+++ /dev/null
-import { WebSocketSubject, WebSocketSubjectConfig } from './WebSocketSubject';
-
-/**
- * Wrapper around the w3c-compatible WebSocket object provided by the browser.
- *
- * <span class="informal">{@link Subject} that communicates with a server via WebSocket</span>
- *
- * `webSocket` is a factory function that produces a `WebSocketSubject`,
- * which can be used to make WebSocket connection with an arbitrary endpoint.
- * `webSocket` accepts as an argument either a string with url of WebSocket endpoint, or an
- * {@link WebSocketSubjectConfig} object for providing additional configuration, as
- * well as Observers for tracking lifecycle of WebSocket connection.
- *
- * When `WebSocketSubject` is subscribed, it attempts to make a socket connection,
- * unless there is one made already. This means that many subscribers will always listen
- * on the same socket, thus saving resources. If however, two instances are made of `WebSocketSubject`,
- * even if these two were provided with the same url, they will attempt to make separate
- * connections. When consumer of a `WebSocketSubject` unsubscribes, socket connection is closed,
- * only if there are no more subscribers still listening. If after some time a consumer starts
- * subscribing again, connection is reestablished.
- *
- * Once connection is made, whenever a new message comes from the server, `WebSocketSubject` will emit that
- * message as a value in the stream. By default, a message from the socket is parsed via `JSON.parse`. If you
- * want to customize how deserialization is handled (if at all), you can provide custom `resultSelector`
- * function in {@link WebSocketSubject}. When connection closes, stream will complete, provided it happened without
- * any errors. If at any point (starting, maintaining or closing a connection) there is an error,
- * stream will also error with whatever WebSocket API has thrown.
- *
- * By virtue of being a {@link Subject}, `WebSocketSubject` allows for receiving and sending messages from the server. In order
- * to communicate with a connected endpoint, use `next`, `error` and `complete` methods. `next` sends a value to the server, so bear in mind
- * that this value will not be serialized beforehand. Because of This, `JSON.stringify` will have to be called on a value by hand,
- * before calling `next` with a result. Note also that if at the moment of nexting value
- * there is no socket connection (for example no one is subscribing), those values will be buffered, and sent when connection
- * is finally established. `complete` method closes socket connection. `error` does the same,
- * as well as notifying the server that something went wrong via status code and string with details of what happened.
- * Since status code is required in WebSocket API, `WebSocketSubject` does not allow, like regular `Subject`,
- * arbitrary values being passed to the `error` method. It needs to be called with an object that has `code`
- * property with status code number and optional `reason` property with string describing details
- * of an error.
- *
- * Calling `next` does not affect subscribers of `WebSocketSubject` - they have no
- * information that something was sent to the server (unless of course the server
- * responds somehow to a message). On the other hand, since calling `complete` triggers
- * an attempt to close socket connection. If that connection is closed without any errors, stream will
- * complete, thus notifying all subscribers. And since calling `error` closes
- * socket connection as well, just with a different status code for the server, if closing itself proceeds
- * without errors, subscribed Observable will not error, as one might expect, but complete as usual. In both cases
- * (calling `complete` or `error`), if process of closing socket connection results in some errors, *then* stream
- * will error.
- *
- * **Multiplexing**
- *
- * `WebSocketSubject` has an additional operator, not found in other Subjects. It is called `multiplex` and it is
- * used to simulate opening several socket connections, while in reality maintaining only one.
- * For example, an application has both chat panel and real-time notifications about sport news. Since these are two distinct functions,
- * it would make sense to have two separate connections for each. Perhaps there could even be two separate services with WebSocket
- * endpoints, running on separate machines with only GUI combining them together. Having a socket connection
- * for each functionality could become too resource expensive. It is a common pattern to have single
- * WebSocket endpoint that acts as a gateway for the other services (in this case chat and sport news services).
- * Even though there is a single connection in a client app, having the ability to manipulate streams as if it
- * were two separate sockets is desirable. This eliminates manually registering and unregistering in a gateway for
- * given service and filter out messages of interest. This is exactly what `multiplex` method is for.
- *
- * Method accepts three parameters. First two are functions returning subscription and unsubscription messages
- * respectively. These are messages that will be sent to the server, whenever consumer of resulting Observable
- * subscribes and unsubscribes. Server can use them to verify that some kind of messages should start or stop
- * being forwarded to the client. In case of the above example application, after getting subscription message with proper identifier,
- * gateway server can decide that it should connect to real sport news service and start forwarding messages from it.
