TFTPServer Control

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The TFTP Server Control is used to create a TFTP Server.

Syntax

TFTPServer

Remarks

The TFTP Server control provides a simple way to create a TFTP Server. Any TFTP client will be able to connect and transfer files to and from the server.

Getting Started

By default, the server will listen on port 69. You can specify the listening port by setting the LocalPort property.

Optionally, you can set the LocalDir property to a valid local path. If this property is set, the control will serve files from this location. When clients connect, they can request files from this location. If this property is not set, then the control will fire events allowing customized responses for each operation.

To start the server, call the StartListening method.

Handling Events

Event handlers are the primary method of customizing the control's functionality. When a client attempts to connect or open a file, the corresponding TFTP Server event will fire to allow for custom handling of the client's request.

The following events are fired once the requested operation is executed:

• Error
• Log
• Connected
• ConnectionRequest
• Disconnected
• EndTransfer
• StartTransfer
• Transfer

Property List

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

ConnCount Property (TFTPServer Control)

The number of records in the Conn arrays.

Syntax

tftpservercontrol.ConnCount

Default Value

0

Remarks

This property controls the size of the following arrays:

• ConnConnectionId
• ConnFileData
• ConnFileName
• ConnLocalFile
• ConnRemoteHost
• ConnRemotePort
• ConnTransferMode

The array indices start at 0 and end at ConnCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

ConnConnectionId Property (TFTPServer Control)

This property contains a unique identifier for this connection.

Syntax

tftpservercontrol.ConnConnectionId(ConnId)

Default Value

0

Remarks

This property contains a unique identifier for this connection.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is read-only and not available at design time.

Data Type

Integer

ConnFileData Property (TFTPServer Control)

This property is available only for sending data to a connected client.

Syntax

tftpservercontrol.ConnFileData(ConnId)[=string]

Default Value

""

Remarks

This property is available only for sending data to a connected client. If this property is set, then this will be the data sent when a connected client attempts to download a file from the server.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .ConnFileDataB.

This property is not available at design time.

Data Type

Binary String

ConnFileName Property (TFTPServer Control)

This property represents the filename of the file the client wants to upload or download.

Syntax

tftpservercontrol.ConnFileName(ConnId)

Default Value

""

Remarks

This property represents the filename of the file the client wants to upload or download.

Note: FileData must be empty to use this property.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is read-only and not available at design time.

Data Type

String

ConnLocalFile Property (TFTPServer Control)

This property is the local file on the server.

Syntax

tftpservercontrol.ConnLocalFile(ConnId)[=string]

Default Value

""

Remarks

This property is the local file on the server. This file is written to when a client puts a file. Data are pulled from this file when a client requests a file.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is not available at design time.

Data Type

String

ConnRemoteHost Property (TFTPServer Control)

This property represents the IP address of the connected client.

Syntax

tftpservercontrol.ConnRemoteHost(ConnId)

Default Value

""

Remarks

This property represents the IP address of the connected client.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is read-only and not available at design time.

Data Type

String

ConnRemotePort Property (TFTPServer Control)

This property represents the port of the connected client.

Syntax

tftpservercontrol.ConnRemotePort(ConnId)

Default Value

0

Remarks

This property represents the port of the connected client.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is read-only and not available at design time.

Data Type

Integer

ConnTransferMode Property (TFTPServer Control)

This property specifies whether transfers are done in octet mode 0 or netascii mode 1 .

Syntax

tftpservercontrol.ConnTransferMode(ConnId)

Default Value

""

Remarks

This property specifies whether transfers are done in octet mode 0 or netascii mode 1.

The ConnId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnCount property.

This property is read-only and not available at design time.

Data Type

String

Listening Property (TFTPServer Control)

This property indicates whether the control is listening for incoming connections on LocalPort.

Syntax

tftpservercontrol.Listening

Default Value

False

Remarks

This property indicates whether the control is listening for connections on the port specified by the LocalPort property. Use the StartListening and StopListening methods to control whether the control is listening.

This property is read-only and not available at design time.

Data Type

Boolean

LocalDir Property (TFTPServer Control)

This property defines the local file directory for the server.

Syntax

tftpservercontrol.LocalDir[=string]

Default Value

""

Remarks

This property defines the local file directory on the server. Files can be downloaded to or uploaded from this directory.

This property is not available at design time.

Data Type

String

LocalHost Property (TFTPServer Control)

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

Syntax

tftpservercontrol.LocalHost[=string]

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 control initiate connections (or accept in the case of server controls) 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 control 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.

Data Type

String

LocalPort Property (TFTPServer Control)

This property includes the port that the server will listen on.

Syntax

tftpservercontrol.LocalPort[=integer]

Default Value

69

Remarks

This property contains the port that the TFTP Server listens on. The default value is 69.

Data Type

Integer

MaxRetransmits Property (TFTPServer Control)

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

Syntax

tftpservercontrol.MaxRetransmits[=integer]

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.

