com.trolltech.qt.network
Class QFtp

java.lang.Object
  extended by com.trolltech.qt.QSignalEmitter
      extended by com.trolltech.qt.QtJambiObject
          extended by com.trolltech.qt.core.QObject
              extended by com.trolltech.qt.network.QFtp
All Implemented Interfaces:
QtJambiInterface

public class QFtp
extends QObject

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

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(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 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:

    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.

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. We hope to fix this in a future version of Qt.

See Also:
QHttp, Example

Nested Class Summary
static class QFtp.Command
          This enum is used as the return value for the currentCommand function.
static class QFtp.Error
          This enum identifies the error that occurred.
static class QFtp.State
          This enum defines the connection state.
static class QFtp.TransferMode
          FTP works with two socket connections; one for commands and another for transmitting data.
static class QFtp.TransferType
          This enum identifies the data transfer type used with get and put commands.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I>
 
Field Summary
 QSignalEmitter.Signal2<java.lang.Integer,java.lang.Boolean> commandFinished
          This signal is emitted when processing the command identified by arg__1 has finished.
 QSignalEmitter.Signal1<java.lang.Integer> commandStarted
          This signal is emitted when processing the command identified by arg__1 starts.
 QSignalEmitter.Signal2<java.lang.Long,java.lang.Long> dataTransferProgress
          This signal is emitted in response to a get or put request to indicate the current progress of the download or upload.
 QSignalEmitter.Signal1<java.lang.Boolean> done
          This signal is emitted when the last pending command has finished; (it is emitted after the last command's commandFinished signal).
 QSignalEmitter.Signal1<QUrlInfo> listInfo
          This signal is emitted for each directory entry the list command finds.
 QSignalEmitter.Signal2<java.lang.Integer,java.lang.String> rawCommandReply
          This signal is emitted in response to the rawCommand function.
 QSignalEmitter.Signal0 readyRead
          This signal is emitted in response to a get command when there is new data to read.
 QSignalEmitter.Signal1<java.lang.Integer> stateChanged
          This signal is emitted when the state of the connection changes.
 
Constructor Summary
QFtp()
          Equivalent to QFtp(0).
QFtp(QObject parent)
          Constructs a QFtp object with the given parent.
 
Method Summary
 void abort()
          Aborts the current command and deletes all scheduled commands.
 long bytesAvailable()
          Returns the number of bytes that can be read from the data socket at the moment.
 int cd(java.lang.String dir)
          Changes the working directory of the server to dir.
 void clearPendingCommands()
          Deletes all pending commands from the list of scheduled commands.
 int close()
          Closes the connection to the FTP server.
 int connectToHost(java.lang.String host)
          Equivalent to connectToHost(host, 21).
 int connectToHost(java.lang.String host, char port)
          Connects to the FTP server host using port port.
 QFtp.Command currentCommand()
          Returns the command type of the FTP command being executed or None if there is no command being executed.
 QIODevice currentDevice()
          Returns the QIODevice pointer that is used by the FTP command to read data from or store data to.
 int currentId()
          Returns the identifier of the FTP command that is being executed or 0 if there is no command being executed.
 QFtp.Error error()
          Returns the last error that occurred.
 java.lang.String errorString()
          Returns a human-readable description of the last error that occurred.
static QFtp fromNativePointer(QNativePointer nativePointer)
          This function returns the QFtp instance pointed to by nativePointer
 int get(java.lang.String file)
          Equivalent to get(file, 0, Binary).
 int get(java.lang.String file, QIODevice dev)
          Equivalent to get(file, dev, Binary).
 int get(java.lang.String file, QIODevice dev, QFtp.TransferType type)
          Downloads the file file from the server.
 boolean hasPendingCommands()
          Returns true if there are any commands scheduled that have not yet been executed; otherwise returns false.
 int list()
          Equivalent to list(QString()).
 int list(java.lang.String dir)
          Lists the contents of directory dir on the FTP server.
 int login()
          Equivalent to login(QString(), QString()).
 int login(java.lang.String user)
          Equivalent to login(user, QString()).
 int login(java.lang.String user, java.lang.String password)
          Logs in to the FTP server with the username user and the password password.
 int mkdir(java.lang.String dir)
          Creates a directory called dir on the server.
 int put(QByteArray data, java.lang.String file)
          Equivalent to put(data, file, Binary).
 int put(QByteArray data, java.lang.String file, QFtp.TransferType type)
          Writes a copy of the given data to the file called file on the server.
 int put(QIODevice dev, java.lang.String file)
          Equivalent to put(dev, file, Binary).
 int put(QIODevice dev, java.lang.String file, QFtp.TransferType type)
          Reads the data from the IO device dev, and writes it to the file called file on the server.
 int rawCommand(java.lang.String command)
          Sends the raw FTP command command to the FTP server.
 int read(byte[] data)
          Reads from the data socket into data and returns the number of bytes read.
 QByteArray readAll()
          Reads all the bytes available from the data socket and returns them.
 int remove(java.lang.String file)
          Deletes the file called file from the server.
 int rename(java.lang.String oldname, java.lang.String newname)
          Renames the file called oldname to newname on the server.
 int rmdir(java.lang.String dir)
          Removes the directory called dir from the server.
 int setProxy(java.lang.String host, char port)
          Enables use of the FTP proxy on host host and port port.
 int setTransferMode(QFtp.TransferMode mode)
          Sets the current FTP transfer mode to mode.
 QFtp.State state()
          Returns the current state of the object.
 
