Development/Tutorials/KWallet

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Abstract

A simple introduction for using the KWallet API, a secure storage framework.

Prerequisites: Basic KDE knowledge, C++.

Example

The API is fun and easy to use, and will guarantee you a long and stable life.

In KWallet, entries are organized in Folders (or think of it as categories), and in them there are binary data, maps, passwords and a catch-all unknown. Binary entries are application-specific arrays of bytes, maps should be known from QMaps, where a series of values are accessed by keys. Passwords are simply strings, and Unknown is for everything else.

dialog.cpp

#include "dialog.h"

#include <QLayout>
#include <QLabel>
#include <QPushButton>
#include <QMap>
#include <QVBoxLayout>
#include <QSpacerItem>

Dialog::Dialog(QWidget *parent) :
    QDialog(parent)
{
    setLayout(new QVBoxLayout);
    m_wallet = Wallet::openWallet(Wallet::NetworkWallet(),
                                  winId(),
                                  Wallet::Asynchronous);

    QLabel *explanation = new QLabel("<b>HELLO!</b><br/>"
                                     "Please type in something to save in the wallet!<br/>"
                                     "It will be saved in the form data folder, under <br/>"
                                     "the entry <i>http://test.com/#form</i>.");
    m_statusLabel = new QLabel("Opening wallet...", this);
    m_statusLabel->setAlignment(Qt::AlignCenter);
    m_keyInput = new QLineEdit(this);
    m_valueInput = new QLineEdit(this);
    m_launchButton = new QPushButton("Save!", this);
    m_launchButton->setDisabled(true);

    layout()->addWidget(explanation);
    qobject_cast<QVBoxLayout*>(layout())->addStretch();
    layout()->addWidget(m_statusLabel);
    layout()->addWidget(new QLabel("Key:", this));
    layout()->addWidget(m_keyInput);
    layout()->addWidget(new QLabel("Value:", this));
    layout()->addWidget(m_valueInput);
    layout()->addWidget(m_launchButton);

    connect(m_launchButton, SIGNAL(clicked()), SLOT(doSave()));
    connect(m_wallet, SIGNAL(walletOpened(bool)), SLOT(walletOpened(bool)));
    setMinimumSize(500, 200);
}

void Dialog::walletOpened(bool ok)
{

    if (ok &&
        (m_wallet->hasFolder(KWallet::Wallet::FormDataFolder()) ||
        m_wallet->createFolder(KWallet::Wallet::FormDataFolder())) &&
        m_wallet->setFolder(KWallet::Wallet::FormDataFolder())) {
        m_launchButton->setDisabled(false);
        m_statusLabel->setText("Idle.");
    } else
        m_statusLabel->setText("Error opening wallet!");

}

void Dialog::doSave()
{
    if (m_keyInput->text().isEmpty() || m_valueInput->text().isEmpty()) {
        m_statusLabel->setText("Empty field!");
        return;
    }

    m_launchButton->setDisabled(true);

    m_statusLabel->setText("Saving ...");

    QMap<QString, QString> map;
    map[m_keyInput->text()] = m_valueInput->text();
    if (m_wallet->writeMap("http://test.com/#form", map)) m_statusLabel->setText("Something went wrong!");
    else {
        m_statusLabel->setText("Saved!");
        m_keyInput->clear();
        m_valueInput->clear();
    }
    m_launchButton->setDisabled(false);
}

dialog.h

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QLabel>
#include <QLineEdit>
#include <KWallet/Wallet>

using KWallet::Wallet;

class Dialog : public QDialog
{
Q_OBJECT
public:
    Dialog(QWidget *parent = 0);

private slots:
    void doSave();
    void walletOpened(bool ok);

private:
    Wallet *m_wallet;
    QLineEdit *m_keyInput;
    QLineEdit *m_valueInput;
    QLabel *m_statusLabel;
    QPushButton *m_launchButton;
};

#endif // DIALOG_H

main.cpp

#include "dialog.h"

#include <KAboutData>
#include <KApplication>
#include <KCmdLineArgs>

static KAboutData about(
    "KWalletDemoApplication",
    "",
    ki18n("KWalletDemoApplication"),
    "1.0",
    ki18n("Demonstrates basic KWallet usage."),
    KAboutData::License_LGPL,
    ki18n("(C) 2010 Martin Sandsmark"),
    KLocalizedString(),
    "http://www.mts.ms/");

int main(int argc, char *argv[])
{
    about.addAuthor(ki18n("Martin Sandsmark"), ki18n("Maintainer"), "[email protected]", "http://iskrembilen.com/");

    KCmdLineArgs::init(argc, argv, &about);
    KApplication app;

    Dialog dialog;
    dialog.show();
    return app.exec();
}

CMakeLists.txt

project(Importer)

find_package(KDE4 REQUIRED)
add_definitions(${QT_DEFINITIONS} ${KDE4_DEFINITIONS})
include(KDE4Defaults)
include(MacroLibrary)
include_directories(${KDE4_INCLUDES} ${KDE4_INCLUDE_DIR} ${QT_INCLUDES})

set(SRCS main.cpp dialog.cpp)

kde4_add_executable(kwallet-demo ${SRCS})
target_link_libraries(kwallet-demo ${KDE4_KDECORE_LIBS} ${KDE4_KPARTS_LIBS} ${KDE4_KDEUI_LIBS})
install(TARGETS kwallet-demo ${INSTALL_TARGETS_DEFAULT_ARGS})