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# TQFtp Class Reference
[network module]

The TQFtp class provides an implementation of the FTP protocol. More...

`#include <ntqftp.h>`

Inherits TQNetworkProtocol.

List of all member functions.

## Public Members

- TQFtp ()
- TQFtp ( TQObject * parent, const char * name = 0 )
- virtual ~TQFtp ()
- 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 TQString & host, TQ_UINT16 port = 21 )
- int login ( const TQString & user = TQString::null, const TQString & password = TQString::null )
- int close ()
- int list ( const TQString & dir = TQString::null )
- int cd ( const TQString & dir )
- int get ( const TQString & file, TQIODevice * dev = 0 )
- int put ( const TQByteArray & data, const TQString & file )
- int put ( TQIODevice * dev, const TQString & file )
- int remove ( const TQString & file )
- int mkdir ( const TQString & dir )
- int rmdir ( const TQString & dir )
- int rename ( const TQString & oldname, const TQString & newname )
- int rawCommand ( const TQString & command )
- TQ_ULONG bytesAvailable () const
- TQ_LONG readBlock ( char * data, TQ_ULONG maxlen )
- TQByteArray readAll ()
- int currentId () const
- TQIODevice * currentDevice () const
- Command currentCommand () const
- bool hasPendingCommands () const
- void clearPendingCommands ()
- State state () const
- Error error () const
- TQString errorString () const

## Public Slots

- void abort ()

## Signals

- void stateChanged ( int state )
- void listInfo ( const TQUrlInfo & i )
- void readyRead ()
- void dataTransferProgress ( int done, int total )
- void rawCommandReply ( int replyCode, const TQString & detail )
- void commandStarted ( int id )
- void commandFinished ( int id, bool error )
- void done ( bool error )

## Detailed Description

The TQFtp class provides an implementation of the FTP protocol.

This class provides two different interfaces: one is the TQNetworkProtocol interface that allows you to use FTP through the TQUrlOperator 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 TQFtp with the TQNetworkProtocol interface, you do not use it directly, but rather through a TQUrlOperator, for example:

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

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

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:

        TQFtp *ftp = new TQFtp( this ); // this is an optional TQObject 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 TQUrlOperator() 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 TQt Network Documentation, TQNetworkProtocol, TQUrlOperator, TQHttp, and Input/Output and Networking.

## Member Type Documentation

### TQFtp::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.

- `TQFtp::None` - No command is being executed.
- `TQFtp::ConnectToHost` - connectToHost() is being executed.
- `TQFtp::Login` - login() is being executed.
- `TQFtp::Close` - close() is being executed.
- `TQFtp::List` - list() is being executed.
- `TQFtp::Cd` - cd() is being executed.
- `TQFtp::Get` - get() is being executed.
- `TQFtp::Put` - put() is being executed.
- `TQFtp::Remove` - remove() is being executed.
- `TQFtp::Mkdir` - mkdir() is being executed.
- `TQFtp::Rmdir` - rmdir() is being executed.
- `TQFtp::Rename` - rename() is being executed.
- `TQFtp::RawCommand` - rawCommand() is being executed.

See also currentCommand().

### TQFtp::Error

This enum identifies the error that occurred.

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

See also error().

### TQFtp::State

This enum defines the connection state:

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

### TQFtp::TQFtp ()

Constructs a TQFtp object.

### TQFtp::TQFtp ( TQObject * parent, const char * name = 0 )

Constructs a TQFtp object. The parent and name parameters are passed to the TQObject constructor.

### TQFtp::~TQFtp ()`[virtual]`

Destructor.

### void TQFtp::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.

### TQ_ULONG TQFtp::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 TQFtp::cd ( const TQString & 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 TQFtp::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 TQFtp::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 TQFtp::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 TQFtp::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 TQFtp::connectToHost ( const TQString & host, TQ_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 TQFtp::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.

### TQIODevice * TQFtp::currentDevice () const

Returns the TQIODevice 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 TQIODevice in the slot connected to the commandFinished() signal.

See also get() and put().

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

### int TQFtp::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 TQFtp::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 TQFtp 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 TQProgressBar, 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 TQProgressBar::progress.

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

### void TQFtp::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 TQFtp::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.

### TQString TQFtp::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 TQt, the string has already passed through tr().

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

### int TQFtp::get ( const TQString & file, TQIODevice * 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 readBlock() 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 TQFtp::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 TQFtp::list ( const TQString & dir = TQString::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 TQFtp::listInfo ( const TQUrlInfo & 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 TQFtp::login ( const TQString & user = TQString::null, const TQString & password = TQString::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 TQFtp::mkdir ( const TQString & 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 TQFtp::put ( TQIODevice * dev, const TQString & 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 TQFtp::put ( const TQByteArray & data, const TQString & 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 TQFtp::rawCommand ( const TQString & 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 TQFtp 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 TQFtp::rawCommandReply ( int replyCode, const TQString & 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.

### TQByteArray TQFtp::readAll ()

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

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

### TQ_LONG TQFtp::readBlock ( char * data, TQ_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 TQFtp::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 TQFtp::remove ( const TQString & 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 TQFtp::rename ( const TQString & oldname, const TQString & 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 TQFtp::rmdir ( const TQString & 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 TQFtp::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 TQFtp::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.

This file is part of the TQt toolkit. Copyright © 1995-2007 Trolltech. All Rights Reserved.