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RedHat 9 (Linux i386) - man page for qftp (redhat section 3qt)

QFtp(3qt)										QFtp(3qt)

NAME
       QFtp - Implementation of the FTP protocol

SYNOPSIS
       #include <qftp.h>

       Inherits QNetworkProtocol.

   Public Members
       QFtp ()
       QFtp ( QObject * parent, const char * name = 0 )
       virtual ~QFtp ()
       enum State { Unconnected, HostLookup, Connecting, Connected, LoggedIn, Closing }
       enum Error { NoError, UnknownError, HostNotFound, ConnectionRefused, NotConnected }
       enum Command { None, ConnectToHost, Login, Close, List, Cd, Get, Put, Remove, Mkdir,
	   Rmdir, Rename, RawCommand }
       int connectToHost ( const QString & host, Q_UINT16 port = 21 )
       int login ( const QString & user = QString::null, const QString & password = QString::null
	   )
       int close ()
       int list ( const QString & dir = QString::null )
       int cd ( const QString & dir )
       int get ( const QString & file, QIODevice * dev = 0 )
       int put ( const QByteArray & data, const QString & file )
       int put ( QIODevice * dev, const QString & file )
       int remove ( const QString & file )
       int mkdir ( const QString & dir )
       int rmdir ( const QString & dir )
       int rename ( const QString & oldname, const QString & newname )
       int rawCommand ( const QString & command )
       Q_ULONG bytesAvailable () const
       Q_LONG readBlock ( char * data, Q_ULONG maxlen )
       QByteArray readAll ()
       int currentId () const
       QIODevice * currentDevice () const
       Command currentCommand () const
       bool hasPendingCommands () const
       void clearPendingCommands ()
       State state () const
       Error error () const
       QString errorString () const

   Public Slots
       void abort ()

   Signals
       void stateChanged ( int state )
       void listInfo ( const QUrlInfo & i )
       void readyRead ()
       void dataTransferProgress ( int done, int total )
       void rawCommandReply ( int replyCode, const QString & detail )
       void commandStarted ( int id )
       void commandFinished ( int id, bool error )
       void done ( bool error )

DESCRIPTION
       The QFtp class provides an implementation of the FTP protocol.

       This class provides two different interfaces: one is the QNetworkProtocol interface that
       allows you to use FTP through the QUrlOperator abstraction. The other is a direct
       interface to FTP that gives you lower-level access to the FTP protocol for finer control.
       Using the direct interface you can also execute arbitrary FTP commands.

       Don't mix the two interfaces, since the behavior is not well-defined.

       If you want to use QFtp with the QNetworkProtocol interface, you do not use it directly,
       but rather through a QUrlOperator, for example:

	   QUrlOperator op( "ftp://ftp.trolltech.com" );
	   op.listChildren(); // Asks the server to provide a directory listing

       This code will only work if the QFtp class is registered; to register the class, you must
       call qInitNetworkProtocols() before using a QUrlOperator with QFtp.

       The rest of this descrption describes the direct interface to FTP.

       The class works asynchronously, so there are no blocking functions. If an operation cannot
       be executed immediately, the function will still return straight away and the operation
       will be scheduled for later execution. The results of scheduled operations are reported
       via signals. This approach depends on the event loop being in operation.

       The operations that can be scheduled (they are called "commands" in the rest of the
       documentation) are the following: connectToHost(), login(), close(), list(), cd(), get(),
       put(), remove(), mkdir(), rmdir(), rename() and rawCommand().

       All of these commands return a unique identifier that allows you to keep track of the
       command that is currently being executed. When the execution of a command starts, the
       commandStarted() signal with the command's identifier is emitted. When the command is
       finished, the commandFinished() signal is emitted with the command's identifier and a bool
       that indicates whether the command finished with an error.

