/* Copyright 2020 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 { copyResponse } from 'workbox-core/copyResponse.js'; import { cacheNames } from 'workbox-core/_private/cacheNames.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 { Strategy } from 'workbox-strategies/Strategy.js'; import './_version.js'; /** * A {@link workbox-strategies.Strategy} implementation * specifically designed to work with * {@link workbox-precaching.PrecacheController} * to both cache and fetch precached assets. * * Note: an instance of this class is created automatically when creating a * `PrecacheController`; it's generally not necessary to create this yourself. * * @extends workbox-strategies.Strategy * @memberof workbox-precaching */ class PrecacheStrategy extends Strategy { /** * * @param {Object} [options] * @param {string} [options.cacheName] Cache name to store and retrieve * requests. Defaults to the cache names provided by * {@link workbox-core.cacheNames}. * @param {Array} [options.plugins] {@link https://developers.google.com/web/tools/workbox/guides/using-plugins|Plugins} * to use in conjunction with this caching strategy. * @param {Object} [options.fetchOptions] Values passed along to the * {@link https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters|init} * of all fetch() requests made by this strategy. * @param {Object} [options.matchOptions] The * {@link https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions|CacheQueryOptions} * for any `cache.match()` or `cache.put()` calls made by this strategy. * @param {boolean} [options.fallbackToNetwork=true] Whether to attempt to * get the response from the network if there's a precache miss. */ constructor(options = {}) { options.cacheName = cacheNames.getPrecacheName(options.cacheName); super(options); this._fallbackToNetwork = options.fallbackToNetwork === false ? false : true; // Redirected responses cannot be used to satisfy a navigation request, so // any redirected response must be "copied" rather than cloned, so the new // response doesn't contain the `redirected` flag. See: // https://bugs.chromium.org/p/chromium/issues/detail?id=669363&desc=2#c1 this.plugins.push(PrecacheStrategy.copyRedirectedCacheableResponsesPlugin); } /** * @private * @param {Request|string} request A request to run this strategy for. * @param {workbox-strategies.StrategyHandler} handler The event that * triggered the request. * @return {Promise} */ async _handle(request, handler) { const response = await handler.cacheMatch(request); if (response) { return response; } // If this is an `install` event for an entry that isn't already cached, // then populate the cache. if (handler.event && handler.event.type === 'install') { return await this._handleInstall(request, handler); } // Getting here means something went wrong. An entry that should have been // precached wasn't found in the cache. return await this._handleFetch(request, handler); } async _handleFetch(request, handler) { let response; const params = (handler.params || {}); // Fall back to the network if we're configured to do so. if (this._fallbackToNetwork) { if (process.env.NODE_ENV !== 'production') { logger.warn(`The precached response for ` + `${getFriendlyURL(request.url)} in ${this.cacheName} was not ` + `found. Falling back to the network.`); } const integrityInManifest = params.integrity; const integrityInRequest = request.integrity; const noIntegrityConflict = !integrityInRequest || integrityInRequest === integrityInManifest; // Do not add integrity if the original request is no-cors // See https://github.com/GoogleChrome/workbox/issues/3096 response = await handler.fetch(new Request(request, { integrity: request.mode !== 'no-cors' ? integrityInRequest || integrityInManifest : undefined, })); // It's only "safe" to repair the cache if we're using SRI to guarantee // that the response matches the precache manifest's expectations, // and there's either a) no integrity property in the incoming request // or b) there is an integrity, and it matches the precache manifest. // See https://github.com/GoogleChrome/workbox/issues/2858 // Also if the original request users no-cors we don't use integrity. // See https://github.com/GoogleChrome/workbox/issues/3096 if (integrityInManifest && noIntegrityConflict && request.mode !