C++ Qt开发之使用QNetworkAccessManager实现Web网页访问

#include <QCoreApplication>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    // 创建网络访问管理器
    QNetworkAccessManager manager;

    // 创建GET请求
    QNetworkRequest request(QUrl("http://www.baidu.com"));

    // 发送GET请求
    QNetworkReply *reply = manager.get(request);

    // 连接信号槽，处理响应
    QObject::connect(reply, &QNetworkReply::finished, [&]()
    {
        if (reply->error() == QNetworkReply::NoError)
        {
            // 获取请求的 URL
            qDebug() << "Request URL:" << reply->request().url();

            // 输出请求头信息
            qDebug() << "Request Headers:";
            QList<QByteArray> requestHeaders = reply->request().rawHeaderList();
            foreach (const QByteArray &header, requestHeaders) {
                qDebug() << header << ":" << reply->request().rawHeader(header);
            }

            // 获取响应码
            int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
            qDebug() << "HttpStatusCodeAttribute:" << statusCode;

            // 连接是否加密的标志
            bool connectionEncryptedAttribute = reply->attribute(QNetworkRequest::ConnectionEncryptedAttribute).toBool();
            qDebug() << "ConnectionEncryptedAttribute:" << connectionEncryptedAttribute;

            // 请求是否来自缓存的标志
            bool sourceIsFromCacheAttribute = reply->attribute(QNetworkRequest::SourceIsFromCacheAttribute).toBool();
            qDebug() << "SourceIsFromCacheAttribute:" << sourceIsFromCacheAttribute;

            // HTTP请求是否被允许进行流水线处理的标志
            bool httpPipeliningAllowedAttribute = reply->attribute(QNetworkRequest::HttpPipeliningAllowedAttribute).toBool();
            qDebug() << "HttpPipeliningAllowedAttribute:" << httpPipeliningAllowedAttribute;

            // 输出响应头信息
            qDebug() << "Response Headers:";
            QList<QByteArray> responseHeaders = reply->rawHeaderList();
            foreach (const QByteArray &header, responseHeaders) {
                qDebug() << header << ":" << reply->rawHeader(header);
            }

            // 处理响应内容，这里可以使用 readAll() 方法获取响应内容
            // qDebug() << "Response Content:" << reply->readAll();
        } else
        {
            qDebug() << "Error:" << reply->errorString();
        }

        // 释放资源
        reply->deleteLater();
        QCoreApplication::quit();
    });

    return a.exec();
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    //自定义槽函数
    void on_finished();
    void on_readyRead();

    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
    QNetworkAccessManager networkManager;   // 网络管理
    QNetworkReply *reply;                   // 网络响应
};

void MainWindow::on_pushButton_clicked()
{
    // 读入URL地址
    QString urlSpec = ui->lineEdit->text().trimmed();
    if (urlSpec.isEmpty())
    {
        QMessageBox::information(this, "错误", "请指定URL");
        return;
    }

    // 格式化URL
    QUrl newUrl = QUrl::fromUserInput(urlSpec);
    if (!newUrl.isValid())
    {
        QMessageBox::information(this, "错误", QString("无效URL: %1").arg(urlSpec));
        return;
    }

    // 访问页面
    reply = networkManager.get(QNetworkRequest(newUrl));

    // 完成时的槽函数绑定
    connect(reply, SIGNAL(finished()), this, SLOT(on_finished()));

    // 读入数据的槽函数绑定
    connect(reply, SIGNAL(readyRead()), this, SLOT(on_readyRead()));

}

void MainWindow::on_finished()
{
    // 获取响应码
    int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();

    if(statusCode == 200)
    {
        ui->plainTextEdit_2->appendPlainText("响应头数据:");
        // 输出响应头信息
        QList<QByteArray> responseHeaders = reply->rawHeaderList();
        foreach (const QByteArray &header, responseHeaders)
        {
            ui->plainTextEdit_2->appendPlainText(header + " : " + reply->rawHeader(header));
        }
    }
}

// 读入页面源代码
void MainWindow::on_readyRead()
{
    ui->plainTextEdit->setPlainText(reply->readAll());
}