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