/
socket.ts
551 lines (480 loc) · 14 KB
/
socket.ts
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import { EventEmitter } from "events";
import debugModule from "debug";
import { IncomingMessage } from "http";
import { Transport } from "./transport";
import { Server } from "./server";
import { setTimeout, clearTimeout } from "timers";
const debug = debugModule("engine:socket");
export class Socket extends EventEmitter {
public readonly protocol: number;
public readonly request: IncomingMessage;
public readonly remoteAddress: string;
public _readyState: string;
public transport: Transport;
private server: Server;
private upgrading: boolean;
private upgraded: boolean;
private writeBuffer: any[];
private packetsFn: any[];
private sentCallbackFn: any[];
private cleanupFn: any[];
private checkIntervalTimer;
private upgradeTimeoutTimer;
private pingTimeoutTimer;
private pingIntervalTimer;
private readonly id: string;
get readyState() {
return this._readyState;
}
set readyState(state) {
debug("readyState updated from %s to %s", this._readyState, state);
this._readyState = state;
}
/**
* Client class (abstract).
*
* @api private
*/
constructor(id, server, transport, req, protocol) {
super();
this.id = id;
this.server = server;
this.upgrading = false;
this.upgraded = false;
this.readyState = "opening";
this.writeBuffer = [];
this.packetsFn = [];
this.sentCallbackFn = [];
this.cleanupFn = [];
this.request = req;
this.protocol = protocol;
// Cache IP since it might not be in the req later
if (req.websocket && req.websocket._socket) {
this.remoteAddress = req.websocket._socket.remoteAddress;
} else {
this.remoteAddress = req.connection.remoteAddress;
}
this.checkIntervalTimer = null;
this.upgradeTimeoutTimer = null;
this.pingTimeoutTimer = null;
this.pingIntervalTimer = null;
this.setTransport(transport);
this.onOpen();
}
/**
* Called upon transport considered open.
*
* @api private
*/
private onOpen() {
this.readyState = "open";
// sends an `open` packet
this.transport.sid = this.id;
this.sendPacket(
"open",
JSON.stringify({
sid: this.id,
upgrades: this.getAvailableUpgrades(),
pingInterval: this.server.opts.pingInterval,
pingTimeout: this.server.opts.pingTimeout
})
);
if (this.server.opts.initialPacket) {
this.sendPacket("message", this.server.opts.initialPacket);
}
this.emit("open");
if (this.protocol === 3) {
// in protocol v3, the client sends a ping, and the server answers with a pong
this.resetPingTimeout(
this.server.opts.pingInterval + this.server.opts.pingTimeout
);
} else {
// in protocol v4, the server sends a ping, and the client answers with a pong
this.schedulePing();
}
}
/**
* Called upon transport packet.
*
* @param {Object} packet
* @api private
*/
private onPacket(packet) {
if ("open" !== this.readyState) {
return debug("packet received with closed socket");
}
// export packet event
debug(`received packet ${packet.type}`);
this.emit("packet", packet);
// Reset ping timeout on any packet, incoming data is a good sign of
// other side's liveness
this.resetPingTimeout(
this.server.opts.pingInterval + this.server.opts.pingTimeout
);
switch (packet.type) {
case "ping":
if (this.transport.protocol !== 3) {
this.onError("invalid heartbeat direction");
return;
}
debug("got ping");
this.sendPacket("pong");
this.emit("heartbeat");
break;
case "pong":
if (this.transport.protocol === 3) {
this.onError("invalid heartbeat direction");
return;
}
debug("got pong");
this.pingIntervalTimer.refresh();
this.emit("heartbeat");
break;
case "error":
this.onClose("parse error");
break;
case "message":
this.emit("data", packet.data);
this.emit("message", packet.data);
break;
}
}
/**
* Called upon transport error.
*
* @param {Error} error object
* @api private
*/
private onError(err) {
debug("transport error");
this.onClose("transport error", err);
}
/**
* Pings client every `this.pingInterval` and expects response
* within `this.pingTimeout` or closes connection.
*
* @api private
*/
private schedulePing() {
this.pingIntervalTimer = setTimeout(() => {
debug(
"writing ping packet - expecting pong within %sms",
this.server.opts.pingTimeout
);
this.sendPacket("ping");
this.resetPingTimeout(this.server.opts.pingTimeout);
}, this.server.opts.pingInterval);
}
/**
* Resets ping timeout.
