This library finds the public address of the running server. This can
be used to construct URLs that are visible from anywhere on the
internet. This module was introduced to deal with OpenID, where a
request is redirected to the OpenID server, which in turn redirects to
our server (see
The address is established from the settings
http:public_port if provided. Otherwise it is deduced from
false), try to replace a local hostname by a world-wide accessible name.
This predicate performs the following steps to find the host and port:
X-Forwarded-Hostheader, which applies if this server runs behind a proxy.
Hostheader, which applies for HTTP 1.1 if we are contacted directly.
|Request||is the current request. If it is left unbound, and the request is needed, it is obtained with http_current_request/1.|