TFTPClient Class

Properties   Methods   Events   Config Settings   Errors  

The TFTPClient class is used to exchange files with TFTP servers via the TFTP protocol defined in RFC 783.

Syntax

ipworks.TFTPClient

Remarks

To use the class, first specify the TFTPServer, then a LocalFile and a RemoteFile, and then call GetFile or PutFile. The Transfer event shows the progress of the transfer.

Potential transmission errors and packet loss are managed by the Timeout property, which controls the maximum time to wait for a response from the server, and the MaxRetransmits property, which specifies how many times to resend a failed packet before giving up.

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

Idle Property (TFTPClient Class)

The current status of the class.

Syntax

public boolean isIdle();

Default Value

True

Remarks

This property will be False if the component is currently busy (communicating or waiting for an answer), and True at all other times.

This property is read-only.

LocalFile Property (TFTPClient Class)

This property includes a file on the local host to transfer the data to or from.

Syntax

public String getLocalFile();
public void setLocalFile(String localFile);

Default Value

""

Remarks

If GetFile is called, and LocalFile already exists, it is overwritten. If PutFile is called, LocalFile must point to a valid file or an error will be returned.

LocalHost Property (TFTPClient Class)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

public String getLocalHost();
public void setLocalHost(String localHost);

Default Value

""

Remarks

This property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

Note: LocalHost is not persistent. You must always set it in code, and never in the property window.

MaxRetransmits Property (TFTPClient Class)

This property specifies the number of times to retry sending a failed packet before disconnecting.

Syntax

public int getMaxRetransmits();
public void setMaxRetransmits(int maxRetransmits);

Default Value

3

Remarks

This property allows you to specify the number of times that you would like to try resending the last data packet if the original packet fails.

The RetransmitTimeout determines the wait time (in seconds) between successive retransmissions.

The default value for the MaxRetransmits property is 3.

RemoteFile Property (TFTPClient Class)

This property includes the file on the remote host.

Syntax

public String getRemoteFile();
public void setRemoteFile(String remoteFile);

Default Value

""

Remarks

When the GetFile is called, this must be a valid file on the TFTPServer.

RetransmitTimeout Property (TFTPClient Class)

This property includes the maximum time in seconds to wait for a reply packet from the server before retransmitting the last packet.

Syntax

public int getRetransmitTimeout();
public void setRetransmitTimeout(int retransmitTimeout);

Default Value

5

Remarks

Please refer to the MaxRetransmits property for the number of retransmit efforts before an error is returned.

The default value for the RetransmitTimeout is 5 seconds.

TFTPPort Property (TFTPClient Class)

This property specifies the User Datagram Protocol (UDP) port where the remote TFTP server is listening.

Syntax

public int getTFTPPort();
public void setTFTPPort(int TFTPPort);

Default Value

69

Remarks

The TFTPPort is the UDP port on the TFTPServer to send TFTP requests to.

This property is not available at design time.

TFTPServer Property (TFTPClient Class)

This property includes the address of the TFTP server to exchange files with.

Syntax

public String getTFTPServer();
public void setTFTPServer(String TFTPServer);

Default Value

""

Remarks

To be able to transfer file via TFTP, the remote host must be running TFTP services on port TFTPPort (default 69).

Example. Get a File:

TFTPControl.TFTPServer = "MyServer" TFTPControl.LocalFile = "C:\filename.txt" TFTPControl.RemoteFile = "/remotefile.txt" TFTPControl.GetFile()

Timeout Property (TFTPClient Class)

The timeout for the class.

Syntax

public int getTimeout();
public void setTimeout(int timeout);

Default Value

60

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the class will wait for the operation to complete before returning control.

The class will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the class throws an exception.

Note: By default, all timeouts are inactivity timeouts, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

Config Method (TFTPClient Class)

Sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DoEvents Method (TFTPClient Class)

This method processes events from the internal message queue.

Syntax

public void doEvents();

Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

GetFile Method (TFTPClient Class)

This method downloads a RemoteFile from the TFTP server.

Syntax

public void getFile();

Remarks

The remote file specified by RemoteFile is downloaded to the local file specified by LocalFile, or it is retrieved through the Transfer event, if the LocalFile property is "" (empty string).

