1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at http://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22/* Stream-parse a document using the streaming Expat parser. 23 * Written by David Strauss 24 * 25 * Expat => http://www.libexpat.org/ 26 * 27 * gcc -Wall -I/usr/local/include xmlstream.c -lcurl -lexpat -o xmlstream 28 * 29 */ 30 31#include <stdio.h> 32#include <stdlib.h> 33#include <string.h> 34#include <assert.h> 35 36#include <expat.h> 37#include <curl/curl.h> 38 39struct MemoryStruct { 40 char *memory; 41 size_t size; 42}; 43 44struct ParserStruct { 45 int ok; 46 size_t tags; 47 size_t depth; 48 struct MemoryStruct characters; 49}; 50 51static void startElement(void *userData, const XML_Char *name, const XML_Char **atts) 52{ 53 struct ParserStruct *state = (struct ParserStruct *) userData; 54 state->tags++; 55 state->depth++; 56 57 /* Get a clean slate for reading in character data. */ 58 free(state->characters.memory); 59 state->characters.memory = NULL; 60 state->characters.size = 0; 61} 62 63static void characterDataHandler(void *userData, const XML_Char *s, int len) 64{ 65 struct ParserStruct *state = (struct ParserStruct *) userData; 66 struct MemoryStruct *mem = &state->characters; 67 68 mem->memory = realloc(mem->memory, mem->size + len + 1); 69 if(mem->memory == NULL) { 70 /* Out of memory. */ 71 fprintf(stderr, "Not enough memory (realloc returned NULL).\n"); 72 state->ok = 0; 73 return; 74 } 75 76 memcpy(&(mem->memory[mem->size]), s, len); 77 mem->size += len; 78 mem->memory[mem->size] = 0; 79} 80 81static void endElement(void *userData, const XML_Char *name) 82{ 83 struct ParserStruct *state = (struct ParserStruct *) userData; 84 state->depth--; 85 86 printf("%5lu %10lu %s\n", state->depth, state->characters.size, name); 87} 88 89static size_t parseStreamCallback(void *contents, size_t length, size_t nmemb, void *userp) 90{ 91 XML_Parser parser = (XML_Parser) userp; 92 size_t real_size = length * nmemb; 93 struct ParserStruct *state = (struct ParserStruct *) XML_GetUserData(parser); 94 95 /* Only parse if we're not already in a failure state. */ 96 if (state->ok && XML_Parse(parser, contents, real_size, 0) == 0) { 97 int error_code = XML_GetErrorCode(parser); 98 fprintf(stderr, "Parsing response buffer of length %lu failed with error code %d (%s).\n", 99 real_size, error_code, XML_ErrorString(error_code)); 100 state->ok = 0; 101 } 102 103 return real_size; 104} 105 106int main(void) 107{ 108 CURL *curl_handle; 109 CURLcode res; 110 XML_Parser parser; 111 struct ParserStruct state; 112 113 /* Initialize the state structure for parsing. */ 114 memset(&state, 0, sizeof(struct ParserStruct)); 115 state.ok = 1; 116 117 /* Initialize a namespace-aware parser. */ 118 parser = XML_ParserCreateNS(NULL, '\0'); 119 XML_SetUserData(parser, &state); 120 XML_SetElementHandler(parser, startElement, endElement); 121 XML_SetCharacterDataHandler(parser, characterDataHandler); 122 123 /* Initalize a libcurl handle. */ 124 curl_global_init(CURL_GLOBAL_ALL ^ CURL_GLOBAL_SSL); 125 curl_handle = curl_easy_init(); 126 curl_easy_setopt(curl_handle, CURLOPT_URL, "http://www.w3schools.com/xml/simple.xml"); 127 curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, parseStreamCallback); 128 curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)parser); 129 130 printf("Depth Characters Closing Tag\n"); 131 132 /* Perform the request and any follow-up parsing. */ 133 res = curl_easy_perform(curl_handle); 134 if(res != CURLE_OK) { 135 fprintf(stderr, "curl_easy_perform() failed: %s\n", 136 curl_easy_strerror(res)); 137 } 138 else if (state.ok) { 139 /* Expat requires one final call to finalize parsing. */ 140 if (XML_Parse(parser, NULL, 0, 1) == 0) { 141 int error_code = XML_GetErrorCode(parser); 142 fprintf(stderr, "Finalizing parsing failed with error code %d (%s).\n", 143 error_code, XML_ErrorString(error_code)); 144 } 145 else { 146 printf(" --------------\n"); 147 printf(" %lu tags total\n", state.tags); 148 } 149 } 150 151 /* Clean up. */ 152 free(state.characters.memory); 153 XML_ParserFree(parser); 154 curl_easy_cleanup(curl_handle); 155 curl_global_cleanup(); 156 157 return 0; 158} 159