/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2013, 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 http://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. * ***************************************************************************/ /* Stream-parse a document using the streaming Expat parser. * Written by David Strauss * * Expat => http://www.libexpat.org/ * * 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; mem->memory = realloc(mem->memory, mem->size + len + 1); if(mem->memory == NULL) { /* Out of memory. */ fprintf(stderr, "Not enough memory (realloc returned NULL).\n"); state->ok = 0; return; } 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); /* Initalize a libcurl handle. */ curl_global_init(CURL_GLOBAL_ALL ^ CURL_GLOBAL_SSL); curl_handle = curl_easy_init(); curl_easy_setopt(curl_handle, CURLOPT_URL, "http://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; }