import { Subject, AnonymousSubject } from '../../Subject';
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import { Subscriber } from '../../Subscriber';
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import { Observable } from '../../Observable';
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import { Subscription } from '../../Subscription';
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import { Operator } from '../../Operator';
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import { ReplaySubject } from '../../ReplaySubject';
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import { Observer, NextObserver } from '../../types';
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/**
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* WebSocketSubjectConfig is a plain Object that allows us to make our
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* webSocket configurable.
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*
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* <span class="informal">Provides flexibility to {@link webSocket}</span>
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*
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* It defines a set of properties to provide custom behavior in specific
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* moments of the socket's lifecycle. When the connection opens we can
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* use `openObserver`, when the connection is closed `closeObserver`, if we
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* are interested in listening for data coming from server: `deserializer`,
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* which allows us to customize the deserialization strategy of data before passing it
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* to the socket client. By default, `deserializer` is going to apply `JSON.parse` to each message coming
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* from the Server.
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*
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* ## Examples
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*
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* **deserializer**, the default for this property is `JSON.parse` but since there are just two options
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* for incoming data, either be text or binary data. We can apply a custom deserialization strategy
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* or just simply skip the default behaviour.
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*
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* ```ts
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* import { webSocket } from 'rxjs/webSocket';
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*
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* const wsSubject = webSocket({
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* url: 'ws://localhost:8081',
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* //Apply any transformation of your choice.
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* deserializer: ({ data }) => data
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* });
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*
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* wsSubject.subscribe(console.log);
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*
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* // Let's suppose we have this on the Server: ws.send('This is a msg from the server')
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* //output
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* //
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* // This is a msg from the server
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* ```
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*
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* **serializer** allows us to apply custom serialization strategy but for the outgoing messages.
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*
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* ```ts
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* import { webSocket } from 'rxjs/webSocket';
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*
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* const wsSubject = webSocket({
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* url: 'ws://localhost:8081',
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* // Apply any transformation of your choice.
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* serializer: msg => JSON.stringify({ channel: 'webDevelopment', msg: msg })
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* });
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*
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* wsSubject.subscribe(() => subject.next('msg to the server'));
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*
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* // Let's suppose we have this on the Server:
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* // ws.on('message', msg => console.log);
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* // ws.send('This is a msg from the server');
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* // output at server side:
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* //
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* // {"channel":"webDevelopment","msg":"msg to the server"}
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* ```
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*
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* **closeObserver** allows us to set a custom error when an error raises up.
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*
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* ```ts
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* import { webSocket } from 'rxjs/webSocket';
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*
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* const wsSubject = webSocket({
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* url: 'ws://localhost:8081',
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* closeObserver: {
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* next() {
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* const customError = { code: 6666, reason: 'Custom evil reason' }
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* console.log(`code: ${ customError.code }, reason: ${ customError.reason }`);
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* }
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* }
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* });
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*
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* // output
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* // code: 6666, reason: Custom evil reason
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* ```
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*
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* **openObserver**, Let's say we need to make some kind of init task before sending/receiving msgs to the
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* webSocket or sending notification that the connection was successful, this is when
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* openObserver is useful for.
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*
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* ```ts
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* import { webSocket } from 'rxjs/webSocket';
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*
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* const wsSubject = webSocket({
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* url: 'ws://localhost:8081',
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* openObserver: {
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* next: () => {
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* console.log('Connection ok');
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* }
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* }
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* });
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*
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* // output
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* // Connection ok
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* ```
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*/
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export interface WebSocketSubjectConfig<T> {
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/** The url of the socket server to connect to */
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url: string;
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/** The protocol to use to connect */
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protocol?: string | Array<string>;
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/** @deprecated Will be removed in v8. Use {@link deserializer} instead. */
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resultSelector?: (e: MessageEvent) => T;
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/**
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* A serializer used to create messages from passed values before the
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* messages are sent to the server. Defaults to JSON.stringify.
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*/
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serializer?: (value: T) => WebSocketMessage;
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/**
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* A deserializer used for messages arriving on the socket from the
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* server. Defaults to JSON.parse.