Methods inherited from class com.trolltech.qt.core.QObject
blockSignals, childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, property, removeEventFilter, setObjectName, setParent, setProperty, signalsBlocked, startTimer, thread, timerEvent
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
disconnect, disconnect, signalSender
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

commandFinished

public final QSignalEmitter.Signal2<java.lang.Integer,java.lang.Boolean> commandFinished

This signal is emitted when processing the command identified by arg__1 has finished. arg__2 is true if an error occurred during the processing; otherwise arg__2 is false.

Compatible Slot Signatures:
void mySlot(int arg__1, boolean arg__2)
void mySlot(int arg__1)
void mySlot()
See Also:
commandStarted, done, error, errorString


commandStarted

public final QSignalEmitter.Signal1<java.lang.Integer> commandStarted

This signal is emitted when processing the command identified by arg__1 starts.

Compatible Slot Signatures:
void mySlot(int arg__1)
void mySlot()
See Also:
commandFinished, done


dataTransferProgress

public final QSignalEmitter.Signal2<java.lang.Long,java.lang.Long> dataTransferProgress

This signal is emitted in response to a get or put request to indicate the current progress of the download or upload.

arg__1 is the amount of data that has already been transferred and arg__2 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 arg__2 is 0. (If you connect this signal to a QProgressBar, the progress bar shows a busy indicator if the total is 0).

Warning: arg__1 and arg__2 are not necessarily the size in bytes, since for large files these values might need to be "scaled" to avoid overflow.

Compatible Slot Signatures:
void mySlot(long arg__1, long arg__2)
void mySlot(long arg__1)
void mySlot()
See Also:
get, put, QProgressBar


done

public final QSignalEmitter.Signal1<java.lang.Boolean> done

This signal is emitted when the last pending command has finished; (it is emitted after the last command's commandFinished signal). arg__1 is true if an error occurred during the processing; otherwise arg__1 is false.

Compatible Slot Signatures:
void mySlot(boolean arg__1)
void mySlot()
See Also:
commandFinished, error, errorString


listInfo

public final QSignalEmitter.Signal1<QUrlInfo> listInfo

This signal is emitted for each directory entry the list command finds. The details of the entry are stored in arg__1.

Compatible Slot Signatures:
void mySlot(com.trolltech.qt.network.QUrlInfo arg__1)
void mySlot()
See Also:
list


rawCommandReply

public final QSignalEmitter.Signal2<java.lang.Integer,java.lang.String> rawCommandReply

This signal is emitted in response to the rawCommand function. arg__1 is the 3 digit reply code and arg__2 is the text that follows the reply code.

