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):

/****************************************************************************
** $Id$
**
** 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):

/****************************************************************************
** $Id$
**
** 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.