// demo.cpp : Define the entrance for the console application.
    //
    
    #include "stdafx.h"
    #include "curl/curl.h"
    #pragma comment(lib, "libcurl.lib")
    
    //Under the CURLOPT_WRITEFUNCTION setting property, use the callback write_buff_data for processing
    static size_t write_buff_data(char *buffer, size_t size, size_t nitems, void *outstream)
    {
        memcpy(outstream, buffer, nitems*size);
        return nitems*size;
    }
    
    /*
    Use http proxy
    */
    int GetUrlHTTP(char *url, char *buff)
    {
        CURL *curl;
        CURLcode res;
        curl = curl_easy_init();
        if (curl)
        {
            curl_easy_setopt(curl, CURLOPT_PROXY,"http://proxy host:port");//Set proxy
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)buff);//void* buff will be passed to the fourth parameter of the callback function write_buff_data void* outstream
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_buff_data);//Under the CURLOPT_WRITEFUNCTION setting property, use the callback write_buff_data for processing
            curl_easy_setopt(curl, CURLOPT_URL, url);//Set domain to visit
            /* Abort if speed drops below 50 bytes/second for 10 seconds */
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 10L);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 50L);
            curl_easy_setopt(curl, CURLOPT_MAX_RECV_SPEED_LARGE, 2000000L);/*Highest download speed*/
            res = curl_easy_perform(curl);
            curl_easy_cleanup(curl);
            if (res == CURLE_OK){
                return res;
            }else {
                printf("Error code:%d\n", res);
                MessageBox(NULL, TEXT("Error in getting IP"), TEXT("assistant"), MB_ICONINFORMATION | MB_YESNO);
            }
        }
        return res;
    }
    /*
    Use socks5 proxy
    */
    int GetUrlSocks5(char *url, char *buff)
    {
        CURL *curl;
        CURLcode res;
        curl = curl_easy_init();
        if (curl)
        {
            curl_easy_setopt(curl, CURLOPT_PROXY, "socks5://Proxy host:port");//Set proxy
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)buff);
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_buff_data);
            curl_easy_setopt(curl, CURLOPT_URL, url);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 10L);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 50L);
            curl_easy_setopt(curl, CURLOPT_MAX_RECV_SPEED_LARGE, 2000000L);/*Highest download speed*/
            res = curl_easy_perform(curl);
            curl_easy_cleanup(curl);
            if (res == CURLE_OK) {
                return res;
            }
            else {
                printf("Error code:%d\n", res);
                MessageBox(NULL, TEXT("Error in getting IP"), TEXT("assistant"), MB_ICONINFORMATION | MB_YESNO);
            }
        }
        return res;
    }
    /*
    Not use proxy
    */
    int GetUrl(char *url, char *buff)
    {
        CURL *curl;
        CURLcode res;
        curl = curl_easy_init();
        if (curl)
        {
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)buff);
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_buff_data);
            curl_easy_setopt(curl, CURLOPT_URL, url);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 10L);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 50L);
            curl_easy_setopt(curl, CURLOPT_MAX_RECV_SPEED_LARGE, 2000000L);/*Highest download speed*/
            res = curl_easy_perform(curl);
            curl_easy_cleanup(curl);
            if (res == CURLE_OK)
            {
                return res;
            }
            else {
                printf("Error code:%d\n", res);
                    
                MessageBox(NULL, TEXT("Error in getting IP"), TEXT("assistant"), MB_ICONINFORMATION | MB_YESNO);
            }
        }
        return res;
    }
    int main()
    {
        char *buff=(char*)malloc(1024*1024);
        memset(buff, 0, 1024 * 1024);
    
        GetUrl("http://baidu.com", buff);
        printf("Not use proxy：%s\n", buff);
    
        memset(buff, 0, 1024 * 1024);
        GetUrlHTTP("http://baidu.com", buff);
        printf("result of http：%s\n", buff);
    
        memset(buff, 0,1024 * 1024);
        GetUrlSocks5("http://baidu.com", buff);
        printf("result of socks5：%s\n", buff);
    
        free(buff);
        Sleep(10 * 1000);//Wait 10 seconds to exit
        
        return 0;
    }