How can I cache a third party json?

[ChristianBorresen]

Hi,

I've created an API that is served through a static json on a separate domain. I would like to cache this json on my server and pass it through my app so that I don't have to hit my API with every visitor. I'm not very experienced, so I'm not sure how I would achieve this.

Currently, my routes are being cached, but they are still sending the http request to my third party json. Let's assume that my api url is https://exampleapi.com/item.json

This is what I currently have (none of my attempts at json caching has worked):

var cache = (duration) => {
  return (req, res, next) => {
    let key = '__express__' + req.originalUrl || req.url
    let cachedBody = mcache.get(key)
    if (cachedBody) {
      console.log('There is a cachedBody')
      res.send(cachedBody)
      return
    } else {
      console.log('There is not a cachedBody')
      res.sendResponse = res.send
      res.send = (body) => {
        mcache.put(key, body, duration *1000);
        res.sendResponse(body)
      }
      next()
    }
  }
}

app.get('/', cache(60), function(req, res) {
  setTimeout(() => {
    res.render('../dist/index', {
      req: req,
      res: res
    });
    console.timeEnd(`GET: ${req.originalUrl}`);
  }, 5000);
});

[slidenerd]

JSON objects are storable in this lib, check the code below for example

'use strict';
const cache = require('memory-cache')