       In some cases, you might want to execute a sequence of commands, e.g. if you want to
       connect and login to a FTP server. This is simply achieved:

	   QFtp *ftp = new QFtp( this ); // this is an optional QObject parent
	   ftp->connectToHost( "ftp.trolltech.com" );
	   ftp->login();

       In this case two FTP commands have been scheduled. When the last scheduled command has
       finished, a done() signal is emitted with a bool argument that tells you whether the
       sequence finished with an error.

       If an error occurs during the execution of one of the commands in a sequence of commands,
       all the pending commands (i.e. scheduled, but not yet executed commands) are cleared and
       no signals are emitted for them.

       Some commands, e.g. list(), emit additional signals to report their results.

       Example: If you want to download the INSTALL file from Trolltech's FTP server, you would
       write this:

	   ftp->connectToHost( "ftp.trolltech.com" );  // id == 1
	   ftp->login();			       // id == 2
	   ftp->cd( "qt" );			       // id == 3
	   ftp->get( "INSTALL" );		       // id == 4
	   ftp->close();			       // id == 5

       For this example the following sequence of signals is emitted (with small variations,
       depending on network traffic, etc.):

	   start( 1 )
	   stateChanged( HostLookup )
	   stateChanged( Connecting )
	   stateChanged( Connected )
	   finished( 1, FALSE )
	   start( 2 )
	   stateChanged( LoggedIn )
	   finished( 2, FALSE )
	   start( 3 )
	   finished( 3, FALSE )
	   start( 4 )
	   dataTransferProgress( 0, 3798 )
	   dataTransferProgress( 2896, 3798 )
	   readyRead()
	   dataTransferProgress( 3798, 3798 )
	   readyRead()
	   finished( 4, FALSE )
	   start( 5 )
	   stateChanged( Closing )
	   stateChanged( Unconnected )
	   finished( 5, FALSE )
	   done( FALSE )

       The dataTransferProgress() signal in the above example is useful if you want to show a
       progressbar to inform the user about the progress of the download. The readyRead() signal
       tells you that there is data ready to be read. The amount of data can be queried then with
       the bytesAvailable() function and it can be read with the readBlock() or readAll()
       function.

       If the login fails for the above example, the signals would look like this:

	   start( 1 )
	   stateChanged( HostLookup )
	   stateChanged( Connecting )
	   stateChanged( Connected )
	   finished( 1, FALSE )
	   start( 2 )
	   finished( 2, TRUE )
	   done( TRUE )

       You can then get details about the error with the error() and errorString() functions.

       The functions currentId() and currentCommand() provide more information about the
       currently executing command.

       The functions hasPendingCommands() and clearPendingCommands() allow you to query and clear
       the list of pending commands.

       The safest and easiest way to use the FTP protocol is to use QUrlOperator() or the FTP
       commands described above. If you are an experienced network programmer and want to have
       complete control you can use rawCommand() to execute arbitrary FTP commands.

       See also Qt Network Documentation, QNetworkProtocol, QUrlOperator, QHttp, and Input/Output
       and Networking.

   Member Type Documentation
QFtp::Command
       This enum is used as the return value for the currentCommand() function. This allows you
       to perform specific actions for particular commands, e.g. in a FTP client, you might want
       to clear the directory view when a list() command is started; in this case you can simply
       check in the slot connected to the start() signal if the currentCommand() is List.

       QFtp::None - No command is being executed.

       QFtp::ConnectToHost - connectToHost() is being executed.

       QFtp::Login - login() is being executed.

       QFtp::Close - close() is being executed.

       QFtp::List - list() is being executed.

       QFtp::Cd - cd() is being executed.

       QFtp::Get - get() is being executed.

       QFtp::Put - put() is being executed.

       QFtp::Remove - remove() is being executed.

       QFtp::Mkdir - mkdir() is being executed.

       QFtp::Rmdir - rmdir() is being executed.

       QFtp::Rename - rename() is being executed.

       QFtp::RawCommand - rawCommand() is being executed.

       See also currentCommand().

QFtp::Error
       This enum identifies the error that occurred.

       QFtp::NoError - No error occurred.

       QFtp::HostNotFound - The host name lookup failed.

