xref: /third_party/curl/docs/examples/headerapi.c (revision 13498266)
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 * Extract headers post transfer with the header API
26 * </DESC>
27 */
28#include <stdio.h>
29#include <curl/curl.h>
30
31static size_t write_cb(char *data, size_t n, size_t l, void *userp)
32{
33  /* take care of the data here, ignored in this example */
34  (void)data;
35  (void)userp;
36  return n*l;
37}
38
39int main(void)
40{
41  CURL *curl;
42
43  curl = curl_easy_init();
44  if(curl) {
45    CURLcode res;
46    struct curl_header *header;
47    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
48    /* example.com is redirected, so we tell libcurl to follow redirection */
49    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
50
51    /* this example just ignores the content */
52    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_cb);
53
54    /* Perform the request, res will get the return code */
55    res = curl_easy_perform(curl);
56    /* Check for errors */
57    if(res != CURLE_OK)
58      fprintf(stderr, "curl_easy_perform() failed: %s\n",
59              curl_easy_strerror(res));
60
61    if(CURLHE_OK == curl_easy_header(curl, "Content-Type", 0, CURLH_HEADER,
62                                     -1, &header))
63      printf("Got content-type: %s\n", header->value);
64
65    printf("All server headers:\n");
66    {
67      struct curl_header *h;
68      struct curl_header *prev = NULL;
69      do {
70        h = curl_easy_nextheader(curl, CURLH_HEADER, -1, prev);
71        if(h)
72          printf(" %s: %s (%u)\n", h->name, h->value, (int)h->amount);
73        prev = h;
74      } while(h);
75
76    }
77    /* always cleanup */
78    curl_easy_cleanup(curl);
79  }
80  return 0;
81}
82