QT让应用程序检查sourceforge.net上是否有更新

时间:2016-09-17 08:29:34

标签: c++ qt sourceforge

我希望我的QT应用程序检查sourceforge.net上是否有更新。为此,我使用了请求:https://sourceforge.net/projects/kidbasic/best_release.json 如果您将此链接用于浏览器,您将获得一些json回复。 所以,这是代码:

app.pro

QT       += core gui
QT       += network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = app
TEMPLATE = app
SOURCES += main.cpp\
        mainwindow.cpp
HEADERS  += mainwindow.h

的main.cpp

#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QNetworkReply>
#include <QNetworkAccessManager>
#include <QPushButton>


class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

public slots:
    void replyFinished(QNetworkReply* reply);
    void checkForUpdate(void);
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget * wdg = new QWidget(this);
    QPushButton *train_button = new QPushButton(wdg);
    train_button->setText(tr("check update"));
    setCentralWidget(wdg);
    QObject::connect(train_button, SIGNAL(released()), this, SLOT(checkForUpdate()));
}

MainWindow::~MainWindow(){    }

void MainWindow::checkForUpdate(void){
    QNetworkRequest request;
    QNetworkAccessManager *manager = new QNetworkAccessManager(this);
    QSslConfiguration config = QSslConfiguration::defaultConfiguration();
    config.setProtocol(QSsl::SecureProtocols);
    request.setSslConfiguration(config);

    request.setUrl(QUrl("https://sourceforge.net/projects/kidbasic/best_release.json"));
    //other urls to test
    //request.setUrl(QUrl("https://sourceforge.net/projects/openofficeorg.mirror/files/stats/json?start_date=2014-10-29&end_date=2014-11-04"));
    //request.setUrl(QUrl("https://ro.gravatar.com/205e460b479e2e5b48aec07710c08d50.json"));
    //request.setUrl(QUrl("http://headers.jsontest.com/"));

    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
    manager->get(request);
    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(replyFinished(QNetworkReply*)));
}


void MainWindow::replyFinished(QNetworkReply* reply){
    qDebug() << reply->error();
    if(reply->error() == QNetworkReply::NoError) {
        //process json reply
        QString strReply = (QString)reply->readAll();
        qDebug() << strReply;
    } else {
        qDebug() << "ERROR";
    }
    reply->deleteLater();
}

(为了让它在没有警告的情况下工作,我从https://indy.fulgan.com/SSL/获取libeay32.dllssleay32.dll并将这些文件放在我的应用程序的同一文件夹中 - 因为https)。

如果我尝试其他网址,我会得到正确答复。如果我使用任何surceforge.net请求,则会收到此错误:QNetworkReply::NetworkError(RemoteHostClosedError)

我使用https://www.hurl.it发出相同的请求,一切似乎都没问题。我也使用https://httpstatus.io/获得了相同的结果。

如何通过QT获得surceforge.net的有效回复?

1 个答案:

答案 0 :(得分:1)

当HTTP请求的用户代理字符串为sourceforge.net时,

Mozilla/5.0似乎正在关闭连接(这是QNetworkAccessManager在没有QNetworkRequest::UserAgentHeader时使用的默认用户代理设定)。

您可能必须在发送请求之前设置自定义用户代理:

request.setHeader(QNetworkRequest::UserAgentHeader, "App/1.0");