1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@cs.vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (C): 2020, VU University Amsterdam
    7
    8    This program is free software; you can redistribute it and/or
    9    modify it under the terms of the GNU General Public License
   10    as published by the Free Software Foundation; either version 2
   11    of the License, or (at your option) any later version.
   12
   13    This program is distributed in the hope that it will be useful,
   14    but WITHOUT ANY WARRANTY; without even the implied warranty of
   15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16    GNU General Public License for more details.
   17
   18    You should have received a copy of the GNU General Public
   19    License along with this library; if not, write to the Free Software
   20    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   21
   22    As a special exception, if you link this library with other files,
   23    compiled with a Free Software compiler, to produce an executable, this
   24    library does not by itself cause the resulting executable to be covered
   25    by the GNU General Public License. This exception does not however
   26    invalidate any other reasons why the executable file might be covered by
   27    the GNU General Public License.
   28*/
   29
   30:- module(plweb_api,
   31          []).   32:- use_module(library(http/http_dispatch)).   33:- use_module(library(http/http_cors)).   34:- use_module(library(http/http_json)).   35:- use_module(library(http/http_parameters)).   36:- use_module(library(pldoc/man_index)).   37:- use_module(library(pldoc/doc_util)).   38:- use_module(library(prolog_code)).   39:- use_module(library(prolog_source)).   40:- use_module(library(apply)).   41:- use_module(library(error)).   42:- use_module(library(pairs)).   43:- use_module(library(option)).   44
   45:- http_handler(root(doc_link), doc_link, []).   46
   47%!  doc_link(+Request)
   48%
   49%   Get a link to the documentation for a predicate reference.  This
   50%   hander may be used in two ways:
   51%
   52%      - GET
   53%        Adding a parameter `for` providing the predicate you want
   54%        to have information about.
   55%      - POST
   56%        Passing a JSON list of strings.  The reply is a JSON object
   57%        with for each string the corresponding reply object (`null`
   58%        if the predicate is not known).
   59
   60doc_link(Request) :-
   61    reply_options(Request, [get,post]),
   62    !.
   63doc_link(Request) :-
   64    memberchk(method(post), Request),
   65    !,
   66    http_read_json_dict(Request, Atoms,
   67                        [value_string_as(atom)]),
   68    cors_enable(Request, [methods([get,post])]),
   69    must_be(list(atom), Atoms),
   70    for_links(Atoms, Pairs),
   71    dict_create(Dict, json, Pairs),
   72    reply_json_dict(Dict).
   73doc_link(Request) :-
   74    http_parameters(Request,
   75                    [ for(For, [])
   76                    ]),
   77    cors_enable(Request, [methods([get,post])]),
   78    (   for_link(For, Link)
   79    ->  reply_json_dict(Link)
   80    ;   reply_json_dict(null, [status(404)])
   81    ).
   82
   83for_links([], []).
   84for_links([H|T0], [H-I|T]) :-
   85    (   for_link(H, I)
   86    ->  true
   87    ;   I = null
   88    ),
   89    for_links(T0, T).
   90
   91for_link(For, Info) :-
   92    atom_to_object(For, Obj),
   93    current_man_object(Obj),
   94    findall(Prop, obj_property(Obj, Prop), Props),
   95    format(string(URL),
   96           'https://www.swi-prolog.org/pldoc/doc_for?object=~w',
   97           [For]),
   98    dict_pairs(Info, json, [url-URL|Props]).
   99
  100obj_property(Obj, summary-Summary) :-
  101    once(man_object_property(Obj, summary(Summary))).
  102obj_property(PI, Prop) :-
  103    pi_head(PI, Head0),
  104    (   Head0 = M:_
  105    ->  Head = Head0
  106    ;   Head = M:Head0
  107    ),
  108    (   M=system,
  109        predicate_property(Head, iso)
  110    ->  Prop = (class-iso)
  111    ;   M=system,
  112        predicate_property(Head, built_in)
  113    ->  Prop = (class-builtin)
  114    ;   predicate_property(Head, autoload(File))
  115    ->  (   Prop = (class-autoload)
  116        ;   library_prop(File, Prop)
  117        )
  118    ;   predicate_property(Head, file(File)),
  119        predicate_property(Head, exported)
  120    ->  (   Prop = (class-library)
  121        ;   library_prop(File, Prop)
  122        )
  123    ).
  124
  125library_prop(File, library-LibS) :-
  126    file_name_extension(File, pl, LibFile),
  127    file_name_on_path(LibFile, library(Lib)),
  128    format(string(LibS), '~w', [Lib]).
  129
  130%!  reply_options(+Request, +Methods) is semidet.
  131%
  132%   Reply the HTTP OPTIONS request
  133
  134reply_options(Request, Allowed) :-
  135    option(method(options), Request),
  136    !,
  137    cors_enable(Request,
  138                [ methods(Allowed)
  139                ]),
  140    format('Content-type: text/plain\r\n'),
  141    format('~n').                   % empty body