85 lines
2.3 KiB
JavaScript
85 lines
2.3 KiB
JavaScript
// Keep an LRU cache of recently-uploaded files for OCR.
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// We keep them in IDB to avoid tainted canvas errors after a refresh.
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// https://github.com/nolanlawson/pinafore/issues/1901
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import { get, set, keys, del } from '../_thirdparty/idb-keyval/idb-keyval.js'
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const PREFIX = 'media-cache-'
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const DELIMITER = '-cache-'
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const LIMIT = 4 // you can upload 4 images per post, this seems reasonable despite cross-instance usage
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export const DELETE_AFTER = 604800000 // 7 days
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let deleteAfter = DELETE_AFTER
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function keyToData (key) {
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key = key.substring(PREFIX.length)
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const index = key.indexOf(DELIMITER)
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// avoiding str.split() to not have to worry about ids containing the delimiter string somehow
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return [key.substring(0, index), key.substring(index + DELIMITER.length)]
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}
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function dataToKey (timestamp, id) {
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return `${PREFIX}${timestamp}${DELIMITER}${id}`
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}
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async function getAllKeys () {
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return (await keys()).filter(key => key.startsWith(PREFIX)).sort()
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}
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export async function getCachedMediaFile (id) {
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const allKeys = await getAllKeys()
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for (const key of allKeys) {
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const otherId = keyToData(key)[1]
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if (id === otherId) {
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return get(key)
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}
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}
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}
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export async function setCachedMediaFile (id, file) {
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const allKeys = await getAllKeys()
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if (allKeys.map(keyToData).map(_ => _[1]).includes(id)) {
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return // do nothing, it's already in there
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}
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while (allKeys.length >= LIMIT) {
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// already sorted in chronological order, so delete the oldest
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await del(allKeys.shift())
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}
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// delete anything that's too old, while we're at it
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for (const key of allKeys) {
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const timestamp = keyToData(key)[0]
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if (Date.now() - Date.parse(timestamp) >= deleteAfter) {
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await del(key)
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}
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}
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const key = dataToKey(new Date().toISOString(), id)
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await set(key, file)
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}
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export async function deleteCachedMediaFile (id) {
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const allKeys = await getAllKeys()
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for (const key of allKeys) {
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const otherId = keyToData(key)[1]
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if (otherId === id) {
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await del(key)
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}
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}
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}
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// The following are only used in tests
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export async function getAllCachedFileIds () {
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return (await getAllKeys()).map(keyToData).map(_ => _[1])
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}
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export function setDeleteCachedMediaFilesAfter (newDeleteAfter) {
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deleteAfter = newDeleteAfter
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}
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