QNetworkRequest导致内存损坏

如何解决QNetworkRequest导致内存损坏

我创建了一个库，该库将处理所有HTTP请求以及JSON格式的响应数据解析。当我在主应用程序（带有GUI）中调用包含get请求的方法时，收到了内存损坏错误。因此，我添加了QEventLoop和一个计时器来等待响应，然后再继续其他过程。我能够通过调用QNetworkReply.readall（）获得响应数据。我需要获取响应数据的char *值，因此我调用了QNetworkReply.data（），但它为空。为什么？

这是我写的代码：

处理HTTP请求的库：

void HttpRequest::getRequest(string param1,string param2)
{
    pManager_ = new QNetworkAccessManager(this);

    QUrl cUrl(sampleUrl);
    qnetworkrequest request(cUrl);
    request.setRawHeader(keyHeader.c_str(),param1.c_str());

    connect(pManager_,SIGNAL(finished(QNetworkReply*)),this,SLOT(requestFinished(QNetworkReply*)));
    connect(pManager_,SIGNAL(sslErrors(QNetworkReply*,const QList<QSslError> & )),SLOT(handleSslErrors(QNetworkReply*,const QList<QSslError> & )));

    cUrl.addQueryItem("name",QString::fromStdString(param2));

    pManager_->get(request); // memory corruption error encountered in main application after calling this

    std::cout << "after calling get" << std::endl;
}

void HttpRequest::requestFinished(QNetworkReply *pReply)
{
    QByteArray responseData;

    std::cout << " request finished" << std::endl;
    int responseStatus = pReply->attribute(qnetworkrequest::HttpStatusCodeAttribute).toInt();
    std::cout << " status code: " << responseStatus << std::endl;

    if(pReply->error())
        std::cout << " Error: " << pReply->errorString().toStdString() << std::endl;
    else
    {
        responseData = pReply->readAll();
        qDebug() << " Response data: " << responseData; 
        const char* pResponseData = responseData.data(); 
       qDebug() << "pResponseData: " << pResponseData ; 
        
        // parsing here
    }

    pReply->deleteLater();
    pManager_->deleteLater();
}

void HttpRequest::handleSslErrors(QNetworkReply *pReply,const QList<QSslError> & )
{
    std::cout << " SSL ERROR" << std::endl;
    int responseStatus = pReply->attribute(qnetworkrequest::HttpStatusCodeAttribute).toInt();
}

GUI主应用程序：

DialogTest::DialogTest(QWidget *parent) :
    QDialog(parent),ui(new Ui::DialogTest)
{

    // some codes here
    
    if(enabled)
    {
        HttpRequest::instance()->getinformation(param1,param2); // memory corruption happened here when I called getRequest() method with no event loop
    }
    
    // other threads here
}

以下是使用QEventLoop的代码：

void HttpRequest::getRequest(string param1,string param2)
{
    QTimer qTimer;
    QEventLoop loop;
    
    pManager_ = new QNetworkAccessManager(this);

    QUrl cUrl(sampleUrl);
    qnetworkrequest request(cUrl);
    request.setRawHeader(keyHeader.c_str(),param1.c_str());
   
    connect(&qTimer,SIGNAL(timeout()),&loop,SLOT(quit()));
    connect(pManager_,SLOT(quit()));

    QNetworkReply *pReply = pManager_->get(request);

    qTimer.start(1000);
    loop.exec();

    int responseCode = pReply->attribute(qnetworkrequest::HttpStatusCodeAttribute).toInt();
    std::cout << "status code: " << responseCode << std::endl;

    if(pReply->error())
    {
        std::cout << " Error: " << pReply->errorString().toStdString() << std::endl;
    }
    else
    {
        qDebug() << "[HttpRequest] Response data: " << pReply->readAll();
        QByteArray response = pReply->readAll(); // it printed this value: "{"count":3,"codes":["x00000A","x00000B","x00000C"]}" which is correct
        char* pResponseData = response.data(); 
       qDebug() << "pResponseData: " << pResponseData ; //it printed this: pResponseData:
    }

    delete pReply;
    delete pManager_;
}

我期望从HTTP get命令获得以下响应数据： “ {” count“：3，”代码“：[” x00000A“，” x00000B“，” x00000C“]}”“

问题： 实现此目的的最佳方法是什么？我想将所有HTTP请求都放在一个库中，然后使用GUI将其称为我的主应用程序。请注意：

• 当我在库中使用QEventLoop等待响应时，QNetworkReply.data（）为空。我需要QNetworkReply.data（）的值进行解析。
• 当我不使用QEventLoop而不单独使用信号和插槽时（如上面的代码所示），执行HTTP get命令后，主应用程序中发生了内存损坏。没有收到响应数据。

解决方法

建议：

请勿对QObject使用直接删除。不好：

delete pReply;
delete pManager_;

Qt方式，很好：

pReply->deleteLater();
pManager->deleteLater();

更好：没有“新”（动态内存）

QNetworkAccessManager Manager_;
...
connect(&Manager_,SIGNAL(finished(QNetworkReply*)),&loop,SLOT(quit()));
 
..
pReply->deleteLater();