app.post won't work, expressJS - node.js

Question

I want to integrate a button on my website that will open a port, recieve some data, update a database and then render the home page. Basically I need that botton to execute the code between the app.post's curly brackets.
That works fine when I click the button for first time but then, after rendering, I have to restart the server to do that again.
app.post('/test', isLoggedIn, (req, res) => {
port.on('data', function (data) {
sirDeAfisat+=data.toString('ascii');
if(checker.sfarsitSir(data)==true) {
if(checker.sirOk(sirDeAfisat)==true){
fs.appendFile("./log/date.txt",sirDeAfisat,(err)=>{
if(err) console.log(err.message);
});
const child=fork('./parser_ok.js');
child.send(`${sirDeAfisat}`);
child.on('message',(answ)=>{
console.log(`Sunt portul, am primit de la parser : ${answ}`)
child.kill('SIGINT');
});
}else{
fs.appendFile('./log/erori.txt',new Date().toISOString(),function (err){
if(err) console.log(err.message);
});
fs.appendFile('./log/erori.txt',"SIR !OK",sirDeAfisat,(err)=>{
if(err) console.log(err.message);
});
}
sirDeAfisat='';
port.close();
res.send(201);
return;
}
});
port.on('readable',() =>{
port.read();
});
});
isLoggedIn:
function isLoggedIn (req, res, next) {
if (req.isAuthenticated()) {
return next();
}
res.redirect('/');
}
and this is test.ejs
<!-- form -->
<form action="/test" method="post">
<input type="submit" class="btn btn-dark btn-lg">
</form>