1/*  Part of SWISH
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2014-2018, VU University Amsterdam
    7			      CWI, Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(swish_page,
   37	  [ swish_reply/2,			% +Options, +Request
   38	    swish_reply_resource/1,		% +Request
   39	    swish_page//1,			% +Options
   40
   41	    swish_navbar//1,			% +Options
   42	    swish_content//1,			% +Options
   43
   44	    pengine_logo//1,			% +Options
   45	    swish_logo//1,			% +Options
   46
   47	    swish_resources//0,
   48	    swish_js//0,
   49	    swish_css//0
   50	  ]).   51:- use_module(library(http/http_open)).   52:- use_module(library(http/http_dispatch)).   53:- use_module(library(http/http_parameters)).   54:- use_module(library(http/http_header)).   55:- use_module(library(http/html_write)).   56:- use_module(library(http/js_write)).   57:- use_module(library(http/json)).   58:- use_module(library(http/http_json)).   59:- use_module(library(http/http_path)).   60:- if(exists_source(library(http/http_ssl_plugin))).   61:- use_module(library(http/http_ssl_plugin)).   62:- endif.   63:- use_module(library(debug)).   64:- use_module(library(time)).   65:- use_module(library(lists)).   66:- use_module(library(option)).   67:- use_module(library(uri)).   68:- use_module(library(error)).   69:- use_module(library(http/http_client)).   70
   71:- use_module(config).   72:- use_module(help).   73:- use_module(search).   74:- use_module(chat).   75:- use_module(authenticate).   76:- use_module(pep).   77
   78/** <module> Provide the SWISH application as Prolog HTML component
   79
   80This library provides the SWISH page  and   its  elements as Prolog HTML
   81grammer rules. This allows for server-side   generated  pages to include
   82swish or parts of swish easily into a page.
   83*/
   84
   85http:location(pldoc, swish(pldoc), [priority(100)]).
   86
   87:- http_handler(swish(.), swish_reply([]), [id(swish), prefix]).   88:- http_handler('/sitemap.xml', http_reply_file('sitemap.xml', []),[]).   89:- http_handler('/robots.txt', http_reply_file('robots.txt', []),[]).   90
   91:- multifile
   92	swish_config:logo//1,
   93	swish_config:title//1,
   94	swish_config:source_alias/2,
   95	swish_config:reply_page/1,
   96	swish_config:li_login_button//1.   97
   98%%	swish_reply(+Options, +Request)
   99%
  100%	HTTP handler to reply the  default   SWISH  page.  Processes the
  101%	following parameters:
  102%
  103%	  - code(Code)
  104%	  Use Code as initial code. Code is either an HTTP url or
  105%	  - url(URL)
  106%	  Download code from URL.  As code(URL), but makes the browser
  107%	  download the source rather than the server.
  108%	  - background(Code)
  109%	  Similar to Code, but not displayed in the editor.
  110%	  - examples(Code)
  111%	  Provide examples. Each example starts with ?- at the beginning
  112%	  of a line.
  113%	  - q(Query)
  114%	  Use Query as the initial query.
  115%	  - show_beware(Boolean)
  116%	  Control showing the _beware limited edition_ warning.
  117%	  - preserve_state(Boolean)
  118%	  If `true`, save state on unload and restore old state on load.
  119
  120swish_reply(Options, Request) :-
  121	(   option(identity(_), Options)
  122	->  Options2 = Options
  123	;   authenticate(Request, Auth),
  124	    Options2 = [identity(Auth)|Options]
  125	),
  126	swish_reply2(Options2, Request).
  127
  128swish_reply2(Options, Request) :-
  129	option(method(Method), Request),
  130	Method \== get, Method \== head, !,
  131	swish_rest_reply(Method, Request, Options).
  132swish_reply2(_, Request) :-
  133	swish_reply_resource(Request), !.
  134swish_reply2(Options, Request) :-
  135	swish_reply_config(Request, Options), !.
