1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2011, 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 http://curl.haxx.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 ***************************************************************************/
22/* An example source code that issues a HTTP POST and we provide the actual
23 * data through a read callback.
24 */
25#include <stdio.h>
26#include <string.h>
27#include <curl/curl.h>
28
29const char data[]="this is what we post to the silly web server";
30
31struct WriteThis {
32  const char *readptr;
33  int sizeleft;
34};
35
36static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
37{
38  struct WriteThis *pooh = (struct WriteThis *)userp;
39
40  if(size*nmemb < 1)
41    return 0;
42
43  if(pooh->sizeleft) {
44    *(char *)ptr = pooh->readptr[0]; /* copy one single byte */
45    pooh->readptr++;                 /* advance pointer */
46    pooh->sizeleft--;                /* less data left */
47    return 1;                        /* we return 1 byte at a time! */
48  }
49
50  return 0;                          /* no more data left to deliver */
51}
52
53int main(void)
54{
55  CURL *curl;
56  CURLcode res;
57
58  struct WriteThis pooh;
59
60  pooh.readptr = data;
61  pooh.sizeleft = strlen(data);
62
63  curl = curl_easy_init();
64  if(curl) {
65    /* First set the URL that is about to receive our POST. */
66    curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/index.cgi");
67
68    /* Now specify we want to POST data */
69    curl_easy_setopt(curl, CURLOPT_POST, 1L);
70
71    /* we want to use our own read function */
72    curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
73
74    /* pointer to pass to our read function */
75    curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
76
77    /* get verbose debug output please */
78    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
79
80    /*
81      If you use POST to a HTTP 1.1 server, you can send data without knowing
82      the size before starting the POST if you use chunked encoding. You
83      enable this by adding a header like "Transfer-Encoding: chunked" with
84      CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
85      specify the size in the request.
86    */
87#ifdef USE_CHUNKED
88    {
89      struct curl_slist *chunk = NULL;
90
91      chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
92      res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
93      /* use curl_slist_free_all() after the *perform() call to free this
94         list again */
95    }
96#else
97    /* Set the expected POST size. If you want to POST large amounts of data,
98       consider CURLOPT_POSTFIELDSIZE_LARGE */
99    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (curl_off_t)pooh.sizeleft);
100#endif
101
102#ifdef DISABLE_EXPECT
103    /*
104      Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
105      header.  You can disable this header with CURLOPT_HTTPHEADER as usual.
106      NOTE: if you want chunked transfer too, you need to combine these two
107      since you can only set one list of headers with CURLOPT_HTTPHEADER. */
108
109    /* A less good option would be to enforce HTTP 1.0, but that might also
110       have other implications. */
111    {
112      struct curl_slist *chunk = NULL;
113
114      chunk = curl_slist_append(chunk, "Expect:");
115      res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
116      /* use curl_slist_free_all() after the *perform() call to free this
117         list again */
118    }
119#endif
120
121    /* Perform the request, res will get the return code */
122    res = curl_easy_perform(curl);
123
124    /* always cleanup */
125    curl_easy_cleanup(curl);
126  }
127  return 0;
128}
129