198 lines
7.8 KiB
JavaScript
198 lines
7.8 KiB
JavaScript
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/*
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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 { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.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
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* [network first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#network-first-falling-back-to-cache)
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* request strategy.
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*
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* By default, this strategy will cache responses with a 200 status code as
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* well as [opaque responses](https://developer.chrome.com/docs/workbox/caching-resources-during-runtime/#opaque-responses).
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* Opaque responses are are cross-origin requests where the response doesn't
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* support [CORS](https://enable-cors.org/).
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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 NetworkFirst extends Strategy {
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/**
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* @param {Object} [options]
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* @param {string} [options.cacheName] Cache name to store and retrieve
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* requests. Defaults to cache names provided by
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* {@link workbox-core.cacheNames}.
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* @param {Array<Object>} [options.plugins] [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins}
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* to use in conjunction with this caching strategy.
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* @param {Object} [options.fetchOptions] Values passed along to the
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* [`init`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters)
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* of [non-navigation](https://github.com/GoogleChrome/workbox/issues/1796)
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* `fetch()` requests made by this strategy.
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* @param {Object} [options.matchOptions] [`CacheQueryOptions`](https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions)
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* @param {number} [options.networkTimeoutSeconds] If set, any network requests
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* that fail to respond within the timeout will fallback to the cache.
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*
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* This option can be used to combat
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* "[lie-fi]{@link https://developers.google.com/web/fundamentals/performance/poor-connectivity/#lie-fi}"
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* scenarios.
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*/
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constructor(options = {}) {
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super(options);
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// If this instance contains no plugins with a 'cacheWillUpdate' callback,
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// prepend the `cacheOkAndOpaquePlugin` plugin to the plugins list.
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if (!this.plugins.some((p) => 'cacheWillUpdate' in p)) {
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this.plugins.unshift(cacheOkAndOpaquePlugin);
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}
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this._networkTimeoutSeconds = options.networkTimeoutSeconds || 0;
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if (process.env.NODE_ENV !== 'production') {
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if (this._networkTimeoutSeconds) {
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assert.isType(this._networkTimeoutSeconds, 'number', {
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moduleName: 'workbox-strategies',
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className: this.constructor.name,
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funcName: 'constructor',
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paramName: 'networkTimeoutSeconds',
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});
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}
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}
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}
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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: 'handle',
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paramName: 'makeRequest',
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});
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}
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const promises = [];
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let timeoutId;
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if (this._networkTimeoutSeconds) {
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const { id, promise } = this._getTimeoutPromise({ request, logs, handler });
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timeoutId = id;
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promises.push(promise);
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}
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const networkPromise = this._getNetworkPromise({
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timeoutId,
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request,
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logs,
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handler,
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});
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promises.push(networkPromise);
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const response = await handler.waitUntil((async () => {
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// Promise.race() will resolve as soon as the first promise resolves.
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return ((await handler.waitUntil(Promise.race(promises))) ||
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// If Promise.race() resolved with null, it might be due to a network
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// timeout + a cache miss. If that were to happen, we'd rather wait until
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// the networkPromise resolves instead of returning null.
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// Note that it's fine to await an already-resolved promise, so we don't
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// have to check to see if it's still "in flight".
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(await networkPromise));
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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 });
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}
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return response;
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}
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/**
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* @param {Object} options
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* @param {Request} options.request
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* @param {Array} options.logs A reference to the logs array
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* @param {Event} options.event
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* @return {Promise<Response>}
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*
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* @private
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*/
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_getTimeoutPromise({ request, logs, handler, }) {
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let timeoutId;
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const timeoutPromise = new Promise((resolve) => {
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const onNetworkTimeout = async () => {
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if (process.env.NODE_ENV !== 'production') {
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logs.push(`Timing out the network response at ` +
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`${this._networkTimeoutSeconds} seconds.`);
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}
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resolve(await handler.cacheMatch(request));
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};
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timeoutId = setTimeout(onNetworkTimeout, this._networkTimeoutSeconds * 1000);
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});
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return {
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promise: timeoutPromise,
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id: timeoutId,
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};
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}
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/**
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* @param {Object} options
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* @param {number|undefined} options.timeoutId
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* @param {Request} options.request
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* @param {Array} options.logs A reference to the logs Array.
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* @param {Event} options.event
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* @return {Promise<Response>}
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*
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* @private
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*/
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async _getNetworkPromise({ timeoutId, request, logs, handler, }) {
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let error;
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let response;
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try {
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response = await handler.fetchAndCachePut(request);
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}
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catch (fetchError) {
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if (fetchError instanceof Error) {
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error = fetchError;
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}
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}
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if (timeoutId) {
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clearTimeout(timeoutId);
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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. Will respond ` +
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`with a cached response.`);
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}
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}
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if (error || !response) {
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response = await handler.cacheMatch(request);
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if (process.env.NODE_ENV !== 'production') {
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if (response) {
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logs.push(`Found a cached response in the '${this.cacheName}'` + ` cache.`);
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}
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else {
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logs.push(`No response found in the '${this.cacheName}' cache.`);
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}
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}
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}
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return response;
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}
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}
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export { NetworkFirst };
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