       QFtp::ConnectionRefused - The server refused the connection.

       QFtp::NotConnected - Tried to send a command, but there is no connection to a server.

       QFtp::UnknownError - An error other than those specified above occurred.

       See also error().

QFtp::State
       This enum defines the connection state:

       QFtp::Unconnected - There is no connection to the host.

       QFtp::HostLookup - A host name lookup is in progress.

       QFtp::Connecting - An attempt to connect to the host is in progress.

       QFtp::Connected - Connection to the host has been achieved.

       QFtp::LoggedIn - Connection and user login have been achieved.

       QFtp::Closing - The connection is closing down, but it is not yet closed. (The state will
       be Unconnected when the connection is closed.)

       See also stateChanged() and state().

MEMBER FUNCTION DOCUMENTATION
QFtp::QFtp ()
       Constructs a QFtp object.

QFtp::QFtp ( QObject * parent, const char * name = 0 )
       Constructs a QFtp object. The parent and name parameters are passed to the QObject
       constructor.

QFtp::~QFtp () [virtual]
       Destructor.

void QFtp::abort () [slot]
       Aborts the current command and deletes all scheduled commands.

       If there is an unfinished command (i.e. a command for which the commandStarted() signal
       has been emitted, but for which the commandFinished() signal has not been emitted), this
       function sends an ABORT command to the server. When the server replies that the command is
       aborted, the commandFinished() signal with the error argument set to TRUE is emitted for
       the command. Due to timing issues, it is possible that the command had already finished
       before the abort request reached the server, in which case, the commandFinished() signal
       is emitted with the error argument set to FALSE.

       For all other commands that are affected by the abort(), no signals are emitted.

       If you don't start further FTP commands directly after the abort(), there won't be any
       scheduled commands and the done() signal is emitted.

       Warning: Some FTP servers, for example the BSD FTP daemon (version 0.3), wrongly return a
       positive reply even when an abort has occurred. For these servers the commandFinished()
       signal has its error flag set to FALSE, even though the command did not complete
       successfully.

       See also clearPendingCommands().

       Example: network/ftpclient/ftpmainwindow.ui.h.

Q_ULONG QFtp::bytesAvailable () const
       Returns the number of bytes that can be read from the data socket at the moment.

       See also get(), readyRead(), readBlock(), and readAll().

int QFtp::cd ( const QString & dir )
       Changes the working directory of the server to dir.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::clearPendingCommands ()
       Deletes all pending commands from the list of scheduled commands. This does not affect the
       command that is being executed. If you want to stop this this as well, use abort().

       See also hasPendingCommands() and abort().

int QFtp::close ()
       Closes the connection to the FTP server.

       The stateChanged() signal is emitted when the state of the connecting process changes,
       e.g. to Closing, then Unconnected.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also stateChanged(), commandStarted(), and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::commandFinished ( int id, bool error ) [signal]
       This signal is emitted when processing the command identified by id has finished. error is
       TRUE if an error occurred during the processing; otherwise error is FALSE.

       See also commandStarted(), done(), error(), and errorString().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::commandStarted ( int id ) [signal]
       This signal is emitted when processing the command identified by id starts.

       See also commandFinished() and done().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::connectToHost ( const QString & host, Q_UINT16 port = 21 )
       Connects to the FTP server host using port port.

       The stateChanged() signal is emitted when the state of the connecting process changes,
       e.g. to HostLookup, then Connecting, then Connected.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also stateChanged(), commandStarted(), and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

Command QFtp::currentCommand () const
       Returns the command type of the FTP command being executed or None if there is no command
       being executed.

       See also currentId().

       Example: network/ftpclient/ftpmainwindow.ui.h.

QIODevice * QFtp::currentDevice () const
       Returns the QIODevice pointer that is used by the FTP command to read data from or store
       data to. If there is no current FTP command being executed or if the command does not use
       an IO device, this function returns 0.

       This function can be used to delete the QIODevice in the slot connected to the
       commandFinished() signal.

