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# An FTP client

This example implements a FTP client. It uses QFtp to perform its FTP commands. The GUI parts are done in the Designer.

The implementation of the FTP commands (ftpmainwindow.ui.h):

    /****************************************************************************
    ** $Id: qt/ftpmainwindow.ui.h   3.1.1   edited Aug 16 17:00 $
    **
    ** Copyright (C) 1992-2002 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    /****************************************************************************
    **
    ** ui.h extension file, included from the uic-generated form implementation.
    **
    ** The init() function is used in place of a constructor.
    ** The destroy() function is used in place of a destructor.
    ** The slots uploadFile(), downloadFile(), removeFile() and connectToHost() are
    ** connected with the resp. actions of the GUI.
    **
    *****************************************************************************/

    #include <qftp.h>
    #include <qlineedit.h>
    #include <qspinbox.h>
    #include <qstatusbar.h>
    #include <qmessagebox.h>
    #include <qfiledialog.h>
    #include <qprogressdialog.h>
    #include <qapplication.h>

    #include "connectdialog.h"
    #include "ftpviewitem.h"

    void FtpMainWindow::init()
    {
        stateFtp = new QLabel( tr("Unconnected"), statusBar() );
        statusBar()->addWidget( stateFtp, 0, TRUE );

        ftp = new QFtp( this );
        connect( ftp, SIGNAL(commandStarted(int)),
                SLOT(ftp_commandStarted()) );
        connect( ftp, SIGNAL(commandFinished(int,bool)),
                SLOT(ftp_commandFinished()) );
        connect( ftp, SIGNAL(done(bool)),
                SLOT(ftp_done(bool)) );
        connect( ftp, SIGNAL(stateChanged(int)),
                SLOT(ftp_stateChanged(int)) );
        connect( ftp, SIGNAL(listInfo(const QUrlInfo &)),
                SLOT(ftp_listInfo(const QUrlInfo &)) );
        connect( ftp, SIGNAL(rawCommandReply(int, const QString &)),
                SLOT(ftp_rawCommandReply(int, const QString &)) );
    }

    void FtpMainWindow::destroy()
    {
        if ( ftp->state() != QFtp::Unconnected )
            ftp->close();
    }

    void FtpMainWindow::uploadFile()
    {
        QString fileName = QFileDialog::getOpenFileName(
                QString::null,
                QString::null,
                this,
                "upload file dialog",
                tr("Choose a file to upload") );
        if ( fileName.isNull() )
            return;

        QFile *file = new QFile( fileName );
        if ( !file->open( IO_ReadOnly ) ) {
            QMessageBox::critical( this, tr("Upload error"),
                    tr("Can't open file '%1' for reading.").arg(fileName) );
            delete file;
            return;
        }

        QProgressDialog progress(
                tr("Uploading file..."),
                tr("Cancel"),
                0,
                this,
                "upload progress dialog",
                TRUE );
        connect( ftp, SIGNAL(dataTransferProgress(int,int)),
                &progress, SLOT(setProgress(int,int)) );
        connect( ftp, SIGNAL(commandFinished(int,bool)),
                &progress, SLOT(reset()) );
        connect( &progress, SIGNAL(cancelled()),
                ftp, SLOT(abort()) );

        QFileInfo fi( fileName );
        ftp->put( file, fi.fileName() );
        progress.exec(); // ### takes a lot of time!!!

        ftp->list();
    }

    void FtpMainWindow::downloadFile()
    {
        FtpViewItem *item = (FtpViewItem*)remoteView->selectedItem();
        if ( !item || item->isDir() )
            return;

        QString fileName = QFileDialog::getSaveFileName(
                item->text(0),
                QString::null,
                this,
                "download file dialog",
                tr("Save downloaded file as") );
        if ( fileName.isNull() )
            return;

        // create file on the heap because it has to be valid throughout the whole
        // asynchronous download operation
        QFile *file = new QFile( fileName );
        if ( !file->open( IO_WriteOnly ) ) {
            QMessageBox::critical( this, tr("Download error"),
                    tr("Can't open file '%1' for writing.").arg(fileName) );
            delete file;
            return;
        }

