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)). 42:- use_module(library(http/http_cors)). 43:- use_module(library(debug)). 44:- use_module(library(lists)).

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 */

66pengines:write_result(csv, Event, OptionDict) :- 67 ( Disposition = OptionDict.get(disposition) 68 -> Options = [disposition(Disposition)] 69 ; Options = [] 70 ), 71 csv(Event, Options). 72 73csv(create(_Id, Features), Options) :- !, 74 memberchk(answer(Answer), Features), 75 csv(Answer, Options). 76csv(destroy(_Id, Wrapped), Options) :- !, 77 csv(Wrapped, Options). 78csv(success(_Id, Answers, Projection, _Time, More), Options) :- !, 79 VarTerm =.. [row|Projection], 80 success(Answers, VarTerm, [more(More)|Options]). 81csv(error(_Id, Error), _Options) :- !, 82 message_to_string(Error, Msg), 83 format('Status: 400 Bad request~n'), 84 format('Content-type: text/plain~n~n'), 85 format('ERROR: ~w~n', [Msg]). 86csv(output(_Id, message(_Term, _Class, HTML, _Where)), _Opts) :- !, 87 format('Status: 400 Bad request~n'), 88 format('Content-type: text/html~n~n'), 89 format('<html>~n~s~n</html>~n', [HTML]). 90csv(page(Page, Event), Options) :- 91 csv(Event, [page(Page)|Options]). 92csv(failure(_Id, _Time), Options) :- !, 93 success([], -, [more(false)|Options]). 94csv(Event, _) :- 95 print_term(Event, [output(user_error)]). 96 97success(Answers, VarTerm, Options) :- 98 write_answers(Answers, VarTerm, Options), !. 99success(Answers, VarTerm, Options) :- 100 write_answers(Answers, VarTerm), !, 101 assertion(\+option(page(_), Options)). 102success(Answers, _VarTerm, Options) :- 103 option(page(Page), Options), 104 Page > 1, !, 105 maplist(csv_answer, Answers, Rows), 106 forall(paginate(100, OutPage, Rows), 107 csv_write_stream(current_output, OutPage, [])). 108success(Answers, VarTerm, Options) :- 109 option(disposition(Disposition), Options, 'swish-result.csv'), 110 maplist(csv_answer, Answers, Rows), 111 cors_enable, 112 format('Content-encoding: chunked~n'), 113 format('Content-disposition: attachment; filename="~w"~n', [Disposition]), 114 format('Content-type: text/csv~n~n'), 115 projection_row(VarTerm), 116 forall(paginate(100, Page, Rows), 117 csv_write_stream(current_output, Page, [])). 118 119projection_row(-) :- !. 120projection_row(row) :- !. 121projection_row(VarTerm) :- 122 csv_write_stream(current_output, [VarTerm], []). 123 124paginate(Len, Page, List) :- 125 length(Page0, Len), 126 ( append(Page0, Rest, List) 127 -> ( Page = Page0 128 ; paginate(Len, Page, Rest) 129 ) 130 ; Page = List 131 ). 132 133 134csv_answer(JSON, Row) :- 135 is_dict(JSON), !, 136 dict_pairs(JSON, _, Pairs), 137 pairs_values(Pairs, Values), 138 maplist(csv_value, Values, CVSValues), 139 Row =.. [row|CVSValues]. 140csv_answer(RowIn, Row) :- 141 compound(RowIn), !, 142 RowIn =.. [_|Values], 143 maplist(csv_value, Values, CVSValues), 144 Row =.. [row|CVSValues]. 145 146csv_value(Var, '') :- 147 var(Var), !. 148csv_value(Number, Number) :- 149 number(Number), !. 150csv_value(Atom, Atom) :- 151 atom(Atom), !. 152csv_value(String, String) :- 153 string(String), !. 154csv_value(Term, Value) :- 155 term_string(Term, Value)