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) 2016, 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(swish_csv, []). 36:- use_module(library(pengines), []). 37:- use_module(library(pairs)). 38:- use_module(library(csv), [csv_write_stream/3]). 39:- use_module(library(apply)). 40:- use_module(library(pprint)). 41:- use_module(library(option)).

Support CSV output from a Pengines server

This module defines the result-format csv for Pengines. It allows SWISH users to post a query against the core Prolog system or a saved SWISH program and obtain the results using a simple web client such as curl. An example shell script is provided in client/swish-ask.sh.

To be done: - Provide streaming output */

63pengines:write_result(csv, Event, OptionDict) :- 64 ( Disposition = OptionDict.get(disposition) 65 -> Options = [disposition(Disposition)] 66 ; Options = [] 67 ), 68 csv(Event, Options). 69 70csv(create(_Id, Features), Options) :- !, 71 memberchk(answer(Answer), Features), 72 csv(Answer, Options). 73csv(destroy(_Id, Wrapped), Options) :- !, 74 csv(Wrapped, Options). 75csv(success(_Id, Answers, Projection, _Time, More), Options) :- !, 76 VarTerm =.. [row|Projection], 77 success(Answers, VarTerm, [more(More)|Options]). 78csv(error(_Id, Error), _Options) :- !, 79 message_to_string(Error, Msg), 80 format('Status: 400 Bad request~n'), 81 format('Content-type: text/plain~n~n'), 82 format('ERROR: ~w~n', [Msg]). 83csv(output(_Id, message(_Term, _Class, HTML, _Where)), _Opts) :- !, 84 format('Status: 400 Bad request~n'), 85 format('Content-type: text/html~n~n'), 86 format('<html>~n~s~n</html>~n', [HTML]). 87csv(page(Page, Event), Options) :- 88 csv(Event, [page(Page)|Options]). 89csv(failure(_Id, _Time), Options) :- !, 90 success([], -, [more(false)|Options]). 91csv(Event, _) :- 92 print_term(Event, [output(user_error)]). 93 94success(Answers, VarTerm, Options) :- 95 write_answers(Answers, VarTerm, Options), !. 96success(Answers, VarTerm, Options) :- 97 write_answers(Answers, VarTerm), !, 98 assertion(\+option(page(_), Options)). 99success(Answers, _VarTerm, Options) :- 100 option(page(Page), Options), 101 Page > 1, !, 102 maplist(csv_answer, Answers, Rows), 103 forall(paginate(100, OutPage, Rows), 104 csv_write_stream(current_output, OutPage, [])). 105success(Answers, VarTerm, Options) :- 106 option(disposition(Disposition), Options, 'swish-result.csv'), 107 maplist(csv_answer, Answers, Rows), 108 format('Content-encoding: chunked~n'), 109 format('Content-disposition: attachment; filename="~w"~n', [Disposition]), 110 format('Content-type: text/csv~n~n'), 111 projection_row(VarTerm), 112 forall(paginate(100, Page, Rows), 113 csv_write_stream(current_output, Page, [])). 114 115projection_row(-) :- !. 116projection_row(VarTerm) :- 117 csv_write_stream(current_output, [VarTerm], []). 118 119paginate(Len, Page, List) :- 120 length(Page0, Len), 121 ( append(Page0, Rest, List) 122 -> ( Page = Page0 123 ; paginate(Len, Page, Rest) 124 ) 125 ; Page = List 126 ). 127 128 129csv_answer(JSON, Row) :- 130 is_dict(JSON), !, 131 dict_pairs(JSON, _, Pairs), 132 pairs_values(Pairs, Values), 133 maplist(csv_value, Values, CVSValues), 134 Row =.. [row|CVSValues]. 135csv_answer(RowIn, Row) :- 136 compound(RowIn), !, 137 RowIn =.. [_|Values], 138 maplist(csv_value, Values, CVSValues), 139 Row =.. [row|CVSValues]. 140 141csv_value(Var, '') :- 142 var(Var), !. 143csv_value(Number, Number) :- 144 number(Number), !. 145csv_value(Atom, Atom) :- 146 atom(Atom), !. 147csv_value(String, String) :- 148 string(String), !. 149csv_value(Term, Value) :- 150 term_string(Term, Value)