134 lines
3.9 KiB
JavaScript
134 lines
3.9 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.mjs';
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import {assert} from 'workbox-core/_private/assert.mjs';
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import './_version.mjs';
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/**
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* Takes either a Response, a ReadableStream, or a
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* [BodyInit](https://fetch.spec.whatwg.org/#bodyinit) and returns the
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* ReadableStreamReader object associated with it.
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*
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* @param {workbox.streams.StreamSource} source
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* @return {ReadableStreamReader}
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* @private
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*/
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function _getReaderFromSource(source) {
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if (source.body && source.body.getReader) {
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return source.body.getReader();
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}
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if (source.getReader) {
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return source.getReader();
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}
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// TODO: This should be possible to do by constructing a ReadableStream, but
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// I can't get it to work. As a hack, construct a new Response, and use the
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// reader associated with its body.
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return new Response(source).body.getReader();
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}
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/**
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* Takes multiple source Promises, each of which could resolve to a Response, a
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* ReadableStream, or a [BodyInit](https://fetch.spec.whatwg.org/#bodyinit).
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*
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* Returns an object exposing a ReadableStream with each individual stream's
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* data returned in sequence, along with a Promise which signals when the
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* stream is finished (useful for passing to a FetchEvent's waitUntil()).
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*
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* @param {Array<Promise<workbox.streams.StreamSource>>} sourcePromises
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* @return {Object<{done: Promise, stream: ReadableStream}>}
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*
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* @memberof workbox.streams
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*/
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function concatenate(sourcePromises) {
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if (process.env.NODE_ENV !== 'production') {
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assert.isArray(sourcePromises, {
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moduleName: 'workbox-streams',
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funcName: 'concatenate',
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paramName: 'sourcePromises',
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});
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}
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const readerPromises = sourcePromises.map((sourcePromise) => {
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return Promise.resolve(sourcePromise).then((source) => {
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return _getReaderFromSource(source);
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});
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});
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let fullyStreamedResolve;
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let fullyStreamedReject;
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const done = new Promise((resolve, reject) => {
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fullyStreamedResolve = resolve;
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fullyStreamedReject = reject;
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});
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let i = 0;
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const logMessages = [];
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const stream = new ReadableStream({
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pull(controller) {
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return readerPromises[i]
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.then((reader) => reader.read())
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.then((result) => {
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if (result.done) {
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if (process.env.NODE_ENV !== 'production') {
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logMessages.push(['Reached the end of source:',
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sourcePromises[i]]);
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}
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i++;
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if (i >= readerPromises.length) {
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// Log all the messages in the group at once in a single group.
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if (process.env.NODE_ENV !== 'production') {
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logger.groupCollapsed(
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`Concatenating ${readerPromises.length} sources.`);
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for (const message of logMessages) {
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if (Array.isArray(message)) {
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logger.log(...message);
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} else {
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logger.log(message);
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}
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}
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logger.log('Finished reading all sources.');
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logger.groupEnd();
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}
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controller.close();
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fullyStreamedResolve();
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return;
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}
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return this.pull(controller);
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} else {
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controller.enqueue(result.value);
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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.error('An error occurred:', error);
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}
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fullyStreamedReject(error);
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throw error;
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});
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},
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cancel() {
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if (process.env.NODE_ENV !== 'production') {
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logger.warn('The ReadableStream was cancelled.');
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}
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fullyStreamedResolve();
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},
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});
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return {done, stream};
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}
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export {concatenate};
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