mirror of https://github.com/jkjoy/sunpeiwen.git
69 lines
3.0 KiB
JavaScript
69 lines
3.0 KiB
JavaScript
/*
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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 { logger } from 'workbox-core/_private/logger.js';
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import { createHeaders } from './utils/createHeaders.js';
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import { concatenateToResponse } from './concatenateToResponse.js';
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import { isSupported } from './isSupported.js';
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import './_version.js';
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/**
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* A shortcut to create a strategy that could be dropped-in to Workbox's router.
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*
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* On browsers that do not support constructing new `ReadableStream`s, this
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* strategy will automatically wait for all the `sourceFunctions` to complete,
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* and create a final response that concatenates their values together.
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*
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* @param {Array<function({event, request, url, params})>} sourceFunctions
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* An array of functions similar to {@link workbox-routing~handlerCallback}
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* but that instead return a {@link workbox-streams.StreamSource} (or a
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* Promise which resolves to one).
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* @param {HeadersInit} [headersInit] If there's no `Content-Type` specified,
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* `'text/html'` will be used by default.
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* @return {workbox-routing~handlerCallback}
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* @memberof workbox-streams
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*/
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function strategy(sourceFunctions, headersInit) {
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return async ({ event, request, url, params }) => {
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const sourcePromises = sourceFunctions.map((fn) => {
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// Ensure the return value of the function is always a promise.
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return Promise.resolve(fn({ event, request, url, params }));
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});
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if (isSupported()) {
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const { done, response } = concatenateToResponse(sourcePromises, headersInit);
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if (event) {
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event.waitUntil(done);
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}
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return response;
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}
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if (process.env.NODE_ENV !== 'production') {
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logger.log(`The current browser doesn't support creating response ` +
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`streams. Falling back to non-streaming response instead.`);
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}
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// Fallback to waiting for everything to finish, and concatenating the
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// responses.
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const blobPartsPromises = sourcePromises.map(async (sourcePromise) => {
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const source = await sourcePromise;
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if (source instanceof Response) {
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return source.blob();
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}
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else {
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// Technically, a `StreamSource` object can include any valid
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// `BodyInit` type, including `FormData` and `URLSearchParams`, which
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// cannot be passed to the Blob constructor directly, so we have to
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// convert them to actual Blobs first.
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return new Response(source).blob();
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}
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});
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const blobParts = await Promise.all(blobPartsPromises);
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const headers = createHeaders(headersInit);
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// Constructing a new Response from a Blob source is well-supported.
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// So is constructing a new Blob from multiple source Blobs or strings.
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return new Response(new Blob(blobParts), { headers });
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};
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}
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export { strategy };
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