40 lines
1.2 KiB
TypeScript
40 lines
1.2 KiB
TypeScript
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/*
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* https://github.com/morethanwords/tweb
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* Copyright (C) 2019-2021 Eduard Kuzmenko
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* https://github.com/morethanwords/tweb/blob/master/LICENSE
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*/
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const ctx = self as any as ServiceWorkerGlobalScope;
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export const CACHE_ASSETS_NAME = 'cachedAssets';
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function isCorrectResponse(response: Response) {
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return response.ok && response.status === 200;
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}
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export async function requestCache(event: FetchEvent) {
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try {
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const cache = await ctx.caches.open(CACHE_ASSETS_NAME);
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const file = await cache.match(event.request, {ignoreVary: true});
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if(file && isCorrectResponse(file)) {
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return file;
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}
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const headers: HeadersInit = {'Vary': '*'};
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let response = await fetch(event.request, {headers});
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if(isCorrectResponse(response)) {
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cache.put(event.request, response.clone());
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} else if(response.status === 304) { // possible fix for 304 in Safari
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const url = event.request.url.replace(/\?.+$/, '') + '?' + (Math.random() * 100000 | 0);
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response = await fetch(url, {headers});
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if(isCorrectResponse(response)) {
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cache.put(event.request, response.clone());
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}
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}
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return response;
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} catch(err) {
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return fetch(event.request);
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}
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}
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