/* 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 { logger } from 'workbox-core/_private/logger.js'; import { WorkboxError } from 'workbox-core/_private/WorkboxError.js'; import { Strategy } from './Strategy.js'; import { messages } from './utils/messages.js'; import './_version.js'; /** * An implementation of a [cache-first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#cache-first-falling-back-to-network) * request strategy. * * A cache first strategy is useful for assets that have been revisioned, * such as URLs like `/styles/example.a8f5f1.css`, since they * can be cached for long periods of time. * * If the network request fails, and there is no cache match, this will throw * a `WorkboxError` exception. * * @extends workbox-strategies.Strategy * @memberof workbox-strategies */ class CacheFirst extends Strategy { /** * @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 logs = []; if (process.env.NODE_ENV !== 'production') { assert.isInstance(request, Request, { moduleName: 'workbox-strategies', className: this.constructor.name, funcName: 'makeRequest', paramName: 'request', }); } let response = await handler.cacheMatch(request); let error = undefined; if (!response) { if (process.env.NODE_ENV !== 'production') { logs.push(`No response found in the '${this.cacheName}' cache. ` + `Will respond with a network request.`); } try { response = await handler.fetchAndCachePut(request); } catch (err) { if (err instanceof Error) { error = err; } } if (process.env.NODE_ENV !== 'production') { if (response) { logs.push(`Got response from network.`); } else { logs.push(`Unable to get a response from the network.`); } } } else { if (process.env.NODE_ENV !== 'production') { logs.push(`Found a cached response in the '${this.cacheName}' cache.`); } } if (process.env.NODE_ENV !== 'production') { logger.groupCollapsed(messages.strategyStart(this.constructor.name, 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; } } export { CacheFirst };