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/***************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * $Id: post-callback.c,v 1.4 2004/08/23 14:22:44 bagder Exp $ * * An example source code that issues a HTTP POST and we provide the actual * data through a read callback. * */ #include <stdio.h> #include <string.h> #include <curl/curl.h>
char data[]="this is what we post to the silly web server";
struct WriteThis { char *readptr; int sizeleft; };
size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp) { struct WriteThis *pooh = (struct WriteThis *)userp;
if(size*nmemb < 1) return 0;
if(pooh->sizeleft) { *(char *)ptr = pooh->readptr[0]; /* copy one single byte */ pooh->readptr++; /* advance pointer */ pooh->sizeleft--; /* less data left */ return 1; /* we return 1 byte at a time! */ }
return -1; /* no more data left to deliver */ }
int main(void) { CURL *curl; CURLcode res;
struct WriteThis pooh;
pooh.readptr = data; pooh.sizeleft = strlen(data);
curl = curl_easy_init(); if(curl) { /* First set the URL that is about to receive our POST. */ curl_easy_setopt(curl, CURLOPT_URL, "http://receivingsite.com.pooh/index.cgi"); /* Now specify we want to POST data */ curl_easy_setopt(curl, CURLOPT_POST, TRUE);
/* 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, &pooh);
/* get verbose debug output please */ curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
/* If you use POST to a 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 { curl_slist *chunk = NULL;
chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked"); res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER); /* 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, pooh.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. */ { curl_slist *chunk = NULL;
chunk = curl_slist_append(chunk, "Expect:"); res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER); /* 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);
/* always cleanup */ curl_easy_cleanup(curl); } return 0; }
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