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, University of Amsterdam, 7 VU University 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(api_json, 37 [ 38 ]). 39:- use_module(library(semweb/rdf_db)). 40:- use_module(library(semweb/rdf_json)). 41:- use_module(library(semweb/rdf_describe)). 42:- use_module(library(http/http_dispatch)). 43:- use_module(library(http/http_parameters)). 44:- use_module(library(http/http_json)). 45 46:- http_handler(json(describe), json_describe, []). 47:- http_handler(json(prefixes), json_prefixes, []). 48:- http_handler(json(resource_representation), json_resource_representation, []). 49 50/* <module> Describe resources in JSON 51 52This module produces a JSON description for a resource. 53 54@see sparql.pl implements a SPARQL frontend. The SPARQL DESCRIBE 55 keyword provides similar functionality, but it has no arguments 56 to specify how to describe a resource and it cannot return JSON. 57@see lod.pl implements Linked Open Data (LOD) descriptions. 58*/ 59 60%! json_describe(+Request) 61% 62% HTTP handler that describes a resource using a JSON 63% serialization. 64% 65% @see http://n2.talis.com/wiki/RDF_JSON_Specification describes 66% the used graph-serialization. 67% @see http://n2.talis.com/wiki/Bounded_Descriptions_in_RDF for 68% a description of the various descriptions 69% @bug Currently only supports =cbd=. 70 71json_describe(Request) :- 72 http_parameters(Request, 73 [ r(URI, 74 [ description('The resource to describe') 75 ]), 76 how(_How, 77 [ %oneof([cbd, scdb, ifcbd, lcbd, hcbd]), 78 oneof([cbd]), 79 default(cbd), 80 description('Algorithm that determines \c 81 the description') 82 ]) 83 ]), 84 resource_CBD(rdf, URI, Graph), 85 graph_json(Graph, JSON), 86 reply_json(JSON). 87 88%! json_prefixes(+Request) 89% 90% Return a JSON object mapping prefixes to URIs. 91 92json_prefixes(_Request) :- 93 findall(Prefix-URI, 94 rdf_current_ns(Prefix, URI), 95 Pairs), 96 dict_pairs(Dict, prefixes, Pairs), 97 reply_json(Dict). 98 99%! json_resource_representation(+Request) 100% 101% HTTP Handler to represent a resource in a given language 102 103json_resource_representation(Request) :- 104 http_parameters(Request, 105 [ r(URI, 106 [ description('The resource to format') 107 ]), 108 language(Lang, 109 [ oneof([sparql,turtle,prolog,xml]), 110 default(turtle), 111 description('Target language') 112 ]) 113 ]), 114 format_resource(Lang, URI, String), 115 reply_json_dict(String). 116 117format_resource(sparql, URI, String) :- 118 !, 119 format_resource(turtle, URI, String). 120format_resource(turtle, URI, String) :- 121 ( rdf_global_id(Prefix:Local, URI) 122 -> format(string(String), '~w:~w', [Prefix, Local]) 123 ; format(string(String), '<~w>', [URI]) 124 ). 125format_resource(xml, URI, String) :- 126 ( rdf_global_id(Prefix:Local, URI), 127 xml_name(URI, utf8) 128 -> format(string(String), '~w:~w', [Prefix, Local]) 129 ; format(string(String), '"~w"', [URI]) 130 ). 131format_resource(prolog, URI, String) :- 132 ( rdf_global_id(Prefix:Local, URI) 133 -> format(string(String), '~q', [Prefix:Local]) 134 ; format(string(String), '~q', [URI]) 135 )