1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2011, 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/* Example source code to show how the callback function can be used to 23 * download data into a chunk of memory instead of storing it in a file. 24 */ 25 26#include <stdio.h> 27#include <stdlib.h> 28#include <string.h> 29 30#include <curl/curl.h> 31 32struct MemoryStruct { 33 char *memory; 34 size_t size; 35}; 36 37 38static size_t 39WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) 40{ 41 size_t realsize = size * nmemb; 42 struct MemoryStruct *mem = (struct MemoryStruct *)userp; 43 44 mem->memory = realloc(mem->memory, mem->size + realsize + 1); 45 if (mem->memory == NULL) { 46 /* out of memory! */ 47 printf("not enough memory (realloc returned NULL)\n"); 48 exit(EXIT_FAILURE); 49 } 50 51 memcpy(&(mem->memory[mem->size]), contents, realsize); 52 mem->size += realsize; 53 mem->memory[mem->size] = 0; 54 55 return realsize; 56} 57 58 59int main(void) 60{ 61 CURL *curl_handle; 62 63 struct MemoryStruct chunk; 64 65 chunk.memory = malloc(1); /* will be grown as needed by the realloc above */ 66 chunk.size = 0; /* no data at this point */ 67 68 curl_global_init(CURL_GLOBAL_ALL); 69 70 /* init the curl session */ 71 curl_handle = curl_easy_init(); 72 73 /* specify URL to get */ 74 curl_easy_setopt(curl_handle, CURLOPT_URL, "http://www.example.com/"); 75 76 /* send all data to this function */ 77 curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback); 78 79 /* we pass our 'chunk' struct to the callback function */ 80 curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk); 81 82 /* some servers don't like requests that are made without a user-agent 83 field, so we provide one */ 84 curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0"); 85 86 /* get it! */ 87 curl_easy_perform(curl_handle); 88 89 /* cleanup curl stuff */ 90 curl_easy_cleanup(curl_handle); 91 92 /* 93 * Now, our chunk.memory points to a memory block that is chunk.size 94 * bytes big and contains the remote file. 95 * 96 * Do something nice with it! 97 * 98 * You should be aware of the fact that at this point we might have an 99 * allocated data block, and nothing has yet deallocated that data. So when 100 * you're done with it, you should free() it as a nice application. 101 */ 102 103 printf("%lu bytes retrieved\n", (long)chunk.size); 104 105 if(chunk.memory) 106 free(chunk.memory); 107 108 /* we're done with libcurl, so clean it up */ 109 curl_global_cleanup(); 110 111 return 0; 112} 113