Example. Get a File:

TFTPControl.TFTPServer = "MyServer" TFTPControl.LocalFile = "C:\filename.txt" TFTPControl.RemoteFile = "/remotefile.txt" TFTPControl.GetFile()

Interrupt Method (TFTPClient Class)

This method interrupts the current method.

Syntax

public void interrupt();

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

PutFile Method (TFTPClient Class)

This method uploads a file specified by LocalFile to the TFTP server.

Syntax

public void putFile();

Remarks

The local file specified by LocalFile is uploaded to the remote file specified by RemoteFile.

Example. Put a File:

TFTPControl.TFTPServer = "MyServer" TFTPControl.LocalFile = "C:\filename.txt" TFTPControl.RemoteFile = "/remotefile.txt" TFTPControl.PutFile()

Reset Method (TFTPClient Class)

This method resets the class.

Syntax

public void reset();

Remarks

This method will reset the class's properties to their default values.

SetDownloadStream Method (TFTPClient Class)

This method sets the stream to which the downloaded data from the server will be written.

Syntax

public void setDownloadStream(java.io.OutputStream downloadStream);

Remarks

If a download stream is set before the GetFile method is called, the downloaded data will be written to the stream. The stream should be open and normally set to position 0. The class will automatically close this stream if CloseStreamAfterTransfer is set to True (default). If the stream is closed, you will need to call SetDownloadStream again before calling GetFile again. The downloaded content will be written starting at the current position in the stream.

Note: SetDownloadStream and LocalFile will reset the other.

SetUploadStream Method (TFTPClient Class)

This method sets the stream to be uploaded to the server.

Syntax

public void setUploadStream(java.io.InputStream uploadStream);

Remarks

If an upload stream is set before the PutFile method is called, the content of the stream will be read by the class and uploaded to the server; The stream should be open and normally set to position 0. The class will automatically close this stream if CloseStreamAfterTransfer is set to True (default). If the stream is closed, you will need to call SetUploadStream again before calling PutFile again. The content of the stream will be read from the current position all the way to the end.

Note: SetUploadStream and LocalFile will reset the other.

EndTransfer Event (TFTPClient Class)

This event is fired when a file finishes downloading or uploading.

Syntax

public class DefaultTFTPClientEventListener implements TFTPClientEventListener {
  ...
  public void endTransfer(TFTPClientEndTransferEvent e) {}
  ...
}

public class TFTPClientEndTransferEvent {
  public int direction;
}

Remarks

The EndTransfer event fires when a Data Interface connection is closed. This occurs when the file finishes transferring or a directory listing is finished.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Error Event (TFTPClient Class)

Fired when information is available about errors during data delivery.

Syntax

public class DefaultTFTPClientEventListener implements TFTPClientEventListener {
  ...
  public void error(TFTPClientErrorEvent e) {}
  ...
}

public class TFTPClientErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

StartTransfer Event (TFTPClient Class)

This event fires when a file starts downloading or uploading.

Syntax

public class DefaultTFTPClientEventListener implements TFTPClientEventListener {
  ...
  public void startTransfer(TFTPClientStartTransferEvent e) {}
  ...
}

public class TFTPClientStartTransferEvent {
  public int direction;
}

Remarks

The StartTransfer event fires when a Data Interface connection is created. This is when the file starts transferring or a directory listing is started.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Transfer Event (TFTPClient Class)

This event is fired during the file download or upload.

Syntax

public class DefaultTFTPClientEventListener implements TFTPClientEventListener {
  ...
  public void transfer(TFTPClientTransferEvent e) {}
  ...
}

public class TFTPClientTransferEvent {
  public int direction;
  public long bytesTransferred;
  public int percentDone;
  public byte[] text;
}

Remarks

One or more Transfer events are fired during file transfer. The BytesTransferred parameter shows the number of bytes transferred since the beginning of the transfer.

Text contains the portion of the file data being delivered.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

The PercentDone parameter shows the progress of the transfer in the corresponding direction. If PercentDone can not be calculated the value will be -1.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Config Settings (TFTPClient Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

TFTPClient Config Settings

UDP Config Settings

Socket Config Settings

Base Config Settings

Trappable Errors (TFTPClient Class)

TFTPClient Errors

UDP Errors

SSL Errors

TCP/IP Errors