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118 lines
5.1 KiB
118 lines
5.1 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 { logger } from 'workbox-core/_private/logger.js'; |
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import { WorkboxError } from 'workbox-core/_private/WorkboxError.js'; |
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import { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.js'; |
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import { Strategy } from './Strategy.js'; |
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import { messages } from './utils/messages.js'; |
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import './_version.js'; |
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/** |
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* An implementation of a |
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* [stale-while-revalidate](https://developer.chrome.com/docs/workbox/reference/workbox-strategies/#type-StaleWhileRevalidate) |
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* request strategy. |
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* |
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* Resources are requested from both the cache and the network in parallel. |
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* The strategy will respond with the cached version if available, otherwise |
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* wait for the network response. The cache is updated with the network response |
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* with each successful request. |
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* |
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* By default, this strategy will cache responses with a 200 status code as |
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* well as [opaque responses](https://developer.chrome.com/docs/workbox/caching-resources-during-runtime/#opaque-responses). |
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* Opaque responses are cross-origin requests where the response doesn't |
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* support [CORS](https://enable-cors.org/). |
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* |
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* If the network request fails, and there is no cache match, this will throw |
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* a `WorkboxError` exception. |
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* |
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* @extends workbox-strategies.Strategy |
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* @memberof workbox-strategies |
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*/ |
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class StaleWhileRevalidate extends Strategy { |
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/** |
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* @param {Object} [options] |
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* @param {string} [options.cacheName] Cache name to store and retrieve |
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* requests. Defaults to cache names provided by |
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* {@link workbox-core.cacheNames}. |
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* @param {Array<Object>} [options.plugins] [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins} |
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* to use in conjunction with this caching strategy. |
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* @param {Object} [options.fetchOptions] Values passed along to the |
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* [`init`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters) |
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* of [non-navigation](https://github.com/GoogleChrome/workbox/issues/1796) |
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* `fetch()` requests made by this strategy. |
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* @param {Object} [options.matchOptions] [`CacheQueryOptions`](https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions) |
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*/ |
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constructor(options = {}) { |
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super(options); |
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// If this instance contains no plugins with a 'cacheWillUpdate' callback, |
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// prepend the `cacheOkAndOpaquePlugin` plugin to the plugins list. |
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if (!this.plugins.some((p) => 'cacheWillUpdate' in p)) { |
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this.plugins.unshift(cacheOkAndOpaquePlugin); |
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} |
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} |
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/** |
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* @private |
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* @param {Request|string} request A request to run this strategy for. |
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* @param {workbox-strategies.StrategyHandler} handler The event that |
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* triggered the request. |
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* @return {Promise<Response>} |
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*/ |
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async _handle(request, handler) { |
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const logs = []; |
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if (process.env.NODE_ENV !== 'production') { |
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assert.isInstance(request, Request, { |
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moduleName: 'workbox-strategies', |
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className: this.constructor.name, |
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funcName: 'handle', |
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paramName: 'request', |
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}); |
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} |
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const fetchAndCachePromise = handler.fetchAndCachePut(request).catch(() => { |
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// Swallow this error because a 'no-response' error will be thrown in |
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// main handler return flow. This will be in the `waitUntil()` flow. |
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}); |
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void handler.waitUntil(fetchAndCachePromise); |
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let response = await handler.cacheMatch(request); |
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let error; |
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if (response) { |
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if (process.env.NODE_ENV !== 'production') { |
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logs.push(`Found a cached response in the '${this.cacheName}'` + |
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` cache. Will update with the network response in the background.`); |
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} |
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} |
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else { |
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if (process.env.NODE_ENV !== 'production') { |
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logs.push(`No response found in the '${this.cacheName}' cache. ` + |
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`Will wait for the network response.`); |
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} |
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try { |
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// NOTE(philipwalton): Really annoying that we have to type cast here. |
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// https://github.com/microsoft/TypeScript/issues/20006 |
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response = (await fetchAndCachePromise); |
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} |
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catch (err) { |
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if (err instanceof Error) { |
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error = err; |
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} |
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} |
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} |
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if (process.env.NODE_ENV !== 'production') { |
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logger.groupCollapsed(messages.strategyStart(this.constructor.name, request)); |
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for (const log of logs) { |
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logger.log(log); |
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} |
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messages.printFinalResponse(response); |
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logger.groupEnd(); |
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} |
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if (!response) { |
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throw new WorkboxError('no-response', { url: request.url, error }); |
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} |
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return response; |
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} |
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} |
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export { StaleWhileRevalidate };
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