311 lines
8.5 KiB
TypeScript
311 lines
8.5 KiB
TypeScript
// Thanks: https://github.com/kwhitley/apicache
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// We duplicated the library because it is unmaintened and prevent us to upgrade to recent NodeJS versions
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import express from 'express'
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import { OutgoingHttpHeaders } from 'http'
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import { isTestInstance, parseDurationToMs } from '@server/helpers/core-utils'
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import { logger } from '@server/helpers/logger'
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import { Redis } from '@server/lib/redis'
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import { asyncMiddleware } from '@server/middlewares'
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import { HttpStatusCode } from '@shared/models'
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export interface APICacheOptions {
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headerBlacklist?: string[]
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excludeStatus?: HttpStatusCode[]
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}
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interface CacheObject {
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status: number
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headers: OutgoingHttpHeaders
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data: any
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encoding: BufferEncoding
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timestamp: number
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}
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export class ApiCache {
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private readonly options: APICacheOptions
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private readonly timers: { [ id: string ]: NodeJS.Timeout } = {}
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private readonly index = {
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groups: [] as string[],
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all: [] as string[]
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}
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// Cache keys per group
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private groups: { [groupIndex: string]: string[] } = {}
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constructor (options: APICacheOptions) {
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this.options = {
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headerBlacklist: [],
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excludeStatus: [],
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...options
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}
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}
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buildMiddleware (strDuration: string) {
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const duration = parseDurationToMs(strDuration)
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return asyncMiddleware(
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async (req: express.Request, res: express.Response, next: express.NextFunction) => {
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const key = this.getCacheKey(req)
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const redis = Redis.Instance.getClient()
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if (!Redis.Instance.isConnected()) return this.makeResponseCacheable(res, next, key, duration)
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try {
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const obj = await redis.hgetall(key)
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if (obj?.response) {
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return this.sendCachedResponse(req, res, JSON.parse(obj.response), duration)
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}
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return this.makeResponseCacheable(res, next, key, duration)
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} catch (err) {
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return this.makeResponseCacheable(res, next, key, duration)
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}
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}
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)
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}
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clearGroupSafe (group: string) {
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const run = async () => {
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const cacheKeys = this.groups[group]
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if (!cacheKeys) return
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for (const key of cacheKeys) {
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try {
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await this.clear(key)
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} catch (err) {
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logger.error('Cannot clear ' + key, { err })
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}
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}
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delete this.groups[group]
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}
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void run()
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}
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private getCacheKey (req: express.Request) {
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return Redis.Instance.getPrefix() + 'api-cache-' + req.originalUrl
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}
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private shouldCacheResponse (response: express.Response) {
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if (!response) return false
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if (this.options.excludeStatus.includes(response.statusCode)) return false
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return true
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}
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private addIndexEntries (key: string, res: express.Response) {
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this.index.all.unshift(key)
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const groups = res.locals.apicacheGroups || []
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for (const group of groups) {
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if (!this.groups[group]) this.groups[group] = []
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this.groups[group].push(key)
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}
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}
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private filterBlacklistedHeaders (headers: OutgoingHttpHeaders) {
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return Object.keys(headers)
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.filter(key => !this.options.headerBlacklist.includes(key))
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.reduce((acc, header) => {
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acc[header] = headers[header]
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return acc
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}, {})
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}
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private createCacheObject (status: number, headers: OutgoingHttpHeaders, data: any, encoding: BufferEncoding) {
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return {
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status,
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headers: this.filterBlacklistedHeaders(headers),
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data,
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encoding,
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// Seconds since epoch, used to properly decrement max-age headers in cached responses.
