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/* 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    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
59int 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  if(chunk.memory)
110    free(chunk.memory);
111
112  /* we're done with libcurl, so clean it up */
113  curl_global_cleanup();
114
115  return 0;
116}
117