Posts empty body to site with cookies using libcurl to retrieve e.g. daily login bonus. Site must return code 200 when logged and another when not e.g. 404.

site_caller.cpp

#include <stdio.h>
#include <curl/curl.h>
#include <iostream>
#include <unistd.h>

size_t CurlWrite_CallbackFunc_StdString(void *contents, size_t size, size_t nmemb, std::string *s)
{
    size_t newLength = size * nmemb;
    size_t oldLength = s->size();
    try
    {
        s->resize(oldLength + newLength);
    }
    catch (std::bad_alloc &e)
    {
        // TODO: handle memory problem
        return 0;
    }

    std::copy((char *)contents, (char *)contents + newLength, s->begin() + oldLength);
    return size * nmemb;
}

void starting();

void callSite()
{
    CURL *curl;
    CURLcode res;
    struct curl_slist *headerlist = NULL;

    curl_global_init(CURL_GLOBAL_ALL);
    curl = curl_easy_init();
    std::string s;
    long http_code = 0;
    if (curl)
    {
        curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

        // write response to function
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, CurlWrite_CallbackFunc_StdString);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &s);

        // disable logs
        curl_easy_setopt(curl, CURLOPT_VERBOSE, 0L); 

        // set headers
        headerlist = curl_slist_append(headerlist, "referer: https://example.com/");
        headerlist = curl_slist_append(headerlist, "dnt: 1");
        headerlist = curl_slist_append(headerlist, "sec-metadata: cause=\"forced\", destination=\"document\", site=\"cross-site\"");
        headerlist = curl_slist_append(headerlist, "upgrade-insecure-requests: 1");
        headerlist = curl_slist_append(headerlist, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36");
        headerlist = curl_slist_append(headerlist, "accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8");
        headerlist = curl_slist_append(headerlist, "accept-encoding: gzip, deflate, br");
        headerlist = curl_slist_append(headerlist, "accept-language: de-DE,de;q=0.9,en-DE;q=0.8,en;q=0.7,en-US;q=0.6");
        headerlist = curl_slist_append(headerlist, "cache-control: max-age=0");
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);

        // set cookie
        curl_easy_setopt(curl, CURLOPT_COOKIE, "cookie1=test1; cookie2=test2;");

        res = curl_easy_perform(curl);
        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
        // check for errors
        if (res != CURLE_OK)
            fprintf(stderr, "curl_easy_perform() failed: %s\n",
                    curl_easy_strerror(res));

        // check status code
        if (http_code == 200)
        {
            printf("Success\n");
        }
        else
        {
            printf("Failed\n");
        }
        curl_easy_cleanup(curl);
    }
    curl_global_cleanup();
    
    // print response
    std::cout<<s<<std::endl;
    
    // every 6 hours
    sleep(6 * 60 * 60);
    
    // start over
    starting();
}

void starting()
{
    printf("Calling Site - ");
    callSite();
}

int main(void)
{
    starting();
}