How to Enable CORS for a Node.js Express Server Communicating with a Different Port?

Enabling CORS for Node.js Express Server with Different Port

Background

Cross-Origin Resource Sharing (CORS) allows web applications to securely make requests to resources on other websites. When using Node.js Express server to communicate with another API running on a different port, it's necessary to enable CORS to avoid cross-origin errors.

Enable CORS with Express

To enable CORS in Express, install the cors package:

npm install cors --save

Import the cors package and the Express module:

const cors = require('cors');
const express = require('express');

Initialize the Express app:

const app = express();

Use the cors middleware to enable CORS for all requests:

app.use(cors());

Configure CORS for Specific Routes

If you want to enable CORS only for specific routes, use the following syntax:

app.get('/products/:id', cors(), (req, res, next) => {
  res.json({ msg: 'This is CORS-enabled for a Single Route' });
});

Example

In the provided example, you want to enable CORS on port 8080, where dcm4chee runs. To do this, assume you have the following code in your Node.js app:

const express = require('express');
const app = express();

app.get('/request-from-browser', (req, res, next) => {
  // Your code to handle the request
});

app.listen(3000, () => {
  console.log('Node.js app listening on port 3000');
});

To enable CORS for the /request-from-browser route on port 8080, add the following middleware before the route code:

app.use('/request-from-browser', cors());

This will enable CORS for requests made to /request-from-browser on port 8080.

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