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import { PacketType } from "socket.io-parser";
import { on } from "./on.js";
import { Emitter, } from "@socket.io/component-emitter";
import debugModule from "debug"; // debug()
const debug = debugModule("socket.io-client:socket"); // debug()
/**
* 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,
});
export class Socket extends Emitter {
/**
* `Socket` constructor.
*
* @public
*/
constructor(io, nsp, opts) {
super();
this.connected = false;
this.receiveBuffer = [];
this.sendBuffer = [];
this.ids = 0;
this.acks = {};
this.flags = {};
this.io = io;
this.nsp = nsp;
if (opts && opts.auth) {
this.auth = opts.auth;
}
if (this.io._autoConnect)
this.open();
}
/**
* Whether the socket is currently disconnected
*/
get disconnected() {
return !this.connected;
}
/**
* Subscribe to open, close and packet events
*
* @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, "error", this.onerror.bind(this)),
on(io, "close", this.onclose.bind(this)),
];
}
/**
* Whether the Socket will try to reconnect when its Manager connects or reconnects
*/
get active() {
return !!this.subs;
}
/**
* "Opens" the socket.
*
* @public
*/
connect() {
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()
*/
open() {
return this.connect();
}
/**
* Sends a `message` event.
*
* @return self
* @public
*/
send(...args) {
args.unshift("message");
this.emit.apply(this, args);
return this;
}
/**
* Override `emit`.
* If the event is in `events`, it's emitted normally.
*
* @return self
* @public
*/
emit(ev, ...args) {
if (RESERVED_EVENTS.hasOwnProperty(ev)) {
throw new Error('"' + ev + '" is a reserved event name');
}
args.unshift(ev);
const packet = {
type: PacketType.EVENT,
data: args,
};
packet.options = {};
packet.options.compress = this.flags.compress !== false;
// event ack callback
if ("function" === typeof args[args.length - 1]) {
const id = this.ids++;
debug("emitting packet with ack id %d", id);
const ack = args.pop();
this._registerAckCallback(id, ack);
packet.id = id;
}
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.notifyOutgoingListeners(packet);
this.packet(packet);
}
else {
this.sendBuffer.push(packet);
}
this.flags = {};
return this;
}
/**
* @private
*/
_registerAckCallback(id, ack) {
const timeout = this.flags.timeout;
if (timeout === undefined) {
this.acks[id] = ack;
return;
}
// @ts-ignore
const timer = this.io.setTimeoutFn(() => {
delete this.acks[id];
for (let i = 0; i < this.sendBuffer.length; i++) {
if (this.sendBuffer[i].id === id) {
debug("removing packet with ack id %d from the buffer", id);
this.sendBuffer.splice(i, 1);
}
}
debug("event with ack id %d has timed out after %d ms", id, timeout);
ack.call(this, new Error("operation has timed out"));
}, timeout);
this.acks[id] = (...args) => {
// @ts-ignore
this.io.clearTimeoutFn(timer);
ack.apply(this, [null, ...args]);
};
}
/**
* Sends a packet.
*
* @param packet
* @private
*/
packet(packet) {
packet.nsp = this.nsp;
this.io._packet(packet);
}
/**
* Called upon engine `open`.
*
* @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 or manager `error`.
*
* @param err
* @private
*/
onerror(err) {
if (!this.connected) {
this.emitReserved("connect_error", err);
}
}
/**
* Called upon engine `close`.
*
* @param reason
* @param description
* @private
*/
onclose(reason, description) {
debug("close (%s)", reason);
this.connected = false;
delete this.id;
this.emitReserved("disconnect", reason, description);
}
/**
* Called with socket packet.
*
* @param packet
* @private
*/
onpacket(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 {
this.emitReserved("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:
case PacketType.BINARY_EVENT:
this.onevent(packet);
break;
case PacketType.ACK:
case PacketType.BINARY_ACK:
this.onack(packet);
break;
case PacketType.DISCONNECT:
this.ondisconnect();
break;
case PacketType.CONNECT_ERROR:
this.destroy();
const err = new Error(packet.data.message);
// @ts-ignore
err.data = packet.data.data;
this.emitReserved("connect_error", err);
break;
}
}
/**
* Called upon a server event.
*
* @param packet
* @private
*/
onevent(packet) {
const args = 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));
}
}
emitEvent(args) {
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
*/
ack(id) {
const self = this;
let sent = false;
return function (...args) {
// 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
*/
onack(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
*/
onconnect(id) {
debug("socket connected with id %s", id);
this.id = id;
this.connected = true;
this.emitBuffered();
this.emitReserved("connect");
}
/**
* Emit buffered events (received and emitted).
*
* @private
*/
emitBuffered() {
this.receiveBuffer.forEach((args) => this.emitEvent(args));
this.receiveBuffer = [];
this.sendBuffer.forEach((packet) => {
this.notifyOutgoingListeners(packet);
this.packet(packet);
});
this.sendBuffer = [];
}
/**
* Called upon server disconnect.
*
* @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
*/
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
*/
disconnect() {
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
*/
close() {
return this.disconnect();
}
/**
* Sets the compress flag.
*
* @param compress - if `true`, compresses the sending data
* @return self
* @public
*/
compress(compress) {
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
*/
get volatile() {
this.flags.volatile = true;
return this;
}
/**
* Sets a modifier for a subsequent event emission that the callback will be called with an error when the
* given number of milliseconds have elapsed without an acknowledgement from the server:
*
* ```
* socket.timeout(5000).emit("my-event", (err) => {
* if (err) {
* // the server did not acknowledge the event in the given delay
* }
* });
* ```
*
* @returns self
* @public
*/
timeout(timeout) {
this.flags.timeout = timeout;
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
*/
onAny(listener) {
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
*/
prependAny(listener) {
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
*/
offAny(listener) {
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
*/
listenersAny() {
return this._anyListeners || [];
}
/**
* 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
*
* <pre><code>
*
* socket.onAnyOutgoing((event, ...args) => {
* console.log(event);
* });
*
* </pre></code>
*
* @public
*/
onAnyOutgoing(listener) {
this._anyOutgoingListeners = this._anyOutgoingListeners || [];
this._anyOutgoingListeners.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
*
* <pre><code>
*
* socket.prependAnyOutgoing((event, ...args) => {
* console.log(event);
* });
*
* </pre></code>
*
* @public
*/
prependAnyOutgoing(listener) {
this._anyOutgoingListeners = this._anyOutgoingListeners || [];
this._anyOutgoingListeners.unshift(listener);
return this;
}
/**
* Removes the listener that will be fired when any event is emitted.
*
* @param listener
*
* <pre><code>
*
* const handler = (event, ...args) => {
* console.log(event);
* }
*
* socket.onAnyOutgoing(handler);
*
* // then later
* socket.offAnyOutgoing(handler);
*
* </pre></code>
*
* @public
*/
offAnyOutgoing(listener) {
if (!this._anyOutgoingListeners) {
return this;
}
if (listener) {
const listeners = this._anyOutgoingListeners;
for (let i = 0; i < listeners.length; i++) {
if (listener === listeners[i]) {
listeners.splice(i, 1);
return this;
}
}
}
else {
this._anyOutgoingListeners = [];
}
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
*/
listenersAnyOutgoing() {
return this._anyOutgoingListeners || [];
}
/**
* Notify the listeners for each packet sent
*
* @param packet
*
* @private
*/
notifyOutgoingListeners(packet) {
if (this._anyOutgoingListeners && this._anyOutgoingListeners.length) {
const listeners = this._anyOutgoingListeners.slice();
for (const listener of listeners) {
listener.apply(this, packet.data);
}
}
}
}