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    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:  *
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   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: 
   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: 
   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: }