/* 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 { createPartialResponse } from './createPartialResponse.js'; import './_version.js'; /** * The range request plugin makes it easy for a request with a 'Range' header to * be fulfilled by a cached response. * * It does this by intercepting the `cachedResponseWillBeUsed` plugin callback * and returning the appropriate subset of the cached response body. * * @memberof module:workbox-range-requests */ class RangeRequestsPlugin { constructor() { /** * @param {Object} options * @param {Request} options.request The original request, which may or may not * contain a Range: header. * @param {Response} options.cachedResponse The complete cached response. * @return {Promise} If request contains a 'Range' header, then a * new response with status 206 whose body is a subset of `cachedResponse` is * returned. Otherwise, `cachedResponse` is returned as-is. * * @private */ this.cachedResponseWillBeUsed = async ({ request, cachedResponse }) => { // Only return a sliced response if there's something valid in the cache, // and there's a Range: header in the request. if (cachedResponse && request.headers.has('range')) { return await createPartialResponse(request, cachedResponse); } // If there was no Range: header, or if cachedResponse wasn't valid, just // pass it through as-is. return cachedResponse; }; } } export { RangeRequestsPlugin };