1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
/* -*- Mode: c; c-basic-offset: 2 -*-
*
* example8.c - Redland example code SPARQL querying and formatting
*
* Copyright (C) 2010, David Beckett http://www.dajobe.org/
*
* This package is Free Software and part of Redland http://librdf.org/
*
* It is licensed under the following three licenses as alternatives:
* 1. GNU Lesser General Public License (LGPL) V2.1 or any newer version
* 2. GNU General Public License (GPL) V2 or any newer version
* 3. Apache License, V2.0 or any newer version
*
* You may not use this file except in compliance with at least one of
* the above three licenses.
*
* See LICENSE.html or LICENSE.txt at the top of this package for the
* complete terms and further detail along with the license texts for
* the licenses in COPYING.LIB, COPYING and LICENSE-2.0.txt respectively.
*
* USAGE:
* To get json variable bindings
* ./example8 http://librdf.org/redland.rdf json 'select * where { ?s ?p ?o}'
* To get json triples (graph formatted):
* ./example8 http://librdf.org/redland.rdf json 'construct {?s ?p ?o} where { ?s ?p ?o}'
*
*/
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <redland.h>
/* one prototype needed */
int main(int argc, char *argv[]);
int
main(int argc, char *argv[])
{
char *program = argv[0];
librdf_world* world;
librdf_storage *storage;
librdf_model* model;
const char *parser_name;
librdf_parser* parser;
librdf_query* query;
librdf_query_results* results;
librdf_uri *uri;
const unsigned char *query_string = NULL;
const char *format;
unsigned char* string = NULL;
size_t length;
world = librdf_new_world();
librdf_world_open(world);
if(argc != 4) {
fprintf(stderr, "USAGE: %s DATA-URI FORMAT|- QUERY-STRING\n", program);
return 1;
}
uri = librdf_new_uri(world, (const unsigned char*)argv[1]);
format = argv[2];
if(!strcmp(format, "-"))
format = NULL;
query_string = (const unsigned char*)argv[3];
storage = librdf_new_storage(world, "memory", "test", NULL);
if(storage)
model = librdf_new_model(world, storage, NULL);
if(!model || !storage) {
fprintf(stderr, "%s: Failed to make model or storage\n", program);
return 1;
}
parser_name = librdf_parser_guess_name2(world, NULL, NULL, librdf_uri_as_string(uri));
parser = librdf_new_parser(world, parser_name, NULL, NULL);
librdf_parser_parse_into_model(parser, uri, NULL, model);
librdf_free_parser(parser);
librdf_free_uri(uri);
query = librdf_new_query(world, "sparql", NULL, query_string, NULL);
results = librdf_model_query_execute(model, query);
if(!results) {
fprintf(stderr, "%s: Query of model with '%s' failed\n",
program, query_string);
return 1;
}
if(librdf_query_results_is_bindings(results) ||
librdf_query_results_is_boolean(results)) {
string = librdf_query_results_to_counted_string2(results, format,
NULL, NULL, NULL, &length);
if(!string) {
fprintf(stderr, "%s: Failed to turn query results to format '%s'\n",
program, format);
return 1;
}
} else {
/* triples */
librdf_serializer* serializer;
librdf_stream* stream;
serializer = librdf_new_serializer(world, format, NULL, NULL);
if(!serializer) {
fprintf(stderr,
"%s: Failed to create triples serializer for format '%s'\n",
program, format);
return 1;
}
stream = librdf_query_results_as_stream(results);
string = librdf_serializer_serialize_stream_to_counted_string(serializer,
NULL, stream, &length);
librdf_free_stream(stream);
if(!string) {
fprintf(stderr, "%s: Failed to turn query results to format '%s'\n",
program, format);
return 1;
}
}
fprintf(stderr, "%s: query returned %ld bytes string\n", program, length);
fwrite(string, sizeof(char), length, stdout);
free(string);
librdf_free_query_results(results);
librdf_free_query(query);
librdf_free_model(model);
librdf_free_storage(storage);
librdf_free_world(world);
/* keep gcc -Wall happy */
return(0);
}
|
