c++ - 我怎么知道 QNetWorkReply 来自哪个代理？

Question

是一种HTTP请求发送方式。当目标网站响应时，将调用 httpFinished()。

void HTTPClientBase:: HttpRequestGet()
{
    network_manager.setProxy(proxy);
    QNetworkRequest network_request;

    network_request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    network_request.setUrl(URL);


    reply = network_manager.get(network_request);
    connect(reply, SIGNAL(finished(QNetWorkReply*)), this, SLOT(httpFinished(QNetWorkReply*)));
}

void HTTPClientBase::httpFinished(QNetWorkReply* reply)
{
    // How do I know this reply comes from which proxy?
}

我可以在循环中调用 HttpRequestGet()。

static HTTPClientBase myClient;
for(int i=0; i<20; i++)
{
  myClient.setUrl("https:\\www.google.com");
  myClient.setProxy("123.123.123.123:1234"); // The proxy changes every time in this loop.
  myClient.HttpRequestGet();
}

当 HTTPClientBase::httpFinished(QNetWorkReply* reply) 被调用时，我怎么知道这个回复来自哪个代理？

Answer 1

根据 QNetworkReply文档，可以使用成员函数QNetworkReply::request()获取对应的请求.

无论如何，QNetworkRequest 没有setProxy 的成员函数。

但是如果你为 QNetworkAccessManager 设置代理您可以通过 QNetworkReply::manager() 获得指向相应管理器的指针.

注意连接命令。 finished() 没有 QNetworkReply* 参数，因此您的 connect 命令也会失败，您必须更改 HTTPClientBase::httpFinished(QNetWorkReply * 回复) 到 HTTPClientBase::httpFinished()。

...
    connect(reply, SIGNAL(finished()), this, 
    SLOT(httpFinished()));
}

void HTTPClientBase::httpFinished()
{
    QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender());
    if(reply){
        QNetworkAccessManager * manager = reply->manager();
        QNetworkProxy proxy = manager->proxy();
        // now you have the proxy 
    }

}

如您所见，您必须使用 sender()获取实际的信号发送者。您需要创建不同的 QNetworkAccessManager您拥有的每个代理的实例。如果您有代理池，请创建您的 QNetworkAccessManager首先实例，然后根据您的特定需求选择它们。

如果你不想为每个代理创建一个新的 QNetworkAccessManager，你可以这样做:

void HTTPClientBase:: HttpRequestGet()
{
    network_manager.setProxy(proxy);
    QNetworkRequest network_request;

    network_request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    network_request.setUrl(URL);

    reply = network_manager.get(network_request);
    //new member variable: QHash<QNetworkReply*,QString> m_RequestToProxy;
    m_RequestToProxy.insert(reply,proxy);

    connect(reply, SIGNAL(finished()), this, SLOT(httpFinished()));
}

void HTTPClientBase::httpFinished()
{
    QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender());
    if(reply){
        QString proxy = m_RequestToProxy.take(reply);
        //check if proxy is valid
        //and then do whatever you want
    }
}

另一个更好的解决方案是设置回复属性并将其放入槽中。

void HTTPClientBase:: HttpRequestGet()
{
    network_manager.setProxy(proxy);
    QNetworkRequest network_request;

    network_request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    network_request.setUrl(URL);

    reply = network_manager.get(network_request);
    reply->setProperty("_proxy_",proxy);

    connect(reply, SIGNAL(finished()), this, SLOT(httpFinished()));
}

void HTTPClientBase::httpFinished()
{
    QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender());
    if(reply){
        QVariant v_proxy = reply->property("_proxy_");
        //check if proxy is valid
        if(v_proxy.isValid()){
             QString proxy = v_proxy.toString();
             //and then do whatever you want
        }

    }
}