*
* @api private
*/
private resetPingTimeout(timeout) {
clearTimeout(this.pingTimeoutTimer);
this.pingTimeoutTimer = setTimeout(() => {
if (this.readyState === "closed") return;
this.onClose("ping timeout");
}, timeout);
}
/**
* Attaches handlers for the given transport.
*
* @param {Transport} transport
* @api private
*/
private setTransport(transport) {
const onError = this.onError.bind(this);
const onPacket = this.onPacket.bind(this);
const flush = this.flush.bind(this);
const onClose = this.onClose.bind(this, "transport close");
this.transport = transport;
this.transport.once("error", onError);
this.transport.on("packet", onPacket);
this.transport.on("drain", flush);
this.transport.once("close", onClose);
// this function will manage packet events (also message callbacks)
this.setupSendCallback();
this.cleanupFn.push(function() {
transport.removeListener("error", onError);
transport.removeListener("packet", onPacket);
transport.removeListener("drain", flush);
transport.removeListener("close", onClose);
});
}
/**
* Upgrades socket to the given transport
*
* @param {Transport} transport
* @api private
*/
private maybeUpgrade(transport) {
debug(
'might upgrade socket transport from "%s" to "%s"',
this.transport.name,
transport.name
);
this.upgrading = true;
// set transport upgrade timer
this.upgradeTimeoutTimer = setTimeout(() => {
debug("client did not complete upgrade - closing transport");
cleanup();
if ("open" === transport.readyState) {
transport.close();
}
}, this.server.opts.upgradeTimeout);
const onPacket = packet => {
if ("ping" === packet.type && "probe" === packet.data) {
debug("got probe ping packet, sending pong");
transport.send([{ type: "pong", data: "probe" }]);
this.emit("upgrading", transport);
clearInterval(this.checkIntervalTimer);
this.checkIntervalTimer = setInterval(check, 100);
} else if ("upgrade" === packet.type && this.readyState !== "closed") {
debug("got upgrade packet - upgrading");
cleanup();
this.transport.discard();
this.upgraded = true;
this.clearTransport();
this.setTransport(transport);
this.emit("upgrade", transport);
this.flush();
if (this.readyState === "closing") {
transport.close(() => {
this.onClose("forced close");
});
}
} else {
cleanup();
transport.close();
}
};
// we force a polling cycle to ensure a fast upgrade
const check = () => {
if ("polling" === this.transport.name && this.transport.writable) {
debug("writing a noop packet to polling for fast upgrade");
this.transport.send([{ type: "noop" }]);
}
};
const cleanup = () => {
this.upgrading = false;
clearInterval(this.checkIntervalTimer);
this.checkIntervalTimer = null;
clearTimeout(this.upgradeTimeoutTimer);
this.upgradeTimeoutTimer = null;
transport.removeListener("packet", onPacket);
transport.removeListener("close", onTransportClose);
transport.removeListener("error", onError);
this.removeListener("close", onClose);
};
const onError = err => {
debug("client did not complete upgrade - %s", err);
cleanup();
transport.close();
transport = null;
};
const onTransportClose = () => {
onError("transport closed");
};
const onClose = () => {
onError("socket closed");
};
transport.on("packet", onPacket);
transport.once("close", onTransportClose);
transport.once("error", onError);
this.once("close", onClose);
}
/**
* Clears listeners and timers associated with current transport.
*
* @api private
*/
private clearTransport() {
let cleanup;
const toCleanUp = this.cleanupFn.length;
for (let i = 0; i < toCleanUp; i++) {
cleanup = this.cleanupFn.shift();
cleanup();
}
// silence further transport errors and prevent uncaught exceptions
this.transport.on("error", function() {
debug("error triggered by discarded transport");
});
// ensure transport won't stay open
this.transport.close();
clearTimeout(this.pingTimeoutTimer);
}
/**
* Called upon transport considered closed.
