server/middlewares/cache.ts

   1 import * as express from 'express'
   2 import { Redis } from '../lib/redis'
   3 import { logger } from '../helpers/logger'
   4
   5 function cacheRoute (lifetime: number) {
   6   return async function (req: express.Request, res: express.Response, next: express.NextFunction) {
   7     const cached = await Redis.Instance.getCachedRoute(req)
   8
   9     // Not cached
  10     if (!cached) {
  11       logger.debug('Not cached result for route %s.', req.originalUrl)
  12
  13       const sendSave = res.send.bind(res)
  14
  15       res.send = (body) => {
  16         if (res.statusCode >= 200 && res.statusCode < 400) {
  17           const contentType = res.getHeader('content-type').toString()
  18           Redis.Instance.setCachedRoute(req, body, lifetime, contentType, res.statusCode)
  19                .catch(err => logger.error('Cannot cache route.', { err }))
  20         }
  21
  22         return sendSave(body)
  23       }
  24
  25       return next()
  26     }
  27
  28     if (cached.contentType) res.contentType(cached.contentType)
  29
  30     if (cached.statusCode) {
  31       const statusCode = parseInt(cached.statusCode, 10)
  32       if (!isNaN(statusCode)) res.status(statusCode)
  33     }
  34
  35     logger.debug('Use cached result for %s.', req.originalUrl)
  36     return res.send(cached.body).end()
  37   }
  38 }
  39
  40 // ---------------------------------------------------------------------------
  41
  42 export {
  43   cacheRoute
  44 }