WIP - add extractor, generate snippet_data

node_modules/workbox-strategies/NetworkFirst.mjs

@@ -0,0 +1,310 @@
+/*
+ Copyright 2018 Google Inc. All Rights Reserved.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+import {cacheNames} from 'workbox-core/_private/cacheNames.mjs';
+import {cacheWrapper} from 'workbox-core/_private/cacheWrapper.mjs';
+import {fetchWrapper} from 'workbox-core/_private/fetchWrapper.mjs';
+import {assert} from 'workbox-core/_private/assert.mjs';
+import {logger} from 'workbox-core/_private/logger.mjs';
+import {getFriendlyURL} from 'workbox-core/_private/getFriendlyURL.mjs';
+
+import messages from './utils/messages.mjs';
+import cacheOkAndOpaquePlugin from './plugins/cacheOkAndOpaquePlugin.mjs';
+import './_version.mjs';
+
+/**
+ * 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/}.
+ *
+ * @memberof 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 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) {
+      let 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;
+    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 || null;
+    this._matchOptions = options.matchOptions || null;
+  }
+
+  /**
+   * This method will perform a request strategy and follows an API that
+   * will work with the
+   * [Workbox Router]{@link workbox.routing.Router}.
+   *
+   * @param {Object} options
+   * @param {FetchEvent} options.event The fetch event to run this strategy
+   * against.
+   * @return {Promise<Response>}
+   */
+  async handle({event}) {
+    if (process.env.NODE_ENV !== 'production') {
+      assert.isInstance(event, FetchEvent, {
+        moduleName: 'workbox-strategies',
+        className: 'NetworkFirst',
+        funcName: 'handle',
+        paramName: 'event',
+      });
+    }
+
+    return this.makeRequest({
+      event,
+      request: event.request,
+    });
+  }
+
+  /**
+   * This method can be used to perform a make a standalone request outside the
+   * context of the [Workbox Router]{@link workbox.routing.Router}.
+   *
+   * See "[Advanced Recipes](https://developers.google.com/web/tools/workbox/guides/advanced-recipes#make-requests)"
+   * for more usage information.
+   *
+   * @param {Object} options
+   * @param {Request|string} options.request Either a
+   *     [`Request`]{@link https://developer.mozilla.org/en-US/docs/Web/API/Request}
+   *     object, or a string URL, corresponding to the request to be made.
+   * @param {FetchEvent} [options.event] If provided, `event.waitUntil()` will
+   *     be called automatically to extend the service worker's lifetime.
+   * @return {Promise<Response>}
+   */
+  async makeRequest({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 (let log of logs) {
+        logger.log(log);
+      }
+      messages.printFinalResponse(response);
+      logger.groupEnd();
+    }
+
+    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(event.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};