CMakeLua/Utilities/cmcurl-7.19.0/docs/examples/post-callback.c

   1 /*****************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * $Id: post-callback.c,v 1.1.1.1 2008-09-23 16:32:05 hoffman Exp $
   9  *
  10  * An example source code that issues a HTTP POST and we provide the actual
  11  * data through a read callback.
  12  *
  13  */
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <curl/curl.h>
  17
  18 const char data[]="this is what we post to the silly web server";
  19
  20 struct WriteThis {
  21   const char *readptr;
  22   int sizeleft;
  23 };
  24
  25 static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
  26 {
  27   struct WriteThis *pooh = (struct WriteThis *)userp;
  28
  29   if(size*nmemb < 1)
  30     return 0;
  31
  32   if(pooh->sizeleft) {
  33     *(char *)ptr = pooh->readptr[0]; /* copy one single byte */
  34     pooh->readptr++;                 /* advance pointer */
  35     pooh->sizeleft--;                /* less data left */
  36     return 1;                        /* we return 1 byte at a time! */
  37   }
  38
  39   return 0;                          /* no more data left to deliver */
  40 }
  41
  42 int main(void)
  43 {
  44   CURL *curl;
  45   CURLcode res;
  46
  47   struct WriteThis pooh;
  48
  49   pooh.readptr = data;
  50   pooh.sizeleft = strlen(data);
  51
  52   curl = curl_easy_init();
  53   if(curl) {
  54     /* First set the URL that is about to receive our POST. */
  55     curl_easy_setopt(curl, CURLOPT_URL,
  56                      "http://receivingsite.com.pooh/index.cgi");
  57     /* Now specify we want to POST data */
  58     curl_easy_setopt(curl, CURLOPT_POST, 1L);
  59
  60     /* we want to use our own read function */
  61     curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
  62
  63     /* pointer to pass to our read function */
  64     curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
  65
  66     /* get verbose debug output please */
  67     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
  68
  69     /*
  70       If you use POST to a HTTP 1.1 server, you can send data without knowing
  71       the size before starting the POST if you use chunked encoding. You
  72       enable this by adding a header like "Transfer-Encoding: chunked" with
  73       CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
  74       specify the size in the request.
  75     */
  76 #ifdef USE_CHUNKED
  77     {
  78       struct curl_slist *chunk = NULL;
  79
  80       chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
  81       res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
  82       /* use curl_slist_free_all() after the *perform() call to free this
  83          list again */
  84     }
  85 #else
  86     /* Set the expected POST size. If you want to POST large amounts of data,
  87        consider CURLOPT_POSTFIELDSIZE_LARGE */
  88     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (curl_off_t)pooh.sizeleft);
  89 #endif
  90
  91 #ifdef DISABLE_EXPECT
  92     /*
  93       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
  94       header.  You can disable this header with CURLOPT_HTTPHEADER as usual.
  95       NOTE: if you want chunked transfer too, you need to combine these two
  96       since you can only set one list of headers with CURLOPT_HTTPHEADER. */
  97
  98     /* A less good option would be to enforce HTTP 1.0, but that might also
  99        have other implications. */
 100     {
 101       struct curl_slist *chunk = NULL;
 102
 103       chunk = curl_slist_append(chunk, "Expect:");
 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 #endif
 109
 110     /* Perform the request, res will get the return code */
 111     res = curl_easy_perform(curl);
 112
 113     /* always cleanup */
 114     curl_easy_cleanup(curl);
 115   }
 116   return 0;
 117 }