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*/
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deserializer?: (e: MessageEvent) => T;
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/**
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* An Observer that watches when open events occur on the underlying web socket.
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*/
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openObserver?: NextObserver<Event>;
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/**
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* An Observer that watches when close events occur on the underlying web socket
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*/
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closeObserver?: NextObserver<CloseEvent>;
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/**
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* An Observer that watches when a close is about to occur due to
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* unsubscription.
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*/
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closingObserver?: NextObserver<void>;
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/**
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* A WebSocket constructor to use. This is useful for situations like using a
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* WebSocket impl in Node (WebSocket is a DOM API), or for mocking a WebSocket
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* for testing purposes
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*/
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WebSocketCtor?: { new (url: string, protocols?: string | string[]): WebSocket };
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/** Sets the `binaryType` property of the underlying WebSocket. */
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binaryType?: 'blob' | 'arraybuffer';
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}
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const DEFAULT_WEBSOCKET_CONFIG: WebSocketSubjectConfig<any> = {
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url: '',
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deserializer: (e: MessageEvent) => JSON.parse(e.data),
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serializer: (value: any) => JSON.stringify(value),
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};
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const WEBSOCKETSUBJECT_INVALID_ERROR_OBJECT =
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'WebSocketSubject.error must be called with an object with an error code, and an optional reason: { code: number, reason: string }';
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export type WebSocketMessage = string | ArrayBuffer | Blob | ArrayBufferView;
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export class WebSocketSubject<T> extends AnonymousSubject<T> {
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// @ts-ignore: Property has no initializer and is not definitely assigned
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private _config: WebSocketSubjectConfig<T>;
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/** @internal */
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// @ts-ignore: Property has no initializer and is not definitely assigned
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_output: Subject<T>;
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private _socket: WebSocket | null = null;
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constructor(urlConfigOrSource: string | WebSocketSubjectConfig<T> | Observable<T>, destination?: Observer<T>) {
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super();
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if (urlConfigOrSource instanceof Observable) {
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this.destination = destination;
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this.source = urlConfigOrSource as Observable<T>;
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} else {
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const config = (this._config = { ...DEFAULT_WEBSOCKET_CONFIG });
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this._output = new Subject<T>();
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if (typeof urlConfigOrSource === 'string') {
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config.url = urlConfigOrSource;
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} else {
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for (const key in urlConfigOrSource) {
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if (urlConfigOrSource.hasOwnProperty(key)) {
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(config as any)[key] = (urlConfigOrSource as any)[key];
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}
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}
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}
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if (!config.WebSocketCtor && WebSocket) {
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config.WebSocketCtor = WebSocket;
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} else if (!config.WebSocketCtor) {
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throw new Error('no WebSocket constructor can be found');
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}
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this.destination = new ReplaySubject();
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}
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}
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/** @deprecated Internal implementation detail, do not use directly. Will be made internal in v8. */
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lift<R>(operator: Operator<T, R>): WebSocketSubject<R> {
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const sock = new WebSocketSubject<R>(this._config as WebSocketSubjectConfig<any>, this.destination as any);
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sock.operator = operator;
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sock.source = this;
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return sock;
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}
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private _resetState() {
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this._socket = null;
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if (!this.source) {
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this.destination = new ReplaySubject();
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}
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this._output = new Subject<T>();
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}
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/**
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* Creates an {@link Observable}, that when subscribed to, sends a message,
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* defined by the `subMsg` function, to the server over the socket to begin a
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* subscription to data over that socket. Once data arrives, the
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* `messageFilter` argument will be used to select the appropriate data for
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* the resulting Observable. When finalization occurs, either due to
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* unsubscription, completion, or error, a message defined by the `unsubMsg`
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* argument will be sent to the server over the WebSocketSubject.
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*
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* @param subMsg A function to generate the subscription message to be sent to
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* the server. This will still be processed by the serializer in the
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* WebSocketSubject's config. (Which defaults to JSON serialization)
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* @param unsubMsg A function to generate the unsubscription message to be
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* sent to the server at finalization. This will still be processed by the
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* serializer in the WebSocketSubject's config.
