49 lines
1.8 KiB
JavaScript
49 lines
1.8 KiB
JavaScript
const { NotCachedError } = require('./errors.js')
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const CacheEntry = require('./entry.js')
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const remote = require('../remote.js')
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// do whatever is necessary to get a Response and return it
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const cacheFetch = async (request, options) => {
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// try to find a cached entry that satisfies this request
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const entry = await CacheEntry.find(request, options)
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if (!entry) {
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// no cached result, if the cache mode is 'only-if-cached' that's a failure
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if (options.cache === 'only-if-cached') {
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throw new NotCachedError(request.url)
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}
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// otherwise, we make a request, store it and return it
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const response = await remote(request, options)
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const newEntry = new CacheEntry({ request, response, options })
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return newEntry.store('miss')
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}
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// we have a cached response that satisfies this request, however if the cache
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// mode is 'no-cache' then we send the revalidation request no matter what
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if (options.cache === 'no-cache') {
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return entry.revalidate(request, options)
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}
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// if the cached entry is not stale, or if the cache mode is 'force-cache' or
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// 'only-if-cached' we can respond with the cached entry. set the status
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// based on the result of needsRevalidation and respond
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const _needsRevalidation = entry.policy.needsRevalidation(request)
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if (options.cache === 'force-cache' ||
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options.cache === 'only-if-cached' ||
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!_needsRevalidation) {
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return entry.respond(request.method, options, _needsRevalidation ? 'stale' : 'hit')
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}
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// if we got here, the cache entry is stale so revalidate it
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return entry.revalidate(request, options)
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}
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cacheFetch.invalidate = async (request, options) => {
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if (!options.cachePath) {
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return
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}
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return CacheEntry.invalidate(request, options)
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}
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module.exports = cacheFetch
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