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timestamp: new Date().getTime() / 1000
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} as CacheObject
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}
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private async cacheResponse (key: string, value: object, duration: number) {
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const redis = Redis.Instance.getClient()
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if (Redis.Instance.isConnected()) {
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await Promise.all([
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redis.hset(key, 'response', JSON.stringify(value)),
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redis.hset(key, 'duration', duration + ''),
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redis.expire(key, duration / 1000)
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])
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}
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// add automatic cache clearing from duration, includes max limit on setTimeout
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this.timers[key] = setTimeout(() => {
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this.clear(key)
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.catch(err => logger.error('Cannot clear Redis key %s.', key, { err }))
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}, Math.min(duration, 2147483647))
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}
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private accumulateContent (res: express.Response, content: any) {
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if (!content) return
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if (typeof content === 'string') {
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res.locals.apicache.content = (res.locals.apicache.content || '') + content
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return
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}
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if (Buffer.isBuffer(content)) {
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let oldContent = res.locals.apicache.content
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if (typeof oldContent === 'string') {
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oldContent = Buffer.from(oldContent)
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}
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if (!oldContent) {
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oldContent = Buffer.alloc(0)
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}
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res.locals.apicache.content = Buffer.concat(
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[ oldContent, content ],
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oldContent.length + content.length
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)
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return
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}
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res.locals.apicache.content = content
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}
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private makeResponseCacheable (res: express.Response, next: express.NextFunction, key: string, duration: number) {
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const self = this
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res.locals.apicache = {
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write: res.write,
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writeHead: res.writeHead,
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end: res.end,
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cacheable: true,
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content: undefined,
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headers: undefined
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}
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// Patch express
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res.writeHead = function () {
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if (self.shouldCacheResponse(res)) {
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res.setHeader('cache-control', 'max-age=' + (duration / 1000).toFixed(0))
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} else {
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res.setHeader('cache-control', 'no-cache, no-store, must-revalidate')
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}
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res.locals.apicache.headers = Object.assign({}, res.getHeaders())
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return res.locals.apicache.writeHead.apply(this, arguments as any)
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}
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res.write = function (chunk: any) {
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self.accumulateContent(res, chunk)
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return res.locals.apicache.write.apply(this, arguments as any)
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}
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res.end = function (content: any, encoding: BufferEncoding) {
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if (self.shouldCacheResponse(res)) {
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self.accumulateContent(res, content)
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if (res.locals.apicache.cacheable && res.locals.apicache.content) {
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self.addIndexEntries(key, res)
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const headers = res.locals.apicache.headers || res.getHeaders()
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const cacheObject = self.createCacheObject(
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res.statusCode,
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headers,
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res.locals.apicache.content,
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encoding
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)
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self.cacheResponse(key, cacheObject, duration)
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.catch(err => logger.error('Cannot cache response', { err }))
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}
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}
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res.locals.apicache.end.apply(this, arguments as any)
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} as any
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next()
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}
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private sendCachedResponse (request: express.Request, response: express.Response, cacheObject: CacheObject, duration: number) {
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const headers = response.getHeaders()
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if (isTestInstance()) {
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Object.assign(headers, {
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'x-api-cache-cached': 'true'
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})
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}
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Object.assign(headers, this.filterBlacklistedHeaders(cacheObject.headers || {}), {
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// Set properly decremented max-age header
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// This ensures that max-age is in sync with the cache expiration
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'cache-control':
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'max-age=' +
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Math.max(
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0,
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(duration / 1000 - (new Date().getTime() / 1000 - cacheObject.timestamp))
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).toFixed(0)
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})
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// unstringify buffers
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let data = cacheObject.data
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if (data && data.type === 'Buffer') {
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data = typeof data.data === 'number'
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? Buffer.alloc(data.data)
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: Buffer.from(data.data)
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}
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// Test Etag against If-None-Match for 304
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const cachedEtag = cacheObject.headers.etag
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const requestEtag = request.headers['if-none-match']
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if (requestEtag && cachedEtag === requestEtag) {
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response.writeHead(304, headers)
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return response.end()
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}
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response.writeHead(cacheObject.status || 200, headers)
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return response.end(data, cacheObject.encoding)
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}
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private async clear (target: string) {
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const redis = Redis.Instance.getClient()
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if (target) {
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clearTimeout(this.timers[target])
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delete this.timers[target]
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try {
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await redis.del(target)
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} catch (err) {
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logger.error('Cannot delete %s in redis cache.', target, { err })
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}
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this.index.all = this.index.all.filter(key => key !== target)
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} else {
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for (const key of this.index.all) {
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clearTimeout(this.timers[key])
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delete this.timers[key]
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try {
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await redis.del(key)
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} catch (err) {
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logger.error('Cannot delete %s in redis cache.', key, { err })
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}
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}
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this.index.all = []
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}
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return this.index
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}
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}
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