expressjs cache

main.ts

// Cache layer for expressjs in typescript
// Based on https://medium.com/the-node-js-collection/simple-server-side-cache-for-express-js-with-node-js-45ff296ca0f0 
// Caches the headers specifically to resolve CORS Errors i was running into with the implementation above. 
var mcache = require('memory-cache');
let cache = (duration: number) => {
  return (req: any, res: any, next: any) => {
    let key = '__express__' + req.originalUrl || req.url
    let headerkey = key + '-header'

    let cachedBody = mcache.get(key)
    let cachedheader = mcache.get(headerkey)

    if (cachedBody) {
      
      res.set(cachedheader)
      res.send(cachedBody)
      return
    } else {
      res.sendResponse = res.send
      res.send = (body: any) => {
        mcache.put(key, body, duration * 1000);
        mcache.put(headerkey, res.headers, duration * 1000);
        res.sendResponse(body)
      }
      next()
    }
  }
}

module.exports = function(app: any) {
  var internal = require('../controllers/main');

  app.route('/')
    .get(cache(600))
    .get(internal.query)
    
    
};