1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel (at) 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 32 struct MemoryStruct { 33 char *memory; 34 size_t size; 35 }; 36 37 38 static size_t 39 WriteMemoryCallback(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 return 0; 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 59 int main(void) 60 { 61 CURL *curl_handle; 62 CURLcode res; 63 64 struct MemoryStruct chunk; 65 66 chunk.memory = malloc(1); /* will be grown as needed by the realloc above */ 67 chunk.size = 0; /* no data at this point */ 68 69 curl_global_init(CURL_GLOBAL_ALL); 70 71 /* init the curl session */ 72 curl_handle = curl_easy_init(); 73 74 /* specify URL to get */ 75 curl_easy_setopt(curl_handle, CURLOPT_URL, "http://www.example.com/"); 76 77 /* send all data to this function */ 78 curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback); 79 80 /* we pass our 'chunk' struct to the callback function */ 81 curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk); 82 83 /* some servers don't like requests that are made without a user-agent 84 field, so we provide one */ 85 curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0"); 86 87 /* get it! */ 88 res = curl_easy_perform(curl_handle); 89 90 /* check for errors */ 91 if(res != CURLE_OK) { 92 fprintf(stderr, "curl_easy_perform() failed: %s\n", 93 curl_easy_strerror(res)); 94 } 95 else { 96 /* 97 * Now, our chunk.memory points to a memory block that is chunk.size 98 * bytes big and contains the remote file. 99 * 100 * Do something nice with it! 101 */ 102 103 printf("%lu bytes retrieved\n", (long)chunk.size); 104 } 105 106 /* cleanup curl stuff */ 107 curl_easy_cleanup(curl_handle); 108 109 free(chunk.memory); 110 111 /* we're done with libcurl, so clean it up */ 112 curl_global_cleanup(); 113 114 return 0; 115 } 116
