SWI-Prolog -- openid

Availability::- use_module(library(http/http_openid)).

openid_verify(+Options, +Request)

Handle the initial login form presented to the user by the relying party (consumer). This predicate discovers the OpenID server, associates itself with this server and redirects the user's browser to the OpenID server, providing the extra openid.X name-value pairs. Options is, against the conventions, placed in front of the Request to allow for smooth cooperation with http_dispatch.pl. Options processes:

return_to(+URL): Specifies where the OpenID provider should return to. Normally, that is the current location.
trust_root(+URL): Specifies the openid.trust_root attribute. Defaults to the root of the current server (i.e., http://host[.port]/).
realm(+URL): Specifies the openid.realm attribute. Default is the trust_root.
ax(+Spec): Request the exchange of additional attributes from the identity provider. See http_ax_attributes/2 for details.

The OpenId server will redirect to the openid.return_to URL.

throws: http_reply(moved_temporary(Redirect))