1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2015, 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.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 /* <DESC>
23 * An example source code that issues a HTTP POST and we provide the actual
24 * data through a read callback.
25 * </DESC>
26 */
27 #include <stdio.h>
28 #include <string.h>
29 #include <curl/curl.h>
30
31 const char data[]="this is what we post to the silly web server";
32
33 struct WriteThis {
34 const char *readptr;
35 long sizeleft;
36 };
37
read_callback(void * ptr,size_t size,size_t nmemb,void * userp)38 static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
39 {
40 struct WriteThis *pooh = (struct WriteThis *)userp;
41
42 if(size*nmemb < 1)
43 return 0;
44
45 if(pooh->sizeleft) {
46 *(char *)ptr = pooh->readptr[0]; /* copy one single byte */
47 pooh->readptr++; /* advance pointer */
48 pooh->sizeleft--; /* less data left */
49 return 1; /* we return 1 byte at a time! */
50 }
51
52 return 0; /* no more data left to deliver */
53 }
54
main(void)55 int main(void)
56 {
57 CURL *curl;
58 CURLcode res;
59
60 struct WriteThis pooh;
61
62 pooh.readptr = data;
63 pooh.sizeleft = (long)strlen(data);
64
65 /* In windows, this will init the winsock stuff */
66 res = curl_global_init(CURL_GLOBAL_DEFAULT);
67 /* Check for errors */
68 if(res != CURLE_OK) {
69 fprintf(stderr, "curl_global_init() failed: %s\n",
70 curl_easy_strerror(res));
71 return 1;
72 }
73
74 /* get a curl handle */
75 curl = curl_easy_init();
76 if(curl) {
77 /* First set the URL that is about to receive our POST. */
78 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/index.cgi");
79
80 /* Now specify we want to POST data */
81 curl_easy_setopt(curl, CURLOPT_POST, 1L);
82
83 /* we want to use our own read function */
84 curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
85
86 /* pointer to pass to our read function */
87 curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
88
89 /* get verbose debug output please */
90 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
91
92 /*
93 If you use POST to a HTTP 1.1 server, you can send data without knowing
94 the size before starting the POST if you use chunked encoding. You
95 enable this by adding a header like "Transfer-Encoding: chunked" with
96 CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
97 specify the size in the request.
98 */
99 #ifdef USE_CHUNKED
100 {
101 struct curl_slist *chunk = NULL;
102
103 chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
104 res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
105 /* use curl_slist_free_all() after the *perform() call to free this
106 list again */
107 }
108 #else
109 /* Set the expected POST size. If you want to POST large amounts of data,
110 consider CURLOPT_POSTFIELDSIZE_LARGE */
111 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, pooh.sizeleft);
112 #endif
113
114 #ifdef DISABLE_EXPECT
115 /*
116 Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
117 header. You can disable this header with CURLOPT_HTTPHEADER as usual.
118 NOTE: if you want chunked transfer too, you need to combine these two
119 since you can only set one list of headers with CURLOPT_HTTPHEADER. */
120
121 /* A less good option would be to enforce HTTP 1.0, but that might also
122 have other implications. */
123 {
124 struct curl_slist *chunk = NULL;
125
126 chunk = curl_slist_append(chunk, "Expect:");
127 res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
128 /* use curl_slist_free_all() after the *perform() call to free this
129 list again */
130 }
131 #endif
132
133 /* Perform the request, res will get the return code */
134 res = curl_easy_perform(curl);
135 /* Check for errors */
136 if(res != CURLE_OK)
137 fprintf(stderr, "curl_easy_perform() failed: %s\n",
138 curl_easy_strerror(res));
139
140 /* always cleanup */
141 curl_easy_cleanup(curl);
142 }
143 curl_global_cleanup();
144 return 0;
145 }
146