  136swish_reply2(SwishOptions, Request) :-
  137	Params = [ code(_,	  [optional(true)]),
  138		   url(_,	  [optional(true)]),
  139		   label(_,	  [optional(true)]),
  140		   show_beware(_, [optional(true)]),
  141		   background(_,  [optional(true)]),
  142		   examples(_,    [optional(true)]),
  143		   q(_,           [optional(true)]),
  144		   format(_,      [oneof([swish,raw,json]), default(swish)])
  145		 ],
  146	http_parameters(Request, Params),
  147	params_options(Params, Options0),
  148	add_show_beware(Options0, Options1),
  149	add_preserve_state(Options1, Options2),
  150	merge_options(Options2, SwishOptions, Options3),
  151	source_option(Request, Options3, Options4),
  152	option(format(Format), Options4),
  153	swish_reply3(Format, Options4).
  154
  155swish_reply3(raw, Options) :-
  156	option(code(Code), Options), !,
  157	format('Content-type: text/x-prolog~n~n'),
  158	format('~s', [Code]).
  159swish_reply3(json, Options) :-
  160	option(code(Code), Options), !,
  161	option(meta(Meta), Options, _{}),
  162	option(chat_count(Count), Options, 0),
  163	reply_json_dict(json{data:Code, meta:Meta, chats:_{total:Count}}).
  164swish_reply3(_, Options) :-
  165	swish_config:reply_page(Options), !.
  166swish_reply3(_, Options) :-
  167	reply_html_page(
  168	    swish(main),
  169	    \swish_title(Options),
  170	    \swish_page(Options)).
  171
  172params_options([], []).
  173params_options([H0|T0], [H|T]) :-
  174	arg(1, H0, Value), nonvar(Value), !,
  175	functor(H0, Name, _),
  176	H =.. [Name,Value],
  177	params_options(T0, T).
  178params_options([_|T0], T) :-
  179	params_options(T0, T).
  180
  181%!	add_show_beware(+Options0, -Option) is det.
  182%
  183%	Add show_beware(false) when called with code, query or examples.
  184%	These are dedicated calls that do not justify this message.
  185
  186add_show_beware(Options0, Options) :-
  187	implicit_no_show_beware(Options0), !,
  188	Options = [show_beware(false)|Options0].
  189add_show_beware(Options, Options).
  190
  191implicit_no_show_beware(Options) :-
  192	option(show_beware(_), Options), !,
  193	fail.
  194implicit_no_show_beware(Options) :-
  195	\+ option(format(swish), Options), !,
  196	fail.
  197implicit_no_show_beware(Options) :-
  198	option(code(_), Options).
  199implicit_no_show_beware(Options) :-
  200	option(q(_), Options).
  201implicit_no_show_beware(Options) :-
  202	option(examples(_), Options).
  203implicit_no_show_beware(Options) :-
  204	option(background(_), Options).
  205
  206%!	add_preserve_state(+Options0, -Option) is det.
  207%
  208%	Add preserve_state(false) when called with code.
  209
  210add_preserve_state(Options0, Options) :-
  211	option(preserve_state(_), Options0), !,
  212	Options = Options0.
  213add_preserve_state(Options0, Options) :-
  214	option(code(_), Options0), !,
  215	Options = [preserve_state(false)|Options0].
  216add_preserve_state(Options, Options).
  217
  218
  219%%	source_option(+Request, +Options0, -Options)
  220%
  221%	If the data was requested  as   '/Alias/File',  reply using file
  222%	Alias(File).
  223
  224source_option(_Request, Options0, Options) :-
  225	option(code(Code), Options0),
  226	option(format(swish), Options0), !,
  227	(   uri_is_global(Code)
  228	->  Options = [url(Code),st_type(external)|Options0]
  229	;   Options = Options0
  230	).
  231source_option(_Request, Options0, Options) :-
  232	option(url(_), Options0),
  233	option(format(swish), Options0), !,
  234	Options = [st_type(external),download(browser)|Options0].
  235source_option(Request, Options0, Options) :-
  236	source_file(Request, File, Options0), !,
  237	option(path(Path), Request),
  238	(   source_data(File, String, Options1)
  239	->  append([ [code(String), url(Path), st_type(filesys)],
  240		     Options1,
  241		     Options0
  242		   ], Options)
  243	;   http_404([], Request)
  244	).
  245source_option(_, Options, Options).
  246
  247%%	source_file(+Request, -File, +Options) is semidet.
