59 lines
1.3 KiB
TypeScript
59 lines
1.3 KiB
TypeScript
import { createHash } from 'crypto'
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import Router from '@koa/router'
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import IORedis from 'ioredis'
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import IORedisMock from 'ioredis-mock'
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import { koaBody } from 'koa-body'
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const Redis = IORedis.default
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const RedisMock = IORedisMock.default
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// cache expires in 12 hours (in seconds)
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const CACHE_EXPIRE = 12 * 60 * 60
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const redis =
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process.env.NODE_ENV === 'production' && process.env.SCALINGO_REDIS_URL
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? new Redis(process.env.SCALINGO_REDIS_URL, {
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enableOfflineQueue: false,
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keyPrefix: 'cache',
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})
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: new RedisMock()
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export const redisCacheMiddleware = () => {
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const router = new Router()
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router.post('/evaluate', koaBody(), async (ctx, next) => {
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if (!redis || !ctx.request.body) {
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await next()
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return
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}
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const cacheKey = createHash('sha1')
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.update(JSON.stringify(ctx.request.body))
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.digest('base64')
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const cachedResponse = await redis.get(cacheKey)
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if (cachedResponse) {
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ctx.body = JSON.parse(cachedResponse) as unknown
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return
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}
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await next()
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if (ctx.status === 200) {
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const responseCachedAt = Date.now()
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const cacheExpiresAt = responseCachedAt + CACHE_EXPIRE * 1000
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await redis.set(
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cacheKey,
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JSON.stringify({ responseCachedAt, cacheExpiresAt, ...ctx.body }),
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'EX',
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CACHE_EXPIRE
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)
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}
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})
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return router.routes()
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}
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