/* 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 { cacheNames } from 'workbox-core/_private/cacheNames.js'; import { WorkboxError } from 'workbox-core/_private/WorkboxError.js'; import { logger } from 'workbox-core/_private/logger.js'; import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js'; import { StrategyHandler } from './StrategyHandler.js'; import './_version.js'; /** * An abstract base class that all other strategy classes must extend from: * * @memberof workbox-strategies */ class Strategy { /** * Creates a new instance of the strategy and sets all documented option * properties as public instance properties. * * Note: if a custom strategy class extends the base Strategy class and does * not need more than these properties, it does not need to define its own * constructor. * * @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] [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 [non-navigation](https://github.com/GoogleChrome/workbox/issues/1796) * `fetch()` requests made by this strategy. * @param {Object} [options.matchOptions] The * [`CacheQueryOptions`]{@link https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions} * for any `cache.match()` or `cache.put()` calls made by this strategy. */ constructor(options = {}) { /** * Cache name to store and retrieve * requests. Defaults to the cache names provided by * {@link workbox-core.cacheNames}. * * @type {string} */ this.cacheName = cacheNames.getRuntimeName(options.cacheName); /** * The list * [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins} * used by this strategy. * * @type {Array} */ this.plugins = options.plugins || []; /** * Values passed along to the * [`init`]{@link https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters} * of all fetch() requests made by this strategy. * * @type {Object} */ this.fetchOptions = options.fetchOptions; /** * The * [`CacheQueryOptions`]{@link https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions} * for any `cache.match()` or `cache.put()` calls made by this strategy. * * @type {Object} */ this.matchOptions = options.matchOptions; } /** * Perform a request strategy and returns a `Promise` that will resolve with * a `Response`, invoking all relevant plugin callbacks. * * When a strategy instance is registered with a Workbox * {@link workbox-routing.Route}, this method is automatically * called when the route matches. * * Alternatively, this method can be used in a standalone `FetchEvent` * listener by passing it to `event.respondWith()`. * * @param {FetchEvent|Object} options A `FetchEvent` or an object with the * properties listed below. * @param {Request|string} options.request A request to run this strategy for. * @param {ExtendableEvent} options.event The event associated with the * request. * @param {URL} [options.url] * @param {*} [options.params] */ handle(options) { const [responseDone] = this.handleAll(options); return responseDone; } /** * Similar to {@link workbox-strategies.Strategy~handle}, but * instead of just returning a `Promise` that resolves to a `Response` it * it will return an tuple of `[response, done]` promises, where the former * (`response`) is equivalent to what `handle()` returns, and the latter is a * Promise that will resolve once any promises that were added to * `event.waitUntil()` as part of performing the strategy have completed. * * You can await the `done` promise to ensure any extra work performed by * the strategy (usually caching responses) completes successfully. * * @param {FetchEvent|Object} options A `FetchEvent` or an object with the * properties listed below. * @param {Request|string} options.request A request to run this strategy for. * @param {ExtendableEvent} options.event The event associated with the * request. * @param {URL} [options.url] * @param {*} [options.params] * @return {Array} A tuple of [response, done] * promises that can be used to determine when the response resolves as * well as when the handler has completed all its work. */ handleAll(options) { // Allow for flexible options to be passed. if (options instanceof FetchEvent) { options = { event: options, request: options.request, }; } const event = options.event; const request = typeof options.request === 'string' ? new Request(options.request) : options.request; const params = 'params' in options ? options.params : undefined; const handler = new StrategyHandler(this, { event, request, params }); const responseDone = this._getResponse(handler, request, event); const handlerDone = this._awaitComplete(responseDone, handler, request, event); // Return an array of promises, suitable for use with Promise.all(). return [responseDone, handlerDone]; } async _getResponse(handler, request, event) { await handler.runCallbacks('handlerWillStart', { event, request }); let response = undefined; try { response = await this._handle(request, handler); // The "official" Strategy subclasses all throw this error automatically, // but in case a third-party Strategy doesn't, ensure that we have a // consistent failure when there's no response or an error response. if (!response || response.type === 'error') { throw new WorkboxError('no-response', { url: request.url }); } } catch (error) { if (error instanceof Error) { for (const callback of handler.iterateCallbacks('handlerDidError')) { response = await callback({ error, event, request }); if (response) { break; } } } if (!response) { throw error; } else if (process.env.NODE_ENV !== 'production') { logger.log(`While responding to '${getFriendlyURL(request.url)}', ` + `an ${error instanceof Error ? error.toString() : ''} error occurred. Using a fallback response provided by ` + `a handlerDidError plugin.`); } } for (const callback of handler.iterateCallbacks('handlerWillRespond')) { response = await callback({ event, request, response }); } return response; } async _awaitComplete(responseDone, handler, request, event) { let response; let error; try { response = await responseDone; } catch (error) { // Ignore errors, as response errors should be caught via the `response` // promise above. The `done` promise will only throw for errors in // promises passed to `handler.waitUntil()`. } try { await handler.runCallbacks('handlerDidRespond', { event, request, response, }); await handler.doneWaiting(); } catch (waitUntilError) { if (waitUntilError instanceof Error) { error = waitUntilError; } } await handler.runCallbacks('handlerDidComplete', { event, request, response, error: error, }); handler.destroy(); if (error) { throw error; } } } export { Strategy }; /** * Classes extending the `Strategy` based class should implement this method, * and leverage the {@link workbox-strategies.StrategyHandler} * arg to perform all fetching and cache logic, which will ensure all relevant * cache, cache options, fetch options and plugins are used (per the current * strategy instance). * * @name _handle * @instance * @abstract * @function * @param {Request} request * @param {workbox-strategies.StrategyHandler} handler * @return {Promise} * * @memberof workbox-strategies.Strategy */