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
The address is established from the settings
http:public_port if provided. Otherwise it is deduced from the request.
- http_public_url(+Request, -URL) is det
- True when URL is an absolute URL for the current request.
Typically, the login page should redirect to this URL to avoid
losing the session.
- http_public_host_url(+Request, -URL) is det
- True when URL is the public URL at which this server can be
contacted. This value is not easy to obtain. See
http_public_host/4 for the hardest part: find the host and
- http_public_host(?Request, -Hostname, -Port, +Options) is det
- Current global host and port of the HTTP server. This is the
basis to form absolute address, which we need for redirection
based interaction such as the OpenID protocol. Options are:
false), try to replace a local hostname
by a world-wide accessible name.
This predicate performs the following steps to find the host and
- Use the settings
X-Forwarded-Host header, which applies if this server
runs behind a proxy.
- Use the
Host header, which applies for HTTP 1.1 if we are
- Use gethostname/1 to find the host and
http_current_server/2 to find the port.
|Request||- is the current request. If it is left unbound,
and the request is needed, it is obtained with
- http_current_host(?Request, -Hostname, -Port, +Options) is det
- - Use http_public_host/4 (same semantics)
- primary_forwarded_host(+Spec, -Host) is det[private]
- x_forwarded host contains multiple hosts separated by ', ' if
there are multiple proxy servers in between. The first one is
the one the user's browser knows about.
- global_host(+HostIn, -Host)[private]
- Globalize a hostname. Used if we need to pass our hostname to a
client and expect the client to be able to contact us. In this
case we cannot use a name such as `localhost' or the plain
hostname of the machine. We assume (possibly wrongly) that if
the host contains a '.', it is globally accessible.
If the heuristics used by this predicate do not suffice, the
setting http:public_host can be used to override.