hexo/node_modules/workbox-strategies/NetworkFirst.js

/*
  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 };