119 lines
5.1 KiB
JavaScript
119 lines
5.1 KiB
JavaScript
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/*
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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/caching-strategies-overview/#stale-while-revalidate)
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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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