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      1 /***************************************************************************
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      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel (at) 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 
     29 const char data[]="this is what we post to the silly web server";
     30 
     31 struct WriteThis {
     32   const char *readptr;
     33   long sizeleft;
     34 };
     35 
     36 static 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 
     53 int main(void)
     54 {
     55   CURL *curl;
     56   CURLcode res;
     57 
     58   struct WriteThis pooh;
     59 
     60   pooh.readptr = data;
     61   pooh.sizeleft = (long)strlen(data);
     62 
     63   /* In windows, this will init the winsock stuff */
     64   res = curl_global_init(CURL_GLOBAL_DEFAULT);
     65   /* Check for errors */
     66   if(res != CURLE_OK) {
     67     fprintf(stderr, "curl_global_init() failed: %s\n",
     68             curl_easy_strerror(res));
     69     return 1;
     70   }
     71 
     72   /* get a curl handle */
     73   curl = curl_easy_init();
     74   if(curl) {
     75     /* First set the URL that is about to receive our POST. */
     76     curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/index.cgi");
     77 
     78     /* Now specify we want to POST data */
     79     curl_easy_setopt(curl, CURLOPT_POST, 1L);
     80 
     81     /* we want to use our own read function */
     82     curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
     83 
     84     /* pointer to pass to our read function */
     85     curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
     86 
     87     /* get verbose debug output please */
     88     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
     89 
     90     /*
     91       If you use POST to a HTTP 1.1 server, you can send data without knowing
     92       the size before starting the POST if you use chunked encoding. You
     93       enable this by adding a header like "Transfer-Encoding: chunked" with
     94       CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
     95       specify the size in the request.
     96     */
     97 #ifdef USE_CHUNKED
     98     {
     99       struct curl_slist *chunk = NULL;
    100 
    101       chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
    102       res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
    103       /* use curl_slist_free_all() after the *perform() call to free this
    104          list again */
    105     }
    106 #else
    107     /* Set the expected POST size. If you want to POST large amounts of data,
    108        consider CURLOPT_POSTFIELDSIZE_LARGE */
    109     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, pooh.sizeleft);
    110 #endif
    111 
    112 #ifdef DISABLE_EXPECT
    113     /*
    114       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
    115       header.  You can disable this header with CURLOPT_HTTPHEADER as usual.
    116       NOTE: if you want chunked transfer too, you need to combine these two
    117       since you can only set one list of headers with CURLOPT_HTTPHEADER. */
    118 
    119     /* A less good option would be to enforce HTTP 1.0, but that might also
    120        have other implications. */
    121     {
    122       struct curl_slist *chunk = NULL;
    123 
    124       chunk = curl_slist_append(chunk, "Expect:");
    125       res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
    126       /* use curl_slist_free_all() after the *perform() call to free this
    127          list again */
    128     }
    129 #endif
    130 
    131     /* Perform the request, res will get the return code */
    132     res = curl_easy_perform(curl);
    133     /* Check for errors */
    134     if(res != CURLE_OK)
    135       fprintf(stderr, "curl_easy_perform() failed: %s\n",
    136               curl_easy_strerror(res));
    137 
    138     /* always cleanup */
    139     curl_easy_cleanup(curl);
    140   }
    141   curl_global_cleanup();
    142   return 0;
    143 }
    144