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1 | import * as express from 'express' | |
2 | import * as AsyncLock from 'async-lock' | |
3 | import { Redis } from '../lib/redis' | |
4 | import { logger } from '../helpers/logger' | |
5 | ||
6 | const lock = new AsyncLock({ timeout: 5000 }) | |
7 | ||
8 | function cacheRoute (lifetime: number) { | |
9 | return async function (req: express.Request, res: express.Response, next: express.NextFunction) { | |
10 | const redisKey = Redis.Instance.buildCachedRouteKey(req) | |
11 | ||
12 | await lock.acquire(redisKey, async (done) => { | |
13 | const cached = await Redis.Instance.getCachedRoute(req) | |
14 | ||
15 | // Not cached | |
16 | if (!cached) { | |
17 | logger.debug('No cached results for route %s.', req.originalUrl) | |
18 | ||
19 | const sendSave = res.send.bind(res) | |
20 | ||
21 | res.send = (body) => { | |
22 | if (res.statusCode >= 200 && res.statusCode < 400) { | |
23 | const contentType = res.getHeader('content-type').toString() | |
24 | Redis.Instance.setCachedRoute(req, body, lifetime, contentType, res.statusCode) | |
25 | .then(() => done()) | |
26 | .catch(err => { | |
27 | logger.error('Cannot cache route.', { err }) | |
28 | return done(err) | |
29 | }) | |
30 | } | |
31 | ||
32 | return sendSave(body) | |
33 | } | |
34 | ||
35 | return next() | |
36 | } | |
37 | ||
38 | if (cached.contentType) res.contentType(cached.contentType) | |
39 | ||
40 | if (cached.statusCode) { | |
41 | const statusCode = parseInt(cached.statusCode, 10) | |
42 | if (!isNaN(statusCode)) res.status(statusCode) | |
43 | } | |
44 | ||
45 | logger.debug('Use cached result for %s.', req.originalUrl) | |
46 | res.send(cached.body).end() | |
47 | ||
48 | return done() | |
49 | }) | |
50 | } | |
51 | } | |
52 | ||
53 | // --------------------------------------------------------------------------- | |
54 | ||
55 | export { | |
56 | cacheRoute | |
57 | } |