curl / libcurl / API / Examples / httpput-postfields.c

httpput-postfields.c

/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/
/* <DESC>
 * HTTP PUT using CURLOPT_POSTFIELDS
 * </DESC>
 */
#include <stdio.h>
#include <fcntl.h>
 
#include <curl/curl.h>
 
static const char olivertwist[] =
  "Among other public buildings in a certain town, which for many reasons "
  "it is prudent to refrain from mentioning, and to which I assign "
  "no fictitious name, there is one anciently common to most towns, great or "
  "small: to ___, a workhouse; and in this workhouse was born; on a day and "
  "date which I need not trouble myself to repeat, inasmuch as it can be of "
  "no possible consequence to the reader, in this stage of the business at "
  "all events; the item of mortality whose name is prefixed";
 
/* ... to the head of this chapter. String cut off to stick within the C90
   509 byte limit. */
 
/*
 * This example shows an HTTP PUT operation that sends a fixed buffer with
 * CURLOPT_POSTFIELDS to the URL given as an argument.
 */
 
int main(int argc, const char **argv)
{
  CURL *curl;
  CURLcode result;
  const char *url;
 
  if(argc < 2)
    return 1;
 
  url = argv[1];
 
  /* In Windows, this inits the Winsock stuff */
  result = curl_global_init(CURL_GLOBAL_ALL);
  if(result != CURLE_OK)
    return (int)result;
 
  /* get a curl handle */
  curl = curl_easy_init();
  if(curl) {
    struct curl_slist *headers = NULL;
 
    /* default type with postfields is application/x-www-form-urlencoded,
       change it if you want */
    headers = curl_slist_append(headers, "Content-Type: literature/classic");
    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
 
    /* pass on content in request body. When CURLOPT_POSTFIELDSIZE is not used,
       curl does strlen to get the size. */
    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, olivertwist);
 
    /* override the POST implied by CURLOPT_POSTFIELDS
     *
     * Warning: CURLOPT_CUSTOMREQUEST is problematic, especially if you want
     * to follow redirects. Be aware.
     */
    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
 
    /* specify target URL, and note that this URL should include a file
       name, not only a directory */
    curl_easy_setopt(curl, CURLOPT_URL, url);
 
    /* Now run off and do what you have been told! */
    result = curl_easy_perform(curl);
    /* Check for errors */
    if(result != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(result));
 
    /* always cleanup */
    curl_easy_cleanup(curl);
 
    /* free headers */
    curl_slist_free_all(headers);
  }
 
  curl_global_cleanup();
  return (int)result;
}

Notice

This source code example is simplified and may ignore return codes and error checks. We do this to highlight the libcurl function calls and related options and reduce unrelated code.

A real-world application does of course properly check every return value and exit correctly at the first serious error.