uri:uri_authority_components/2

uri_authority_components(+Authority, -Components) is det
uri_authority_components(-Authority, +Components) is det: Break-down the authority component of a URI. The fields of the structure Components can be accessed using uri_authority_data/3. This predicate deals with IPv6 addresses written as [ip], returning the ip as host, without the enclosing []. When constructing an authority string and the host contains :, the host is embraced in []. If [] is not used correctly, the behavior should be considered poorly defined. If there is no balancing `]` or the host part does not end with `]`, these characters are considered normal characters and part of the (invalid) host name.