* Possible reasons: `ping timeout`, `client error`, `parse error`,
* `transport error`, `server close`, `transport close`
*/
private onClose(reason: string, description?) {
if ("closed" !== this.readyState) {
this.readyState = "closed";
// clear timers
clearTimeout(this.pingIntervalTimer);
clearTimeout(this.pingTimeoutTimer);
clearInterval(this.checkIntervalTimer);
this.checkIntervalTimer = null;
clearTimeout(this.upgradeTimeoutTimer);
// clean writeBuffer in next tick, so developers can still
// grab the writeBuffer on 'close' event
process.nextTick(() => {
this.writeBuffer = [];
});
this.packetsFn = [];
this.sentCallbackFn = [];
this.clearTransport();
this.emit("close", reason, description);
}
}
/**
* Setup and manage send callback
*
* @api private
*/
private setupSendCallback() {
// the message was sent successfully, execute the callback
const onDrain = () => {
if (this.sentCallbackFn.length > 0) {
const seqFn = this.sentCallbackFn.splice(0, 1)[0];
if ("function" === typeof seqFn) {
debug("executing send callback");
seqFn(this.transport);
} else if (Array.isArray(seqFn)) {
debug("executing batch send callback");
const l = seqFn.length;
let i = 0;
for (; i < l; i++) {
if ("function" === typeof seqFn[i]) {
seqFn[i](this.transport);
}
}
}
}
};
this.transport.on("drain", onDrain);
this.cleanupFn.push(() => {
this.transport.removeListener("drain", onDrain);
});
}
/**
* Sends a message packet.
*
* @param {String} message
* @param {Object} options
* @param {Function} callback
* @return {Socket} for chaining
* @api public
*/
public send(data, options, callback?) {
this.sendPacket("message", data, options, callback);
return this;
}
public write(data, options, callback?) {
this.sendPacket("message", data, options, callback);
return this;
}
/**
* Sends a packet.
*
* @param {String} packet type
* @param {String} optional, data
* @param {Object} options
* @api private
*/
private sendPacket(type, data?, options?, callback?) {
if ("function" === typeof options) {
callback = options;
options = null;
}
options = options || {};
options.compress = false !== options.compress;
if ("closing" !== this.readyState && "closed" !== this.readyState) {
debug('sending packet "%s" (%s)', type, data);
const packet: any = {
type: type,
options: options
};
if (data) packet.data = data;
// exports packetCreate event
this.emit("packetCreate", packet);
this.writeBuffer.push(packet);
// add send callback to object, if defined
if (callback) this.packetsFn.push(callback);
this.flush();
}
}
/**
* Attempts to flush the packets buffer.
*
* @api private
*/
private flush() {
if (
"closed" !== this.readyState &&
this.transport.writable &&
this.writeBuffer.length
) {
debug("flushing buffer to transport");
this.emit("flush", this.writeBuffer);
this.server.emit("flush", this, this.writeBuffer);
const wbuf = this.writeBuffer;
this.writeBuffer = [];
if (!this.transport.supportsFraming) {
this.sentCallbackFn.push(this.packetsFn);
} else {
this.sentCallbackFn.push.apply(this.sentCallbackFn, this.packetsFn);
}
this.packetsFn = [];
this.transport.send(wbuf);
this.emit("drain");
this.server.emit("drain", this);
}
}
/**
* Get available upgrades for this socket.
*
* @api private
*/
private getAvailableUpgrades() {
const availableUpgrades = [];
const allUpgrades = this.server.upgrades(this.transport.name);
let i = 0;
const l = allUpgrades.length;
for (; i < l; ++i) {
const upg = allUpgrades[i];
if (this.server.opts.transports.indexOf(upg) !== -1) {
availableUpgrades.push(upg);
}
}
return availableUpgrades;
}
/**
* Closes the socket and underlying transport.
*
* @param {Boolean} discard - optional, discard the transport
* @return {Socket} for chaining
* @api public
*/
public close(discard?: boolean) {
if ("open" !== this.readyState) return;
this.readyState = "closing";
if (this.writeBuffer.length) {
this.once("drain", this.closeTransport.bind(this, discard));
return;
}
this.closeTransport(discard);
}
/**
* Closes the underlying transport.
*
* @param {Boolean} discard
* @api private
*/
private closeTransport(discard) {
if (discard) this.transport.discard();
this.transport.close(this.onClose.bind(this, "forced close"));
}
}