90 lines
3.2 KiB
JavaScript
90 lines
3.2 KiB
JavaScript
/*
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Copyright 2018 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 { assert } from 'workbox-core/_private/assert.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 './Strategy.js';
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import { messages } from './utils/messages.js';
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import './_version.js';
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/**
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* An implementation of a [cache-first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#cache-first-falling-back-to-network)
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* request strategy.
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*
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* A cache first strategy is useful for assets that have been revisioned,
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* such as URLs like `/styles/example.a8f5f1.css`, since they
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* can be cached for long periods of time.
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*
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* If the network request fails, and there is no cache match, this will throw
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* a `WorkboxError` exception.
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*
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* @extends workbox-strategies.Strategy
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* @memberof workbox-strategies
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*/
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class CacheFirst extends Strategy {
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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 logs = [];
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if (process.env.NODE_ENV !== 'production') {
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assert.isInstance(request, Request, {
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moduleName: 'workbox-strategies',
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className: this.constructor.name,
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funcName: 'makeRequest',
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paramName: 'request',
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});
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}
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let response = await handler.cacheMatch(request);
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let error = undefined;
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if (!response) {
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if (process.env.NODE_ENV !== 'production') {
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logs.push(`No response found in the '${this.cacheName}' cache. ` +
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`Will respond with a network request.`);
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}
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try {
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response = await handler.fetchAndCachePut(request);
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}
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catch (err) {
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if (err instanceof Error) {
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error = err;
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}
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}
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if (process.env.NODE_ENV !== 'production') {
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if (response) {
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logs.push(`Got response from network.`);
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}
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else {
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logs.push(`Unable to get a response from the network.`);
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}
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}
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}
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else {
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if (process.env.NODE_ENV !== 'production') {
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logs.push(`Found a cached response in the '${this.cacheName}' cache.`);
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}
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}
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if (process.env.NODE_ENV !== 'production') {
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logger.groupCollapsed(messages.strategyStart(this.constructor.name, request));
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for (const log of logs) {
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logger.log(log);
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}
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messages.printFinalResponse(response);
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logger.groupEnd();
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}
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if (!response) {
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throw new WorkboxError('no-response', { url: request.url, error });
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}
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return response;
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}
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}
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export { CacheFirst };
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