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- /*
- 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<Object>} [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<Response>}
- */
- 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 };
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