java - How to get host name with port from a http or https request

Question

I have two applications deployed in a JBoss container (same unix box). If I receive a request from app1, I need to send a corresponding request for app2.

An Example: If app1 requests: http://example.com/context?param1=123, then I need to extract http://example.com/, so that I can send the request for the second app.

I tried using

  HttpServletRequest.getServerName() & 
  HttpServletRequest.getServerPort() & 
  HttpServletRequest.getHeader("host")

but how can I destinguish between http or https?

Answer 1

You can use HttpServletRequest.getScheme() to retrieve either "http" or "https".

Using it along with HttpServletRequest.getServerName() should be enough to rebuild the portion of the URL you need.

You don't need to explicitly put the port in the URL if you're using the standard ones (80 for http and 443 for https).

Edit: If your servlet container is behind a reverse proxy or load balancer that terminates the SSL, it's a bit trickier because the requests are forwarded to the servlet container as plain http. You have a few options:

1) Use HttpServletRequest.getHeader("x-forwarded-proto") instead; this only works if your load balancer sets the header correctly (Apache should afaik).

2) Configure a RemoteIpValve in JBoss/Tomcat that will make getScheme() work as expected. Again, this will only work if the load balancer sets the correct headers.

3) If the above don't work, you could configure two different connectors in Tomcat/JBoss, one for http and one for https, as described in this article.