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Fix discord URL cache purge

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Cadence Ember 2024-09-14 19:11:23 +12:00
parent a6a1b7fb28
commit b3daa6b84c
1 changed files with 12 additions and 14 deletions
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26
src/web/routes/download-discord.js
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@ -17,21 +17,16 @@ const schema = {
/** @type {Map<string, Promise<string>>} */ /** @type {Map<string, Promise<string>>} */
const cache = new Map() const cache = new Map()
function hasExpired(url) { /** @param {string} url */
function timeUntilExpiry(url) {
const params = new URL(url).searchParams const params = new URL(url).searchParams
const ex = params.get("ex") const ex = params.get("ex")
assert(ex) // refreshed urls from the discord api always include this parameter assert(ex) // refreshed urls from the discord api always include this parameter
return parseInt(ex, 16) < Date.now() / 1000 const time = parseInt(ex, 16)*1000 - Date.now()
if (time > 0) return time
return false
} }
// purge expired urls from cache every hour
setInterval(() => {
for (const entry of cache.entries()) {
if (hasExpired(entry[1])) cache.delete(entry[0])
}
console.log(`purged discord media cache, it now has ${cache.size} urls`)
}, 60 * 60 * 1000).unref()
as.router.get(`/download/discordcdn/:channel_id/:attachment_id/:file_name`, defineEventHandler(async event => { as.router.get(`/download/discordcdn/:channel_id/:attachment_id/:file_name`, defineEventHandler(async event => {
const params = await getValidatedRouterParams(event, schema.params.parse) const params = await getValidatedRouterParams(event, schema.params.parse)
@ -45,18 +40,21 @@ as.router.get(`/download/discordcdn/:channel_id/:attachment_id/:file_name`, defi
const url = `https://cdn.discordapp.com/attachments/${params.channel_id}/${params.attachment_id}/${params.file_name}` const url = `https://cdn.discordapp.com/attachments/${params.channel_id}/${params.attachment_id}/${params.file_name}`
let promise = cache.get(url) let promise = cache.get(url)
/** @type {string | undefined} */
let refreshed let refreshed
if (promise) { if (promise) {
console.log("using existing cache entry")
refreshed = await promise refreshed = await promise
if (hasExpired(refreshed)) promise = undefined if (!timeUntilExpiry(refreshed)) promise = undefined
console.log(promise)
} }
if (!promise) { if (!promise) {
console.log("refreshing and storing")
promise = discord.snow.channel.refreshAttachmentURLs([url]).then(x => x.refreshed_urls[0].refreshed) promise = discord.snow.channel.refreshAttachmentURLs([url]).then(x => x.refreshed_urls[0].refreshed)
cache.set(url, promise) cache.set(url, promise)
refreshed = await promise refreshed = await promise
const time = timeUntilExpiry(refreshed)
assert(time) // the just-refreshed URL will always be in the future
setTimeout(() => {
cache.delete(url)
}, time).unref()
} }
assert(refreshed) // will have been assigned by one of the above branches assert(refreshed) // will have been assigned by one of the above branches