GoScrobble/web/node_modules/workbox-expiration/ExpirationPlugin.js

/*
  Copyright 2018 Google LLC

  Use of this source code is governed by an MIT-style
  license that can be found in the LICENSE file or at
  https://opensource.org/licenses/MIT.
*/
import { assert } from 'workbox-core/_private/assert.js';
import { cacheNames } from 'workbox-core/_private/cacheNames.js';
import { dontWaitFor } from 'workbox-core/_private/dontWaitFor.js';
import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
import { logger } from 'workbox-core/_private/logger.js';
import { registerQuotaErrorCallback } from 'workbox-core/registerQuotaErrorCallback.js';
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import { CacheExpiration } from './CacheExpiration.js';
import './_version.js';
/**
 * This plugin can be used in the Workbox APIs to regularly enforce a
 * limit on the age and / or the number of cached requests.
 *
 * Whenever a cached request is used or updated, this plugin will look
 * at the used Cache and remove any old or extra requests.
 *
 * When using `maxAgeSeconds`, requests may be used *once* after expiring
 * because the expiration clean up will not have occurred until *after* the
 * cached request has been used. If the request has a "Date" header, then
 * a light weight expiration check is performed and the request will not be
 * used immediately.
 *
 * When using `maxEntries`, the entry least-recently requested will be removed
 * from the cache first.
 *
 * @memberof module:workbox-expiration
 */
class ExpirationPlugin {
    /**
     * @param {Object} config
     * @param {number} [config.maxEntries] The maximum number of entries to cache.
     * Entries used the least will be removed as the maximum is reached.
     * @param {number} [config.maxAgeSeconds] The maximum age of an entry before
     * it's treated as stale and removed.
     * @param {boolean} [config.purgeOnQuotaError] Whether to opt this cache in to
     * automatic deletion if the available storage quota has been exceeded.
     */
    constructor(config = {}) {
        /**
         * A "lifecycle" callback that will be triggered automatically by the
         * `workbox-strategies` handlers when a `Response` is about to be returned
         * from a [Cache](https://developer.mozilla.org/en-US/docs/Web/API/Cache) to
         * the handler. It allows the `Response` to be inspected for freshness and
         * prevents it from being used if the `Response`'s `Date` header value is
         * older than the configured `maxAgeSeconds`.
         *
         * @param {Object} options
         * @param {string} options.cacheName Name of the cache the response is in.
         * @param {Response} options.cachedResponse The `Response` object that's been
         *     read from a cache and whose freshness should be checked.
         * @return {Response} Either the `cachedResponse`, if it's
         *     fresh, or `null` if the `Response` is older than `maxAgeSeconds`.
         *
         * @private
         */
        this.cachedResponseWillBeUsed = async ({ event, request, cacheName, cachedResponse }) => {
            if (!cachedResponse) {
                return null;
            }
            const isFresh = this._isResponseDateFresh(cachedResponse);
            // Expire entries to ensure that even if the expiration date has
            // expired, it'll only be used once.
            const cacheExpiration = this._getCacheExpiration(cacheName);
            dontWaitFor(cacheExpiration.expireEntries());
            // Update the metadata for the request URL to the current timestamp,
            // but don't `await` it as we don't want to block the response.
            const updateTimestampDone = cacheExpiration.updateTimestamp(request.url);
            if (event) {
                try {
                    event.waitUntil(updateTimestampDone);
                }
                catch (error) {
                    if (process.env.NODE_ENV !== 'production') {
                        // The event may not be a fetch event; only log the URL if it is.
                        if ('request' in event) {
                            logger.warn(`Unable to ensure service worker stays alive when ` +
                                `updating cache entry for ` +
                                `'${getFriendlyURL(event.request.url)}'.`);
                        }
                    }
                }
            }
            return isFresh ? cachedResponse : null;
        };
        /**
         * A "lifecycle" callback that will be triggered automatically by the
         * `workbox-strategies` handlers when an entry is added to a cache.
         *
         * @param {Object} options
         * @param {string} options.cacheName Name of the cache that was updated.
         * @param {string} options.request The Request for the cached entry.
