How do I save cookies with Qt? - c++

Question

I am trying to save cookies that are produced by my app to disk location such as C:\Users\Username\AppData\Local\MyCompany\MyApp. I have implemented a webview and have pretty much finished coding my simple browser the final thing to do is save cookies.
I am can qDebug() the cookies I get from the webapp and they show the cookies are formed correctly but I am a)unsure where to go from there and b) not 100% sure on how to make a subclass of the cookiejar class?
Below I create my cookiejar object in my MainWindow constructor
view = new QWebView(this);
jar = new QNetworkCookieJar;
view->page()->networkAccessManager()->setCookieJar(jar);
And in my replyfinished slot I can see the cookie contained in the reply and I attempt to save it but nothing happens and I receive no run time errors. There isn't a great deal of stuff out there on this and have seen a few posts where the instruction was to make a subclass QNetworkCookieJar but have not made a subclass in Qt/C++ before.
Is there a simple way to store cookies, I am not looking for anything fancy. The cookies just make sure some check boxes are ticked on the login page.
// SLOT that accepts the read data from the webpage
void MainWindow::slotReplyFinished(QNetworkReply *reply){
if(reply->isFinished()){
QVariant variantCookies = reply->header(QNetworkRequest::SetCookieHeader);
QList<QNetworkCookie> cookies = qvariant_cast<QList<QNetworkCookie> >(variantCookies);
qDebug() << "Cookies reply: " << cookies;
QNetworkCookie cookie; //Create a cookie
jar = new QNetworkCookieJar;
//view->page()->networkAccessManager()->setCookieJar(jar);
jar->setCookiesFromUrl(cookies, reply->request().url());
//qDebug() << "Saved cookies: " << jar->getAllCookies();
}
qDebug() << "Network reply: " << reply->errorString() << reply->error() << reply->request().url();
}

Answer 1

You will need to subclass QNetworkCookieJar and in that class you should implement your own persistent storage.
class MyNetworkCookieJar : public QNetworkCookieJar {
public:
bool saveCookiesToDisk() {
// .. my implementation
return true; // if i did
}
bool loadCookiesFromDisk() {
// .. load from disk
return false; // if unable to.
}
}
The sample application from Qt project implements a persistent cookie store, it could be a good starting point for you: http://qt.gitorious.org/qt/qt/trees/4.8/demos/browser
look at cookiejar.h and cookiejar.cpp

Answer 2

Base of qt example, http://qt.gitorious.org/qt/qt/trees/4.8/demos/browser, i wrote this class that save and use one cookie for me. Perhaps it helps you too. Note that it just save one cookie and not list of cookies.
#include "cookiejar.h"
CookieJar::CookieJar(QObject *parent)
: QNetworkCookieJar(parent)
, m_loaded(false)
{
}
void CookieJar::load()
{
if (m_loaded)
return;
QSettings settings;
settings.beginGroup(QLatin1String("cookies"));
QList<QNetworkCookie> savedCookies = QNetworkCookie::parseCookies(settings.value("cookies").toByteArray());
for (int j = 0; j < savedCookies.count(); j++)
insertCookie(savedCookies.at(j));
m_loaded = true;
emit cookiesChanged();
}
void CookieJar::save()
{
if (!m_loaded)
return;
QList<QNetworkCookie> cookies = allCookies();
QSettings settings;
settings.beginGroup(QLatin1String("cookies"));
settings.setValue("cookies", cookies[0].toRawForm());
}
QList<QNetworkCookie> CookieJar::cookiesForUrl(const QUrl &url) const
{
// This function is called by the default QNetworkAccessManager::createRequest(),
// which adds the cookies returned by this function to the request being sent.
CookieJar *that = const_cast<CookieJar*>(this);
if (!m_loaded)
that->load();
return QNetworkCookieJar::cookiesForUrl(url);
}
bool CookieJar::setCookiesFromUrl(const QList<QNetworkCookie> &cookieList, const QUrl &url)
{
if (!m_loaded)
load();
QNetworkCookieJar::setCookiesFromUrl(cookieList, url);
save(); //Save cookie permanently in setting file.
emit cookiesChanged();
return true;
}

Answer 3

#Musa's answer is good but it only saves one cookie. I recommend using the Qt folk's implementation from the old qmlviewer located here: http://code.qt.io/cgit/qt/qt.git/tree/tools/qml/qmlruntime.cpp?h=4.7#n438
Here's the code:
class PersistentCookieJar : public QNetworkCookieJar {
public:
PersistentCookieJar(QObject *parent) : QNetworkCookieJar(parent) { load(); }
~PersistentCookieJar() { save(); }
virtual QList<QNetworkCookie> cookiesForUrl(const QUrl &url) const
{
QMutexLocker lock(&mutex);
return QNetworkCookieJar::cookiesForUrl(url);
}
virtual bool setCookiesFromUrl(const QList<QNetworkCookie> &cookieList, const QUrl &url)
{
QMutexLocker lock(&mutex);
return QNetworkCookieJar::setCookiesFromUrl(cookieList, url);
}
private:
void save()
{
QMutexLocker lock(&mutex);
QList<QNetworkCookie> list = allCookies();
QByteArray data;
foreach (QNetworkCookie cookie, list) {
if (!cookie.isSessionCookie()) {
data.append(cookie.toRawForm());
data.append("\n");
}
}
QSettings settings;
settings.setValue("Cookies",data);
}
void load()
{
QMutexLocker lock(&mutex);
QSettings settings;
QByteArray data = settings.value("Cookies").toByteArray();
setAllCookies(QNetworkCookie::parseCookies(data));
}
mutable QMutex mutex;
};