I cleared and merged the codes. And I created a new endpoint as /export to export the data as CSV file. I couldn't test it so let me know if it doesn't work.
const express = require('express');
const bodyParser = require('body-parser');
const app = express();
const MongoClient = require('mongodb').MongoClient;
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use(express.static('public'));
app.set('views', './src/views');
app.get('/', async (req, res) => {
const db = await mongoDB();
const person = await db.collection('person').find().toArray();
res.render('index.ejs', { person: person })
})
app.get('/export', async (req, res) => {
await convertCSV();
res.status(200).send( { success: 1 });
})
app.post('/person', async (req, res) => {
res.redirect('/');
})
app.listen(process.env.PORT, function () {
console.log(`server: http://${process.env.HOST}:${process.env.PORT}`);
})
const mongoDB = () => {
return new Promise((resolve, reject) => {
const url = 'mongodb://127.0.0.1:27017';
MongoClient.connect(url, { useUnifiedTopology: true })
.then(client => {
const db = client.db('users')
resolve(db);
})
.catch(error => reject(error))
});
}
const convertCSV = () => {
return new Promise((resolve, reject) => {
const converter = require("json-2-csv");
const fetch = require("node-fetch");
const fs = require("fs");
const flatten = require('flat');
const maxRecords = 10;
const getJson = async () => {
const response = await fetch(`http://${process.env.HOST}:${process.env.PORT}/users.json`);
const responseJson = await response.json();
return responseJson;
};
const convertToCSV = async () => {
const json = await getJson();
let keys = Object.keys(flatten(json[0]));
let options = {
keys: keys
};
converter.json2csv(json, json2csvCallback, options);
};
let json2csvCallback = function (err, csv) {
if (err) throw err;
const headers = csv.split('\n').slice(0, 1);
const records = csv.split('\n').slice(0,);
for (let i = 1; i < records.length; i = i + maxRecords) {
let dataOut = headers.concat(records.slice(i, i + 3)).join('\n');
let id = Math.floor(i / maxRecords) + 1;
fs.writeFileSync('data' + id + '.csv', dataOut)
}
};
await convertToCSV();
resolve();
})
}
However, it is not a good practice at all to using controller, index and route in the same file. A better approach would be to create routes, controllers folders and put the codes in a more orderly form.
Something like this (You can find better ones of course mine is just advice):
- index.js
- router.js (A router to manage your endpoints)
- controllers (Controller when you call the endpoint)
-> export.controller.js
-> person.controller.js
- routes (Endpoints)
-> export.route.js
-> person.route.js
- helpers
-> databaseHandler.js (Database connection handler)
