Allow IBM HTTP Server behind a proxy/LB that performs SSL offloading to become aware that the original request uses https

In a situation where IHS is behind another proxy/LB that performs SSL offloading, it would be beneficent to implement a behavior similar to WAS, to check a http header defined by the web container custom property 'httpsIndicatorHeader' to know that the original request uses https. The web container property 'httpsIndicatorHeader' is configured for WAS and the LB sends the configured header with the request. With this setup, WAS is able to determine that the original request was sent with https and the getServerPort method returns 443 (default https port since the Host header does not contain port number). This works as expected during virtual host mapping as the server would try to match virtual host <hostname>:443.

However, for IHS, the case is different. IHS seems to be unable to determine that the original request was sent over https. And since the Host header of the request has no port number (request is made through a web browser), IHS would set $WSSP private header to the default http port 80, and while virtual host mapping, it would try to map <hostname>:80 instead of the expected <hostname>:443. Because of this, we had to add an extra alias <hostname>:80 to the virtual host configuration in WAS, something that is misleading as the original request is a https request that is received on LB on port 443.

By allowing IHS to inspect a request header like WAS with httpsIndicatorHeader, it would assist in situations similar to the above.