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- /*
- 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 { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.js';
- import { Strategy } from './Strategy.js';
- import { messages } from './utils/messages.js';
- import './_version.js';
- /**
- * An implementation of a
- * [network first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#network-first-falling-back-to-cache)
- * request strategy.
- *
- * By default, this strategy will cache responses with a 200 status code as
- * well as [opaque responses](https://developer.chrome.com/docs/workbox/caching-resources-during-runtime/#opaque-responses).
- * Opaque responses are are cross-origin requests where the response doesn't
- * support [CORS](https://enable-cors.org/).
- *
- * 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 NetworkFirst extends Strategy {
- /**
- * @param {Object} [options]
- * @param {string} [options.cacheName] Cache name to store and retrieve
- * requests. Defaults to cache names provided by
- * {@link workbox-core.cacheNames}.
- * @param {Array<Object>} [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] [`CacheQueryOptions`](https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions)
- * @param {number} [options.networkTimeoutSeconds] If set, any network requests
- * that fail to respond within the timeout will fallback to the cache.
- *
- * This option can be used to combat
- * "[lie-fi]{@link https://developers.google.com/web/fundamentals/performance/poor-connectivity/#lie-fi}"
- * scenarios.
- */
- constructor(options = {}) {
- super(options);
- // If this instance contains no plugins with a 'cacheWillUpdate' callback,
- // prepend the `cacheOkAndOpaquePlugin` plugin to the plugins list.
- if (!this.plugins.some((p) => 'cacheWillUpdate' in p)) {
- this.plugins.unshift(cacheOkAndOpaquePlugin);
- }
- this._networkTimeoutSeconds = options.networkTimeoutSeconds || 0;
- if (process.env.NODE_ENV !== 'production') {
- if (this._networkTimeoutSeconds) {
- assert.isType(this._networkTimeoutSeconds, 'number', {
- moduleName: 'workbox-strategies',
- className: this.constructor.name,
- funcName: 'constructor',
- paramName: 'networkTimeoutSeconds',
- });
- }
- }
- }
- /**
- * @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 logs = [];
- if (process.env.NODE_ENV !== 'production') {
- assert.isInstance(request, Request, {
- moduleName: 'workbox-strategies',
- className: this.constructor.name,
- funcName: 'handle',
- paramName: 'makeRequest',
- });
- }
- const promises = [];
- let timeoutId;
- if (this._networkTimeoutSeconds) {
- const { id, promise } = this._getTimeoutPromise({ request, logs, handler });
- timeoutId = id;
- promises.push(promise);
- }
- const networkPromise = this._getNetworkPromise({
- timeoutId,
- request,
- logs,
- handler,
- });
- promises.push(networkPromise);
- const response = await handler.waitUntil((async () => {
- // Promise.race() will resolve as soon as the first promise resolves.
- return ((await handler.waitUntil(Promise.race(promises))) ||
- // If Promise.race() resolved with null, it might be due to a network
- // timeout + a cache miss. If that were to happen, we'd rather wait until
- // the networkPromise resolves instead of returning null.
- // Note that it's fine to await an already-resolved promise, so we don't
- // have to check to see if it's still "in flight".
- (await networkPromise));
- })());
- 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 });
- }
- return response;
- }
- /**
- * @param {Object} options
- * @param {Request} options.request
- * @param {Array} options.logs A reference to the logs array
- * @param {Event} options.event
- * @return {Promise<Response>}
- *
- * @private
- */
- _getTimeoutPromise({ request, logs, handler, }) {
- let timeoutId;
- const timeoutPromise = new Promise((resolve) => {
- const onNetworkTimeout = async () => {
- if (process.env.NODE_ENV !== 'production') {
- logs.push(`Timing out the network response at ` +
- `${this._networkTimeoutSeconds} seconds.`);
- }
- resolve(await handler.cacheMatch(request));
- };
- timeoutId = setTimeout(onNetworkTimeout, this._networkTimeoutSeconds * 1000);
- });
- return {
- promise: timeoutPromise,
- id: timeoutId,
- };
- }
- /**
- * @param {Object} options
- * @param {number|undefined} options.timeoutId
- * @param {Request} options.request
- * @param {Array} options.logs A reference to the logs Array.
- * @param {Event} options.event
- * @return {Promise<Response>}
- *
- * @private
- */
- async _getNetworkPromise({ timeoutId, request, logs, handler, }) {
- let error;
- let response;
- try {
- response = await handler.fetchAndCachePut(request);
- }
- catch (fetchError) {
- if (fetchError instanceof Error) {
- error = fetchError;
- }
- }
- if (timeoutId) {
- clearTimeout(timeoutId);
- }
- if (process.env.NODE_ENV !== 'production') {
- if (response) {
- logs.push(`Got response from network.`);
- }
- else {
- logs.push(`Unable to get a response from the network. Will respond ` +
- `with a cached response.`);
- }
- }
- if (error || !response) {
- response = await handler.cacheMatch(request);
- if (process.env.NODE_ENV !== 'production') {
- if (response) {
- logs.push(`Found a cached response in the '${this.cacheName}'` + ` cache.`);
- }
- else {
- logs.push(`No response found in the '${this.cacheName}' cache.`);
- }
- }
- }
- return response;
- }
- }
- export { NetworkFirst };
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