);
break;
}
}
/**
* Called upon a server event.
*
* @param packet
* @private
*/
private onevent(packet: Packet) {
const args: Array<any> = packet.data || [];
debug("emitting event %j", args);
if (null != packet.id) {
debug("attaching ack callback to event");
args.push(this.ack(packet.id));
}
if (this.connected) {
this.emitEvent(args);
} else {
this.receiveBuffer.push(Object.freeze(args));
}
}
private emitEvent(args: ReadonlyArray<any>) {
if (this._anyListeners && this._anyListeners.length) {
const listeners = this._anyListeners.slice();
for (const listener of listeners) {
listener.apply(this, args);
}
}
super.emit.apply(this, args);
}
/**
* Produces an ack callback to emit with an event.
*
* @private
*/
private ack(id: number) {
const self = this;
let sent = false;
return function (...args: any[]) {
// prevent double callbacks
if (sent) return;
sent = true;
debug("sending ack %j", args);
self.packet({
type: PacketType.ACK,
id: id,
data: args,
});
};
}
/**
* Called upon a server acknowlegement.
*
* @param packet
* @private
*/
private onack(packet: Packet) {
const ack = this.acks[packet.id];
if ("function" === typeof ack) {
debug("calling ack %s with %j", packet.id, packet.data);
ack.apply(this, packet.data);
delete this.acks[packet.id];
} else {
debug("bad ack %s", packet.id);
}
}
/**
* Called upon server connect.
*
* @private
*/
private onconnect(id: string) {
debug("socket connected with id %s", id);
this.id = id;
this.connected = true;
this.disconnected = false;
super.emit("connect");
this.emitBuffered();
}
/**
* Emit buffered events (received and emitted).
*
* @private
*/
private emitBuffered() {
this.receiveBuffer.forEach((args) => this.emitEvent(args));
this.receiveBuffer = [];
this.sendBuffer.forEach((packet) => this.packet(packet));
this.sendBuffer = [];
}
/**
* Called upon server disconnect.
*
* @private
*/
private ondisconnect() {
debug("server disconnect (%s)", this.nsp);
this.destroy();
this.onclose("io server disconnect");
}
/**
* Called upon forced client/server side disconnections,
* this method ensures the manager stops tracking us and
* that reconnections don't get triggered for this.
*
* @private
*/
private destroy() {
if (this.subs) {
// clean subscriptions to avoid reconnections
this.subs.forEach((subDestroy) => subDestroy());
this.subs = undefined;
}
this.io["_destroy"](this);
}
/**
* Disconnects the socket manually.
*
* @return self
* @public
*/
public disconnect(): Socket {
if (this.connected) {
debug("performing disconnect (%s)", this.nsp);
this.packet({ type: PacketType.DISCONNECT });
}
// remove socket from pool
this.destroy();
if (this.connected) {
// fire events
this.onclose("io client disconnect");
}
return this;
}
/**
* Alias for disconnect()
*
* @return self
* @public
*/
public close(): Socket {
return this.disconnect();
}
/**
* Sets the compress flag.
*
* @param compress - if `true`, compresses the sending data
* @return self
* @public
*/
public compress(compress: boolean): Socket {
this.flags.compress = compress;
return this;
}
/**
* Sets a modifier for a subsequent event emission that the event message will be dropped when this socket is not
* ready to send messages.
*
* @returns self
* @public
*/
public get volatile(): Socket {
this.flags.volatile = true;
return this;
}
/**
* Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
* callback.
*
* @param listener
* @public
*/
public onAny(listener: (...args: any[]) => void): Socket {
this._anyListeners = this._anyListeners || [];
this._anyListeners.push(listener);
return this;
}
/**
* Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
* callback. The listener is added to the beginning of the listeners array.
*
* @param listener
* @public
*/
public prependAny(listener: (...args: any[]) => void): Socket {
this._anyListeners = this._anyListeners || [];
this._anyListeners.unshift(listener);
return this;
}
/**
* Removes the listener that will be fired when any event is emitted.
*
* @param listener
* @public
*/
public offAny(listener?: (...args: any[]) => void): Socket {
if (!this._anyListeners) {
return this;
}
if (listener) {
const listeners = this._anyListeners;
for (let i = 0; i < listeners.length; i++) {
if (listener === listeners[i]) {
listeners.splice(i, 1);
return this;
}
}
} else {
this._anyListeners = [];
}
return this;
}
/**
* Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
* e.g. to remove listeners.
*
* @public
*/
public listenersAny() {
return this._anyListeners || [];
}
}
export namespace Socket {
export type DisconnectReason =
| "io server disconnect"
| "io client disconnect"
| "ping timeout"
| "transport close"
| "transport error";
}