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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 { cacheNames } from 'workbox-core/_private/cacheNames.js';
- import { cacheWrapper } from 'workbox-core/_private/cacheWrapper.js';
- import { fetchWrapper } from 'workbox-core/_private/fetchWrapper.js';
- import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
- import { logger } from 'workbox-core/_private/logger.js';
- import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
- import { messages } from './utils/messages.js';
- import { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.js';
- import './_version.js';
- /**
- * An implementation of a
- * [network first]{@link https://developers.google.com/web/fundamentals/instant-and-offline/offline-cookbook/#network-falling-back-to-cache}
- * request strategy.
- *
- * By default, this strategy will cache responses with a 200 status code as
- * well as [opaque responses]{@link https://developers.google.com/web/tools/workbox/guides/handle-third-party-requests}.
- * Opaque responses are are cross-origin requests where the response doesn't
- * support [CORS]{@link https://enable-cors.org/}.
- *
- * If the network request fails, and there is no cache match, this will throw
- * a `WorkboxError` exception.
- *
- * @memberof module:workbox-strategies
- */
- class NetworkFirst {
- /**
- * @param {Object} options
- * @param {string} options.cacheName Cache name to store and retrieve
- * requests. Defaults to cache names provided by
- * [workbox-core]{@link module: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 all 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 = {}) {
- this._cacheName = cacheNames.getRuntimeName(options.cacheName);
- if (options.plugins) {
- const isUsingCacheWillUpdate = options.plugins.some((plugin) => !!plugin.cacheWillUpdate);
- this._plugins = isUsingCacheWillUpdate ?
- options.plugins : [cacheOkAndOpaquePlugin, ...options.plugins];
- }
- else {
- // No plugins passed in, use the default plugin.
- this._plugins = [cacheOkAndOpaquePlugin];
- }
- this._networkTimeoutSeconds = options.networkTimeoutSeconds || 0;
- if (process.env.NODE_ENV !== 'production') {
- if (this._networkTimeoutSeconds) {
- assert.isType(this._networkTimeoutSeconds, 'number', {
- moduleName: 'workbox-strategies',
- className: 'NetworkFirst',
- funcName: 'constructor',
- paramName: 'networkTimeoutSeconds',
- });
- }
- }
- this._fetchOptions = options.fetchOptions;
- this._matchOptions = options.matchOptions;
- }
- /**
- * This method will perform a request strategy and follows an API that
- * will work with the
- * [Workbox Router]{@link module:workbox-routing.Router}.
- *
- * @param {Object} options
- * @param {Request|string} options.request A request to run this strategy for.
- * @param {Event} [options.event] The event that triggered the request.
- * @return {Promise<Response>}
- */
- async handle({ event, request }) {
- const logs = [];
- if (typeof request === 'string') {
- request = new Request(request);
- }
- if (process.env.NODE_ENV !== 'production') {
- assert.isInstance(request, Request, {
- moduleName: 'workbox-strategies',
- className: 'NetworkFirst',
- funcName: 'handle',
- paramName: 'makeRequest',
- });
- }
- const promises = [];
- let timeoutId;
- if (this._networkTimeoutSeconds) {
- const { id, promise } = this._getTimeoutPromise({ request, event, logs });
- timeoutId = id;
- promises.push(promise);
- }
- const networkPromise = this._getNetworkPromise({ timeoutId, request, event, logs });
- promises.push(networkPromise);
- // Promise.race() will resolve as soon as the first promise resolves.
- let response = await 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".
- if (!response) {
- response = await networkPromise;
- }
- if (process.env.NODE_ENV !== 'production') {
- logger.groupCollapsed(messages.strategyStart('NetworkFirst', 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, event }) {
- let timeoutId;
- const timeoutPromise = new Promise((resolve) => {
- const onNetworkTimeout = async () => {
- if (process.env.NODE_ENV !== 'production') {
- logs.push(`Timing out the network response at ` +
- `${this._networkTimeoutSeconds} seconds.`);
- }
- resolve(await this._respondFromCache({ request, event }));
- };
- timeoutId = setTimeout(onNetworkTimeout, this._networkTimeoutSeconds * 1000);
- });
- return {
- promise: timeoutPromise,
- id: timeoutId,
- };
- }
- /**
- * @param {Object} options
- * @param {number|undefined} options.timeoutId
- * @param {Request} options.request
- * @param {Array} options.logs A reference to the logs Array.
- * @param {Event} [options.event]
- * @return {Promise<Response>}
- *
- * @private
- */
- async _getNetworkPromise({ timeoutId, request, logs, event }) {
- let error;
- let response;
- try {
- response = await fetchWrapper.fetch({
- request,
- event,
- fetchOptions: this._fetchOptions,
- plugins: this._plugins,
- });
- }
- catch (err) {
- error = err;
- }
- if (timeoutId) {
- clearTimeout(timeoutId);
- }
- if (process.env.NODE_ENV !== 'production') {
- if (response) {
- logs.push(`Got response from network.`);
- }
- else {
- logs.push(`Unable to get a response from the network. Will respond ` +
- `with a cached response.`);
- }
- }
- if (error || !response) {
- response = await this._respondFromCache({ request, event });
- if (process.env.NODE_ENV !== 'production') {
- if (response) {
- logs.push(`Found a cached response in the '${this._cacheName}'` +
- ` cache.`);
- }
- else {
- logs.push(`No response found in the '${this._cacheName}' cache.`);
- }
- }
- }
- else {
- // Keep the service worker alive while we put the request in the cache
- const responseClone = response.clone();
- const cachePut = cacheWrapper.put({
- cacheName: this._cacheName,
- request,
- response: responseClone,
- event,
- plugins: this._plugins,
- });
- if (event) {
- try {
- // The event has been responded to so we can keep the SW alive to
- // respond to the request
- event.waitUntil(cachePut);
- }
- catch (err) {
- if (process.env.NODE_ENV !== 'production') {
- logger.warn(`Unable to ensure service worker stays alive when ` +
- `updating cache for '${getFriendlyURL(request.url)}'.`);
- }
- }
- }
- }
- return response;
- }
- /**
- * Used if the network timeouts or fails to make the request.
- *
- * @param {Object} options
- * @param {Request} request The request to match in the cache
- * @param {Event} [options.event]
- * @return {Promise<Object>}
- *
- * @private
- */
- _respondFromCache({ event, request }) {
- return cacheWrapper.match({
- cacheName: this._cacheName,
- request,
- event,
- matchOptions: this._matchOptions,
- plugins: this._plugins,
- });
- }
- }
- export { NetworkFirst };
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