aboutsummaryrefslogtreecommitdiff
path: root/docs/examples/sftpuploadresume.c
blob: e7d9d23f67b0218cf11f588749d9ca6bffcfa5ea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2019, 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.haxx.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.
 *
 ***************************************************************************/
/* <DESC>
 * Upload to SFTP, resuming a previously aborted transfer.
 * </DESC>
 */

#include <stdlib.h>
#include <stdio.h>
#include <curl/curl.h>

/* read data to upload */
static size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)
{
  FILE *f = (FILE *)stream;
  size_t n;

  if(ferror(f))
    return CURL_READFUNC_ABORT;

  n = fread(ptr, size, nmemb, f) * size;

  return n;
}

/*
 * sftpGetRemoteFileSize returns the remote file size in byte; -1 on error
 */
static curl_off_t sftpGetRemoteFileSize(const char *i_remoteFile)
{
  CURLcode result = CURLE_GOT_NOTHING;
  curl_off_t remoteFileSizeByte = -1;
  CURL *curlHandlePtr = curl_easy_init();

  curl_easy_setopt(curlHandlePtr, CURLOPT_VERBOSE, 1L);

  curl_easy_setopt(curlHandlePtr, CURLOPT_URL, i_remoteFile);
  curl_easy_setopt(curlHandlePtr, CURLOPT_NOPROGRESS, 1);
  curl_easy_setopt(curlHandlePtr, CURLOPT_NOBODY, 1);
  curl_easy_setopt(curlHandlePtr, CURLOPT_HEADER, 1);
  curl_easy_setopt(curlHandlePtr, CURLOPT_FILETIME, 1);

  result = curl_easy_perform(curlHandlePtr);
  if(CURLE_OK == result) {
    result = curl_easy_getinfo(curlHandlePtr,
                               CURLINFO_CONTENT_LENGTH_DOWNLOAD_T,
                               &remoteFileSizeByte);
    if(result)
      return -1;
    printf("filesize: %" CURL_FORMAT_CURL_OFF_T "\n", remoteFileSizeByte);
  }
  curl_easy_cleanup(curlHandlePtr);

  return remoteFileSizeByte;
}


static int sftpResumeUpload(CURL *curlhandle, const char *remotepath,
                            const char *localpath)
{
  FILE *f = NULL;
  CURLcode result = CURLE_GOT_NOTHING;

  curl_off_t remoteFileSizeByte = sftpGetRemoteFileSize(remotepath);
  if(-1 == remoteFileSizeByte) {
    printf("Error reading the remote file size: unable to resume upload\n");
    return -1;
  }

  f = fopen(localpath, "rb");
  if(!f) {
    perror(NULL);
    return 0;
  }

  curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
  curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
  curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
  curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);

#ifdef _WIN32
  _fseeki64(f, remoteFileSizeByte, SEEK_SET);
#else
  fseek(f, (long)remoteFileSizeByte, SEEK_SET);
#endif
  curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L);
  result = curl_easy_perform(curlhandle);

  fclose(f);

  if(result == CURLE_OK)
    return 1;
  else {
    fprintf(stderr, "%s\n", curl_easy_strerror(result));
    return 0;
  }
}

int main(void)
{
  const char *remote = "sftp://user:pass@example.com/path/filename";
  const char *filename = "filename";
  CURL *curlhandle = NULL;

  curl_global_init(CURL_GLOBAL_ALL);
  curlhandle = curl_easy_init();

  if(!sftpResumeUpload(curlhandle, remote, filename)) {
    printf("resumed upload using curl %s failed\n", curl_version());
  }

  curl_easy_cleanup(curlhandle);
  curl_global_cleanup();

  return 0;
}