  248%
  249%	File is the file associated with a SWISH request.  A file is
  250%	associated if _path_info_ is provided.  If the file does not
  251%	exist, an HTTP 404 exception is returned.  Options:
  252%
  253%	  - alias(-Alias)
  254%	    Get the swish_config:source_alias/2 Alias name that
  255%	    was used to find File.
  256
  257source_file(Request, File, Options) :-
  258	option(path_info(PathInfo), Request), !,
  259	PathInfo \== 'index.html',
  260	(   path_info_file(PathInfo, File, Options)
  261	->  true
  262	;   http_404([], Request)
  263	).
  264
  265path_info_file(PathInfo, Path, Options) :-
  266	sub_atom(PathInfo, B, _, A, /),
  267	sub_atom(PathInfo, 0, B, _, Alias),
  268	sub_atom(PathInfo, _, A, 0, File),
  269	catch(swish_config:source_alias(Alias, AliasOptions), E,
  270	      (print_message(warning, E), fail)),
  271	Spec =.. [Alias,File],
  272	http_safe_file(Spec, []),
  273	absolute_file_name(Spec, Path,
  274			   [ access(read),
  275			     file_errors(fail)
  276			   ]),
  277	confirm_access(Path, AliasOptions), !,
  278	option(alias(Alias), Options, _).
  279
  280source_data(Path, Code, [title(Title), type(Ext), meta(Meta)]) :-
  281	setup_call_cleanup(
  282	    open(Path, read, In, [encoding(utf8)]),
  283	    read_string(In, _, Code),
  284	    close(In)),
  285	source_metadata(Path, Code, Meta),
  286	file_base_name(Path, File),
  287	file_name_extension(Title, Ext, File).
  288
  289%%	source_metadata(+Path, +Code, -Meta:dict) is det.
  290%
  291%	Obtain meta information about a local  source file. Defined meta
  292%	info is:
  293%
  294%	  - last_modified:Time
  295%	  Last modified stamp of the file.  Always present.
  296%	  - loaded:true
  297%	  Present of the file is a loaded source file
  298%	  - modified_since_loaded:true
  299%	  Present if the file loaded, has been edited, but not
  300%	  yet reloaded.
  301
  302source_metadata(Path, Code, Meta) :-
  303	findall(Name-Value, source_metadata(Path, Code, Name, Value), Pairs),
  304	dict_pairs(Meta, meta, Pairs).
  305
  306source_metadata(Path, _Code, path, Path).
  307source_metadata(Path, _Code, last_modified, Modified) :-
  308	time_file(Path, Modified).
  309source_metadata(Path, _Code, loaded, true) :-
  310	source_file(Path).
  311source_metadata(Path, _Code, modified_since_loaded, true) :-
  312	source_file_property(Path, modified(ModifiedWhenLoaded)),
  313	time_file(Path, Modified),
  314	ModifiedWhenLoaded \== Modified.
  315source_metadata(Path, _Code, module, Module) :-
  316	file_name_extension(_, Ext, Path),
  317	user:prolog_file_type(Ext, prolog),
  318	xref_public_list(Path, _, [module(Module)]).
  319
  320confirm_access(Path, Options) :-
  321	option(if(Condition), Options), !,
  322	must_be(oneof([loaded]), Condition),
  323	eval_condition(Condition, Path).
  324confirm_access(_, _).
  325
  326eval_condition(loaded, Path) :-
  327	source_file(Path).
  328
  329%%	swish_reply_resource(+Request) is semidet.
  330%
  331%	Serve /swish/Resource files. In recent   Bootstrap versions, the
  332%	path  to  `fonts/`   is   generated    that   should   refer  to
  333%	`node_modules/bootstrap/dist/fonts`. This could  be   a  bug  in
  334%	Bootstrap or in teh CSS cleaning. For   now,  we hack around the
  335%	issue here.
  336
  337swish_reply_resource(Request) :-
  338	option(path_info(Info), Request),
  339	resource_prefix(Prefix),
  340	sub_atom(Info, 0, _, _, Prefix), !,
  341	http_reply_file(swish_web(Info), [], Request).
  342swish_reply_resource(Request) :-	% see above
  343	option(path_info(Info), Request),
  344	sub_atom(Info, 0, _, _, 'fonts/'), !,
  345	atom_concat('node_modules/bootstrap/dist/', Info, Path),
  346	http_reply_file(swish_web(Path), [], Request).
