index.js

const express = require("express");
const swaggerUI = require("swagger-ui-express");
const swaggerJsDoc = require("swagger-jsdoc");
const cache = require("memory-cache");

if (process.env.DEV == 'true') {
  console.log("DEV MODE");
  require("dotenv").config();
}

const routes = require("./routes/routes");
const app = express();
const HTTP_PORT = process.env.PORT || 8000;

const swagger_options = {
  definition: {
    openapi: "3.0.0",
    info: {
      title: "Gas Inventory API",
      version: "1.0.0",
      description: "A simple Gas Emission Inventory API",
    },
    servers: [{
      url: "https://gas-inventory-api.herokuapp.com/",
    }],
  },
  apis: ["./routes/*.js"],
};

const swagger_specs = swaggerJsDoc(swagger_options);

app.use("/api-docs", swaggerUI.serve, swaggerUI.setup(swagger_specs));
app.use('/', routes);
app.use(express.json());

app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  res.contentType('application/json');
  next();
});

// set up using cache middleware for 1 minute
const memCache = new cache.Cache();
const cacheMiddleware = (duration) => {
    return (req, res, next) => {
        let key =  '__express__' + req.originalUrl || req.url;
        let cacheContent = memCache.get(key);
        if (cacheContent) {
            console.log("Cache hit for " + key);
            res.send(cacheContent);
            return;
        } else {
            res.sendResponse = res.send;
            res.send = (body) => {
                memCache.put(key, body, duration * 1000);
                res.sendResponse(body);
            }
            next();
        }
    }
}

app.use(cacheMiddleware(60));


app.listen(HTTP_PORT, '0.0.0.0', () => {
    console.log("Server is listening on port " + HTTP_PORT);
});