The QFtp class provides an implementation of the client side of FTP protocol. More...

#include <qftp.h>

Inheritance diagram for QFtp:

Public Types
enum	Command { None, SetTransferMode, SetProxy, ConnectToHost, Login, Close, List, Cd, Get, Put, Remove, Mkdir, Rmdir, Rename, RawCommand }

enum	Error { NoError, UnknownError, HostNotFound, ConnectionRefused, NotConnected }

enum	State { Unconnected, HostLookup, Connecting, Connected, LoggedIn, Closing }

enum	TransferMode { Active, Passive }

enum	TransferType { Binary, Ascii }

Public Slots
void	abort ()

Signals
void	commandFinished (int, bool)

void	commandStarted (int)

void	dataTransferProgress (qint64, qint64)

void	done (bool)

void	listInfo (const QUrlInfo &)

void	rawCommandReply (int, const QString &)

void	readyRead ()

void	stateChanged (int)

Public Member Functions
qint64	bytesAvailable () const

int	cd (const QString &dir)

void	clearPendingCommands ()

int	close ()

int	connectToHost (const QString &host, quint16 port=21)

Command	currentCommand () const

QIODevice *	currentDevice () const

int	currentId () const

Error	error () const

QString	errorString () const

int	get (const QString &file, QIODevice *dev=0, TransferType type=Binary)

bool	hasPendingCommands () const

int	list (const QString &dir=QString())

int	login (const QString &user=QString(), const QString &password=QString())

int	mkdir (const QString &dir)

int	put (const QByteArray &data, const QString &file, TransferType type=Binary)

int	put (QIODevice *dev, const QString &file, TransferType type=Binary)

	QFtp (QObject *parent=0)

int	rawCommand (const QString &command)

qint64	read (char *data, qint64 maxlen)

QByteArray	readAll ()

int	remove (const QString &file)

int	rename (const QString &oldname, const QString &newname)

int	rmdir (const QString &dir)

int	setProxy (const QString &host, quint16 port)

int	setTransferMode (TransferMode mode)

State	state () const

virtual	~QFtp ()

Private Member Functions
void	_q_piConnectState (int)

void	_q_piError (int, const QString &)

void	_q_piFinished (const QString &)

void	_q_piFtpReply (int, const QString &)

void	_q_startNextCommand ()

Private Attributes
QScopedPointer< QFtpPrivate >	d

Detailed Description

The QFtp class provides an implementation of the client side of FTP protocol.

QtNetwork

This class provides a direct interface to FTP that allows you to have more control over the requests. However, for new applications, it is recommended to use QNetworkAccessManager and QNetworkReply, as those classes possess a simpler, yet more powerful API.

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:

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 the Qt FTP server, you would write this:

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

The dataTransferProgress() signal in the above example is useful if you want to show a progress bar 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 read() or readAll() function.

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

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

For file transfer, QFtp can use both active or passive mode, and it uses passive file transfer mode by default; see the documentation for setTransferMode() for more details about this.

Call setProxy() to make QFtp connect via an FTP proxy server.

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.

If you are an experienced network programmer and want to have complete control you can use rawCommand() to execute arbitrary FTP commands.

Warning: The current version of QFtp doesn't fully support non-Unix FTP servers.

See also: QNetworkAccessManager, QNetworkRequest, QNetworkReply, {FTP Example}

Member Enumeration Documentation

enum 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.

None No command is being executed. SetTransferMode set the transfer mode. SetProxy switch proxying on or off. ConnectToHost connectToHost() is being executed. Login login() is being executed. Close close() is being executed. List list() is being executed. Cd cd() is being executed. Get get() is being executed. Put put() is being executed. Remove remove() is being executed. Mkdir mkdir() is being executed. Rmdir rmdir() is being executed. Rename rename() is being executed. RawCommand rawCommand() is being executed.

See also: currentCommand()

Enumerator
None
SetTransferMode
SetProxy
ConnectToHost
Login
Close
List
Cd
Get
Put
Remove
Mkdir
Rmdir
Rename
RawCommand

enum QFtp::Error

This enum identifies the error that occurred.

NoError No error occurred. HostNotFound The host name lookup failed. ConnectionRefused The server refused the connection. NotConnected Tried to send a command, but there is no connection to a server. UnknownError An error other than those specified above occurred.

See also: error()

Enumerator
NoError
UnknownError
HostNotFound
ConnectionRefused
NotConnected

enum QFtp::State

This enum defines the connection state:

Unconnected There is no connection to the host. HostLookup A host name lookup is in progress. Connecting An attempt to connect to the host is in progress. Connected Connection to the host has been achieved. LoggedIn Connection and user login have been achieved. 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() state()

Enumerator
Unconnected
HostLookup
Connecting
Connected
LoggedIn
Closing

enum QFtp::TransferMode

FTP works with two socket connections; one for commands and another for transmitting data. While the command connection is always initiated by the client, the second connection can be initiated by either the client or the server.

This enum defines whether the client (Passive mode) or the server (Active mode) should set up the data connection.

Passive The client connects to the server to transmit its data.

Active The server connects to the client to transmit its data.

Enumerator
Active
Passive

enum QFtp::TransferType

This enum identifies the data transfer type used with get and put commands.