  347
  348resource_prefix('css/').
  349resource_prefix('help/').
  350resource_prefix('form/').
  351resource_prefix('icons/').
  352resource_prefix('js/').
  353resource_prefix('node_modules/').
  354
  355%%	swish_page(+Options)//
  356%
  357%	Generate the entire SWISH default page.
  358
  359swish_page(Options) -->
  360	swish_navbar(Options),
  361	swish_content(Options).
  362
  363%%	swish_navbar(+Options)//
  364%
  365%	Generate the swish navigation bar.
  366
  367swish_navbar(Options) -->
  368	swish_resources,
  369	html(div([id('navbarhelp'),style('height:40px;margin: 10px 5px;text-align:center')], %;line-height: 40px')],
  370	[div([class('container'),style('display: flex; height: 100px;')],[
  371	  div([style('width: 5%;')],[
  372	    a([href('https://ml.unife.it'),target('_blank')],
  373	      [img([src('/icons/logo-unife.png'),height(40)])])]),
  374	  div([style('flex-grow 1;')],[span([],[span([style('color:maroon')],['cplint on ']),
  375        span([style('color:darkblue')],['SWI']),
  376        span([style('color:maroon')],['SH']),
  377        ' is a web application for probabilistic logic programming',
  378        &(nbsp), &(nbsp),
  379        a([id('about')],['About']),
  380        &(nbsp), &(nbsp),
  381        a([href('http://friguzzi.github.io/cplint/'),target('_blank')],['Help']),
  382				&(nbsp), &(nbsp),
  383				a([href('http://friguzzi.github.io/liftcover/'),target('_blank')],['LIFTCOVER-Help']),
  384				&(nbsp), &(nbsp),
  385				a([href('http://arnaudfadja.github.io/phil/'),target('_blank')],['PHIL-Help']),
  386										&(nbsp), &(nbsp),
  387	a([href('http://friguzzi.github.io/pascal/'),target('_blank')],['PASCAL-Help']),
  388        &(nbsp), &(nbsp),
  389        a([href('/help/credits.html'),target('_blank')],['Credits']),
  390		&(nbsp), &(nbsp),
  391        a([id('dismisslink'),href('')],['Dismiss']),
  392p(['Latest: ',
  393a([href('/e/liftcover/liftcover_examples.swinb')],['Threads and Python in LIFTCOVER']),', ',
  394a([href('/e/course.swinb')],['course']),', ',
  395a([href('/e/phil_examples.swinb')],['PHIL examples']),', ',
  396a([href('http://ml.unife.it/plp-book/'),target('_blank')],["book"])
  397])])
  398       ])])]))
  399        ,
  400
  401	html(nav([ class([navbar, 'navbar-default']),
  402		   role(navigation)
  403		 ],
  404		 [ div(class('navbar-header'),
  405		       [ \collapsed_button,
  406			 \swish_logos(Options)
  407		       ]),
  408		   div([ class([collapse, 'navbar-collapse']),
  409			 id(navbar)
  410		       ],
  411		       [ ul([class([nav, 'navbar-nav', menubar])], []),
  412			 ul([class([nav, 'navbar-nav', 'navbar-right'])],
  413			    [ li(\notifications(Options)),
  414			      li(\search_box(Options)),
  415			      \li_login_button(Options),
  416			      li(\broadcast_bell(Options)),
  417			      li(\updates(Options))
  418			    ])
  419		       ])
  420		 ])).
  421
  422li_login_button(Options) -->
  423	swish_config:li_login_button(Options).
  424li_login_button(_Options) -->
  425	[].
  426
  427collapsed_button -->
  428	html(button([type(button),
  429		     class('navbar-toggle'),
  430		     'data-toggle'(collapse),
  431		     'data-target'('#navbar')
  432		    ],
  433		    [ span(class('sr-only'), 'Toggle navigation'),
  434		      span(class('icon-bar'), []),
  435		      span(class('icon-bar'), []),
  436		      span(class('icon-bar'), [])
  437		    ])).
  438
  439updates(_Options) -->
  440	html([ a(id('swish-updates'), []) ]).
