StaleWhileRevalidate.js
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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
* [stale-while-revalidate]{@link https://developers.google.com/web/fundamentals/instant-and-offline/offline-cookbook/#stale-while-revalidate}
* request strategy.
*
* Resources are requested from both the cache and the network in parallel.
* The strategy will respond with the cached version if available, otherwise
* wait for the network response. The cache is updated with the network response
* with each successful request.
*
* 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 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 StaleWhileRevalidate {
/**
* @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)
*/
constructor(options = {}) {
this._cacheName = cacheNames.getRuntimeName(options.cacheName);
this._plugins = options.plugins || [];
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._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: 'StaleWhileRevalidate',
funcName: 'handle',
paramName: 'request',
});
}
const fetchAndCachePromise = this._getFromNetwork({ request, event });
let response = await cacheWrapper.match({
cacheName: this._cacheName,
request,
event,
matchOptions: this._matchOptions,
plugins: this._plugins,
});
let error;
if (response) {
if (process.env.NODE_ENV !== 'production') {
logs.push(`Found a cached response in the '${this._cacheName}'` +
` cache. Will update with the network response in the background.`);
}
if (event) {
try {
event.waitUntil(fetchAndCachePromise);
}
catch (error) {
if (process.env.NODE_ENV !== 'production') {
logger.warn(`Unable to ensure service worker stays alive when ` +
`updating cache for '${getFriendlyURL(request.url)}'.`);
}
}
}
}
else {
if (process.env.NODE_ENV !== 'production') {
logs.push(`No response found in the '${this._cacheName}' cache. ` +
`Will wait for the network response.`);
}
try {
response = await fetchAndCachePromise;
}
catch (err) {
error = err;
}
}
if (process.env.NODE_ENV !== 'production') {
logger.groupCollapsed(messages.strategyStart('StaleWhileRevalidate', request));
for (const log of logs) {
logger.log(log);
}
messages.printFinalResponse(response);
logger.groupEnd();
}
if (!response) {
throw new WorkboxError('no-response', { url: request.url, error });
}
return response;
}
/**
* @param {Object} options
* @param {Request} options.request
* @param {Event} [options.event]
* @return {Promise<Response>}
*
* @private
*/
async _getFromNetwork({ request, event }) {
const response = await fetchWrapper.fetch({
request,
event,
fetchOptions: this._fetchOptions,
plugins: this._plugins,
});
const cachePutPromise = cacheWrapper.put({
cacheName: this._cacheName,
request,
response: response.clone(),
event,
plugins: this._plugins,
});
if (event) {
try {
event.waitUntil(cachePutPromise);
}
catch (error) {
if (process.env.NODE_ENV !== 'production') {
logger.warn(`Unable to ensure service worker stays alive when ` +
`updating cache for '${getFriendlyURL(request.url)}'.`);
}
}
}
return response;
}
}
export { StaleWhileRevalidate };