c++如何使用Curl Multi-Interface连续循环

c++ How to continuously loop using Curl Multi Interface

本文关键字：连续 循环 Multi-Interface Curl 何使用 c++      更新时间：2023-10-16

im尝试使用curl多接口连续循环。我有一个定时器功能，需要一次连续循环4个url，然后转到下一个4，等等。我已经成功地让curl轮询我的句柄以了解其状态，但当句柄达到0时，我试图重置curl句柄，使用新的url再次循环，但不起作用。我的定时器功能保持正常工作，但curl多次停止，并使用相同的4个url给我相同的curl响应，尽管我每次都试图重置句柄。请帮忙，谢谢。。下面是我的代码片段。。

// Timer function that fires every 30 seconds with 4 different URL's each time 
void timerFunction (QString url1,QString url2,QString url3,QString url4)
{
CURLMsg *msg = NULL;
std::string url1_ = url1.toStdString();
std::string url2_ = url2.toStdString();
std::string url3_ = url3.toStdString();
std::string url4_ = url4.toStdString();
CURLM *curlm;
int handle_count;
curlm = curl_multi_init();
CURL *curl1 = NULL;
curl1 = curl_easy_init();
CURL *curl2 = NULL;
curl2 = curl_easy_init();
CURL *curl3 = NULL;
curl3 = curl_easy_init();
CURL *curl4 = NULL;
curl4 = curl_easy_init();
if(curl1 && curl2 && curl3 && curl4)
{
curl_easy_setopt(curl1, CURLOPT_URL, url1_.c_str());
curl_easy_setopt(curl1, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl1);
curl_easy_setopt(curl2, CURLOPT_URL, url2_.c_str());
curl_easy_setopt(curl2, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl2);
curl_easy_setopt(curl3, CURLOPT_URL, url3_.c_str());
curl_easy_setopt(curl3, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl3);
curl_easy_setopt(curl4, CURLOPT_URL, url4_.c_str());
curl_easy_setopt(curl4, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl4);
CURLMcode code;
while(1)
{
code = curl_multi_perform(curlm, &handle_count);
if(handle_count == 0)
{
qDebug() << "Handle is 0, CURL Processing is done -- Repeat Process ";
break;
}
while ((msg = curl_multi_info_read(curlm, &handle_count)))
{
if (msg->msg == CURLMSG_DONE) 
{
qDebug()  << msg->msg;
curl_easy_reset(curl1);
curl_easy_reset(curl2);
curl_easy_reset(curl3);
curl_easy_reset(curl4);
handle_count = 4;
code = curl_multi_perform(curlm, &handle_count);
}
}   

}
}

curl_easy_reset清楚地说明：

重新初始化以前在指定CURL句柄上设置的所有选项设置为默认值。这将使句柄恢复到与它是在中使用curl_easy_init创建的。

它不会更改保存在句柄中的以下信息：live连接、会话ID缓存、DNS缓存、cookie和股票。

完成响应后，您需要对循环中的每个句柄使用curl_multi_remove_handle，然后使用curl_easy_cleanup。

但是，您还需要在循环之后使用curl_multi_cleanup来移除所有句柄。

你的代码看起来是这样的：

// Timer function that fires every 30 seconds with 4 different URL's each time 
void timerFunction (QString url1,QString url2,QString url3,QString url4)
{
CURLMsg *msg = NULL;
std::string url1_ = url1.toStdString();
std::string url2_ = url2.toStdString();
std::string url3_ = url3.toStdString();
std::string url4_ = url4.toStdString();
CURLM *curlm;
CURL* eh = NULL;
int still_running = 0, i = 0, msgs_left = 0;
curlm = curl_multi_init();
CURL *curl1 = NULL;
curl1 = curl_easy_init();
CURL *curl2 = NULL;
curl2 = curl_easy_init();
CURL *curl3 = NULL;
curl3 = curl_easy_init();
CURL *curl4 = NULL;
curl4 = curl_easy_init();
if(curl1 && curl2 && curl3 && curl4)
{
curl_easy_setopt(curl1, CURLOPT_URL, url1_.c_str());
curl_easy_setopt(curl1, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl1);
curl_easy_setopt(curl2, CURLOPT_URL, url2_.c_str());
curl_easy_setopt(curl2, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl2);
curl_easy_setopt(curl3, CURLOPT_URL, url3_.c_str());
curl_easy_setopt(curl3, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl3);
curl_easy_setopt(curl4, CURLOPT_URL, url4_.c_str());
curl_easy_setopt(curl4, CURLOPT_WRITEFUNCTION, writeCallback);
curl_multi_add_handle(curlm, curl4);
while(1)
{      
curl_multi_perform(curlm, &still_running);
do {
int numfds = 0;
CURLMcode res = curl_multi_wait(curlm, NULL, 0, MAX_WAIT_MSECS, &numfds);
if (res != CURLM_OK) {
// handle error your way
}
curl_multi_perform(curlm, &still_running);
} while (still_running);
while ((msg = curl_multi_info_read(curlm, &msgs_left)))
{
if (msg->msg == CURLMSG_DONE) 
{
eh = msg->easy_handle;
qDebug()  << msg->msg;
curl_multi_remove_handle(curlm, eh);
curl_easy_cleanup(eh);
}
}  
curl_multi_cleanup(cm);     
}
}

还没有测试你的代码，但我修改了它，这样你就知道应该如何做了。

相关文章：