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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
/**
* section: XPath
* synopsis: Evaluate XPath expression and prints result node set.
* purpose: Shows how to evaluate XPath expression and register
* known namespaces in XPath context.
* usage: xpath1 <xml-file> <xpath-expr> [<known-ns-list>]
* author: Aleksey Sanin
* copy: see Copyright for the status of this software.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
#ifdef LIBXML_XPATH_ENABLED
void usage(const char *name);
int execute_xpath_expression(const char* filename, const xmlChar* xpathExpr, const xmlChar* nsList);
int register_namespaces(xmlXPathContextPtr xpathCtx, const xmlChar* nsList);
void print_xpath_nodes(xmlNodeSetPtr nodes, FILE* output);
int
main(int argc, char **argv) {
/* Parse command line and process file */
if((argc < 3) || (argc > 4)) {
fprintf(stderr, "Error: wrong number of arguments.\n");
usage(argv[0]);
return(-1);
}
/* Init libxml */
xmlInitParser();
LIBXML_TEST_VERSION
/* Do the main job */
if(execute_xpath_expression(argv[1], BAD_CAST argv[2], (argc > 3) ? BAD_CAST argv[3] : NULL) < 0) {
usage(argv[0]);
return(-1);
}
/* Shutdown libxml */
xmlCleanupParser();
/*
* this is to debug memory for regression tests
*/
xmlMemoryDump();
return 0;
}
/**
* usage:
* @name: the program name.
*
* Prints usage information.
*/
void
usage(const char *name) {
assert(name);
fprintf(stderr, "Usage: %s <xml-file> <xpath-expr> [<known-ns-list>]\n", name);
fprintf(stderr, "where <known-ns-list> is a list of known namespaces\n");
fprintf(stderr, "in \"<prefix1>=<href1> <prefix2>=href2> ...\" format\n");
}
/**
* execute_xpath_expression:
* @filename: the input XML filename.
* @xpathExpr: the xpath expression for evaluation.
* @nsList: the optional list of known namespaces in
* "<prefix1>=<href1> <prefix2>=href2> ..." format.
*
* Parses input XML file, evaluates XPath expression and prints results.
*
* Returns 0 on success and a negative value otherwise.
*/
int
execute_xpath_expression(const char* filename, const xmlChar* xpathExpr, const xmlChar* nsList) {
xmlDocPtr doc;
xmlXPathContextPtr xpathCtx;
xmlXPathObjectPtr xpathObj;
assert(filename);
assert(xpathExpr);
/* Load XML document */
doc = xmlParseFile(filename);
if (doc == NULL) {
fprintf(stderr, "Error: unable to parse file \"%s\"\n", filename);
return(-1);
}
/* Create xpath evaluation context */
xpathCtx = xmlXPathNewContext(doc);
if(xpathCtx == NULL) {
fprintf(stderr,"Error: unable to create new XPath context\n");
xmlFreeDoc(doc);
return(-1);
}
/* Register namespaces from list (if any) */
if((nsList != NULL) && (register_namespaces(xpathCtx, nsList) < 0)) {
fprintf(stderr,"Error: failed to register namespaces list \"%s\"\n", nsList);
xmlXPathFreeContext(xpathCtx);
xmlFreeDoc(doc);
return(-1);
}
/* Evaluate xpath expression */
xpathObj = xmlXPathEvalExpression(xpathExpr, xpathCtx);
if(xpathObj == NULL) {
fprintf(stderr,"Error: unable to evaluate xpath expression \"%s\"\n", xpathExpr);
xmlXPathFreeContext(xpathCtx);
xmlFreeDoc(doc);
return(-1);
}
/* Print results */
print_xpath_nodes(xpathObj->nodesetval, stdout);
/* Cleanup */
xmlXPathFreeObject(xpathObj);
xmlXPathFreeContext(xpathCtx);
xmlFreeDoc(doc);
return(0);
}
/**
* register_namespaces:
* @xpathCtx: the pointer to an XPath context.
* @nsList: the list of known namespaces in
* "<prefix1>=<href1> <prefix2>=href2> ..." format.
*
* Registers namespaces from @nsList in @xpathCtx.
*
* Returns 0 on success and a negative value otherwise.
*/
int
register_namespaces(xmlXPathContextPtr xpathCtx, const xmlChar* nsList) {
xmlChar* nsListDup;
xmlChar* prefix;
xmlChar* href;
xmlChar* next;
assert(xpathCtx);
assert(nsList);
nsListDup = xmlStrdup(nsList);
if(nsListDup == NULL) {
fprintf(stderr, "Error: unable to strdup namespaces list\n");
return(-1);
}
next = nsListDup;
while(next != NULL) {
/* skip spaces */
while((*next) == ' ') next++;
if((*next) == '\0') break;
/* find prefix */
prefix = next;
next = (xmlChar*)xmlStrchr(next, '=');
if(next == NULL) {
fprintf(stderr,"Error: invalid namespaces list format\n");
xmlFree(nsListDup);
return(-1);
}
*(next++) = '\0';
/* find href */
href = next;
next = (xmlChar*)xmlStrchr(next, ' ');
if(next != NULL) {
*(next++) = '\0';
}
/* do register namespace */
if(xmlXPathRegisterNs(xpathCtx, prefix, href) != 0) {
fprintf(stderr,"Error: unable to register NS with prefix=\"%s\" and href=\"%s\"\n", prefix, href);
xmlFree(nsListDup);
return(-1);
}
}
xmlFree(nsListDup);
return(0);
}
/**
* print_xpath_nodes:
* @nodes: the nodes set.
* @output: the output file handle.
*
* Prints the @nodes content to @output.
*/
void
print_xpath_nodes(xmlNodeSetPtr nodes, FILE* output) {
xmlNodePtr cur;
int size;
int i;
assert(output);
size = (nodes) ? nodes->nodeNr : 0;
fprintf(output, "Result (%d nodes):\n", size);
for(i = 0; i < size; ++i) {
assert(nodes->nodeTab[i]);
if(nodes->nodeTab[i]->type == XML_NAMESPACE_DECL) {
xmlNsPtr ns;
ns = (xmlNsPtr)nodes->nodeTab[i];
cur = (xmlNodePtr)ns->next;
if(cur->ns) {
fprintf(output, "= namespace \"%s\"=\"%s\" for node %s:%s\n",
ns->prefix, ns->href, cur->ns->href, cur->name);
} else {
fprintf(output, "= namespace \"%s\"=\"%s\" for node %s\n",
ns->prefix, ns->href, cur->name);
}
} else if(nodes->nodeTab[i]->type == XML_ELEMENT_NODE) {
cur = nodes->nodeTab[i];
if(cur->ns) {
fprintf(output, "= element node \"%s:%s\"\n",
cur->ns->href, cur->name);
} else {
fprintf(output, "= element node \"%s\"\n",
cur->name);
}
} else {
cur = nodes->nodeTab[i];
fprintf(output, "= node \"%s\": type %d\n", cur->name, cur->type);
}
}
}
#else
int main(void) {
fprintf(stderr, "XPath support not compiled in\n");
exit(1);
}
#endif
|
