#include <string>
#include <iostream>#include <curl/curl.h>
#include <sys/time.h>
#include <unistd.h>using namespace std;size_t curl_writer(void *buffer, size_t size, size_t count, void * stream)
{std::string * pStream = static_cast<std::string *>(stream);(*pStream).append((char *)buffer, size * count);return size * count;
};/*** 生成一个easy curl对象，进行一些简单的设置操作*/
CURL * curl_easy_handler(const std::string & sUrl,const std::string & sProxy,std::string & sRsp,unsigned int uiTimeout)
{CURL * curl = curl_easy_init();curl_easy_setopt(curl, CURLOPT_URL, sUrl.c_str());curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);if (uiTimeout > 0){curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS, uiTimeout);}if (!sProxy.empty()){curl_easy_setopt(curl, CURLOPT_PROXY, sProxy.c_str());}// write function //
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_writer);curl_easy_setopt(curl, CURLOPT_WRITEDATA, &sRsp);return curl;
}/*** 使用select函数监听multi curl文件描述符的状态* 监听成功返回0，监听失败返回-1*/
int curl_multi_select(CURLM * curl_m)
{int ret = 0;struct timeval timeout_tv;fd_set  fd_read;fd_set  fd_write;fd_set  fd_except;int     max_fd = -1;// 注意这里一定要清空fdset,curl_multi_fdset不会执行fdset的清空操作  //
    FD_ZERO(&fd_read);FD_ZERO(&fd_write);FD_ZERO(&fd_except);// 设置select超时时间  //
    timeout_tv.tv_sec = 1;timeout_tv.tv_usec = 0;// 获取multi curl需要监听的文件描述符集合 fd_set //
    curl_multi_fdset(curl_m, &fd_read, &fd_write, &fd_except, &max_fd);/*** When max_fd returns with -1,* you need to wait a while and then proceed and call curl_multi_perform anyway.* How long to wait? I would suggest 100 milliseconds at least,* but you may want to test it out in your own particular conditions to find a suitable value.*/if (-1 == max_fd){return -1;}/*** 执行监听，当文件描述符状态发生改变的时候返回* 返回0，程序调用curl_multi_perform通知curl执行相应操作* 返回-1，表示select错误* 注意：即使select超时也需要返回0，具体可以去官网看文档说明*/int ret_code = ::select(max_fd + 1, &fd_read, &fd_write, &fd_except, &timeout_tv);switch(ret_code){case -1:/* select error */ret = -1;break;case 0:/* select timeout */default:/* one or more of curl's file descriptors say there's data to read or write*/ret = 0;break;}return ret;
}#define MULTI_CURL_NUM 3// 这里设置你需要访问的url //
std::string     URL     = "http://website.com";
// 这里设置代理ip和端口  //
std::string     PROXY   = "ip:port";
// 这里设置超时时间  //
unsigned int    TIMEOUT = 2000; /* ms *//*** multi curl使用demo*/
int curl_multi_demo(int num)
{// 初始化一个multi curl 对象 //
    CURLM * curl_m = curl_multi_init();std::string     RspArray[num];CURL *          CurlArray[num];// 设置easy curl对象并添加到multi curl对象中  //
    for (int idx = 0; idx < num; ++idx){CurlArray[idx] = NULL;CurlArray[idx] = curl_easy_handler(URL, PROXY, RspArray[idx], TIMEOUT);if (CurlArray[idx] == NULL){return -1;}curl_multi_add_handle(curl_m, CurlArray[idx]);}/** 调用curl_multi_perform函数执行curl请求* url_multi_perform返回CURLM_CALL_MULTI_PERFORM时，表示需要继续调用该函数直到返回值不是CURLM_CALL_MULTI_PERFORM为止* running_handles变量返回正在处理的easy curl数量，running_handles为0表示当前没有正在执行的curl请求*/int running_handles;while (CURLM_CALL_MULTI_PERFORM == curl_multi_perform(curl_m, &running_handles)){cout << running_handles << endl;}/*** 为了避免循环调用curl_multi_perform产生的cpu持续占用的问题，采用select来监听文件描述符*/while (running_handles){if (-1 == curl_multi_select(curl_m)){cerr << "select error" << endl;break;} else {// select监听到事件，调用curl_multi_perform通知curl执行相应的操作 //
            while (CURLM_CALL_MULTI_PERFORM == curl_multi_perform(curl_m, &running_handles)){cout << "select: " << running_handles << endl;}}cout << "select: " << running_handles << endl;}// 输出执行结果 //
    int         msgs_left;CURLMsg *   msg;while((msg = curl_multi_info_read(curl_m, &msgs_left))){if (CURLMSG_DONE == msg->msg){int idx;for (idx = 0; idx < num; ++idx){if (msg->easy_handle == CurlArray[idx]) break;}if (idx == num){cerr << "curl not found" << endl;} else{cout << "curl [" << idx << "] completed with status: "<< msg->data.result << endl;cout << "rsp: " << RspArray[idx] << endl;}}}// 这里要注意cleanup的顺序 //
    for (int idx = 0; idx < num; ++idx){curl_multi_remove_handle(curl_m, CurlArray[idx]);}for (int idx = 0; idx < num; ++idx){curl_easy_cleanup(CurlArray[idx]);}curl_multi_cleanup(curl_m);return 0;
}/*** easy curl使用demo*/
int curl_easy_demo(int num)
{std::string     RspArray[num];for (int idx = 0; idx < num; ++idx){CURL * curl = curl_easy_handler(URL, PROXY, RspArray[idx], TIMEOUT);CURLcode code = curl_easy_perform(curl);cout << "curl [" << idx << "] completed with status: "<< code << endl;cout << "rsp: " << RspArray[idx] << endl;// clear handle //
        curl_easy_cleanup(curl);}return 0;
}#define USE_MULTI_CURLstruct timeval begin_tv, end_tv;int main(int argc, char * argv[])
{if (argc < 2){return -1;}int num = atoi(argv[1]);// 获取开始时间 //
    gettimeofday(&begin_tv, NULL);
#ifdef USE_MULTI_CURL// 使用multi接口进行访问 //
    curl_multi_demo(num);
#else// 使用easy接口进行访问 //
    curl_easy_demo(num);
#endif// 获取结束时间  //
    struct timeval end_tv;gettimeofday(&end_tv, NULL);// 计算执行延时并输出，用于比较  //
    int eclapsed = (end_tv.tv_sec - begin_tv.tv_sec) * 1000 +(end_tv.tv_usec - begin_tv.tv_usec) / 1000;cout << "eclapsed time:" << eclapsed << "ms" << endl;return 0;
}