        QProgressDialog progress(
                tr("Downloading file..."),
                tr("Cancel"),
                0,
                this,
                "download progress dialog",
                TRUE );
        connect( ftp, SIGNAL(dataTransferProgress(int,int)),
                &progress, SLOT(setProgress(int,int)) );
        connect( ftp, SIGNAL(commandFinished(int,bool)),
                &progress, SLOT(reset()) );
        connect( &progress, SIGNAL(cancelled()),
                ftp, SLOT(abort()) );

        ftp->get( item->text(0), file );
        progress.exec(); // ### takes a lot of time!!!
    }

    void FtpMainWindow::removeFile()
    {
        FtpViewItem *item = (FtpViewItem*)remoteView->selectedItem();
        if ( !item || item->isDir() )
            return;

        ftp->remove( item->text(0) );
        ftp->list();
    }

    void FtpMainWindow::connectToHost()
    {
        ConnectDialog connectDialog;
        if ( connectDialog.exec() == QDialog::Rejected )
            return;

        remotePath->clear();
        remoteView->clear();

        if ( ftp->state() != QFtp::Unconnected )
            ftp->close();

        ftp->connectToHost( connectDialog.host->text(), connectDialog.port->value() );
        ftp->login( connectDialog.username->text(), connectDialog.password->text() );
        ftp->rawCommand( "PWD" );
        ftp->list();
    }

    // This slot is connected to the QComboBox::activated() signal of the
    // remotePath.
    void FtpMainWindow::changePath( const QString &newPath )
    {
        ftp->cd( newPath );
        ftp->rawCommand( "PWD" );
        ftp->list();
    }

    // This slot is connected to the QListView::doubleClicked() and
    // QListView::returnPressed() signals of the remoteView.
    void FtpMainWindow::changePathOrDownload( QListViewItem *item )
    {
        if ( ((FtpViewItem*)item)->isDir() )
            changePath( item->text(0) );
        else
            downloadFile();
    }

    /****************************************************************************
    **
    ** Slots connected to signals of the QFtp class
    **
    *****************************************************************************/

    void FtpMainWindow::ftp_commandStarted()
    {
        QApplication::setOverrideCursor( QCursor(Qt::WaitCursor) );
        if ( ftp->currentCommand() == QFtp::List ) {
            remoteView->clear();
            if ( currentFtpDir != "/" )
                new FtpViewItem( remoteView, FtpViewItem::Directory, "..", "", "" );
        }
    }

    void FtpMainWindow::ftp_commandFinished()
    {
        QApplication::restoreOverrideCursor();
        delete ftp->currentDevice();
    }

    void FtpMainWindow::ftp_done( bool error )
    {
        if ( error ) {
            QMessageBox::critical( this, tr("FTP Error"), ftp->errorString() );

            // If we are connected, but not logged in, it is not meaningful to stay
            // connected to the server since the error is a really fatal one (login
            // failed).
            if ( ftp->state() == QFtp::Connected )
                ftp->close();
        }
    }

    void FtpMainWindow::ftp_stateChanged( int state )
    {
        switch ( (QFtp::State)state ) {
            case QFtp::Unconnected:
                stateFtp->setText( tr("Unconnected") );
                break;
            case QFtp::HostLookup:
                stateFtp->setText( tr("Host lookup") );
                break;
            case QFtp::Connecting:
                stateFtp->setText( tr("Connecting") );
                break;
            case QFtp::Connected:
                stateFtp->setText( tr("Connected") );
                break;
            case QFtp::LoggedIn:
                stateFtp->setText( tr("Logged in") );
                break;
            case QFtp::Closing:
                stateFtp->setText( tr("Closing") );
                break;
        }
    }

    void FtpMainWindow::ftp_listInfo( const QUrlInfo &i )
    {
        FtpViewItem::Type type;
        if ( i.isDir() )
            type = FtpViewItem::Directory;
        else
            type = FtpViewItem::File;

        new FtpViewItem( remoteView, type,
                i.name(), QString::number(i.size()), i.lastModified().toString() );
    }

    void FtpMainWindow::ftp_rawCommandReply( int code, const QString &text )
    {
        if ( code == 257 ) {
            currentFtpDir = text.section( '"', 1, 1 );

            for ( int i = 0; i<remotePath->count(); i++ ) {
                // make sure that we don't insert duplicates
                if ( remotePath->text( i ) == currentFtpDir )
                    remotePath->removeItem( i );
            }
            remotePath->insertItem( currentFtpDir, 0 );
            remotePath->setCurrentItem( 0 );
        }
    }

Main (main.cpp):

    /****************************************************************************
    ** $Id: qt/main.cpp   3.1.1   edited Nov 8 10:35 $
    **
    ** Copyright (C) 1992-2002 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #include <qapplication.h>
    #include "ftpmainwindow.h"

    int main( int argc, char **argv )
    {
        QApplication a( argc, argv );

        FtpMainWindow m;
        a.setMainWidget( &m );
        m.show();
        a.processEvents();
        m.connectToHost();
        return a.exec();
    }

See also Network Examples.