Compatible Slot Signatures:
void mySlot(int arg__1, java.lang.String arg__2)
void mySlot(int arg__1)
void mySlot()
See Also:
rawCommand


readyRead

public final QSignalEmitter.Signal0 readyRead

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.

Compatible Slot Signature:
void mySlot()
See Also:
get, read, readAll, bytesAvailable


stateChanged

public final QSignalEmitter.Signal1<java.lang.Integer> stateChanged

This signal is emitted when the state of the connection changes. The argument arg__1 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.

Compatible Slot Signatures:
void mySlot(int arg__1)
void mySlot()
See Also:
connectToHost, close, state, State

Constructor Detail

QFtp

public QFtp()

Equivalent to QFtp(0).


QFtp

public QFtp(QObject parent)

Constructs a QFtp object with the given parent.

Method Detail

abort

public final void abort()

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

bytesAvailable

public final long bytesAvailable()

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

See Also:
get, readyRead, read, readAll

cd

public final int cd(java.lang.String 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

clearPendingCommands

public final void 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, abort

close

public final int 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

connectToHost

public final int connectToHost(java.lang.String host)

Equivalent to connectToHost(host, 21).


connectToHost

public final int connectToHost(java.lang.String host,
                               char port)

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

currentCommand

public final QFtp.Command currentCommand()

Returns the command type of the FTP command being executed or None if there is no command being executed.

See Also:
currentId

currentDevice

public final QIODevice currentDevice()

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

currentId

public final int currentId()

Returns the identifier of the FTP command that is being executed or 0 if there is no command being executed.

See Also:
currentCommand

error

public final QFtp.Error error()

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.


errorString

public final java.lang.String errorString()

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().


get

public final int get(java.lang.String file,
                     QIODevice dev)

Equivalent to get(file, dev, Binary).


get

public final int get(java.lang.String file)

Equivalent to get(file, 0, Binary).


get

public final int get(java.lang.String file,
                     QIODevice dev,
                     QFtp.TransferType type)

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.

commandFinished

See Also:
readyRead, dataTransferProgress, commandStarted

hasPendingCommands

public final boolean hasPendingCommands()

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

list

public final int list()

Equivalent to list(QString()).


list

public final int list(java.lang.String dir)

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

login

public final int login(java.lang.String user)

Equivalent to login(user, QString()).


login

public final int login()

Equivalent to login(QString(), QString()).


login

public final int login(java.lang.String user,
                       java.lang.String password)

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

mkdir

public final int mkdir(java.lang.String 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

put

public final int put(QByteArray data,
                     java.lang.String file)

Equivalent to put(data, file, Binary).


put

public final int put(QByteArray data,
                     java.lang.String file,
                     QFtp.TransferType type)

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

put

public final int put(QIODevice dev,
                     java.lang.String file)

Equivalent to put(dev, file, Binary).


put

public final int put(QIODevice dev,
                     java.lang.String file,
                     QFtp.TransferType type)

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).


rawCommand

public final int rawCommand(java.lang.String 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

readAll

public final QByteArray readAll()

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

See Also:
get, readyRead, bytesAvailable, read

remove

public final int remove(java.lang.String 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

rename

public final int rename(java.lang.String oldname,
                        java.lang.String 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

rmdir

public final int rmdir(java.lang.String 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

setProxy

public final int setProxy(java.lang.String host,
                          char 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 QHttp for this.


setTransferMode

public final int setTransferMode(QFtp.TransferMode mode)

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

See Also:
QFtp::TransferMode

state

public final QFtp.State state()

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

See Also:
State, stateChanged

fromNativePointer

public static QFtp fromNativePointer(QNativePointer nativePointer)
This function returns the QFtp instance pointed to by nativePointer

Parameters:
nativePointer - the QNativePointer of which object should be returned.

read

public final int read(byte[] data)
Reads from the data socket into data and returns the number of bytes read. Returns -1 if an error occurred.