1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2017, 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  * Issue an HTTP POST and provide the data through the read callback.
24  * </DESC>
25  */
26 #include <stdio.h>
27 #include <string.h>
28 #include <curl/curl.h>
29 
30 /* silly test data to POST */
31 static const char data[]="Lorem ipsum dolor sit amet, consectetur adipiscing "
32   "elit. Sed vel urna neque. Ut quis leo metus. Quisque eleifend, ex at "
33   "laoreet rhoncus, odio ipsum semper metus, at tempus ante urna in mauris. "
34   "Suspendisse ornare tempor venenatis. Ut dui neque, pellentesque a varius "
35   "eget, mattis vitae ligula. Fusce ut pharetra est. Ut ullamcorper mi ac "
36   "sollicitudin semper. Praesent sit amet tellus varius, posuere nulla non, "
37   "rhoncus ipsum.";
38 
39 struct WriteThis {
40   const char *readptr;
41   size_t sizeleft;
42 };
43 
read_callback(void * dest,size_t size,size_t nmemb,void * userp)44 static size_t read_callback(void *dest, size_t size, size_t nmemb, void *userp)
45 {
46   struct WriteThis *wt = (struct WriteThis *)userp;
47   size_t buffer_size = size*nmemb;
48 
49   if(wt->sizeleft) {
50     /* copy as much as possible from the source to the destination */
51     size_t copy_this_much = wt->sizeleft;
52     if(copy_this_much > buffer_size)
53       copy_this_much = buffer_size;
54     memcpy(dest, wt->readptr, copy_this_much);
55 
56     wt->readptr += copy_this_much;
57     wt->sizeleft -= copy_this_much;
58     return copy_this_much; /* we copied this many bytes */
59   }
60 
61   return 0; /* no more data left to deliver */
62 }
63 
main(void)64 int main(void)
65 {
66   CURL *curl;
67   CURLcode res;
68 
69   struct WriteThis wt;
70 
71   wt.readptr = data;
72   wt.sizeleft = strlen(data);
73 
74   /* In windows, this will init the winsock stuff */
75   res = curl_global_init(CURL_GLOBAL_DEFAULT);
76   /* Check for errors */
77   if(res != CURLE_OK) {
78     fprintf(stderr, "curl_global_init() failed: %s\n",
79             curl_easy_strerror(res));
80     return 1;
81   }
82 
83   /* get a curl handle */
84   curl = curl_easy_init();
85   if(curl) {
86     /* First set the URL that is about to receive our POST. */
87     curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/index.cgi");
88 
89     /* Now specify we want to POST data */
90     curl_easy_setopt(curl, CURLOPT_POST, 1L);
91 
92     /* we want to use our own read function */
93     curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
94 
95     /* pointer to pass to our read function */
96     curl_easy_setopt(curl, CURLOPT_READDATA, &wt);
97 
98     /* get verbose debug output please */
99     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
100 
101     /*
102       If you use POST to a HTTP 1.1 server, you can send data without knowing
103       the size before starting the POST if you use chunked encoding. You
104       enable this by adding a header like "Transfer-Encoding: chunked" with
105       CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
106       specify the size in the request.
107     */
108 #ifdef USE_CHUNKED
109     {
110       struct curl_slist *chunk = NULL;
111 
112       chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
113       res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
114       /* use curl_slist_free_all() after the *perform() call to free this
115          list again */
116     }
117 #else
118     /* Set the expected POST size. If you want to POST large amounts of data,
119        consider CURLOPT_POSTFIELDSIZE_LARGE */
120     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)wt.sizeleft);
121 #endif
122 
123 #ifdef DISABLE_EXPECT
124     /*
125       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
126       header.  You can disable this header with CURLOPT_HTTPHEADER as usual.
127       NOTE: if you want chunked transfer too, you need to combine these two
128       since you can only set one list of headers with CURLOPT_HTTPHEADER. */
129 
130     /* A less good option would be to enforce HTTP 1.0, but that might also
131        have other implications. */
132     {
133       struct curl_slist *chunk = NULL;
134 
135       chunk = curl_slist_append(chunk, "Expect:");
136       res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
137       /* use curl_slist_free_all() after the *perform() call to free this
138          list again */
139     }
140 #endif
141 
142     /* Perform the request, res will get the return code */
143     res = curl_easy_perform(curl);
144     /* Check for errors */
145     if(res != CURLE_OK)
146       fprintf(stderr, "curl_easy_perform() failed: %s\n",
147               curl_easy_strerror(res));
148 
149     /* always cleanup */
150     curl_easy_cleanup(curl);
151   }
152   curl_global_cleanup();
153   return 0;
154 }
155