/* Part of ClioPatria Author: Jan Wielemaker E-mail: J.Wielemaker@cs.vu.nl WWW: http://www.swi-prolog.org Copyright (C): 2010, VU University Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(html_messages, [ call_showing_messages/2 ]). :- use_module(library(http/html_write)). :- use_module(library(http/html_head)). :- use_module(library(option)). /** Run goals that produce messages This module allows executing (long running) Prolog goals and see the messages appear in the browser. */ :- meta_predicate call_showing_messages(0, +). %% call_showing_messages(:Goal, +Options) is det. % % Execute Goal, showing the feedback in the browser. This % predicate builds a default application page with a placeholder % for the messages. It then sends all HTML upto the placeholder % and flushes the output to the browser. During execution, all % output from Goal emitted through print_message/2 is caught in % the message-box. After completion of Goal the page is completed. % % This predicate is intended for action such as loading RDF files, % while providing feedback on files loaded and possible error % messages. Note that this call creates a complete page. % % @bug This call uses =chunked= transfer encoding to send the % page in parts. Not all browsers support this and not % all browsers update the page incrementally. :- create_prolog_flag(html_messages, false, [type(boolean)]). assert_message_hook :- Head = message_hook(_Term, Level, Lines), Body = send_message(Level, Lines), ( clause(user:Head, Body) -> true ; asserta((user:Head :- Body)) ). :- initialization assert_message_hook. call_showing_messages(Goal, Options) :- option(style(Style), Options, default), option(head(Head), Options, title('SWI-Prolog -- make')), option(header(Header), Options, div(class(msg_header), h4('Messages ...'))), ( option(footer(Footer), Options) -> true ; ( option(return_to(ReturnURI), Options) -> FooterRest = [ p(['Go ', a(href(ReturnURI), 'back'), ' to the previous page']) ] ; FooterRest = [] ), Footer = div(class(msg_footer), [ h4('Done') | FooterRest ]) ), format('Content-Type: text/html~n'), format('Transfer-Encoding: chunked~n~n'), header(Style, Head, Header, Footer, FooterTokens), setup_call_cleanup( set_prolog_flag(html_messages, true), catch(Goal, E, print_message(error, E)), set_prolog_flag(html_messages, false)), !, footer(FooterTokens). send_message(Level, Lines) :- current_prolog_flag(html_messages, true), level_css_class(Level, Class), phrase(html(pre(class(Class), \html_message_lines(Lines))), Tokens), with_mutex(html_messages, print_html(Tokens)), flush_output, fail. level_css_class(informational, msg_informational). level_css_class(warning, msg_warning). level_css_class(error, msg_error). html_message_lines([]) --> []. html_message_lines([nl|T]) --> !, html('\n'), % we are in a
 environment
	html_message_lines(T).
html_message_lines([flush]) -->
	[].
html_message_lines([H|T]) --> !,
	html(H),
	html_message_lines(T).


%%	header(+Style, +Head, +Header, +Footer, -FooterTokens)
%
%	Emit all tokens upto the placeholder for the actual messages and
%	return the remaining page-tokens in FooterTokens. Style and Head
%	are passed

header(Style, Head, Header, Footer, FooterTokens) :-
	Magic = '$$$MAGIC$$$',
	Body = [ Header,
		 \(html_messages:html_requires(css('messages.css'))),
		 div(class(messages), Magic),
		 Footer
	       ],
	phrase(html_write:page(Style, Head, Body), Tokens),
	html_write:mailman(Tokens),
	append(HeaderTokens, [Magic|FooterTokens], Tokens), !,
	current_output(Out),
	html_write:write_html(HeaderTokens, Out),
	flush_output(Out).

footer(Footer) :-
	current_output(Out),
	html_write:write_html(Footer, Out).