@stackbit/cms-contentful/src/lazy-poller.ts

Stackbit Contentful CMS Interface

export interface LazyPollerOptions<T> {
    notificationCallback: T;
    sleepTimeoutMs?: number;
    pollingIntervalMs?: number;
    logger: any;
}

export abstract class LazyPoller<T> {
    protected notificationCallback: T;
    private readonly sleepTimeoutMs: number;
    private readonly pollingIntervalMs: number;
    private sleepTimeout: null | ReturnType<typeof setTimeout>;
    private pollTimeout: null | ReturnType<typeof setTimeout>;
    private isSleeping: boolean;
    private logger: any;

    protected constructor({ notificationCallback, sleepTimeoutMs = 30 * 60 * 1000, pollingIntervalMs = 1000, logger }: LazyPollerOptions<T>) {
        this.notificationCallback = notificationCallback;
        this.sleepTimeoutMs = sleepTimeoutMs;
        this.pollingIntervalMs = pollingIntervalMs;
        this.logger = logger;
        this.sleepTimeout = null;
        this.pollTimeout = null;
        this.isSleeping = true;
        this.sleep = this.sleep.bind(this);
        this.callPoll = this.callPoll.bind(this);
    }

    resetSleepTimer() {
        if (this.sleepTimeout) {
            clearTimeout(this.sleepTimeout);
        }
        this.sleepTimeout = setTimeout(this.sleep, this.sleepTimeoutMs);
        if (this.isSleeping) {
            this.logger.debug('start polling');
            this.isSleeping = false;
            this.setPollTimeout();
        }
    }

    sleep() {
        this.logger.debug('sleep');
        if (this.sleepTimeout) {
            clearTimeout(this.sleepTimeout);
            this.sleepTimeout = null;
        }
        this.isSleeping = true;
        if (this.pollTimeout) {
            clearTimeout(this.pollTimeout);
            this.pollTimeout = null;
        }
    }

    private setPollTimeout() {
        this.pollTimeout = setTimeout(this.callPoll, this.pollingIntervalMs);
    }

    private async callPoll() {
        this.pollTimeout = null;
        return Promise.resolve(this.poll(this.notificationCallback))
            .catch((error) => {
                this.logger.error('error in pollCallback', { error: error.message });
            })
            .finally(() => {
                if (!this.isSleeping) {
                    this.setPollTimeout();
                }
            });
    }

    protected abstract poll(notificationCallback: T): any;
}