HTML to Node.js server POST request on localhost with Fetch

Excuse any wrong usage of terms or words, still trying to understand Node.js.

I am running a website with LiveServer and a Node.js server on the same PC. I realise I could be running the website as a Node.js app but I am trying to use POST with Fetch to send a file from the website to the server.

The server will handle file copying and maybe some other things that I find interesting but for now that’s it.

The problem is I can’t even connect to localhost. LiveServer is running on port 5501 and Node server on port 5000.

Below is the code for the index.js file for the website, it just takes a drag&drop event and tries to send the file to localhost:5000:

                var file = event.dataTransfer.items[i].getAsFile();
                console.log('... file[' + i + '].name = ' + file.name);

                var data = new FormData();
                data.append('file', file);

                const url = new URL('http://localhost:5000/');

                fetch(url, {
                    method:'POST',
                    body: data
                })
            }

And here is the Node.js server code:

const express = require('express'); //Import the express dependency
const cors = require('cors');

const app = express();              //Instantiate an express app, the main work horse of this server
const port = 5000;                  //Save the port number where your server will be listening

//setting middleware
app.use('/dist', express.static('dist'));

app.use(cors({
    allowedOrigins: [
        'http://localhost:5000'
    ]
}));

// //Idiomatic expression in express to route and respond to a client request
// app.get('/', (req, res) => {        //get requests to the root ("/") will route here
//     res.sendFile('src/index.html', { root: __dirname });      //server responds by sending the index.html file to the client's browser
//     //the .sendFile method needs the absolute path to the file, see: https://expressjs.com/en/4x/api.html#res.sendFile 
// });


app.listen(port, () => {            //server starts listening for any attempts from a client to connect at port: {port}
    console.log(`Now listening on port ${port}`);
});


app.post('http://localhost:5000/', function (req, res) {
    // const body = req.body.Body
    // res.set('Content-Type', 'text/plain')
    // res.send(`You sent: ${body} to Express`)
    res.sendFile('src/index.html', { root: __dirname });      //server responds by sending the index.html file to the client's browser

})

The error I get in Chrome is: POST http://localhost:5000/ 404 (Not Found)

Is what I am trying to do even possible? I’ve tried different variations of typing the URL and still I get the same error message. Google isn’t helpful either.

Any help is appreciated, thanks in advance.

>Solution :

First argument on the app.METHOD must be the path for which the middleware function is invoked; can be any of:

1. A string representing a path.
2. A path pattern.
3. A regular expression pattern to match paths.
4. An array of combinations of any of the above.

So therefore this line

app.post('http://localhost:5000/', ...)

has to be a pathname only, so replace it with this

app.post('/', ... )