How to use libcurl in c++ to send POST to elasticsearch - c++

Question

does anyone knows the exact syntax for using elasticsearch with libcurl?
#include <stdio.h>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "http://localhost:9200/bro-201409170900/http/ZinAvJ-ETT-mycy2jyRkdg/_update -d");
curl_easy_setopt(curl, CURLOPT_POST, 1);
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "{\"script\" : \"ctx._source.longitude += 3\"}");
curl_easy_perform(curl);
curl_easy_cleanup(curl);
return 1;
}
This code does ont update the longitude parameter and I don't know why.

Answer 1

One should not specify the "-d' in the url. The command line tool is just build on top of libcurl.
If you want to see what the c code for the post request would look like you could use the libcurl option with command line .
example :
curl localhost:9200/bro-201409170900/http/ZinAvJ-ETT-mycy2jyRkdg/… -d '{ "script" : "ctx._source.longitude += 2"}' --libcurl output.c
A simple "C" implementation would look something on these lines
#include <stdio.h>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
char *postFields = "{\"script\" : \"ctx._source.longitude += 3\"}";
curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
curl_easy_setopt(curl, CURLOPT_URL, "http://localhost:9200/bro-201409170900/http/ZinAvJ-ETT-mycy2jyRkdg/_update");
curl_easy_setopt(curl, CURLOPT_POST, 1);
curl_easy_setopt(curl,CURLOPT_POSTFIELDS,postFields);
curl_easy_setopt(curl,CURLOPT_POSTFIELDSIZE,strlen(postFields));
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
return res;
}