server/middlewares/cache.ts


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import * as express from 'express'
import { Redis } from '../lib/redis'
import { logger } from '../helpers/logger'

async function cacheRoute (req: express.Request, res: express.Response, next: express.NextFunction) {
  const cached = await Redis.Instance.getCachedRoute(req)

  // Not cached
  if (!cached) {
    logger.debug('Not cached result for route %s.', req.originalUrl)

    const sendSave = res.send.bind(res)

    res.send = (body) => {
      if (res.statusCode >= 200 && res.statusCode < 400) {
        Redis.Instance.setCachedRoute(req, body, res.getHeader('content-type').toString(), res.statusCode)
             .catch(err => logger.error('Cannot cache route.', { err }))
      }

      return sendSave(body)
    }

    return next()
  }

  if (cached.contentType) res.contentType(cached.contentType)

  if (cached.statusCode) {
    const statusCode = parseInt(cached.statusCode, 10)
    if (!isNaN(statusCode)) res.status(statusCode)
  }

  logger.debug('Use cached result for %s.', req.originalUrl)
  return res.send(cached.body).end()
}

// ---------------------------------------------------------------------------

export {
  cacheRoute
}