       See also get() and put().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::currentId () const
       Returns the identifier of the FTP command that is being executed or 0 if there is no
       command being executed.

       See also currentCommand().

void QFtp::dataTransferProgress ( int done, int total ) [signal]
       This signal is emitted in response to a get() or put() request to indicate the current
       progress of the download or upload.

       done is the amount of data that has already been transferred and total is the total amount
       of data to be read or written. It is possible that the QFtp class is not able to determine
       the total amount of data that should be transferred, in which case total is 0. (If you
       connect this signal to a QProgressBar, the progress bar shows a busy indicator if the
       total is 0).

       Warning: done and total are not necessarily the size in bytes, since for large files these
       values might need to be" scaled" to avoid overflow.

       See also get(), put(), and QProgressBar::progress.

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::done ( bool error ) [signal]
       This signal is emitted when the last pending command has finished; (it is emitted after
       the last command's commandFinished() signal). error is TRUE if an error occurred during
       the processing; otherwise error is FALSE.

       See also commandFinished(), error(), and errorString().

       Example: network/ftpclient/ftpmainwindow.ui.h.

Error QFtp::error () const
       Returns the last error that occurred. This is useful to find out what when wrong when
       receiving a commandFinished() or a done() signal with the error argument set to TRUE.

       If you start a new command, the error status is reset to NoError.

QString QFtp::errorString () const
       Returns a human-readable description of the last error that occurred. This is useful for
       presenting a error message to the user when receiving a commandFinished() or a done()
       signal with the error argument set to TRUE.

       The error string is often (but not always) the reply from the server, so it is not always
       possible to translate the string. If the message comes from Qt, the string has already
       passed through tr().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::get ( const QString & file, QIODevice * dev = 0 )
       Downloads the file file from the server.

       If dev is 0, then the readyRead() signal is emitted when there is data available to read.
       You can then read the data with the readBlock() or readAll() functions.

       If dev is not 0, the data is written directly to the device dev. Make sure that the dev
       pointer is valid for the duration of the operation (it is safe to delete it when the
       commandFinished() signal is emitted). In this case the readyRead() signal is not emitted
       and you cannot read data with the readBlcok or readAll() functions.

       If you don't read the data immediately it becomes available, i.e. when the readyRead()
       signal is emitted, it is still available until the next command is started.

       For example, if you want to present the data to the user as soon as there is something
       available, connect to the readyRead() signal and read the data immediately. On the other
       hand, if you only want to work with the complete data, you can connect to the
       commandFinished() signal and read the data when the get() command is finished.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also readyRead(), dataTransferProgress(), commandStarted(), and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

bool QFtp::hasPendingCommands () const
       Returns TRUE if there are any commands scheduled that have not yet been executed;
       otherwise returns FALSE.

       The command that is being executed is not considered as a scheduled command.

       See also clearPendingCommands(), currentId(), and currentCommand().

int QFtp::list ( const QString & dir = QString::null )
       Lists the contents of directory dir on the FTP server. If dir is empty, it lists the
       contents of the current directory.

       The listInfo() signal is emitted for each directory entry found.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also listInfo(), commandStarted(), and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::listInfo ( const QUrlInfo & i ) [signal]
       This signal is emitted for each directory entry the list() command finds. The details of
       the entry are stored in i.

       See also list().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::login ( const QString & user = QString::null, const QString & password = QString::null
       )
       Logs in to the FTP server with the username user and the password password.

       The stateChanged() signal is emitted when the state of the connecting process changes,
       e.g. to LoggedIn.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::mkdir ( const QString & dir )
       Creates a directory called dir on the server.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

int QFtp::put ( QIODevice * dev, const QString & file )
       Reads the data from the IO device dev, and writes it to the file called file on the
       server. The data is read in chunks from the IO device, so this overload allows you to
       transmit large amounts of data without the need to read all the data into memory at once.

       Make sure that the dev pointer is valid for the duration of the operation (it is safe to
       delete it when the commandFinished() is emitted).