         *
         * @private
         */
        this.cacheDidUpdate = async ({ cacheName, request }) => {
            if (process.env.NODE_ENV !== 'production') {
                assert.isType(cacheName, 'string', {
                    moduleName: 'workbox-expiration',
                    className: 'Plugin',
                    funcName: 'cacheDidUpdate',
                    paramName: 'cacheName',
                });
                assert.isInstance(request, Request, {
                    moduleName: 'workbox-expiration',
                    className: 'Plugin',
                    funcName: 'cacheDidUpdate',
                    paramName: 'request',
                });
            }
            const cacheExpiration = this._getCacheExpiration(cacheName);
            await cacheExpiration.updateTimestamp(request.url);
            await cacheExpiration.expireEntries();
        };
        if (process.env.NODE_ENV !== 'production') {
            if (!(config.maxEntries || config.maxAgeSeconds)) {
                throw new WorkboxError('max-entries-or-age-required', {
                    moduleName: 'workbox-expiration',
                    className: 'Plugin',
                    funcName: 'constructor',
                });
            }
            if (config.maxEntries) {
                assert.isType(config.maxEntries, 'number', {
                    moduleName: 'workbox-expiration',
                    className: 'Plugin',
                    funcName: 'constructor',
                    paramName: 'config.maxEntries',
                });
            }
            if (config.maxAgeSeconds) {
                assert.isType(config.maxAgeSeconds, 'number', {
                    moduleName: 'workbox-expiration',
                    className: 'Plugin',
                    funcName: 'constructor',
                    paramName: 'config.maxAgeSeconds',
                });
            }
        }
        this._config = config;
        this._maxAgeSeconds = config.maxAgeSeconds;
        this._cacheExpirations = new Map();
        if (config.purgeOnQuotaError) {
            registerQuotaErrorCallback(() => this.deleteCacheAndMetadata());
        }
    }
    /**
     * A simple helper method to return a CacheExpiration instance for a given
     * cache name.
     *
     * @param {string} cacheName
     * @return {CacheExpiration}
     *
     * @private
     */
    _getCacheExpiration(cacheName) {
        if (cacheName === cacheNames.getRuntimeName()) {
            throw new WorkboxError('expire-custom-caches-only');
        }
        let cacheExpiration = this._cacheExpirations.get(cacheName);
        if (!cacheExpiration) {
            cacheExpiration = new CacheExpiration(cacheName, this._config);
            this._cacheExpirations.set(cacheName, cacheExpiration);
        }
        return cacheExpiration;
    }
    /**
     * @param {Response} cachedResponse
     * @return {boolean}
     *
     * @private
     */
    _isResponseDateFresh(cachedResponse) {
        if (!this._maxAgeSeconds) {
            // We aren't expiring by age, so return true, it's fresh
            return true;
        }
        // Check if the 'date' header will suffice a quick expiration check.
        // See https://github.com/GoogleChromeLabs/sw-toolbox/issues/164 for
        // discussion.
        const dateHeaderTimestamp = this._getDateHeaderTimestamp(cachedResponse);
        if (dateHeaderTimestamp === null) {
            // Unable to parse date, so assume it's fresh.
            return true;
        }
        // If we have a valid headerTime, then our response is fresh iff the
        // headerTime plus maxAgeSeconds is greater than the current time.
        const now = Date.now();
        return dateHeaderTimestamp >= now - (this._maxAgeSeconds * 1000);
    }
    /**
     * This method will extract the data header and parse it into a useful
     * value.
     *
     * @param {Response} cachedResponse
     * @return {number|null}
     *
     * @private
     */
    _getDateHeaderTimestamp(cachedResponse) {
        if (!cachedResponse.headers.has('date')) {
            return null;
        }
        const dateHeader = cachedResponse.headers.get('date');
        const parsedDate = new Date(dateHeader);
        const headerTime = parsedDate.getTime();
        // If the Date header was invalid for some reason, parsedDate.getTime()
        // will return NaN.
        if (isNaN(headerTime)) {
            return null;
        }
        return headerTime;
    }
    /**
     * This is a helper method that performs two operations:
     *
     * - Deletes *all* the underlying Cache instances associated with this plugin
     * instance, by calling caches.delete() on your behalf.
     * - Deletes the metadata from IndexedDB used to keep track of expiration
     * details for each Cache instance.
     *
     * When using cache expiration, calling this method is preferable to calling
     * `caches.delete()` directly, since this will ensure that the IndexedDB
     * metadata is also cleanly removed and open IndexedDB instances are deleted.
     *
     * Note that if you're *not* using cache expiration for a given cache, calling
     * `caches.delete()` and passing in the cache's name should be sufficient.
     * There is no Workbox-specific method needed for cleanup in that case.
     */
    async deleteCacheAndMetadata() {
        // Do this one at a time instead of all at once via `Promise.all()` to
        // reduce the chance of inconsistency if a promise rejects.
        for (const [cacheName, cacheExpiration] of this._cacheExpirations) {
            await self.caches.delete(cacheName);
            await cacheExpiration.delete();
        }
        // Reset this._cacheExpirations to its initial state.
        this._cacheExpirations = new Map();
    }
}
export { ExpirationPlugin };