How to redirect incoming URL requests by adding additional parameters

Question

Problem: I get an incoming HTTP request to my server application. The request is something like this : http://example.com?id=abc. I need to parse this request, patch additional URL parameters and call a hosted html file. So:

http://example.com?id=abc => http://example.com:8080/temp.html?id=abc&name=cdf.

So the client should see temp.html

Here's the code:

function onRequest(request,response) {
if(request.method =='GET') {
        sys.debug("in get");
        var pathName = url.parse(request.url).pathname;
        sys.debug("Get PathName" + pathName + ":" + request.url);
        var myidArr = request.url.split("=");
        var myid = myidArr[1];
        //Call the redirect function
        redirectUrl(myid);
}
http.createServer(onRequest).listen(8888);

function redirectUrl(myid) {
var temp='';
    var options = {
      host: 'localhost',
      port: 8080,
      path: '/temp.html?id=' + myid + '&name=cdf',
      method: 'GET'
    };
  var req = http.request(options, function(res) {
    console.log('STATUS: ' + res.statusCode);
    console.log('HEADERS: ' + JSON.stringify(res.headers));
    res.setEncoding('utf8');
    res.on('data', function (chunk) {
      temp = temp.concat(chunk);
    });
    res.on('end', function(){
        return temp;
      });
    });
  req.end();
  return temp;
}

Even though this is a really stupid way of going about this issue, I do see the response in the res.end() callback. How to propagate this to the parent calling function onRequest ?

Is there a simpler way of doing this just using node ? I know that there are ways to serve static html files. However, I need to pass URL parameters to temp.html - so I'm not sure how to do this.

Answer 1

Just wondering if a simpler redirect would serve the purpose:

  function onRequest(request,response) {
    if(request.method =='GET') {
       sys.debug("in get");
       var pathName = url.parse(request.url).pathname;
       sys.debug("Get PathName" + pathName + ":" + request.url);
       var myidArr = request.url.split("=");
       var myid = myidArr[1];
       var path = 'http://localhost:8080/temp.html?id=' + myid + '&name=cdf';
       response.writeHead(302, {'Location': path});
       response.end();
    }

Answer 2

This is a classical error when coming to the async world. You don't return the value of the file, you pass a callback as a parameter and execute it with the end value like so:

function proxyUrl(id, cb) {
  http.request(options, function(res) {
    // do stuff
    res.on('data', function (chunk) {
      temp = temp.concat(chunk);
    });
    res.on('end', function(){
      // instead of return you are using a callback function
      cb(temp);
    });
}

function onRequest(req, res) {
  // do stuff
  proxyUrl(id, function(htmlContent) {
    // you can write the htmlContent using req.end here
  });
}

http.createServer(onRequest).listen(8888);

Answer 3

You have to pass the original response to your redirectUrl function, and let it write to the response. Something like:

function redirectUrl(myid, response) {
  var options = {
    host: 'localhost',
    port: 8080,
    path: '/temp.html?id=' + myid + '&name=cdf',
    method: 'GET'
  };
  var req = http.request(options, function(res) {
    console.log('STATUS: ' + res.statusCode);
    console.log('HEADERS: ' + JSON.stringify(res.headers));
    res.setEncoding('utf8');

    // Proxy the headers
    response.writeHead(res.statusCode, res.headers);

    // Proxy the response
    res.on('data', function (chunk) {
      response.write(chunk);
    });
    res.on('end', function(){
        response.end();
      });
    });
  req.end();
}

Calling it:

redirectUrl(myid, response);

Also, since you're already parsing the url, why not do:

var parsedUrl = url.parse(request.url, true);
sys.debug("Get PathName" + parsedUrl.pathname + ":" + request.url);
//Call the redirect function
redirectUrl(parsedUrl.query.id, response);