masto/dist/esm/adapters/ws/web-socket-connector.js

Mastodon API client for JavaScript, TypeScript, Node.js, browsers

import WebSocket from "isomorphic-ws";
import { createPromiseWithResolvers, ExponentialBackoff, } from "../../utils/index.js";
import { MastoWebSocketError } from "../errors/index.js";
import { waitForClose, waitForOpen } from "./wait-for-events.js";
export class WebSocketConnectorImpl {
    props;
    logger;
    ws;
    killed = false;
    queue = [];
    backoff;
    constructor(props, logger) {
        this.props = props;
        this.logger = logger;
        this.backoff = new ExponentialBackoff({
            maxAttempts: this.props.maxAttempts,
        });
        this.spawn();
    }
    acquire() {
        if (this.killed) {
            throw new MastoWebSocketError("WebSocket closed");
        }
        if (this.ws) {
            return Promise.resolve(this.ws);
        }
        const promiseWithResolvers = createPromiseWithResolvers();
        this.queue.push(promiseWithResolvers);
        return promiseWithResolvers.promise;
    }
    async *[Symbol.asyncIterator]() {
        while (!this.killed) {
            yield await this.acquire();
        }
    }
    kill() {
        this.killed = true;
        this.ws?.close();
        this.backoff.clear();
        for (const { reject } of this.queue) {
            reject(new MastoWebSocketError("WebSocket closed"));
        }
        this.queue = [];
    }
    async spawn() {
        while (!this.killed) {
            try {
                await this.backoff.sleep();
            }
            catch {
                break;
            }
            try {
                this.logger?.log("info", "Connecting to WebSocket...");
                {
                    const ctor = (this.props.implementation ??
                        WebSocket);
                    const ws = new ctor(...this.props.constructorParameters);
                    await waitForOpen(ws);
                    this.ws = ws;
                }
                this.logger?.log("info", "Connected to WebSocket");
                for (const { resolve } of this.queue) {
                    resolve(this.ws);
                }
                this.queue = [];
                await waitForClose(this.ws);
                this.logger?.log("info", "WebSocket closed");
                this.backoff.clear();
            }
            catch (error) {
                this.logger?.log("error", "WebSocket error:", error);
            }
            this.ws = undefined;
        }
        for (const { reject } of this.queue) {
            reject(new MastoWebSocketError(`Failed to connect to WebSocket after ${this.props.maxAttempts} attempts`));
        }
        this.queue = [];
    }
}