How to res.send to a new URL in Node.js/Express?

Question

Given a GET request to URL X, how should you define res.send such that it provides a response to a completely separate URL Y?

i.e.

app.get('/', function (req, res) {
    res.send to a new URL external of the app ('Success')
});

Thanks and apologies in advance for ignorance on the topic!

Answer 1

You want to redirect the request by setting the status code and providing a location header. 302 indicates a temporary redirect, 301 is a permanent redirect.

app.get('/', function (req, res) {
  res.statusCode = 302;
  res.setHeader("Location", "http://www.url.com/page");
  res.end();
});

Answer 2

You can only send response to the request source, which is the client. There is no such thing as sending response to another "external-url" (or another server).
However, you CAN make a request to another server, wait for it's response, and respond to our client.

app.get('/', (req, res) => {
    
    var requestOptions = {
        hostname: 'serverB.com', // url or ip address
        port: 8080, // default to 80 if not provided
        path: '/take-request',
        method: 'POST' // HTTP Method
    };

    var externalRequest = http.request(requestOptions, (externalResponse) => {
        
        // ServerB done responding
        externalResponse.on('end', () => {
            
            // Response to client
            res.end('data was send to serverB');
        });
    });
    
    // Free to send anthing to serverB
    externalRequest.write(req.data);
    externalRequest.end();
});