1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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 https://curl.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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24/* <DESC>
25 * Make an HTTP POST with data from memory and receive response in memory.
26 * </DESC>
27 */
28#include <stdio.h>
29#include <stdlib.h>
30#include <string.h>
31#include <curl/curl.h>
32
33struct MemoryStruct {
34  char *memory;
35  size_t size;
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  char *ptr = realloc(mem->memory, mem->size + realsize + 1);
45  if(!ptr) {
46    /* out of memory! */
47    printf("not enough memory (realloc returned NULL)\n");
48    return 0;
49  }
50
51  mem->memory = ptr;
52  memcpy(&(mem->memory[mem->size]), contents, realsize);
53  mem->size += realsize;
54  mem->memory[mem->size] = 0;
55
56  return realsize;
57}
58
59int main(void)
60{
61  CURL *curl;
62  CURLcode res;
63  struct MemoryStruct chunk;
64  static const char *postthis = "Field=1&Field=2&Field=3";
65
66  chunk.memory = malloc(1);  /* will be grown as needed by realloc above */
67  chunk.size = 0;    /* no data at this point */
68
69  curl_global_init(CURL_GLOBAL_ALL);
70  curl = curl_easy_init();
71  if(curl) {
72    curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.org/");
73
74    /* send all data to this function  */
75    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
76
77    /* we pass our 'chunk' struct to the callback function */
78    curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
79
80    /* some servers do not like requests that are made without a user-agent
81       field, so we provide one */
82    curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
83
84    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis);
85
86    /* if we do not provide POSTFIELDSIZE, libcurl will strlen() by
87       itself */
88    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis));
89
90    /* Perform the request, res will get the return code */
91    res = curl_easy_perform(curl);
92    /* Check for errors */
93    if(res != CURLE_OK) {
94      fprintf(stderr, "curl_easy_perform() failed: %s\n",
95              curl_easy_strerror(res));
96    }
97    else {
98      /*
99       * Now, our chunk.memory points to a memory block that is chunk.size
100       * bytes big and contains the remote file.
101       *
102       * Do something nice with it!
103       */
104      printf("%s\n",chunk.memory);
105    }
106
107    /* always cleanup */
108    curl_easy_cleanup(curl);
109  }
110
111  free(chunk.memory);
112  curl_global_cleanup();
113  return 0;
114}
115