#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++;
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) {
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);
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;
memset(&state, 0, sizeof(struct ParserStruct));
state.ok = 1;
parser = XML_ParserCreateNS(NULL, '\0');
XML_SetUserData(parser, &state);
XML_SetElementHandler(parser, startElement, endElement);
XML_SetCharacterDataHandler(parser, characterDataHandler);
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");
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) {
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);
}
}
free(state.characters.memory);
XML_ParserFree(parser);
curl_easy_cleanup(curl_handle);
curl_global_cleanup();
return 0;
}