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