Binary The data will be transferred in Binary mode.

Ascii The data will be transferred in Ascii mode and new line characters will be converted to the local format.

Enumerator
Binary
Ascii

Constructor & Destructor Documentation

QFtp::QFtp ( QObject * parent = 0 )

explicit

Constructs a QFtp object with the given parent.

References _q_piConnectState(), _q_piError(), _q_piFinished(), _q_piFtpReply(), connect(), d, dataTransferProgress(), error(), listInfo(), and readyRead().

QFtp::~QFtp ( )

virtual

Destructor.

References abort(), and close().

Member Function Documentation

void QFtp::_q_piConnectState ( int a )

private

References d.

Referenced by QFtp().

void QFtp::_q_piError	(	int	a,
		const QString &	b
	)

private

References d.

Referenced by QFtp().

void QFtp::_q_piFinished ( const QString & a )

private

References d.

Referenced by QFtp().

void QFtp::_q_piFtpReply	(	int	a,
		const QString &	b
	)

private

References d.

Referenced by QFtp().

void QFtp::_q_startNextCommand ( )

private

References d.

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()

References clearPendingCommands(), and d.

Referenced by ~QFtp().

qint64 QFtp::bytesAvailable ( ) const

Returns the number of bytes that can be read from the data socket at the moment.

See also: get() readyRead() read() readAll()

References d.

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() commandFinished()

References Cd, and d.

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 as well, use abort().

See also: hasPendingCommands() abort()

References d.

Referenced by 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() commandFinished()

References Close, and d.

Referenced by ~QFtp().

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() errorString()

void QFtp::commandStarted ( int id )

signal

This signal is emitted when processing the command identified by id starts.

See also: commandFinished() done()

int QFtp::connectToHost	(	const QString &	host,
		quint16	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() commandFinished()

References ConnectToHost, and d.

QFtp::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()

References d, and None.

Referenced by KvsObject_ftp::slotCommandFinished().

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() put()

References c, d, QFtpCommand::data, QFtpCommand::dev, and QFtpCommand::is_ba.

Referenced by KvsObject_ftp::slotCommandFinished().

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()

References d.

void QFtp::dataTransferProgress	(	qint64	done,
		qint64	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(), QProgressBar

Referenced by QFtp().

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() errorString()

QFtp::Error QFtp::error ( ) const

Returns the last error that occurred. This is useful to find out what went 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.

References d.

Referenced by QFtp().

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().

References d.

Referenced by KvsObject_ftp::slotCommandFinished().

int QFtp::get	(	const QString &	file,
		QIODevice *	dev = `0`,
		TransferType	type = `Binary`
	)

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 read() 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 read() 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 data is transferred as Binary or Ascii depending on the value of type.

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() commandFinished()

References Binary, d, Get, and Passive.

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() currentCommand()

References d.

int QFtp::list ( const QString & dir = QString() )

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() commandFinished()

References d, List, and Passive.

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()

Referenced by QFtp().

int QFtp::login	(	const QString &	user = `QString()`,
		const QString &	password = `QString()`
	)

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() commandFinished()

References d, and Login.

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() commandFinished()

References d, and Mkdir.

int QFtp::put	(	const QByteArray &	data,
		const QString &	file,
		TransferType	type = `Binary`
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

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

The data is transferred as Binary or Ascii depending on the value of type.

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.

Since this function takes a copy of the data, you can discard your own copy when this function returns.

See also: dataTransferProgress() commandStarted() commandFinished()

References Binary, d, Passive, and Put.

int QFtp::put	(	QIODevice *	dev,
		const QString &	file,
		TransferType	type = `Binary`
	)

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.

The data is transferred as Binary or Ascii depending on the value of type.

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).

References Binary, d, Passive, and Put.

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() commandFinished()

References d, and RawCommand.

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()

qint64 QFtp::read	(	char *	data,
		qint64	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() readAll()

References d.

QByteArray QFtp::readAll ( )

Reads all the bytes available from the data socket and returns them.

See also: get() readyRead() bytesAvailable() read()

References d.

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 read() 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() read() readAll() bytesAvailable()

Referenced by QFtp().

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() commandFinished()

References d, and Remove.

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() commandFinished()

References d, and Rename.

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() commandFinished()

References d, and Rmdir.

int QFtp::setProxy	(	const QString &	host,
		quint16	port
	)

Enables use of the FTP proxy on host host and port port. Calling this function with host empty disables proxying.

QFtp does not support FTP-over-HTTP proxy servers. Use QNetworkAccessManager for this.

References d, and SetProxy.

int QFtp::setTransferMode ( TransferMode mode )

Sets the current FTP transfer mode to mode. The default is QFtp::Passive.

See also: QFtp::TransferMode

References d, and SetTransferMode.

QFtp::State QFtp::state ( ) const

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

See also: State stateChanged()

References d.

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() State

Member Data Documentation

QScopedPointer<QFtpPrivate> QFtp::d

private

The documentation for this class was generated from the following files:

src/modules/objects/qtftp/qftp.h
src/modules/objects/qtftp/qftp.cpp

Public Types

Public Slots

Signals

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation