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