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1 | import * as express from 'express' | |
2 | import * as AsyncLock from 'async-lock' | |
3 | import { parseDuration } from '../helpers/core-utils' | |
4 | import { Redis } from '../lib/redis' | |
5 | import { logger } from '../helpers/logger' | |
6 | ||
7 | const lock = new AsyncLock({ timeout: 5000 }) | |
8 | ||
9 | function cacheRoute (lifetimeArg: string | number) { | |
10 | return async function (req: express.Request, res: express.Response, next: express.NextFunction) { | |
11 | const redisKey = Redis.Instance.generateCachedRouteKey(req) | |
12 | ||
13 | try { | |
14 | await lock.acquire(redisKey, async (done) => { | |
15 | const cached = await Redis.Instance.getCachedRoute(req) | |
16 | ||
17 | // Not cached | |
18 | if (!cached) { | |
19 | logger.debug('No cached results for route %s.', req.originalUrl) | |
20 | ||
21 | const sendSave = res.send.bind(res) | |
22 | const redirectSave = res.redirect.bind(res) | |
23 | ||
24 | res.send = (body) => { | |
25 | if (res.statusCode >= 200 && res.statusCode < 400) { | |
26 | const contentType = res.get('content-type') | |
27 | const lifetime = parseDuration(lifetimeArg) | |
28 | ||
29 | Redis.Instance.setCachedRoute(req, body, lifetime, contentType, res.statusCode) | |
30 | .then(() => done()) | |
31 | .catch(err => { | |
32 | logger.error('Cannot cache route.', { err }) | |
33 | return done(err) | |
34 | }) | |
35 | } else { | |
36 | done() | |
37 | } | |
38 | ||
39 | return sendSave(body) | |
40 | } | |
41 | ||
42 | res.redirect = url => { | |
43 | done() | |
44 | ||
45 | return redirectSave(url) | |
46 | } | |
47 | ||
48 | return next() | |
49 | } | |
50 | ||
51 | if (cached.contentType) res.set('content-type', cached.contentType) | |
52 | ||
53 | if (cached.statusCode) { | |
54 | const statusCode = parseInt(cached.statusCode, 10) | |
55 | if (!isNaN(statusCode)) res.status(statusCode) | |
56 | } | |
57 | ||
58 | logger.debug('Use cached result for %s.', req.originalUrl) | |
59 | res.send(cached.body).end() | |
60 | ||
61 | return done() | |
62 | }) | |
63 | } catch (err) { | |
64 | logger.error('Cannot serve cached route.', { err }) | |
65 | return next() | |
66 | } | |
67 | } | |
68 | } | |
69 | ||
70 | // --------------------------------------------------------------------------- | |
71 | ||
72 | export { | |
73 | cacheRoute | |
74 | } |