1/*  Part of ClioPatria SeRQL and SPARQL server
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2010-2018, VU University Amsterdam
    7    All rights reserved.
    8
    9    Redistribution and use in source and binary forms, with or without
   10    modification, are permitted provided that the following conditions
   11    are met:
   12
   13    1. Redistributions of source code must retain the above copyright
   14       notice, this list of conditions and the following disclaimer.
   15
   16    2. Redistributions in binary form must reproduce the above copyright
   17       notice, this list of conditions and the following disclaimer in
   18       the documentation and/or other materials provided with the
   19       distribution.
   20
   21    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   22    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   23    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   24    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   25    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   26    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   27    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   28    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   29    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   31    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   32    POSSIBILITY OF SUCH DAMAGE.
   33*/
   34
   35:- module(cp_messages,
   36          [ call_showing_messages/2,    % :Goal, +Options
   37            after_messages/1            % +HTML
   38          ]).   39:- use_module(library(http/html_write)).   40:- use_module(library(http/html_head)).   41:- use_module(library(http/js_write)).   42:- use_module(library(http/http_wrapper)).   43:- use_module(library(http/http_dispatch)).   44:- use_module(library(http/http_path)).   45:- use_module(library(http/cp_jquery)).   46:- use_module(library(option)).   47:- use_module(library(lists)).

   55:- meta_predicate
   56    call_showing_messages(0, +).   57:- html_meta
   58    after_messages(html).

 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.

   77:- create_prolog_flag(html_messages, false, [type(boolean)]).   78assert_message_hook :-
   79    Head = user:message_hook(_Term, Level, Lines),
   80    Body = send_message(Level, Lines),
   81    (   clause(Head, Body)
   82    ->  true
   83    ;   asserta((Head:-Body))
   84    ).
   85:- initialization
   86    assert_message_hook.   87
   88
   89call_showing_messages(Goal, Options) :-
   90    option(style(Style), Options, cliopatria(default)),
   91    option(head(Head), Options, title('ClioPatria')),
   92    option(header(Header), Options,
   93           div(class(msg_header),
   94               h4('Messages ...'))),
   95    (   option(footer(Footer), Options)
   96    ->  true
   97    ;   (   option(return_to(ReturnURI), Options)
   98        ->  FooterRest = [ p(['Go ', a(href(ReturnURI), 'back'),
   99                              ' to the previous page']) ]
  100        ;   FooterRest = []
  101        ),
  102        Footer = div(class(msg_footer), [ h4('Done') | FooterRest ])
  103    ),
  104    format('Content-Type: text/html~n'),
  105    format('Transfer-Encoding: chunked~n~n'),
  106    header(Style, Head, Header, Footer, FooterTokens),
  107    setup_call_cleanup(
  108        set_prolog_flag(html_messages, true),
  109        catch(once(Goal), E, print_message(error, E)),
  110        set_prolog_flag(html_messages, false)),
  111    footer(FooterTokens).
  112
  113send_message(Level, Lines) :-
  114    current_prolog_flag(html_messages, true),
  115    level_css_class(Level, Class),
  116    phrase(html(pre(class(Class), \html_message_lines(Lines))), Tokens),
  117    with_mutex(html_messages, print_html(Tokens)),
  118    flush_output,
  119    fail.
  120
  121level_css_class(informational, msg_informational).
  122level_css_class(warning,       msg_warning).
  123level_css_class(error,         msg_error).
  124
  125html_message_lines([]) -->
  126    [].
  127html_message_lines([nl|T]) -->
  128    !,
  129    html('\n'),                     % we are in a <pre> environment
  130    html_message_lines(T).
  131html_message_lines([flush]) -->
  132    [].
  133html_message_lines([H|T]) -->
  134    !,
  135    html(H),
  136    html_message_lines(T).

 after_messages(+HTML) is det

Close the message window and emit HTML. This predicate may be called from the Goal of call_showing_messages/2 to indicate that all work has been done.

  145after_messages(HTML) :-
  146    close_messages,
  147    phrase(html(HTML), Tokens),
  148    current_output(Out),
  149    html_write:write_html(Tokens, Out).

 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

  158header(Style, Head, Header, Footer, FooterTokens) :-
  159    http_absolute_location(icons('smiley-thinking.gif'), Image, []),
  160    Magic = '$$$MAGIC$$$',
  161    make_list(Header, HList),
  162    make_list(Footer, FList),
  163    append([ HList,
  164             [ \(cp_messages:html_requires(jquery)),
  165               img([id('smiley-thinking'), src(Image)]),
  166               div(class(messages), Magic),
  167               \(cp_messages:js_script({|javascript||
  168                                        $("#smiley-thinking").hide(1000)|}))
  169             ],
  170             FList
  171           ], Body),
  172    phrase(html_write:page(Style, Head, Body), Tokens),
  173    html_write:mailman(Tokens),
  174    (   append(HeaderTokens, [Magic|FooterTokens0], Tokens)
  175    ->  append(CloseDiv0, [>|FooterTokens], FooterTokens0)
  176    ->  append(CloseDiv0, [>], CloseDiv)
  177    ->  true
  178    ),
  179    nb_setval(html_messages_close, CloseDiv),
  180    current_output(Out),
  181    html_write:write_html(HeaderTokens, Out),
  182    flush_output(Out).
  183
  184make_list(List, List) :-
  185    is_list(List),
  186    !.
  187make_list(Obj, [Obj]).
  188
  189close_messages :-
  190    nb_current(html_messages_close, Tokens),
  191    !,
  192    nb_delete(html_messages_close),
  193    current_output(Out),
  194    html_write:write_html(Tokens, Out).
  195close_messages.
  196
  197footer(FooterTokens) :-
  198    close_messages,
  199    current_output(Out),
  200    html_write:write_html(FooterTokens, Out)