Login to website using Qt

Question

I need to login to a website to retrieve the source code of a page. How would I do this using Qt?

I'm not familiar with how QUrl and QNetworkAcessManager work, but I was able to write code that would allow me to download the source code for any page not behind a login form.

This is what I have so far. I end up just downloading the source for the redirect page:

test = new QNetworkAccessManager(this);
QUrl URL = QUrl("http://website.com/page");
URL.setUserName("user");
URL.setPassword("password");
test->get(QNetworkRequest(URL));

Edit:

QByteArray loginData("username=user&password=password");
QNetworkRequest request(QUrl("http://website.com/login/index.php"));
manager->post(request,loginData);

QUrl URL = QUrl("http://website.com/mod/resource/view.php?id=114198");
manager->get(QNetworkRequest(URL));

I am still retrieving a 303 reply.

The page is on Moodle, which uses a HTTP POST login form.

I've also tried with a different site. POST works but I get the source code of the login page with the login form filled out. Not sure how to get the page after logging in.

Answer 1

This was my solution, for logging into a particular website and retrieving a file. I was getting redirected multiple times before reaching the destination. I test HTTP status codes until I get the final reply. I also test to see if the final URL is the one I requested and not some home page behind the login page. This is because I am downloading a file.

QByteArray loginData;
loginData.append("username="+(ui->lineEdit_2->text())+"&password="+(ui->lineEdit_3->text())+"&action=login");

cookiesHandler* test = new cookiesHandler(this);
QUrl request("http://website.com");
test->sendPostRequest(request, loginData);

Cookies Handler Class

class cookiesHandler: public QObject{
    Q_OBJECT

public:
    cookiesHandler(QObject *parent = 0) : QObject(parent){
        mManager = new QNetworkAccessManager(this);
        mManager->setCookieJar(new QNetworkCookieJar(this));
connect(mManager, SIGNAL(finished(QNetworkReply*)), SLOT(replyFinished(QNetworkReply*)));
    }

    void sendPostRequest(const QUrl &url, const QByteArray &data){
        mUrl = url;
        login = data;
        QNetworkRequest r(mUrl);
        mManager->post(r, data);
    }

    void sendGetRequest(const QUrl &url)
    {
        mUrl = url;
        test = mUrl;
        QNetworkRequest r(mUrl);
        mManager->get(r);
    }




    virtual ~cookiesHandler(){}

private slots:
    void replyFinished(QNetworkReply *reply){
        if (reply->error() != QNetworkReply::NoError){
            qWarning() << "ERROR:" << reply->errorString();
            return;
        }




        //Cookies//
        QList<QNetworkCookie>  cookies = mManager->cookieJar()->cookiesForUrl(mUrl);
        qDebug() << "COOKIES for" << mUrl.host() << cookies;

        QString str;
        QDebug dStream(&str);

        dStream << mUrl.host() << cookies;

        //End Cookies//


        int v = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
                if (v >= 200 && v < 300) // Success
                {
                    getFile(reply);
                     // Here we got the final reply
                   return;
                }
                else if (v >= 300 && v < 400) // Redirection
                {
                    /* Use Cookies for Login */
                qDebug() << "REDIRECTING";
                rUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();

                if(rUrl != mUrl)
                 {
                    mManager->post(QNetworkRequest(rUrl),login);
                    return;}

                out << QString("redirected: " + rUrl.toEncoded()) << endl;

                    QNetworkRequest r(mUrl);
                    QVariant var;
                    var.setValue(cookies);

                    r.setHeader(QNetworkRequest::CookieHeader, var);
                    mManager->get(r);
                    return;

                }




    }