- * Note that both messages will be sent as returned by the functions, they are by default serialized using JSON.stringify, just
- * as messages pushed via `next`. Also bear in mind that these messages will be sent on *every* subscription and
- * unsubscription. This is potentially dangerous, because one consumer of an Observable may unsubscribe and the server
- * might stop sending messages, since it got unsubscription message. This needs to be handled
- * on the server or using {@link publish} on a Observable returned from 'multiplex'.
- *
- * Last argument to `multiplex` is a `messageFilter` function which should return a boolean. It is used to filter out messages
- * sent by the server to only those that belong to simulated WebSocket stream. For example, server might mark these
- * messages with some kind of string identifier on a message object and `messageFilter` would return `true`
- * if there is such identifier on an object emitted by the socket. Messages which returns `false` in `messageFilter` are simply skipped,
- * and are not passed down the stream.
- *
- * Return value of `multiplex` is an Observable with messages incoming from emulated socket connection. Note that this
- * is not a `WebSocketSubject`, so calling `next` or `multiplex` again will fail. For pushing values to the
- * server, use root `WebSocketSubject`.
- *
- * ### Examples
- * #### Listening for messages from the server
- * ```ts
- * import { webSocket } from "rxjs/webSocket";
- * const subject = webSocket("ws://localhost:8081");
- *
- * subject.subscribe(
- * msg => console.log('message received: ' + msg), // Called whenever there is a message from the server.
- * err => console.log(err), // Called if at any point WebSocket API signals some kind of error.
- * () => console.log('complete') // Called when connection is closed (for whatever reason).
- * );
- * ```
- *
- * #### Pushing messages to the server
- * ```ts
- * import { webSocket } from "rxjs/webSocket";
- * const subject = webSocket('ws://localhost:8081');
- *
- * subject.subscribe();
- * // Note that at least one consumer has to subscribe to the created subject - otherwise "nexted" values will be just buffered and not sent,
- * // since no connection was established!
- *
- * subject.next({message: 'some message'});
- * // This will send a message to the server once a connection is made. Remember value is serialized with JSON.stringify by default!
- *
- * subject.complete(); // Closes the connection.
- *
- * subject.error({code: 4000, reason: 'I think our app just broke!'});
- * // Also closes the connection, but let's the server know that this closing is caused by some error.
- * ```
- *
- * #### Multiplexing WebSocket
- * ```ts
- * import { webSocket } from "rxjs/webSocket";
- * const subject = webSocket('ws://localhost:8081');
- *
- * const observableA = subject.multiplex(
- * () => ({subscribe: 'A'}), // When server gets this message, it will start sending messages for 'A'...
- * () => ({unsubscribe: 'A'}), // ...and when gets this one, it will stop.
- * message => message.type === 'A' // If the function returns `true` message is passed down the stream. Skipped if the function returns false.
- * );
- *
- * const observableB = subject.multiplex( // And the same goes for 'B'.
- * () => ({subscribe: 'B'}),
- * () => ({unsubscribe: 'B'}),
- * message => message.type === 'B'
- * );
- *
- * const subA = observableA.subscribe(messageForA => console.log(messageForA));
- * // At this moment WebSocket connection is established. Server gets '{"subscribe": "A"}' message and starts sending messages for 'A',
- * // which we log here.
- *
- * const subB = observableB.subscribe(messageForB => console.log(messageForB));
- * // Since we already have a connection, we just send '{"subscribe": "B"}' message to the server. It starts sending messages for 'B',
- * // which we log here.
- *
- * subB.unsubscribe();
- * // Message '{"unsubscribe": "B"}' is sent to the server, which stops sending 'B' messages.
- *
- * subA.unsubscribe();
- * // Message '{"unsubscribe": "A"}' makes the server stop sending messages for 'A'. Since there is no more subscribers to root Subject,
- * // socket connection closes.
- * ```
- *
- *
- * @param {string|WebSocketSubjectConfig} urlConfigOrSource The WebSocket endpoint as an url or an object with
- * configuration and additional Observers.
- * @return {WebSocketSubject} Subject which allows to both send and receive messages via WebSocket connection.
- */
-export function webSocket<T>(urlConfigOrSource: string | WebSocketSubjectConfig<T>): WebSocketSubject<T> {
- return new WebSocketSubject<T>(urlConfigOrSource);
-}
projects / dotfiles / .git / blobdiff