  441
  442
  443		 /*******************************
  444		 *	      BRANDING		*
  445		 *******************************/
  446
  447%!	swish_title(+Options)// is det.
  448%
  449%	Emit the HTML header options dealing with the title and shortcut
  450%	icons.  This can be hooked using swish_config:title//1.
  451
  452swish_title(Options) -->
  453	swish_config:title(Options), !.
  454swish_title(_Options) -->
  455	html([ title('cplint on SWISH -- Probabilistic Logic Programming'),
  456	      link([ rel('shortcut icon'),
  457		     href('/icons/favicon.ico')
  458		   ]),
  459	      link([ rel('apple-touch-icon'),
  460		     href('/icons/cplint-touch-icon.png')
  461		   ]),
  462              meta([name('msvalidate.01'),
  463                content('A9C78799EC9EDC7CE041CB7CD8E2D76E')])
  464	    ]).
  465
  466%!	swish_logos(+Options)// is det.
  467%
  468%	Emit the navbar branding logos at   the  top-left. Can be hooked
  469%	using swish_config:swish_logos//1.
  470
  471swish_logos(Options) -->
  472	swish_config:logo(Options), !.
  473swish_logos(Options) -->
  474	pengine_logo(Options),
  475	swish_logo(Options).
  476
  477%!	swish_config:logo(+Options)// is semidet.
  478%
  479%	Hook  to  include  the  top-left    logos.   The  default  calls
  480%	pengine_logo//1 and swish_logo//1.  The   implementation  should
  481%	emit     zero     or      more       <a>      elements.      See
  482%	`config_available/branding.pl` for an example.
  483
  484%!	pengine_logo(+Options)// is det.
  485%!	swish_logo(+Options)// is det.
  486%
  487%	Emit an <a> element that provides a   link to Pengines and SWISH
  488%	on this server. These may be called from swish_config:logo//1 to
  489%	include the default logos.
  490
  491pengine_logo(_Options) -->
  492	{ http_absolute_location(root(.), HREF, [])
  493	},
  494	html(a([href(HREF), class('pengine-logo')], &(nbsp))).
  495swish_logo(_Options) -->
  496	{ http_absolute_location(swish(.), HREF, [])
  497	},
  498	html(a([href(HREF), class('swish-logo')], &(nbsp))).
  499
  500
  501		 /*******************************
  502		 *	     CONTENT		*
  503		 *******************************/
  504
  505%%	swish_content(+Options)//
  506%
  507%	Generate the SWISH editor, Prolog output  area and query editor.
  508%	Options processed:
  509%
  510%	  - source(HREF)
  511%	  Load initial source from HREF
  512%	  - chat_count(Count)
  513%	  Indicate the presense of Count chat messages
  514
  515swish_content(Options) -->
  516	{ document_type(Type, Options)
  517	},
  518	swish_resources,
  519	swish_config_hash(Options),
  520	swish_options(Options),
  521	html(div([id(content), class([container, 'tile-top'])],
  522		 [ div([class([tile, horizontal]), 'data-split'('50%')],
  523		       [ div([ class([editors, tabbed])
  524			     ],
  525			     [ \source(Type, Options),
  526			       \notebooks(Type, Options)
  527			     ]),
  528			 div([class([tile, vertical]), 'data-split'('70%')],
  529			     [ div(class('prolog-runners'), []),
  530			       div(class('prolog-query'), \query(Options))
  531			     ])
  532		       ]),
  533		   \background(Options),
  534		   \examples(Options)
  535		 ])).
  536
  537
  538%%	swish_config_hash(+Options)//
  539%
  540%	Set `window.swish.config_hash` to a  hash   that  represents the
  541%	current configuration. This is used by   config.js  to cache the
  542%	configuration in the browser's local store.
  543
  544swish_config_hash(Options) -->
  545	{ swish_config_hash(Hash, Options) },
  546	js_script({|javascript(Hash)||
  547		   window.swish = window.swish||{};
  548		   window.swish.config_hash = Hash;
  549		   |}).
  550
  551
  552%!	swish_options(+Options)//
  553%
  554%	Emit additional options. This is  similar   to  config,  but the
  555%	config object is big and stable   for a particular SWISH server.
  556%	The options are set per session.
