Using Express proxy, how to change the relative url?

Question

In order to avoid the typical CORS problem with client-side javascript code I use a nodejs express server. This server contains the following code:

var app = express();

  app.all('/Api/*', function (req, res) {
    proxy.web(req, res, {
        target: 'https://www.myserver.com',
        changeOrigin:true
    });
  });

So what this does is redirect any call that starts with /Api to my server.

However, this also appends Api to the url path, so Api/getData becomes https://www.myserver.com/Api/getData

Is there way to strip the Api part of the relative url? The end result would be Api/getData becoming https://www.myserver.com/getData

This would allow me to target several servers by changing the first part of the relative url path. Something like this:

Api/getData -> https://www.myserver.com/getData

OtherApi/getData/for/some/path -> https://www.some-other-server.com/getData/for/some/path

This should of course work for all request types, not only for GET

Thanks!

Answer 1

Take a look at the http-proxy-rules module, which is a companion module for node-http-proxy. It allows you to write rules for changing matching routes to different proxy routes.

With it you should be able to define your translations like this:

var proxyRules = new HttpProxyRules({
    rules: {
      '.*/Api': 'http://myserver.com/', // Rule (1)
      '.*/OtherApi*': 'http://some-other-server.com:8080/' // Rule (2)
    },
    default: 'http://myserver.com/' // default target
  });

Then use them like this:

app.all('*', function(req, res) {
  var target = proxyRules.match(req);
  if (target) {
    return proxy.web(req, res, {
      target: target
    });
  }
})

Answer 2

You can try to modify req.url option. Something like:

app.all('/Api/*', function (req, res) {        
    req.url = req.url.split('/Api/')[1];
    proxy.web(req, res, {
        target: 'http://stackoverflow.com/',
        changeOrigin:true
    });
});