limit directory traversal in QFileDialog - qt

Question

I'm using QFileDialog to select a directory. I'm having an issue that I'm unable to resolve. I've spent a lot of time googling for this but have come up with zilch.
I specify the starting directory (say /home/dhoti/downloads) and I want to disable navigation above this directory. For example the user should not be allowed to go to /home/dhoti or /tmp etc. How do I achieve this?
Here is my code:
QFileDialog dlg(this, "Select Firmware Version");
dlg.setDirectory("/home/dhoti/downloads");
dlg.setFileMode(QFileDialog::DirectoryOnly);
dlg.setOption(QFileDialog::ReadOnly, true);
dlg.setOption(QFileDialog::HideNameFilterDetails, true);
dlg.setViewMode(QFileDialog::List);
dlg.setAcceptMode(QFileDialog::AcceptOpen);
dlg.exec();
qDebug() << "selected files: " << dlg.selectedFiles();
thanks for any help
Dhoti

Answer 1

You can detect when the current directory changes and if it is beyond your limit, set the directory back to the limit directory.
You can do this by executing the dialog non-blocking, and connecting the QFileDialog::directoryEntered(const QString& directory) signal to a slot of your own where you can do the checking. If it fails your check, set the current directory to the limit directory by QFileDialog::setDirectory(const QString& directory).
Disclaimer I have not tried this, but I'll be surprised if it does not work.

Answer 2

Try the following:
filedialog.h
#ifndef FILEDIALOG_H
#define FILEDIALOG_H
class QEvent;
#include <QFileDialog>
#include <QString>
class FileDialog : public QFileDialog
{
Q_OBJECT
public:
explicit FileDialog(QWidget *parent = 0);
public:
bool eventFilter(QObject *o, QEvent *e);
void setTopDir(const QString &path);
QString topDir() const;
private:
bool pathFits(const QString &path) const;
private slots:
void checkHistory();
void checkGoToParent();
void checkLineEdit(const QString &text);
private:
QString mtopDir;
};
#endif // FILEDIALOG_H
filedialog.cpp
#include "filedialog.h"
#include <QString>
#include <QStringList>
#include <QFileDialog>
#include <QList>
#include <QToolButton>
#include <QDir>
#include <QLineEdit>
#include <QDialogButtonBox>
#include <QEvent>
#include <QKeyEvent>
#include <QAbstractButton>
#include <QCompleter>
#include <QAbstractItemView>
#include <QFileInfo>
FileDialog::FileDialog(QWidget *parent) :
QFileDialog(parent)
{
connect(this, SIGNAL(directoryEntered(QString)), this, SLOT(checkHistory()));
connect(this, SIGNAL(directoryEntered(QString)), this, SLOT(checkGoToParent()));
connect(findChild<QToolButton *>("backButton"), SIGNAL(clicked()), this, SLOT(checkGoToParent()));
connect(findChild<QToolButton *>("forwardButton"), SIGNAL(clicked()), this, SLOT(checkGoToParent()));
connect(findChild<QLineEdit *>("fileNameEdit"), SIGNAL(textChanged(QString)), this, SLOT(checkLineEdit(QString)));
findChild<QLineEdit *>("fileNameEdit")->installEventFilter(this);
findChild<QWidget *>("listView")->installEventFilter(this);
findChild<QWidget *>("treeView")->installEventFilter(this);
findChild<QLineEdit *>("fileNameEdit")->completer()->popup()->installEventFilter(this);
setOption(DontUseNativeDialog, true);
}
bool FileDialog::eventFilter(QObject *o, QEvent *e)
{
if (e->type() != QEvent::KeyPress)
return false;
int key = static_cast<QKeyEvent *>(e)->key();
if (o->objectName() == "listView" || o->objectName() == "treeView")
{
return (Qt::Key_Backspace == key && !pathFits(directory().absolutePath()));
}
else
{
if (Qt::Key_Return != key && Qt::Key_Enter != key)
return false;
QString text = findChild<QLineEdit *>("fileNameEdit")->text();
QString path = QDir::cleanPath(directory().absolutePath() + (text.startsWith("/") ? "" : "/") + text);
bool a = QDir(text).isAbsolute();
return !((!a && pathFits(path)) || (a && pathFits(text)));
}
}
void FileDialog::setTopDir(const QString &path)
{
if (path == mtopDir)
return;
mtopDir = (!path.isEmpty() && QFileInfo(path).isDir()) ? path : QString();
if (!pathFits(path))
{
setDirectory(mtopDir);
checkHistory();
checkLineEdit(findChild<QLineEdit *>("fileNameEdit")->text());
}
else
{
QLineEdit *ledt = findChild<QLineEdit *>("fileNameEdit");
ledt->setText(ledt->text());
}
findChild<QWidget *>("lookInCombo")->setEnabled(mtopDir.isEmpty());
findChild<QWidget *>("sidebar")->setEnabled(mtopDir.isEmpty());
checkGoToParent();
}
QString FileDialog::topDir() const
{
return mtopDir;
}
bool FileDialog::pathFits(const QString &path) const
{
return mtopDir.isEmpty() || (path.startsWith(mtopDir) && path.length() > mtopDir.length());
}
void FileDialog::checkHistory()
{
QStringList list = history();
for (int i = list.size() - 1; i >= 0; --i)
if (!pathFits(list.at(i)))
list.removeAt(i);
setHistory(list);
}
void FileDialog::checkGoToParent()
{
findChild<QToolButton *>("toParentButton")->setEnabled(pathFits(directory().absolutePath()));
}
void FileDialog::checkLineEdit(const QString &text)
{
QAbstractButton *btn = findChild<QDialogButtonBox *>("buttonBox")->buttons().first();
QString path = QDir::cleanPath(directory().absolutePath() + (text.startsWith("/") ? "" : "/") + text);
bool a = QDir(text).isAbsolute();
btn->setEnabled(btn->isEnabled() && ((!a && pathFits(path)) || (a && pathFits(text))));
}
This code may look like some magic, and it's not perfect, but it works. I searched for QFileDialog child objects names in Qt sources and used
findChild()
method to access them. All you need is just use the
setTopDir()
method to specify a directory above which users are not allowed to go.
Here's an example project using this class: https://docs.google.com/file/d/0B3P3dwuDIZ1-Q19FbkFMY2puUE0/edit?usp=sharing

Answer 3

You can use the solution of #ololoepepe. And clean unwanted entries in the comboBox on the top with this:
connect(findChild<QComboBox *>("lookInCombo"), static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), this, &FileDialog::checkComboBox);
void FileDialog::checkComboBox(int index) {
int i;
QComboBox *cb = findChild<QComboBox *>("lookInCombo");
if (index == 0 && cb->model()->rowCount() > 1) {
for (i = 0; i < cb->model()->rowCount(); ++i) {
if (!pathFits(cb->model()->index(i, 0).data().toString() + "/")) {
cb->model()->removeRow(i);
--i;
}
}
}
}

Answer 4

Here is the simplest solution, with the minimum steps required to limit a directory traversal.
Idea: use public signal directoryEntered(const QString &) of QFileDialog to get notification when directory might be changed, implement slot for it in one of your classes and place there a logic for making sure that directory is the one you need.
QFileDialog dialog(this);
connect(&dialog, SIGNAL(directoryEntered(const QString &)), this, SLOT(onFileDialogDirectoryChanged(const QString &)));