Current File : //opt/cpanel/libcurl/share/doc/ea-libcurl-devel/post-callback.c
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
/* <DESC>
* Issue an HTTP POST and provide the data through the read callback.
* </DESC>
*/
#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
/* silly test data to POST */
static const char data[]="Lorem ipsum dolor sit amet, consectetur adipiscing "
"elit. Sed vel urna neque. Ut quis leo metus. Quisque eleifend, ex at "
"laoreet rhoncus, odio ipsum semper metus, at tempus ante urna in mauris. "
"Suspendisse ornare tempor venenatis. Ut dui neque, pellentesque a varius "
"eget, mattis vitae ligula. Fusce ut pharetra est. Ut ullamcorper mi ac "
"sollicitudin semper. Praesent sit amet tellus varius, posuere nulla non, "
"rhoncus ipsum.";
struct WriteThis {
const char *readptr;
size_t sizeleft;
};
static size_t read_callback(char *dest, size_t size, size_t nmemb, void *userp)
{
struct WriteThis *wt = (struct WriteThis *)userp;
size_t buffer_size = size*nmemb;
if(wt->sizeleft) {
/* copy as much as possible from the source to the destination */
size_t copy_this_much = wt->sizeleft;
if(copy_this_much > buffer_size)
copy_this_much = buffer_size;
memcpy(dest, wt->readptr, copy_this_much);
wt->readptr += copy_this_much;
wt->sizeleft -= copy_this_much;
return copy_this_much; /* we copied this many bytes */
}
return 0; /* no more data left to deliver */
}
int main(void)
{
CURL *curl;
CURLcode res;
struct WriteThis wt;
wt.readptr = data;
wt.sizeleft = strlen(data);
/* In windows, this will init the winsock stuff */
res = curl_global_init(CURL_GLOBAL_DEFAULT);
/* Check for errors */
if(res != CURLE_OK) {
fprintf(stderr, "curl_global_init() failed: %s\n",
curl_easy_strerror(res));
return 1;
}
/* get a curl handle */
curl = curl_easy_init();
if(curl) {
/* First set the URL that is about to receive our POST. */
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/index.cgi");
/* Now specify we want to POST data */
curl_easy_setopt(curl, CURLOPT_POST, 1L);
/* we want to use our own read function */
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
/* pointer to pass to our read function */
curl_easy_setopt(curl, CURLOPT_READDATA, &wt);
/* get verbose debug output please */
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
/*
If you use POST to an HTTP 1.1 server, you can send data without knowing
the size before starting the POST if you use chunked encoding. You
enable this by adding a header like "Transfer-Encoding: chunked" with
CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
specify the size in the request.
*/
#ifdef USE_CHUNKED
{
struct curl_slist *chunk = NULL;
chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
/* use curl_slist_free_all() after the *perform() call to free this
list again */
}
#else
/* Set the expected POST size. If you want to POST large amounts of data,
consider CURLOPT_POSTFIELDSIZE_LARGE */
curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)wt.sizeleft);
#endif
#ifdef DISABLE_EXPECT
/*
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
header. You can disable this header with CURLOPT_HTTPHEADER as usual.
NOTE: if you want chunked transfer too, you need to combine these two
since you can only set one list of headers with CURLOPT_HTTPHEADER. */
/* A less good option would be to enforce HTTP 1.0, but that might also
have other implications. */
{
struct curl_slist *chunk = NULL;
chunk = curl_slist_append(chunk, "Expect:");
res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
/* use curl_slist_free_all() after the *perform() call to free this
list again */
}
#endif
/* Perform the request, res will get the return code */
res = curl_easy_perform(curl);
/* Check for errors */
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
/* always cleanup */
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return 0;
}
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