Data Type

Integer

RetransmitTimeout Property (TFTPServer Control)

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

Syntax

tftpservercontrol.RetransmitTimeout[=integer]

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.

Data Type

Integer

Config Method (TFTPServer Control)

Sets or retrieves a configuration setting.

Syntax

tftpservercontrol.Config ConfigurationString

Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, 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 (TFTPServer Control)

This method processes events from the internal message queue.

Syntax

tftpservercontrol.DoEvents 

Remarks

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

StartListening Method (TFTPServer Control)

This method starts listening for incoming connections.

Syntax

tftpservercontrol.StartListening 

Remarks

This method begins listening for incoming connections on the port specified by LocalPort. Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call StopListening.

StopListening Method (TFTPServer Control)

This method stops listening for new connections.

Syntax

tftpservercontrol.StopListening 

Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

Connected Event (TFTPServer Control)

This event fires immediately after a connection completes (or fails).

Syntax

Sub tftpservercontrol_Connected(ConnectionId As Integer, StatusCode As Integer, Description As String)

Remarks

The ConnectionId is the Id of the connected client that caused the event to fire.

Upon a successful connection, the SatusCode is 0, and the Description is OK. If the connection is not successful, the StatusCode will contain an error code. The Description will contain a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ConnectionRequest Event (TFTPServer Control)

This event fires anytime a connected client attempts a connection to the server.

Syntax

Sub tftpservercontrol_ConnectionRequest(RemoteHost As String, RemotePort As Integer, FileName As String, TransferMode As String, Operation As Integer, Accept As Boolean)

Remarks

The RemoteHost parameter specifies the IP address (IP number in dotted internet format) of the client attempting to connect.

The RemotePort is the port of the client attempting a connection.

The FileName parameter is the path of the file to upload or download.

The TransferMode parameter specifies which transfer mode to use.

The Operation indicates whether the requested operation is read or write.

The Accept parameter indicates whether to accept or deny the connection. All connections are accepted by default. If you want to refuse a connection, set the Accept parameter to false.

Disconnected Event (TFTPServer Control)

This event fires after a transfer is completed.

Syntax

Sub tftpservercontrol_Disconnected(ConnectionId As Integer, StatusCode As Integer, Description As String)

Remarks

ConnectionID will be the ConnectionID of the client that has disconnected.

Upon successful transfer and disconnection, the StatusCode will be 0 and the Description will be OK. If a transfer is unsuccessful or a client disconnects due to an error, the StatusCode will contain an error code. The Description will be a textual description of the error.

EndTransfer Event (TFTPServer Control)

This event fires once a transfer is completed.

Syntax

Sub tftpservercontrol_EndTransfer(ConnectionId As Integer, Direction As Integer)

Remarks

The ConnectionId will be the ConnectionId of the connected client.

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

Error Event (TFTPServer Control)

Fired when information is available about errors during data delivery.

Syntax

Sub tftpservercontrol_Error(ErrorCode As Integer, Description As String)

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the control fails with an error.

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.

Log Event (TFTPServer Control)

This event fires once for each log message.

Syntax

Sub tftpservercontrol_Log(ConnectionId As Integer, LogLevel As Integer, Message As String, LogType As String)

Remarks

This event fires once for each log message generated by the control. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of message. Possible values are as follows:

The value 1 (Info) logs basic information, including users logging in and out, files transferred, and directories listed.

The value 2 (Verbose) includes logs from the PITrail event as well as basic information about data transfer channels.

The value 3 (Debug) logs additional debug information, such as extended socket connection and data transfer information.

Message is the log entry.

LogType identifies the type of log entry. Possible values are as follows:

• "Info"
• "Error"
• "Verbose"
• "Debug"
• "PITrail"

StartTransfer Event (TFTPServer Control)

This event fires immediately after a client initiates a file transfer.

Syntax

Sub tftpservercontrol_StartTransfer(ConnectionId As Integer, Direction As Integer)

Remarks

ConnectionId is the ConnectionId of the connected client. Direction represents the direction in which the transfer is going.

Transfer Event (TFTPServer Control)

This event fires repeatedly while data are being transferred. A transfer is marked as complete once a packet that is less than 512 bytes is received.

Syntax

Sub tftpservercontrol_Transfer(ConnectionId As Integer, Direction As Integer, BytesTransferred As Long64, PercentDone As Integer, Text As String)

Remarks

The ConnectionId parameter is the ConnectionId of the client who initiated the transfer.

BytesTransferred specifies the number of bytes transferred.

The Text parameter contains the data being transferred.

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 (TFTPServer Control)

The control 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 control, access to these internal properties is provided through the Config method.

TFTPServer Config Settings

UDP Config Settings

Socket Config Settings

Base Config Settings

Trappable Errors (TFTPServer Control)

TFTPServer Errors

The control may also return one of the following error codes, which are inherited from other controls.

UDP Errors

SSL Errors

TCP/IP Errors