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254 lines
11 KiB
254 lines
11 KiB
/* |
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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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