ERR_HTTP_HEADERS_SENT node js socket connection - node.js

Question

I am building an API that uses socket connection to interact with a server backend built in C#. This is what I have so far
const request = require('request');
const express = require('express');
const app = express();
var server = require('http').createServer(app);
var cors = require("cors");
app.use(cors());
const net = require('net');
const client = new net.Socket();
const stringToJson=require('./stringToJson')
const port = process.env.PORT;
const host = process.env.HOST;
client.keepAlive=true
client.on('close', function() {
console.log('Connection closed');
});
app.get('/getScores',function (req,res) {
let dataSend=''
client.on('data', function (data) {
console.log('Server Says : ' + data);
if(data!='ANALYSIS-ERROR'){
dataSend=stringToJson.stringToJson(data)
}
else{
dataSend=stringToJson.stringToJson('0:0.0:0.0:0.0:0:0:0.0:0.0:0.0:0.0:0.0:0:0.0:0.0:0.0:0.0:0.0:0:0.0:0.0:0.0:0.0:0.0:0:0.0:0.0:0.0:0.0:0.0')
}
client.destroy()
return res.send(dataSend)
});
client.connect(port, host, function () {
client.write(`GENERAL-ANALYSIS|${req.query.id}|${req.query.website}|`)
return
});
return
})
app.get('/getPlace',function (req,res) {
console.log(req.query)
request(
{ url: `https://maps.googleapis.com/maps/api/place/textsearch/json?query=${req.query.name}+in+${req.query.city}&key=${process.env.API_KEY}` },
(error, response, body) => {
if (error || response.statusCode !== 200) {
return res.status(500).json({ type: 'error', message: error.message });
}
return res.json(JSON.parse(body));
}
)
})
//TODO ADD 404 500 PAGES
app.use((req, res, next) => {
res.status(404).send("Sorry can't find that!");
});
app.use((err, req, res, next) => {
console.error(err.stack);
res.status(500).send('Something broke!');
});
server.listen(9000, () => {
console.log(`App running at http://localhost:9000`);
});
Basically it creates a connection with the server and listens for some data to be sent back. Then processes the string and sends it to the React frontend. The api calls are made by the frontend using axios
It works but if you refresh the page it throws this error Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
How do I fix this?

Answer 1

Try setting the headers as found in the documentation request.setHeader(name, value)
request.setHeader('Content-Type', 'application/json');