import * as ws from 'ws';
import { SessionRequest, OrisonServer, SessionState } from './server';
export declare type WebSocketHandler<T = any> = (context: {
    req: SessionRequest;
    data: any;
    socket: ws;
    service: WebSocketService;
}) => Promise<T>;
export default class WebSocketService {
    private subscriptions;
    private endpoints;
    initialize(): void;
    private getEndpoints;
    handleConnection(_: OrisonServer, socket: ws, req: SessionRequest): void;
    addSubscription(subscription: Subscription): void;
    /**
     * Gets a Subscription added with `addSubscription` by its path name.
     * @param path the path of the subscription
     */
    getSubscription(path: string): Subscription;
}
export declare class Subscription {
    path: string;
    options?: SubscriptionOptions | undefined;
    listeners: [ws, SessionRequest][];
    constructor(path: string, options?: SubscriptionOptions | undefined);
    /**
     * Calls the given function for each subscribed clients, and sends them the data returned by the function.
     * If the data returned by the function is `null` or `undefined`, then the client will not be sent any data.
     * @param dataGenerator the generator for the data to send
     */
    broadcast(dataGenerator: (state: SessionState) => any): void;
}
export interface SubscriptionArgs {
    req: SessionRequest;
    socket: ws;
    data?: any;
}
export interface SubscriptionOptions {
    /**
     * Called when a client socket requests to subscribe.
     * @returns data to return to the client, or `null` or `undefined` if they should not be added to the list of subscribed sockets.
     * An empty object (`{}`) will add the client to the list.
     */
    onSubscribeRequest?: (args: SubscriptionArgs) => Promise<any>;
    /**
     * Called when a client requests to unsubscribe.
     * @returns data to return to the client, or `null` or `undefined` if no data
     */
    onUnsubscribeRequest?: (args: SubscriptionArgs) => Promise<any>;
}