89 lines
3.7 KiB
JavaScript
89 lines
3.7 KiB
JavaScript
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/*
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Copyright 2018 Google LLC
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Use of this source code is governed by an MIT-style
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license that can be found in the LICENSE file or at
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https://opensource.org/licenses/MIT.
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*/
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import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
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import { assert } from 'workbox-core/_private/assert.js';
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import { logger } from 'workbox-core/_private/logger.js';
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import { calculateEffectiveBoundaries } from './utils/calculateEffectiveBoundaries.js';
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import { parseRangeHeader } from './utils/parseRangeHeader.js';
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import './_version.js';
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/**
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* Given a `Request` and `Response` objects as input, this will return a
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* promise for a new `Response`.
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*
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* If the original `Response` already contains partial content (i.e. it has
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* a status of 206), then this assumes it already fulfills the `Range:`
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* requirements, and will return it as-is.
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*
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* @param {Request} request A request, which should contain a Range:
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* header.
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* @param {Response} originalResponse A response.
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* @return {Promise<Response>} Either a `206 Partial Content` response, with
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* the response body set to the slice of content specified by the request's
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* `Range:` header, or a `416 Range Not Satisfiable` response if the
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* conditions of the `Range:` header can't be met.
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*
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* @memberof workbox-range-requests
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*/
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async function createPartialResponse(request, originalResponse) {
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try {
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if (process.env.NODE_ENV !== 'production') {
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assert.isInstance(request, Request, {
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moduleName: 'workbox-range-requests',
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funcName: 'createPartialResponse',
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paramName: 'request',
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});
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assert.isInstance(originalResponse, Response, {
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moduleName: 'workbox-range-requests',
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funcName: 'createPartialResponse',
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paramName: 'originalResponse',
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});
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}
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if (originalResponse.status === 206) {
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// If we already have a 206, then just pass it through as-is;
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// see https://github.com/GoogleChrome/workbox/issues/1720
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return originalResponse;
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}
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const rangeHeader = request.headers.get('range');
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if (!rangeHeader) {
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throw new WorkboxError('no-range-header');
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}
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const boundaries = parseRangeHeader(rangeHeader);
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const originalBlob = await originalResponse.blob();
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const effectiveBoundaries = calculateEffectiveBoundaries(originalBlob, boundaries.start, boundaries.end);
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const slicedBlob = originalBlob.slice(effectiveBoundaries.start, effectiveBoundaries.end);
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const slicedBlobSize = slicedBlob.size;
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const slicedResponse = new Response(slicedBlob, {
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// Status code 206 is for a Partial Content response.
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// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/206
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status: 206,
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statusText: 'Partial Content',
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headers: originalResponse.headers,
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});
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slicedResponse.headers.set('Content-Length', String(slicedBlobSize));
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slicedResponse.headers.set('Content-Range', `bytes ${effectiveBoundaries.start}-${effectiveBoundaries.end - 1}/` +
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`${originalBlob.size}`);
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return slicedResponse;
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}
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catch (error) {
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if (process.env.NODE_ENV !== 'production') {
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logger.warn(`Unable to construct a partial response; returning a ` +
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`416 Range Not Satisfiable response instead.`);
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logger.groupCollapsed(`View details here.`);
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logger.log(error);
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logger.log(request);
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logger.log(originalResponse);
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logger.groupEnd();
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}
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return new Response('', {
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status: 416,
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statusText: 'Range Not Satisfiable',
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});
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}
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}
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export { createPartialResponse };
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