  557
  558swish_options(Options) -->
  559	js_script({|javascript||
  560		   window.swish = window.swish||{};
  561		   window.swish.option = window.swish.option||{};
  562		  |}),
  563	swish_options([show_beware, preserve_state], Options).
  564
  565swish_options([], _) --> [].
  566swish_options([H|T], Options) -->
  567	swish_option(H, Options),
  568	swish_options(T, Options).
  569
  570swish_option(Name, Options) -->
  571	{ Opt =.. [Name,Val],
  572	  option(Opt, Options),
  573	  JSVal = @(Val)
  574	}, !,
  575	js_script({|javascript(Name, JSVal)||
  576		   window.swish.option[Name] = JSVal;
  577		   |}).
  578swish_option(_, _) -->
  579	[].
  580
  581%%	source(+Type, +Options)//
  582%
  583%	Associate the source with the SWISH   page. The source itself is
  584%	stored  in  the  textarea  from  which  CodeMirror  is  created.
  585%	Options:
  586%
  587%	  - code(+String)
  588%	  Initial code of the source editor
  589%	  - file(+File)
  590%	  If present and code(String) is present, also associate the
  591%	  editor with the given file.  See storage.pl.
  592%	  - url(+URL)
  593%	  as file(File), but used if the data is loaded from an
  594%	  alias/file path.
  595%	  - title(+Title)
  596%	  Defines the title used for the tab.
  597
  598source(pl, Options) -->
  599	{ (   option(code(Spec), Options)
  600	  ;   option(download(browser), Options)
  601          ),
  602          !,
  603          download_source(Spec, Source, Options),
  604	  phrase(source_data_attrs(Options), Extra),
  605          option(label(Label), Options, 'Program')
  606	},
  607	html(div([ class(['prolog-editor']),
  608		   'data-label'(Label)
  609		 ],
  610		 [ textarea([ class([source,prolog]),
  611			      style('display:none')
  612			    | Extra
  613			    ],
  614			    Source)
  615		 ])).
  616source(_, _) --> [].
  617
  618source_data_attrs(Options) -->
  619	(source_file_data(Options) -> [] ; []),
  620	(source_url_data(Options) -> [] ; []),
  621	(source_download_data(Options) -> [] ; []),
  622	(source_title_data(Options) -> [] ; []),
  623	(source_meta_data(Options) -> [] ; []),
  624	(source_st_type_data(Options) -> [] ; []),
  625	(source_chat_data(Options) -> [] ; []).
  626
  627source_file_data(Options) -->
  628	{ option(file(File), Options) },
  629	['data-file'(File)].
  630source_url_data(Options) -->
  631	{ option(url(URL), Options) },
  632	['data-url'(URL)].
  633source_download_data(Options) -->
  634	{ option(download(Who), Options) },
  635	['data-download'(Who)].
  636source_title_data(Options) -->
  637	{ option(title(File), Options) },
  638	['data-title'(File)].
  639source_st_type_data(Options) -->
  640	{ option(st_type(Type), Options) },
  641	['data-st_type'(Type)].
  642source_meta_data(Options) -->
  643	{ option(meta(Meta), Options), !,
  644	  atom_json_dict(Text, Meta, [])
  645	},
  646	['data-meta'(Text)].
  647source_chat_data(Options) -->
  648	{ option(chat_count(Count), Options),
  649	  atom_json_term(JSON, _{count:Count}, [as(string)])
  650	},
  651	['data-chats'(JSON)].
  652
  653%%	background(+Options)//
  654%
  655%	Associate  the  background  program  (if  any).  The  background
  656%	program is not displayed in  the  editor,   but  is  sent to the
  657%	pengine for execution.
  658
  659background(Options) -->
  660	{ option(background(Spec), Options), !,
  661	  download_source(Spec, Source, Options)
  662	},
  663	html(textarea([ class([source,prolog,background]),
  664			style('display:none')
  665		      ],
  666		      Source)).
  667background(_) --> [].
  668
  669
  670examples(Options) -->
  671	{ option(examples(Examples), Options), !
  672	},
  673	html(textarea([ class([examples,prolog]),
  674			style('display:none')
  675		      ],
  676		      Examples)).
  677examples(_) --> [].
