前两篇文章
c/c++调用libcurl库发送http请求的两种基本用法
采用libuv的epoll方式实现的异步高性能libcurl发送数据的方法
讲述了采用libcurl发送数据的基础方法和高性能方法，基础方法较为容易但性能一般，高级方法的性能卓越但比较难理解，这里再给出一个保证性能的同时又相对较容易理解的方法，该方法最初是由facebook贡献，实现如下：
#define CURL_MULTI_NUM 5 #define CURL_MAX_WAIT_MSECS 30*1000 //将单条数据添加到总 static void add_multi_curl(CURLM* cm, Task* task) { struct curl_slist* headers = NULL; std::string tmp_str; //添加头信息 tmp_str = "User-Agent: "; tmp_str += task->user_agent; headers = curl_slist_append(headers, tmp_str.c_str()); tmp_str = "Accept-Language: "; tmp_str += task->language; headers = curl_slist_append(headers, tmp_str.c_str()); tmp_str = "X-FORWORDED-FOR: "; tmp_str += task->x_forwarded_for; headers = curl_slist_append(headers, tmp_str.c_str()); CURL* curl = curl_easy_init(); //设置curl参数 curl_easy_setopt(curl, CURLOPT_DNS_CACHE_TIMEOUT, 60 * 60 * 72); curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); curl_easy_setopt(curl, CURLOPT_TIMEOUT, 5); curl_easy_setopt(curl, CURLOPT_HEADER, 0L); curl_easy_setopt(curl, CURLOPT_URL, task->uri.c_str()); curl_easy_setopt(curl, CURLOPT_PRIVATE, task->uri.c_str()); curl_easy_setopt(curl, CURLOPT_VERBOSE, 0L); //添加单条curl信息到总信息中 curl_multi_add_handle(cm, curl); } //发送总数据 bool send_multi_data(CURLM* cm) { CURL* eh = NULL; CURLMsg* msg = NULL; CURLcode return_code = CURLE_OK; int32_t still_running = 0; int32_t msgs_left = 0; int32_t http_status_code; const char* szUrl; //发送数据并用still_running监测数据是否发送完成，如果未发送完成则持续发送 curl_multi_perform(cm, &still_running); do { int numfds = 0; int res = curl_multi_wait(cm, NULL, 0, CURL_MAX_WAIT_MSECS, &numfds); if (res != CURLM_OK) { LOG(WARNING) << "error: curl_multi_wait() returned" << res; return false; } curl_multi_perform(cm, &still_running); } while (still_running); //读取发送返回结果信息 while ((msg = curl_multi_info_read(cm, &msgs_left))) { //是否读取成功 if (msg->msg == CURLMSG_DONE) { eh = msg->easy_handle; return_code = msg->data.result; //检测数据发送结果 if (return_code != CURLE_OK) { LOG(WARNING) << "CURL error code: " << msg->data.result; continue; } //检测HTTP状态 http_status_code = 0; szUrl = NULL; curl_easy_getinfo(eh, CURLINFO_RESPONSE_CODE, &http_status_code); curl_easy_getinfo(eh, CURLINFO_PRIVATE, &szUrl); if (http_status_code != 200) { LOG(WARNING) << "GET of" << szUrl << "returned http status code " << http_status_code; } curl_multi_remove_handle(cm, eh); curl_easy_cleanup(eh); } else { LOG(WARNING) << "error: after curl_multi_info_read(), CURLMsg= " << msg->msg; } } return true; } int main() { int loop() { CURLM* cm = NULL; cm = curl_multi_init(); int add_num = 0; while (!IsStoped()) { Task* task = GetTaskItem(); //获取待发送数据，采取消息队列的方式 if (task == nullptr) { //如果获取不到数据，则将当前已获取的数据做一次性发送后等待 if (add_num == 0) { //循环等待消息队列 WaitTask(); continue; } else { send_multi_data(cm); add_num = 0; } } else { //数据量积累到CURL_MULTI_NUM后做一次性发送 add_multi_curl(cm, task); add_num += 1; if (add_num >= CURL_MULTI_NUM) { send_multi_data(cm); add_num = 0; } else { continue; } } } curl_multi_cleanup(cm); return true; }; };