cache.put('ETH-USD', { "Response": "Success", "Message": "This api will soon move to mi-api path.", "Data": { "Algorithm": "Ethash", "ProofType": "PoW", "BlockNumber": 4239827, "NetHashesPerSecond": 96366939315478.141, "TotalCoinsMined": 94435901.9053, "BlockReward": 5.0, "AggregatedData": { "TYPE": "5", "MARKET": "CCCAGG", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "1", "PRICE": "284.9", "LASTUPDATE": "1504585778", "LASTVOLUME": "0.223", "LASTVOLUMETO": "65.337439", "LASTTRADEID": "1504585778.7719", "VOLUME24HOUR": "1925119.1785345688", "VOLUME24HOURTO": "581958947.8059875", "OPEN24HOUR": "345.53", "HIGH24HOUR": "346.44", "LOW24HOUR": "275.05", "LASTMARKET": "Kraken" }, "Exchanges": [{ "TYPE": "2", "MARKET": "BTCE", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "1", "PRICE": "205.50099", "LASTUPDATE": "1500979696", "LASTVOLUME": "0.93965638", "LASTVOLUMETO": "193.10031634981618", "LASTTRADEID": "113648081", "VOLUME24HOUR": "0", "VOLUME24HOURTO": "0", "OPEN24HOUR": "205.50099", "HIGH24HOUR": "205.50099", "LOW24HOUR": "205.50099" }, { "TYPE": "2", "MARKET": "OKCoin", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "284.2", "LASTUPDATE": "1504585230", "LASTVOLUME": "0.579", "LASTVOLUMETO": "164.5518", "LASTTRADEID": "18448444", "VOLUME24HOUR": "8767.919", "VOLUME24HOURTO": "2655671.7731800014", "OPEN24HOUR": "355", "HIGH24HOUR": "355", "LOW24HOUR": "261" }, { "TYPE": "2", "MARKET": "Kraken", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "1", "PRICE": "292.993", "LASTUPDATE": "1504585778", "LASTVOLUME": "0.223", "LASTVOLUMETO": "65.337439", "LASTTRADEID": "1504585778.7719", "VOLUME24HOUR": "208028.28756465", "VOLUME24HOURTO": "63724039.95610457", "OPEN24HOUR": "348.49", "HIGH24HOUR": "349", "LOW24HOUR": "281.301" }, { "TYPE": "2", "MARKET": "Cexio", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "307.57722229", "LASTUPDATE": "1504585731", "LASTVOLUME": "0.995", "LASTVOLUMETO": "306.03933617855", "LASTTRADEID": "791220", "VOLUME24HOUR": "35567.683433", "VOLUME24HOURTO": "11300633.931886906", "OPEN24HOUR": "359.80558409", "HIGH24HOUR": "361.99999494", "LOW24HOUR": "296.54426928" }, { "TYPE": "2", "MARKET": "Exmo", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "288", "LASTUPDATE": "1504585716", "LASTVOLUME": "0.01916638", "LASTVOLUMETO": "5.51991744", "LASTTRADEID": "19078579", "VOLUME24HOUR": "3236.417659919998", "VOLUME24HOURTO": "1002991.9135371699", "OPEN24HOUR": "349", "HIGH24HOUR": "352.29085857", "LOW24HOUR": "280.00000001" }, { "TYPE": "2", "MARKET": "Coinbase", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "4", "PRICE": "296.61", "LASTUPDATE": "1504585765", "LASTVOLUME": "0.00023529", "LASTVOLUMETO": "0.06978936690000001", "LASTTRADEID": "10323690", "VOLUME24HOUR": "521959.42118457897", "VOLUME24HOURTO": "161553551.0031986", "OPEN24HOUR": "347.72", "HIGH24HOUR": "348.52", "LOW24HOUR": "285" }, { "TYPE": "2", "MARKET": "WavesDEX", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "297.14", "LASTUPDATE": "1502447804", "LASTVOLUME": "1.2", "LASTVOLUMETO": "356.568", "LASTTRADEID": "7", "VOLUME24HOUR": "2.4", "VOLUME24HOURTO": "734.644", "OPEN24HOUR": "315", "HIGH24HOUR": "315", "LOW24HOUR": "297.14" }, { "TYPE": "2", "MARKET": "BitTrex", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "277.29999978", "LASTUPDATE": "1504585744", "LASTVOLUME": "0.405", "LASTVOLUMETO": "112.30649991", "LASTTRADEID": "7429751", "VOLUME24HOUR": "77882.07716049001", "VOLUME24HOURTO": "22848548.07120349", "OPEN24HOUR": "344", "HIGH24HOUR": "344", "LOW24HOUR": "265.5" }, { "TYPE": "2", "MARKET": "Poloniex", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "274.99972021", "LASTUPDATE": "1504585709", "LASTVOLUME": "6.60045348", "LASTVOLUMETO": "1815.12286025", "LASTTRADEID": "3855562", "VOLUME24HOUR": "196341.07716732976", "VOLUME24HOURTO": "58177469.1726234", "OPEN24HOUR": "342.10963005", "HIGH24HOUR": "344.10984123", "LOW24HOUR": "267" }, { "TYPE": "2", "MARKET": "Gemini", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "262.88", "LASTUPDATE": "1504576699", "LASTVOLUME": "2", "LASTVOLUMETO": "525.76", "LASTTRADEID": "1571120198", "VOLUME24HOUR": "216904.2207455004", "VOLUME24HOURTO": "65026987.65402278", "OPEN24HOUR": "343.89", "HIGH24HOUR": "344.87", "LOW24HOUR": "262.88" }, { "TYPE": "2", "MARKET": "Bitfinex", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "275.71", "LASTUPDATE": "1504585690", "LASTVOLUME": "1.62376255", "LASTVOLUMETO": "447.68757266049994", "LASTTRADEID": "62385134", "VOLUME24HOUR": "644798.5421963095", "VOLUME24HOURTO": "192084082.9579", "OPEN24HOUR": "343.16", "HIGH24HOUR": "344.01", "LOW24HOUR": "267.64" }, { "TYPE": "2", "MARKET": "Cryptsy", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "4", "PRICE": "1.85", "LASTUPDATE": "1452789914", "LASTVOLUME": "1.23007147", "LASTVOLUMETO": "2.27563222", "LASTTRADEID": "110935442", "VOLUME24HOUR": "0", "VOLUME24HOURTO": "0", "OPEN24HOUR": "1.85", "HIGH24HOUR": "1.85", "LOW24HOUR": "1.85" }, { "TYPE": "2", "MARKET": "HitBTC", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "1", "PRICE": "275.31", "LASTUPDATE": "1504585763", "LASTVOLUME": "0.052", "LASTVOLUMETO": "14.31612", "LASTTRADEID": "24783526", "VOLUME24HOUR": "9882.125999999998", "VOLUME24HOURTO": "3036674.5280299988", "OPEN24HOUR": "343.06", "HIGH24HOUR": "343.36", "LOW24HOUR": "270.67" }, { "TYPE": "2", "MARKET": "Tidex", "FROMSYMBOL": "ETH", "TOSYMBOL": "WUSD", "FLAGS": "4", "PRICE": "311.94902967", "LASTUPDATE": "1504584562", "LASTVOLUME": "0.80913154", "LASTVOLUMETO": "252.4077987783928", "LASTTRADEID": "1090807", "VOLUME24HOUR": "78.18033999999997", "VOLUME24HOURTO": "24806.22865919628", "OPEN24HOUR": "336.83947443", "HIGH24HOUR": "338.7302818", "LOW24HOUR": "303.943277" }, { "TYPE": "2", "MARKET": "LiveCoin", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "4", "PRICE": "320", "LASTUPDATE": "1504526194", "LASTVOLUME": "0.004", "LASTVOLUMETO": "1.28", "LASTTRADEID": "157477489", "VOLUME24HOUR": "83.27876504", "VOLUME24HOURTO": "27965.89069719821", "OPEN24HOUR": "354.9", "HIGH24HOUR": "356.9997", "LOW24HOUR": "320" }, { "TYPE": "2", "MARKET": "BitBay", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "303.99", "LASTUPDATE": "1504578523", "LASTVOLUME": "0.14476664", "LASTVOLUMETO": "44.0076108936", "LASTTRADEID": "2490275", "VOLUME24HOUR": "57.29266397000001", "VOLUME24HOURTO": "18637.0921285355", "OPEN24HOUR": "379.47", "HIGH24HOUR": "389.57", "LOW24HOUR": "270" }, { "TYPE": "2", "MARKET": "Yobit", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "1", "PRICE": "295.86577392", "LASTUPDATE": "1504585550", "LASTVOLUME": "0.00035522", "LASTVOLUMETO": "0.10509744021186239", "LASTTRADEID": "133304745", "VOLUME24HOUR": "890.36434062", "VOLUME24HOURTO": "276210.2367078599", "OPEN24HOUR": "354.79518826", "HIGH24HOUR": "354.81", "LOW24HOUR": "289.5003864" }, { "TYPE": "2", "MARKET": "CCEX", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "287.888", "LASTUPDATE": "1504583813", "LASTVOLUME": "0.1467777", "LASTVOLUMETO": "42.2555384976", "LASTTRADEID": "1668309", "VOLUME24HOUR": "112.96267008000002", "VOLUME24HOURTO": "36018.73519999543", "OPEN24HOUR": "355", "HIGH24HOUR": "355", "LOW24HOUR": "287.888" }, { "TYPE": "2", "MARKET": "Gatecoin", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "4", "PRICE": "276.001", "LASTUPDATE": "1504584202", "LASTVOLUME": "2.5563", "LASTVOLUMETO": "705.5413562999998", "LASTTRADEID": "44359310", "VOLUME24HOUR": "1059.0328284700001", "VOLUME24HOURTO": "320734.07302390534", "OPEN24HOUR": "350", "HIGH24HOUR": "374.992", "LOW24HOUR": "275.001" }, { "TYPE": "2", "MARKET": "Quoine", "FROMSYMBOL": "ETH", "TOSYMBOL": "USD", "FLAGS": "2", "PRICE": "298", "LASTUPDATE": "1504548341", "LASTVOLUME": "9.26", "LASTVOLUMETO": "2759.48", "LASTTRADEID": "10156637", "VOLUME24HOUR": "105.25999999999999", "VOLUME24HOURTO": "34724.48", "OPEN24HOUR": "380", "HIGH24HOUR": "380", "LOW24HOUR": "298" }] }, "Type": 100 }, 60000, (key, value) => {
    console.log(key + ' was timed out')
})

console.log(cache.get('ETH-USD'))