  678
  679
  680query(Options) -->
  681	{ option(q(Query), Options)
  682	}, !,
  683	html(textarea([ class([query,prolog]),
  684			style('display:none')
  685		      ],
  686		      Query)).
  687query(_) --> [].
  688
  689%%	notebooks(+Type, +Options)//
  690%
  691%	We have opened a notebook. Embed the notebook data in the
  692%	left-pane tab area.
  693
  694notebooks(swinb, Options) -->
  695	{ option(code(Spec), Options),
  696	  download_source(Spec, NoteBookText, Options),
  697	  phrase(source_data_attrs(Options), Extra)
  698	},
  699	html(div([ class('notebook'),
  700		   'data-label'('Notebook')		% Use file?
  701		 ],
  702		 [ pre([ class('notebook-data'),
  703			 style('display:none')
  704		       | Extra
  705		       ],
  706		       NoteBookText)
  707		 ])).
  708notebooks(_, _) --> [].
  709
  710%%	download_source(+HREF, -Source, +Options) is det.
  711%
  712%	Download source from a URL.  Options processed:
  713%
  714%	  - timeout(+Seconds)
  715%	    Max time to wait for reading the source.  Default
  716%	    is 10 seconds.
  717%	  - max_length(+Chars)
  718%	    Maximum lenght of the content.  Default is 1 million.
  719%	  - encoding(+Encoding)
  720%	    Encoding used to interpret the text.  Default is UTF-8.
  721%
  722%	@bug: Should try to interpret the encoding from the HTTP
  723%	      header.
  724
  725download_source(_HREF, Source, Options) :-
  726	option(download(browser), Options),
  727	!,
  728        Source = "".
  729download_source(HREF, Source, Options) :-
  730	uri_is_global(HREF), !,
  731	download_href(HREF, Source, Options).
  732download_source(Source0, Source, Options) :-
  733	option(max_length(MaxLen), Options, 1_000_000),
  734	string_length(Source0, Len),
  735	(   Len =< MaxLen
  736	->  Source = Source0
  737	;   format(string(Source),
  738		   '% ERROR: Content too long (max ~D)~n', [MaxLen])
  739	).
  740
  741download_href(HREF, Source, Options) :-
  742	option(timeout(TMO), Options, 10),
  743	option(max_length(MaxLen), Options, 1_000_000),
  744	catch(call_with_time_limit(
  745		  TMO,
  746		  setup_call_cleanup(
  747		      http_open(HREF, In,
  748				[ cert_verify_hook(cert_accept_any)
  749				]),
  750		      read_source(In, MaxLen, Source, Options),
  751		      close(In))),
  752	      E, load_error(E, Source)).
  753
  754read_source(In, MaxLen, Source, Options) :-
  755	option(encoding(Enc), Options, utf8),
  756	set_stream(In, encoding(Enc)),
  757	ReadMax is MaxLen + 1,
  758	read_string(In, ReadMax, Source0),
  759	string_length(Source0, Len),
  760	(   Len =< MaxLen
  761	->  Source = Source0
  762	;   format(string(Source),
  763		   ' % ERROR: Content too long (max ~D)~n', [MaxLen])
  764	).
  765
  766load_error(E, Source) :-
  767	message_to_string(E, String),
  768	format(string(Source), '% ERROR: ~s~n', [String]).
  769
  770%%	document_type(-Type, +Options) is det.
  771%
  772%	Determine the type of document.
  773%
  774%	@arg Type is one of `swinb` or `pl`
  775
  776document_type(Type, Options) :-
  777	(   option(type(Type0), Options)
  778	->  Type = Type0
  779	;   option(meta(Meta), Options),
  780	    file_name_extension(_, Type0, Meta.name),
  781	    Type0 \== ''
  782	->  Type = Type0
  783	;   option(st_type(external), Options),
  784	    option(url(URL), Options),
  785	    file_name_extension(_, Ext, URL),
  786	    ext_type(Ext, Type)
  787	->  true
  788	;   Type = pl
  789	).
  790
  791ext_type(swinb, swinb).
  792
  793
  794		 /*******************************
  795		 *	     RESOURCES		*
  796		 *******************************/
  797
  798%%	swish_resources//
  799%
  800%	Include  SWISH  CSS  and   JavaScript.    This   does   not  use
  801%	html_require//1  because  we  need  to   include  the  JS  using
  802%	RequireJS, which requires a non-standard script element.
