http_dispatch:http_link_to

http
- http

http_link_to_id(+HandleID, +Parameters, -HREF)

HREF is a link on the local server to a handler with given ID, passing the given Parameters. This predicate is typically used to formulate a HREF that resolves to a handler implementing a particular predicate. The code below provides a typical example. The predicate user_details/1 returns a page with details about a user from a given id. This predicate is registered as a handler. The DCG user_link//1 renders a link to a user, displaying the name and calling user_details/1 when clicked. Note that the location (root(user_details)) is irrelevant in this equation and HTTP locations can thus be moved freely without breaking this code fragment.

:- http_handler(root(user_details), user_details, []).

user_details(Request) :-
    http_parameters(Request,
                    [ user_id(ID)
                    ]),
    ...

user_link(ID) -->
    { user_name(ID, Name),
      http_link_to_id(user_details, [id(ID)], HREF)
    },
    html(a([class(user), href(HREF)], Name)).

Arguments:

`HandleID`	- is either an atom, possibly module qualified predicate or a compound term if the hander is defined using a pattern. See http_handler/3 and http_location_by_id/2.
`Parameters`	- is one of `path_postfix(File)` to pass a single value as the last segment of the HTTP location (path). This way of passing a parameter is commonly used in REST APIs. New code should use a path pattern in the handler declaration and a term ``HandleID`(Arg, ...)` A list of search parameters for a `GET` request.

See also

- http_location_by_id/2 and http_handler/3 for defining and specifying handler IDs.