255 lines
11 KiB
JavaScript
255 lines
11 KiB
JavaScript
/*
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Copyright 2018 Google LLC
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Use of this source code is governed by an MIT-style
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license that can be found in the LICENSE file or at
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https://opensource.org/licenses/MIT.
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*/
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import { assert } from 'workbox-core/_private/assert.js';
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import { cacheNames } from 'workbox-core/_private/cacheNames.js';
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import { dontWaitFor } from 'workbox-core/_private/dontWaitFor.js';
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import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
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import { logger } from 'workbox-core/_private/logger.js';
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import { registerQuotaErrorCallback } from 'workbox-core/registerQuotaErrorCallback.js';
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import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
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import { CacheExpiration } from './CacheExpiration.js';
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import './_version.js';
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/**
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* This plugin can be used in a `workbox-strategy` to regularly enforce a
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* limit on the age and / or the number of cached requests.
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*
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* It can only be used with `workbox-strategy` instances that have a
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* [custom `cacheName` property set](/web/tools/workbox/guides/configure-workbox#custom_cache_names_in_strategies).
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* In other words, it can't be used to expire entries in strategy that uses the
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* default runtime cache name.
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*
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* Whenever a cached response is used or updated, this plugin will look
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* at the associated cache and remove any old or extra responses.
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*
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* When using `maxAgeSeconds`, responses may be used *once* after expiring
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* because the expiration clean up will not have occurred until *after* the
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* cached response has been used. If the response has a "Date" header, then
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* a light weight expiration check is performed and the response will not be
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* used immediately.
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*
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* When using `maxEntries`, the entry least-recently requested will be removed
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* from the cache first.
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*
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* @memberof workbox-expiration
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*/
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class ExpirationPlugin {
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/**
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* @param {ExpirationPluginOptions} config
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* @param {number} [config.maxEntries] The maximum number of entries to cache.
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* Entries used the least will be removed as the maximum is reached.
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* @param {number} [config.maxAgeSeconds] The maximum age of an entry before
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* it's treated as stale and removed.
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* @param {Object} [config.matchOptions] The [`CacheQueryOptions`](https://developer.mozilla.org/en-US/docs/Web/API/Cache/delete#Parameters)
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* that will be used when calling `delete()` on the cache.
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* @param {boolean} [config.purgeOnQuotaError] Whether to opt this cache in to
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* automatic deletion if the available storage quota has been exceeded.
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*/
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constructor(config = {}) {
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/**
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* A "lifecycle" callback that will be triggered automatically by the
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* `workbox-strategies` handlers when a `Response` is about to be returned
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* from a [Cache](https://developer.mozilla.org/en-US/docs/Web/API/Cache) to
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* the handler. It allows the `Response` to be inspected for freshness and
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* prevents it from being used if the `Response`'s `Date` header value is
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* older than the configured `maxAgeSeconds`.
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*
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* @param {Object} options
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* @param {string} options.cacheName Name of the cache the response is in.
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* @param {Response} options.cachedResponse The `Response` object that's been
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* read from a cache and whose freshness should be checked.
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* @return {Response} Either the `cachedResponse`, if it's
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* fresh, or `null` if the `Response` is older than `maxAgeSeconds`.
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*
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* @private
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*/
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this.cachedResponseWillBeUsed = async ({ event, request, cacheName, cachedResponse, }) => {
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if (!cachedResponse) {
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return null;
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}
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const isFresh = this._isResponseDateFresh(cachedResponse);
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// Expire entries to ensure that even if the expiration date has
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// expired, it'll only be used once.
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const cacheExpiration = this._getCacheExpiration(cacheName);
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dontWaitFor(cacheExpiration.expireEntries());
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// Update the metadata for the request URL to the current timestamp,
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// but don't `await` it as we don't want to block the response.
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const updateTimestampDone = cacheExpiration.updateTimestamp(request.url);
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if (event) {
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try {
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event.waitUntil(updateTimestampDone);
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}
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catch (error) {
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if (process.env.NODE_ENV !== 'production') {
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// The event may not be a fetch event; only log the URL if it is.
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if ('request' in event) {
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logger.warn(`Unable to ensure service worker stays alive when ` +
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`updating cache entry for ` +
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`'${getFriendlyURL(event.request.url)}'.`);
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}
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}
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}
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}
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return isFresh ? cachedResponse : null;
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};
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/**
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* A "lifecycle" callback that will be triggered automatically by the
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* `workbox-strategies` handlers when an entry is added to a cache.
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*
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* @param {Object} options
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* @param {string} options.cacheName Name of the cache that was updated.
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* @param {string} options.request The Request for the cached entry.
