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
|
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
/* <DESC>
* Stream-parse a document using the streaming Expat parser.
* </DESC>
*/
/* Written by David Strauss
*
* Expat => https://libexpat.github.io/
*
* gcc -Wall -I/usr/local/include xmlstream.c -lcurl -lexpat -o xmlstream
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <expat.h>
#include <curl/curl.h>
struct MemoryStruct {
char *memory;
size_t size;
};
struct ParserStruct {
int ok;
size_t tags;
size_t depth;
struct MemoryStruct characters;
};
static void startElement(void *userData, const XML_Char *name,
const XML_Char **atts)
{
struct ParserStruct *state = (struct ParserStruct *) userData;
state->tags++;
state->depth++;
/* Get a clean slate for reading in character data. */
free(state->characters.memory);
state->characters.memory = NULL;
state->characters.size = 0;
}
static void characterDataHandler(void *userData, const XML_Char *s, int len)
{
struct ParserStruct *state = (struct ParserStruct *) userData;
struct MemoryStruct *mem = &state->characters;
char *ptr = realloc(mem->memory, mem->size + len + 1);
if(!ptr) {
/* Out of memory. */
fprintf(stderr, "Not enough memory (realloc returned NULL).\n");
state->ok = 0;
return;
}
mem->memory = ptr;
memcpy(&(mem->memory[mem->size]), s, len);
mem->size += len;
mem->memory[mem->size] = 0;
}
static void endElement(void *userData, const XML_Char *name)
{
struct ParserStruct *state = (struct ParserStruct *) userData;
state->depth--;
printf("%5lu %10lu %s\n", state->depth, state->characters.size, name);
}
static size_t parseStreamCallback(void *contents, size_t length, size_t nmemb,
void *userp)
{
XML_Parser parser = (XML_Parser) userp;
size_t real_size = length * nmemb;
struct ParserStruct *state = (struct ParserStruct *) XML_GetUserData(parser);
/* Only parse if we're not already in a failure state. */
if(state->ok && XML_Parse(parser, contents, real_size, 0) == 0) {
int error_code = XML_GetErrorCode(parser);
fprintf(stderr, "Parsing response buffer of length %lu failed"
" with error code %d (%s).\n",
real_size, error_code, XML_ErrorString(error_code));
state->ok = 0;
}
return real_size;
}
int main(void)
{
CURL *curl_handle;
CURLcode res;
XML_Parser parser;
struct ParserStruct state;
/* Initialize the state structure for parsing. */
memset(&state, 0, sizeof(struct ParserStruct));
state.ok = 1;
/* Initialize a namespace-aware parser. */
parser = XML_ParserCreateNS(NULL, '\0');
XML_SetUserData(parser, &state);
XML_SetElementHandler(parser, startElement, endElement);
XML_SetCharacterDataHandler(parser, characterDataHandler);
/* Initialize a libcurl handle. */
curl_global_init(CURL_GLOBAL_DEFAULT);
curl_handle = curl_easy_init();
curl_easy_setopt(curl_handle, CURLOPT_URL,
"https://www.w3schools.com/xml/simple.xml");
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, parseStreamCallback);
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)parser);
printf("Depth Characters Closing Tag\n");
/* Perform the request and any follow-up parsing. */
res = curl_easy_perform(curl_handle);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
}
else if(state.ok) {
/* Expat requires one final call to finalize parsing. */
if(XML_Parse(parser, NULL, 0, 1) == 0) {
int error_code = XML_GetErrorCode(parser);
fprintf(stderr, "Finalizing parsing failed with error code %d (%s).\n",
error_code, XML_ErrorString(error_code));
}
else {
printf(" --------------\n");
printf(" %lu tags total\n", state.tags);
}
}
/* Clean up. */
free(state.characters.memory);
XML_ParserFree(parser);
curl_easy_cleanup(curl_handle);
curl_global_cleanup();
return 0;
}
|
