curl / libcurl / API / Examples / ftpsget.c

ftpsget.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>
 * Get a single file from an FTPS server.
 * </DESC>
 */
#ifdef _MSC_VER
#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS  /* for fopen() */
#endif
#endif
 
#include <stdio.h>
 
#include <curl/curl.h>
 
struct FtpFile {
  const char *filename;
  FILE *stream;
};
 
static size_t write_cb(char *buffer, size_t size, size_t nmemb, void *stream)
{
  struct FtpFile *out = (struct FtpFile *)stream;
  if(!out->stream) {
    /* open file for writing */
    out->stream = fopen(out->filename, "wb");
    if(!out->stream)
      return 0; /* failure, cannot open file to write */
  }
  return fwrite(buffer, size, nmemb, out->stream);
}
 
int main(void)
{
  CURL *curl;
  CURLcode result;
  struct FtpFile ftpfile = {
    "yourfile.bin", /* name to store the file as if successful */
    NULL
  };
 
  result = curl_global_init(CURL_GLOBAL_ALL);
  if(result != CURLE_OK)
    return (int)result;
 
  curl = curl_easy_init();
  if(curl) {
    /*
     * You better replace the URL with one that works! Note that we use an
     * FTP:// URL with standard explicit FTPS. You can also do FTPS:// URLs if
     * you want to do the rarer kind of transfers: implicit.
     */
    curl_easy_setopt(curl, CURLOPT_URL,
                     "ftp://user@server/home/user/file.txt");
    /* Define our callback to get called when there is data to be written */
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_cb);
    /* Set a pointer to our struct to pass to the callback */
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile);
 
    /* We activate SSL and we require it for both control and data */
    curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
 
    /* Switch on full protocol/debug output */
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
 
    result = curl_easy_perform(curl);
 
    /* always cleanup */
    curl_easy_cleanup(curl);
 
    if(result != CURLE_OK) {
      /* we failed */
      fprintf(stderr, "curl told us %d\n", result);
    }
  }
 
  if(ftpfile.stream)
    fclose(ftpfile.stream); /* close the local file */
 
  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.