== 'no-cors') { this._useDefaultCacheabilityPluginIfNeeded(); const wasCached = await handler.cachePut(request, response.clone()); if (process.env.NODE_ENV !== 'production') { if (wasCached) { logger.log(`A response for ${getFriendlyURL(request.url)} ` + `was used to "repair" the precache.`); } } } } else { // This shouldn't normally happen, but there are edge cases: // https://github.com/GoogleChrome/workbox/issues/1441 throw new WorkboxError('missing-precache-entry', { cacheName: this.cacheName, url: request.url, }); } if (process.env.NODE_ENV !== 'production') { const cacheKey = params.cacheKey || (await handler.getCacheKey(request, 'read')); // Workbox is going to handle the route. // print the routing details to the console. logger.groupCollapsed(`Precaching is responding to: ` + getFriendlyURL(request.url)); logger.log(`Serving the precached url: ${getFriendlyURL(cacheKey instanceof Request ? cacheKey.url : cacheKey)}`); logger.groupCollapsed(`View request details here.`); logger.log(request); logger.groupEnd(); logger.groupCollapsed(`View response details here.`); logger.log(response); logger.groupEnd(); logger.groupEnd(); } return response; } async _handleInstall(request, handler) { this._useDefaultCacheabilityPluginIfNeeded(); const response = await handler.fetch(request); // Make sure we defer cachePut() until after we know the response // should be cached; see https://github.com/GoogleChrome/workbox/issues/2737 const wasCached = await handler.cachePut(request, response.clone()); if (!wasCached) { // Throwing here will lead to the `install` handler failing, which // we want to do if *any* of the responses aren't safe to cache. throw new WorkboxError('bad-precaching-response', { url: request.url, status: response.status, }); } return response; } /** * This method is complex, as there a number of things to account for: * * The `plugins` array can be set at construction, and/or it might be added to * to at any time before the strategy is used. * * At the time the strategy is used (i.e. during an `install` event), there * needs to be at least one plugin that implements `cacheWillUpdate` in the * array, other than `copyRedirectedCacheableResponsesPlugin`. * * - If this method is called and there are no suitable `cacheWillUpdate` * plugins, we need to add `defaultPrecacheCacheabilityPlugin`. * * - If this method is called and there is exactly one `cacheWillUpdate`, then * we don't have to do anything (this might be a previously added * `defaultPrecacheCacheabilityPlugin`, or it might be a custom plugin). * * - If this method is called and there is more than one `cacheWillUpdate`, * then we need to check if one is `defaultPrecacheCacheabilityPlugin`. If so, * we need to remove it. (This situation is unlikely, but it could happen if * the strategy is used multiple times, the first without a `cacheWillUpdate`, * and then later on after manually adding a custom `cacheWillUpdate`.) * * See https://github.com/GoogleChrome/workbox/issues/2737 for more context. * * @private */ _useDefaultCacheabilityPluginIfNeeded() { let defaultPluginIndex = null; let cacheWillUpdatePluginCount = 0; for (const [index, plugin] of this.plugins.entries()) { // Ignore the copy redirected plugin when determining what to do. if (plugin === PrecacheStrategy.copyRedirectedCacheableResponsesPlugin) { continue; } // Save the default plugin's index, in case it needs to be removed. if (plugin === PrecacheStrategy.defaultPrecacheCacheabilityPlugin) { defaultPluginIndex = index; } if (plugin.cacheWillUpdate) { cacheWillUpdatePluginCount++; } } if (cacheWillUpdatePluginCount === 0) { this.plugins.push(PrecacheStrategy.defaultPrecacheCacheabilityPlugin); } else if (cacheWillUpdatePluginCount > 1 && defaultPluginIndex !== null) { // Only remove the default plugin; multiple custom plugins are allowed. this.plugins.splice(defaultPluginIndex, 1); } // Nothing needs to be done if cacheWillUpdatePluginCount is 1 } } PrecacheStrategy.defaultPrecacheCacheabilityPlugin = { async cacheWillUpdate({ response }) { if (!response || response.status >= 400) { return null; } return response; }, }; PrecacheStrategy.copyRedirectedCacheableResponsesPlugin = { async cacheWillUpdate({ response }) { return response.redirected ? await copyResponse(response) : response; }, }; export { PrecacheStrategy };