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