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::put ( const QByteArray & data, const QString & file )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Writes the data data to the file called file on the server. The progress of the upload is
       reported by the dataTransferProgress() signal.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also dataTransferProgress(), commandStarted(), and commandFinished().

int QFtp::rawCommand ( const QString & command )
       Sends the raw FTP command command to the FTP server. This is useful for low-level FTP
       access. If the operation you wish to perform has an equivalent QFtp function, we recommend
       using the function instead of raw FTP commands since the functions are easier and safer.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also rawCommandReply(), commandStarted(), and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::rawCommandReply ( int replyCode, const QString & detail ) [signal]
       This signal is emitted in response to the rawCommand() function. replyCode is the 3 digit
       reply code and detail is the text that follows the reply code.

       See also rawCommand().

       Example: network/ftpclient/ftpmainwindow.ui.h.

QByteArray QFtp::readAll ()
       Reads all the bytes available from the data socket and returns them.

       See also get(), readyRead(), bytesAvailable(), and readBlock().

Q_LONG QFtp::readBlock ( char * data, Q_ULONG maxlen )
       Reads maxlen bytes from the data socket into data and returns the number of bytes read.
       Returns -1 if an error occurred.

       See also get(), readyRead(), bytesAvailable(), and readAll().

void QFtp::readyRead () [signal]
       This signal is emitted in response to a get() command when there is new data to read.

       If you specify a device as the second argument in the get() command, this signal is not
       emitted; instead the data is written directly to the device.

       You can read the data with the readAll() or readBlock() functions.

       This signal is useful if you want to process the data in chunks as soon as it becomes
       available. If you are only interested in the complete data, just connect to the
       commandFinished() signal and read the data then instead.

       See also get(), readBlock(), readAll(), and bytesAvailable().

int QFtp::remove ( const QString & file )
       Deletes the file called file from the server.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

       Example: network/ftpclient/ftpmainwindow.ui.h.

int QFtp::rename ( const QString & oldname, const QString & newname )
       Renames the file called oldname to newname on the server.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

int QFtp::rmdir ( const QString & dir )
       Removes the directory called dir from the server.

       The function does not block and returns immediately. The command is scheduled, and its
       execution is performed asynchronously. The function returns a unique identifier which is
       passed by commandStarted() and commandFinished().

       When the command is started the commandStarted() signal is emitted. When it is finished
       the commandFinished() signal is emitted.

       See also commandStarted() and commandFinished().

State QFtp::state () const
       Returns the current state of the object. When the state changes, the stateChanged() signal
       is emitted.

       See also State and stateChanged().

       Example: network/ftpclient/ftpmainwindow.ui.h.

void QFtp::stateChanged ( int state ) [signal]
       This signal is emitted when the state of the connection changes. The argument state is the
       new state of the connection; it is one of the State values.

       It is usually emitted in response to a connectToHost() or close() command, but it can also
       be emitted "spontaneously", e.g. when the server closes the connection unexpectedly.

       See also connectToHost(), close(), state(), and State.

       Example: network/ftpclient/ftpmainwindow.ui.h.

SEE ALSO
       http://doc.trolltech.com/qftp.html http://www.trolltech.com/faq/tech.html

COPYRIGHT
       Copyright 1992-2001 Trolltech AS, http://www.trolltech.com.  See the license file included
       in the distribution for a complete license statement.

AUTHOR
       Generated automatically from the source code.

BUGS
       If you find a bug in Qt, please report it as described in
       http://doc.trolltech.com/bughowto.html.	Good bug reports help us to help you. Thank you.

       The definitive Qt documentation is provided in HTML format; it is located at
       $QTDIR/doc/html and can be read using Qt Assistant or with a web browser. This man page is
       provided as a convenience for those users who prefer man pages, although this format is
       not officially supported by Trolltech.

       If you find errors in this manual page, please report them to qt-bugs@trolltech.com.
       Please include the name of the manual page (qftp.3qt) and the Qt version (3.1.1).

Trolltech AS				 9 December 2002				QFtp(3qt)


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