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* @param messageFilter A predicate for selecting the appropriate messages
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* from the server for the output stream.
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*/
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multiplex(subMsg: () => any, unsubMsg: () => any, messageFilter: (value: T) => boolean) {
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const self = this;
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return new Observable((observer: Observer<T>) => {
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try {
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self.next(subMsg());
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} catch (err) {
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observer.error(err);
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}
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const subscription = self.subscribe({
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next: (x) => {
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try {
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if (messageFilter(x)) {
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observer.next(x);
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}
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} catch (err) {
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observer.error(err);
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}
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},
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error: (err) => observer.error(err),
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complete: () => observer.complete(),
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});
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return () => {
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try {
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self.next(unsubMsg());
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} catch (err) {
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observer.error(err);
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}
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subscription.unsubscribe();
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};
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});
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}
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private _connectSocket() {
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const { WebSocketCtor, protocol, url, binaryType } = this._config;
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const observer = this._output;
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let socket: WebSocket | null = null;
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try {
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socket = protocol ? new WebSocketCtor!(url, protocol) : new WebSocketCtor!(url);
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this._socket = socket;
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if (binaryType) {
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this._socket.binaryType = binaryType;
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}
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} catch (e) {
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observer.error(e);
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return;
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}
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const subscription = new Subscription(() => {
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this._socket = null;
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if (socket && socket.readyState === 1) {
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socket.close();
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}
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});
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socket.onopen = (evt: Event) => {
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const { _socket } = this;
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if (!_socket) {
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socket!.close();
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this._resetState();
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return;
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}
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const { openObserver } = this._config;
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if (openObserver) {
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openObserver.next(evt);
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}
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const queue = this.destination;
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this.destination = Subscriber.create<T>(
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(x) => {
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if (socket!.readyState === 1) {
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try {
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const { serializer } = this._config;
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socket!.send(serializer!(x!));
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} catch (e) {
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this.destination!.error(e);
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}
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}
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},
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(err) => {
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const { closingObserver } = this._config;
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if (closingObserver) {
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closingObserver.next(undefined);
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}
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if (err && err.code) {
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socket!.close(err.code, err.reason);
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} else {
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observer.error(new TypeError(WEBSOCKETSUBJECT_INVALID_ERROR_OBJECT));
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}
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this._resetState();
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},
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() => {
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const { closingObserver } = this._config;
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if (closingObserver) {
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closingObserver.next(undefined);
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}
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socket!.close();
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this._resetState();
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}
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) as Subscriber<any>;
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if (queue && queue instanceof ReplaySubject) {
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subscription.add((queue as ReplaySubject<T>).subscribe(this.destination));
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}
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};
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socket.onerror = (e: Event) => {
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this._resetState();
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observer.error(e);
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};
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socket.onclose = (e: CloseEvent) => {
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if (socket === this._socket) {
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this._resetState();
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}
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const { closeObserver } = this._config;
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if (closeObserver) {
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closeObserver.next(e);
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}
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if (e.wasClean) {
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observer.complete();
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} else {
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observer.error(e);
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}
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};
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socket.onmessage = (e: MessageEvent) => {
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try {
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const { deserializer } = this._config;
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observer.next(deserializer!(e));
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} catch (err) {
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observer.error(err);
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}
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};
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}
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/** @internal */
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protected _subscribe(subscriber: Subscriber<T>): Subscription {
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const { source } = this;
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if (source) {
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return source.subscribe(subscriber);
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}
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if (!this._socket) {
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this._connectSocket();
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}
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this._output.subscribe(subscriber);
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subscriber.add(() => {
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const { _socket } = this;
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if (this._output.observers.length === 0) {
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if (_socket && (_socket.readyState === 1 || _socket.readyState === 0)) {
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_socket.close();
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}
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this._resetState();
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}
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});
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return subscriber;
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}
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unsubscribe() {
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const { _socket } = this;
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if (_socket && (_socket.readyState === 1 || _socket.readyState === 0)) {
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_socket.close();
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}
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this._resetState();
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super.unsubscribe();
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}
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}
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