swilgt HTTP

A few useful imports for web server programming using Logtalk and SWI-Prolog's library(http/http_server).

http.lgt

This object is a proxy to library(http/http_server). Anytime you have a predicate that starts with http_ replace that part with http:: and voila! For example, instead of:

:- http_server([port(7000)]).

Write:

:- http::server([port(7000)]).

If the predicate doesn't have a http_ prefix, you still message the http object. So instead of:

reply_json_dict(D).

It's:

http::reply_json_dict(D).

NB This still needs the meta_predicate/1 declarations double checking. Furthermore, there appears to be some magic behind http_current_handler/2, so you may be getting a false answer when in truth there are handlers registered. It's on the TODO...

handler.lgt

This is a category you can import so when making an object with handlers you can define them like so:

:- object(home,
    imports(handler)).

    :- initialization((
        ^^handler(root(.), say_hi, [])
    )).

    say_hi(_Request) :-
        write('Content-type: text/plain'),
        nl,
        nl,
        write('Hello, world!'),
        nl.

:- end_object.

loader.lgt And A Workaround/With For Existing SWI-Apps

This file loads http and handler. They're the recommended way to do things because if you load these before your routes you'll get to take advantage of static binding between the objects. But, if you're just wanting to add in a Logtalk route to an existing SWI-Prolog web application like so:

:- http_handler(root(.), home::say_hi, []).

You'll find it'll throw an error. You could write:

:- http_handler(root(.), [R]>>home::say_hi(R), []).

Or if you like it to look clean, then you can logtalk_load(swilgt_http(lgt_handlers)), which has a term expansion to re-write your routes into the lambda at compile time.

Installation

See settings.lgt in your logtalk user directory for how to add third party libraries, then clone this repo into your third party library directory.