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*
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* @private
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*/
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this.cacheDidUpdate = async ({ cacheName, request, }) => {
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if (process.env.NODE_ENV !== 'production') {
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assert.isType(cacheName, 'string', {
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moduleName: 'workbox-expiration',
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className: 'Plugin',
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funcName: 'cacheDidUpdate',
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paramName: 'cacheName',
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});
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assert.isInstance(request, Request, {
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moduleName: 'workbox-expiration',
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className: 'Plugin',
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funcName: 'cacheDidUpdate',
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paramName: 'request',
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});
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}
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const cacheExpiration = this._getCacheExpiration(cacheName);
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await cacheExpiration.updateTimestamp(request.url);
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await cacheExpiration.expireEntries();
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};
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if (process.env.NODE_ENV !== 'production') {
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if (!(config.maxEntries || config.maxAgeSeconds)) {
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throw new WorkboxError('max-entries-or-age-required', {
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moduleName: 'workbox-expiration',
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className: 'Plugin',
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funcName: 'constructor',
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});
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}
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if (config.maxEntries) {
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assert.isType(config.maxEntries, 'number', {
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moduleName: 'workbox-expiration',
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className: 'Plugin',
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funcName: 'constructor',
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paramName: 'config.maxEntries',
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});
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}
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if (config.maxAgeSeconds) {
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assert.isType(config.maxAgeSeconds, 'number', {
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moduleName: 'workbox-expiration',
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className: 'Plugin',
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funcName: 'constructor',
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paramName: 'config.maxAgeSeconds',
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});
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}
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}
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this._config = config;
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this._maxAgeSeconds = config.maxAgeSeconds;
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this._cacheExpirations = new Map();
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if (config.purgeOnQuotaError) {
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registerQuotaErrorCallback(() => this.deleteCacheAndMetadata());
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}
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}
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/**
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* A simple helper method to return a CacheExpiration instance for a given
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* cache name.
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*
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* @param {string} cacheName
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* @return {CacheExpiration}
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*
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* @private
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*/
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_getCacheExpiration(cacheName) {
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if (cacheName === cacheNames.getRuntimeName()) {
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throw new WorkboxError('expire-custom-caches-only');
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}
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let cacheExpiration = this._cacheExpirations.get(cacheName);
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if (!cacheExpiration) {
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cacheExpiration = new CacheExpiration(cacheName, this._config);
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this._cacheExpirations.set(cacheName, cacheExpiration);
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}
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return cacheExpiration;
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}
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/**
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* @param {Response} cachedResponse
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* @return {boolean}
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*
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* @private
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*/
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_isResponseDateFresh(cachedResponse) {
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if (!this._maxAgeSeconds) {
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// We aren't expiring by age, so return true, it's fresh
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return true;
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}
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// Check if the 'date' header will suffice a quick expiration check.
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// See https://github.com/GoogleChromeLabs/sw-toolbox/issues/164 for
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// discussion.
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const dateHeaderTimestamp = this._getDateHeaderTimestamp(cachedResponse);
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if (dateHeaderTimestamp === null) {
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// Unable to parse date, so assume it's fresh.
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return true;
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}
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// If we have a valid headerTime, then our response is fresh iff the
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// headerTime plus maxAgeSeconds is greater than the current time.
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const now = Date.now();
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return dateHeaderTimestamp >= now - this._maxAgeSeconds * 1000;
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}
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/**
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* This method will extract the data header and parse it into a useful
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* value.
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*
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* @param {Response} cachedResponse
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* @return {number|null}
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*
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* @private
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*/
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_getDateHeaderTimestamp(cachedResponse) {
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if (!cachedResponse.headers.has('date')) {
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return null;
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}
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const dateHeader = cachedResponse.headers.get('date');
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const parsedDate = new Date(dateHeader);
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const headerTime = parsedDate.getTime();
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// If the Date header was invalid for some reason, parsedDate.getTime()
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// will return NaN.
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if (isNaN(headerTime)) {
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return null;
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}
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return headerTime;
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}
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/**
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* This is a helper method that performs two operations:
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*
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* - Deletes *all* the underlying Cache instances associated with this plugin
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* instance, by calling caches.delete() on your behalf.
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* - Deletes the metadata from IndexedDB used to keep track of expiration
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* details for each Cache instance.
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*
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* When using cache expiration, calling this method is preferable to calling
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* `caches.delete()` directly, since this will ensure that the IndexedDB
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* metadata is also cleanly removed and open IndexedDB instances are deleted.
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*
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* Note that if you're *not* using cache expiration for a given cache, calling
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* `caches.delete()` and passing in the cache's name should be sufficient.
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* There is no Workbox-specific method needed for cleanup in that case.
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*/
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async deleteCacheAndMetadata() {
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// Do this one at a time instead of all at once via `Promise.all()` to
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// reduce the chance of inconsistency if a promise rejects.
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for (const [cacheName, cacheExpiration] of this._cacheExpirations) {
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await self.caches.delete(cacheName);
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await cacheExpiration.delete();
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}
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// Reset this._cacheExpirations to its initial state.
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this._cacheExpirations = new Map();
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}
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}
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export { ExpirationPlugin };
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