93 lines
2.2 KiB
Prolog
93 lines
2.2 KiB
Prolog
/* $Id$
|
|
|
|
Part of SWI-Prolog
|
|
|
|
Author: Jan Wielemaker
|
|
E-mail: wielemak@science.uva.nl
|
|
WWW: http://www.swi-prolog.org
|
|
Copyright (C): Public domain
|
|
*/
|
|
|
|
:- use_module(library('http/thread_httpd')).
|
|
:- use_module(library('http/html_write')).
|
|
:- use_module(library('http/http_session')).
|
|
:- use_module(library('http/http_error')).
|
|
|
|
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|
|
This demo shows session state management in a very simple calculator
|
|
package. It also demonstrates the use of the html_write library. To use
|
|
it, start Prolog, load this file and run
|
|
|
|
?- server.
|
|
|
|
Now direct your browser to http://localhost:3000/
|
|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
|
|
|
|
server :-
|
|
server(3000, []).
|
|
|
|
server(Port, Options) :-
|
|
http_server(reply,
|
|
[ port(Port),
|
|
timeout(20)
|
|
| Options
|
|
]).
|
|
|
|
reply(Request) :-
|
|
memberchk(path(Path), Request),
|
|
reply(Path, Request).
|
|
|
|
reply(/, _Request) :-
|
|
http_session_retractall(formula(_)),
|
|
Formula = 0,
|
|
http_session_assert(formula(Formula)),
|
|
page(Formula).
|
|
|
|
reply('/calc', Request) :-
|
|
memberchk(search(Search), Request),
|
|
memberchk(operation=Op, Search),
|
|
memberchk(value=AtomVal, Search),
|
|
atom_number(AtomVal, Val),
|
|
http_session_retract(formula(Formula0)),
|
|
debug(calc, 'Formula0 = ~w', [Formula0]),
|
|
Formula =.. [Op, Formula0, Val],
|
|
http_session_assert(formula(Formula)),
|
|
page(Formula).
|
|
|
|
|
|
page(Formula) :-
|
|
reply_page('HTTP Session DEMO',
|
|
[ h2('Simple session demo'),
|
|
form([ action('/calc'),
|
|
method('GET')
|
|
],
|
|
table([align(center), border(1)],
|
|
[ tr(td(\formula(Formula))),
|
|
tr(td([ \ops,
|
|
input([ name(value) ]),
|
|
input([ type(submit),
|
|
value('Calc!')
|
|
])
|
|
]))
|
|
]))
|
|
]).
|
|
|
|
formula(Formula) -->
|
|
{ sformat(S, '~w', [Formula]),
|
|
Value is Formula
|
|
},
|
|
html([ S, ' = ', Value ]).
|
|
|
|
ops -->
|
|
html(select(name(operation),
|
|
[ option([selected], +),
|
|
option([], -),
|
|
option([], /),
|
|
option([], *)
|
|
])).
|
|
|
|
reply_page(Title, Content) :-
|
|
phrase(page(title(Title), Content), HTML),
|
|
format('Content-type: text/html~n~n'),
|
|
print_html(HTML).
|