  803
  804swish_resources -->
  805	swish_css,
  806	swish_js.
  807
  808swish_js  --> html_post(head, \include_swish_js).
  809swish_css --> html_post(head, \include_swish_css).
  810
  811include_swish_js -->
  812	html(script([],[
  813      '(function(i,s,o,g,r,a,m){i[''GoogleAnalyticsObject'']=r;i[r]=i[r]||function(){
  814       (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  815        m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
  816        })(window,document,''script'',''//www.google-analytics.com/analytics.js'',''ga'');
  817
  818        ga(''create'', ''UA-16202613-9'', ''auto'');
  819        ga(''send'', ''pageview'');'])),
  820        html(\['<!-- Global site tag (gtag.js) - Google Analytics -->
  821<script async src="https://www.googletagmanager.com/gtag/js?id=G-GL8L9W5NE7"></script>
  822<script>
  823  window.dataLayer = window.dataLayer || [];
  824  function gtag(){dataLayer.push(arguments);}
  825  gtag(''js'', new Date());
  826
  827  gtag(''config'', ''G-GL8L9W5NE7'');
  828</script>']),
  829        { swish_resource(js, JS),
  830	  swish_resource(rjs, RJS),
  831	  http_absolute_location(swish(js/JS), SwishJS, []),
  832	  http_absolute_location(swish(RJS),   SwishRJS, [])
  833	},
  834	rjs_timeout(JS),
  835	html(script([ src(SwishRJS),
  836		      'data-main'(SwishJS)
  837		    ], [])).
  838
  839rjs_timeout('swish-min') --> !,
  840	js_script({|javascript||
  841// Override RequireJS timeout, until main file is loaded.
  842window.require = { waitSeconds: 0 };
  843		  |}).
  844rjs_timeout(_) --> [].
  845
  846
  847include_swish_css -->
  848	{ swish_resource(css, CSS),
  849	  http_absolute_location(swish(css/CSS), SwishCSS, [])
  850	},
  851	html(link([ rel(stylesheet),
  852		    href(SwishCSS)
  853		  ])).
  854
  855swish_resource(Type, ID) :-
  856	alt(Type, ID, File),
  857	(   File == (-)
  858	;   absolute_file_name(File, _P, [file_errors(fail), access(read)])
  859	), !.
  860
  861alt(js,  'swish-min',     swish_web('js/swish-min.js')) :-
  862	\+ debugging(nominified).
  863alt(js,  'swish',         swish_web('js/swish.js')).
  864alt(css, 'swish-min.css', swish_web('css/swish-min.css')) :-
  865	\+ debugging(nominified).
  866alt(css, 'swish.css',     swish_web('css/swish.css')).
  867alt(rjs, 'js/require.js', swish_web('js/require.js')) :-
  868	\+ debugging(nominified).
  869alt(rjs, 'node_modules/requirejs/require.js', -).
  870
  871
  872		 /*******************************
  873		 *	       REST		*
  874		 *******************************/
  875
  876%%	swish_rest_reply(+Method, +Request, +Options) is det.
  877%
  878%	Handle non-GET requests.  Such requests may be used to modify
  879%	source code.
  880
  881swish_rest_reply(put, Request, Options) :-
  882	merge_options(Options, [alias(_)], Options1),
  883	source_file(Request, File, Options1), !,
  884	option(content_type(String), Request),
  885	http_parse_header_value(content_type, String, Type),
  886	read_data(Type, Request, Data, Meta),
  887	authorized(file(update(File,Meta)), Options1),
  888	setup_call_cleanup(
  889	    open(File, write, Out, [encoding(utf8)]),
  890	    format(Out, '~s', [Data]),
  891	    close(Out)),
  892	reply_json_dict(true).
  893
  894read_data(media(Type,_), Request, Data, Meta) :-
  895	http_json:json_type(Type), !,
  896	http_read_json_dict(Request, Dict),
  897	del_dict(data, Dict, Data, Meta).
  898read_data(media(text/_,_), Request, Data, _{}) :-
  899	http_read_data(Request, Data,
  900		       [ to(string),
  901			 input_encoding(utf8)
  902		       ])