Capture ip address from Spring controller to JSP

Question

My spring app has a controller like this: https://my.app.com/project1/token . When a user clicks this link, I redirect them to a jsp in my WEB-INF folder to collect some client-side data from a jsp (info like langauge, local, time, etc). I want to capture the IP address as well, but I'm not able to get any data from my controller. This is the code I have so far:

servletRequest.setAttribute("ip", servletRequest.getHeader("X-FORWARDED-FOR"));
servletRequest.getRequestDispatcher(DEVICE_INFO).forward(servletRequest, servletResponse);

And in my JSP I have:

console.log("IP address is - ${ip}");

But it is coming up empty. Is there a better solution for this? If I just use servletRequest.setAttribute("ip", servletRequest.getRemoteHost()); I get the ip of the jsp host (which is docker at the moment, I want to get the ip address of the user who clicked the link).

Answer 1

The X-FORWARDED-FOR is only set if there is a proxy in the middle, which is setting that header. If you have no proxy, or the proxy is not setting that header, you will not get anything there.

Did you try something like this?

  String remoteAddr = servletRequest.getHeader("X-FORWARDED-FOR");
  if (remoteAddr == null || remoteAddr.equals("")) {
      remoteAddr = servletRequest.getRemoteAddr();
  }

It works on normal setups, not sure what your docker setup is doing.