Error occured while trying to proxy to: localhost:4200/api/v1/generate_uid

Question

I am following a tutorial (https://levelup.gitconnected.com/simple-application-with-angular-6-node-js-express-2873304fff0f) on creating an app with Angula CLI, Node.js and Express. I use a proxy to start the app, the file defining the proxy looks like this:

{
  "/api/*": {
    "target": "http://localhost:3000",
    "secure": false,
    "logLevel": "debug",
    "changeOrigin": true
  }
}

The command I use to start the app is this one:

ng serve --proxy-config proxy.conf.json

The tutorial said that:

All requests made to /api/... from within our application will be forwarded to http://localhost:3000/api/...

To be honest, I don't really know how it is supposed to work, because when I launch the app, I still use the URL: http://localhost:4200/ .

But I didn't have a problem until now. I just created a route with Express.js at the Endpoint /api/v1/generate_uid .

But the problem is when I go to http://localhost:4200/api/v1/generate_uid it shows this message:

Error occured while trying to proxy to: localhost:4200/api/v1/generate_uid .

The following is the message I get in the console:

[HPM] Error occurred while trying to proxy request /api/v1/generate_uid from localhost:4200 to http://localhost:3000 (ECONNREFUSED) (https://nodejs.org/api/errors.html#errors_common_system_errors)

And when I go to http://localhost:3000 it always says that the connection has failed.

For further references, Here are the app.js of my express API and generate_uid.js which defines the route:

app.js

var express = require('express');
var uid = require('uid-safe');

var router = express.Router();

router.get('/', function(req, res, next) {
    var strUid = uid.sync(18);
    res.json({guid: strUid});
});

module.exports = router;

generate_uid.js

var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var users = require('./routes/users');
var generate_uid = require('./routes/generate_uid');

var app = express();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser())

app.use('/api/v1/users', users);
app.use('/api/v1/generate_uid', generate_uid);

module.exports = app;

So I really don't know what the solution is. Thanks in advance for your answers !!

Answer 1

As said in the comments, it looks like the app doesn't have the .listen() function, which is very important to bind to the port.

app.listen(3000, () => {
  console.log("Server started in port 3000!");
});