StaleWhileRevalidate.js 6.96 KB
/*
  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 };