/* 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 { cacheWrapper } from 'workbox-core/_private/cacheWrapper.js'; import { fetchWrapper } from 'workbox-core/_private/fetchWrapper.js'; import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js'; import { logger } from 'workbox-core/_private/logger.js'; import { WorkboxError } from 'workbox-core/_private/WorkboxError.js'; import { messages } from './utils/messages.js'; import { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.js'; import './_version.js'; /** * An implementation of a * [stale-while-revalidate]{@link https://developers.google.com/web/fundamentals/instant-and-offline/offline-cookbook/#stale-while-revalidate} * request strategy. * * Resources are requested from both the cache and the network in parallel. * The strategy will respond with the cached version if available, otherwise * wait for the network response. The cache is updated with the network response * with each successful request. * * By default, this strategy will cache responses with a 200 status code as * well as [opaque responses]{@link https://developers.google.com/web/tools/workbox/guides/handle-third-party-requests}. * Opaque responses are cross-origin requests where the response doesn't * support [CORS]{@link https://enable-cors.org/}. * * If the network request fails, and there is no cache match, this will throw * a `WorkboxError` exception. * * @memberof module:workbox-strategies */ class StaleWhileRevalidate { /** * @param {Object} options * @param {string} options.cacheName Cache name to store and retrieve * requests. Defaults to cache names provided by * [workbox-core]{@link module:workbox-core.cacheNames}. * @param {Array} options.plugins [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins} * to use in conjunction with this caching strategy. * @param {Object} options.fetchOptions Values passed along to the * [`init`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters) * of all fetch() requests made by this strategy. * @param {Object} options.matchOptions [`CacheQueryOptions`](https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions) */ constructor(options = {}) { this._cacheName = cacheNames.getRuntimeName(options.cacheName); this._plugins = options.plugins || []; if (options.plugins) { const isUsingCacheWillUpdate = options.plugins.some((plugin) => !!plugin.cacheWillUpdate); this._plugins = isUsingCacheWillUpdate ? options.plugins : [cacheOkAndOpaquePlugin, ...options.plugins]; } else { // No plugins passed in, use the default plugin. this._plugins = [cacheOkAndOpaquePlugin]; } this._fetchOptions = options.fetchOptions; this._matchOptions = options.matchOptions; } /** * This method will perform a request strategy and follows an API that * will work with the * [Workbox Router]{@link module:workbox-routing.Router}. * * @param {Object} options * @param {Request|string} options.request A request to run this strategy for. * @param {Event} [options.event] The event that triggered the request. * @return {Promise} */ async handle({ event, request }) { const logs = []; if (typeof request === 'string') { request = new Request(request); } if (process.env.NODE_ENV !== 'production') { assert.isInstance(request, Request, { moduleName: 'workbox-strategies', className: 'StaleWhileRevalidate', funcName: 'handle', paramName: 'request', }); } const fetchAndCachePromise = this._getFromNetwork({ request, event }); let response = await cacheWrapper.match({ cacheName: this._cacheName, request, event, matchOptions: this._matchOptions, plugins: this._plugins, }); let error; if (response) { if (process.env.NODE_ENV !== 'production') { logs.push(`Found a cached response in the '${this._cacheName}'` + ` cache. Will update with the network response in the background.`); } if (event) { try { event.waitUntil(fetchAndCachePromise); } catch (error) { if (process.env.NODE_ENV !== 'production') { logger.warn(`Unable to ensure service worker stays alive when ` + `updating cache for '${getFriendlyURL(request.url)}'.`); } } } } else { if (process.env.NODE_ENV !== 'production') { logs.push(`No response found in the '${this._cacheName}' cache. ` + `Will wait for the network response.`); } try { response = await fetchAndCachePromise; } catch (err) { error = err; } } if (process.env.NODE_ENV !== 'production') { logger.groupCollapsed(messages.strategyStart('StaleWhileRevalidate', request)); for (const log of logs) { logger.log(log); } messages.printFinalResponse(response); logger.groupEnd(); } if (!response) { throw new WorkboxError('no-response', { url: request.url, error }); } return response; } /** * @param {Object} options * @param {Request} options.request * @param {Event} [options.event] * @return {Promise} * * @private */ async _getFromNetwork({ request, event }) { const response = await fetchWrapper.fetch({ request, event, fetchOptions: this._fetchOptions, plugins: this._plugins, }); const cachePutPromise = cacheWrapper.put({ cacheName: this._cacheName, request, response: response.clone(), event, plugins: this._plugins, }); if (event) { try { event.waitUntil(cachePutPromise); } catch (error) { if (process.env.NODE_ENV !== 'production') { logger.warn(`Unable to ensure service worker stays alive when ` + `updating cache for '${getFriendlyURL(request.url)}'.`); } } } return response; } } export { StaleWhileRevalidate };