NetworkOnly.ts 3.58 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 {fetchWrapper} from 'workbox-core/_private/fetchWrapper.js';
import {logger} from 'workbox-core/_private/logger.js';
import {WorkboxError} from 'workbox-core/_private/WorkboxError.js';
import {RouteHandlerObject, RouteHandlerCallbackOptions, WorkboxPlugin} from 'workbox-core/types.js';
import {messages} from './utils/messages.js';
import './_version.js';


interface NetworkFirstOptions {
  plugins?: WorkboxPlugin[];
  fetchOptions?: RequestInit;
}

/**
 * An implementation of a
 * [network-only]{@link https://developers.google.com/web/fundamentals/instant-and-offline/offline-cookbook/#network-only}
 * request strategy.
 *
 * This class is useful if you want to take advantage of any
 * [Workbox plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins}.
 *
 * If the network request fails, this will throw a `WorkboxError` exception.
 *
 * @memberof module:workbox-strategies
 */
class NetworkOnly implements RouteHandlerObject {
  private readonly _plugins: WorkboxPlugin[];
  private readonly _fetchOptions?: RequestInit;

  /**
   * @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.
   */
  constructor(options: NetworkFirstOptions = {}) {
    this._plugins = options.plugins || [];
    this._fetchOptions = options.fetchOptions;
  }

  /**
   * 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 The request to run this strategy for.
   * @param {Event} [options.event] The event that triggered the request.
   * @return {Promise<Response>}
   */
  async handle({event, request}: RouteHandlerCallbackOptions): Promise<Response> {
    if (typeof request === 'string') {
      request = new Request(request);
    }

    if (process.env.NODE_ENV !== 'production') {
      assert!.isInstance(request, Request, {
        moduleName: 'workbox-strategies',
        className: 'NetworkOnly',
        funcName: 'handle',
        paramName: 'request',
      });
    }

    let error;
    let response;
    try {
      response = await fetchWrapper.fetch({
        request,
        event,
        fetchOptions: this._fetchOptions,
        plugins: this._plugins,
      });
    } catch (err) {
      error = err;
    }

    if (process.env.NODE_ENV !== 'production') {
      logger.groupCollapsed(
          messages.strategyStart('NetworkOnly', request));
      if (response) {
        logger.log(`Got response from network.`);
      } else {
        logger.log(`Unable to get a response from the network.`);
      }
      messages.printFinalResponse(response);
      logger.groupEnd();
    }

    if (!response) {
      throw new WorkboxError('no-response', {url: request.url, error});
    }
    return response;
  }
}

export {NetworkOnly};