TFTPServer Component

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

Syntax

ipworks.TFTPServer

Remarks

The TFTP Server struct 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 struct will serve files from this location. When clients connect, they can request files from this location. If this property is not set, then the struct 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 struct'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 component 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 component 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 component 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 component with short descriptions. Click on the links for further details.

ConnCount Property (TFTPServer Component)

The number of records in the Conn arrays.

Syntax

func (obj *TFTPServer) ConnCount() (int32, error)

Default Value

0

Remarks

This property controls the size of the following arrays:

• ConnectionId
• ConnFileData
• ConnFileName
• ConnLocalFile
• ConnRemoteHost
• ConnRemotePort
• ConnTransferMode

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

This property is read-only.

Data Type

int32

ConnectionId Property (TFTPServer Component)

This property contains a unique identifier for this connection.

Syntax

func (obj *TFTPServer) ConnectionId(ConnId int32) (int32, error)

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.

Data Type

int32

ConnFileData Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) ConnFileData(ConnId int32) ([]byte, error)
func (obj *TFTPServer) SetConnFileData(ConnId int32, value []byte) error

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.

Data Type

[]byte

ConnFileName Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) ConnFileName(ConnId int32) (string, error)

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.

Data Type

string

ConnLocalFile Property (TFTPServer Component)

This property is the local file on the server.

Syntax

func (obj *TFTPServer) ConnLocalFile(ConnId int32) (string, error)
func (obj *TFTPServer) SetConnLocalFile(ConnId int32, value string) error

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.

Data Type

string

ConnRemoteHost Property (TFTPServer Component)

This property represents the IP address of the connected client.

Syntax

func (obj *TFTPServer) ConnRemoteHost(ConnId int32) (string, error)

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.

Data Type

string

ConnRemotePort Property (TFTPServer Component)

This property represents the port of the connected client.

Syntax

func (obj *TFTPServer) ConnRemotePort(ConnId int32) (int32, error)

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.

Data Type

int32

ConnTransferMode Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) ConnTransferMode(ConnId int32) (string, error)

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.

Data Type

string

Listening Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) Listening() (bool, error)

Default Value

false

Remarks

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

This property is read-only.

Data Type

bool

LocalDir Property (TFTPServer Component)

This property defines the local file directory for the server.

Syntax

func (obj *TFTPServer) LocalDir() (string, error)
func (obj *TFTPServer) SetLocalDir(value string) error

Default Value

""

Remarks

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

Data Type

string

LocalHost Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) LocalHost() (string, error)
func (obj *TFTPServer) SetLocalHost(value string) error

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 struct initiate connections (or accept in the case of server structs) 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 struct 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 Component)

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

Syntax

func (obj *TFTPServer) LocalPort() (int32, error)
func (obj *TFTPServer) SetLocalPort(value int32) error

Default Value

69

Remarks

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

Data Type

int32

MaxRetransmits Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) MaxRetransmits() (int32, error)
func (obj *TFTPServer) SetMaxRetransmits(value int32) error

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

int32

RetransmitTimeout Property (TFTPServer Component)

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

Syntax

func (obj *TFTPServer) RetransmitTimeout() (int32, error)
func (obj *TFTPServer) SetRetransmitTimeout(value int32) error

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

int32

Config Method (TFTPServer Component)

Sets or retrieves a configuration setting.

Syntax

func (obj *TFTPServer) Config(ConfigurationString string) (string, error)

Remarks

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

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

This method processes events from the internal message queue.

Syntax

func (obj *TFTPServer) DoEvents() error

Remarks

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

StartListening Method (TFTPServer Component)

This method starts listening for incoming connections.

Syntax

func (obj *TFTPServer) StartListening() error

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 Component)

This method stops listening for new connections.

Syntax

func (obj *TFTPServer) StopListening() error

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 Component)

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

Syntax

// TFTPServerConnectedEventArgs carries the TFTPServer Connected event's parameters.
type TFTPServerConnectedEventArgs struct {...}

func (args *TFTPServerConnectedEventArgs) ConnectionId() int32
func (args *TFTPServerConnectedEventArgs) StatusCode() int32
func (args *TFTPServerConnectedEventArgs) Description() string
// TFTPServerConnectedEvent defines the signature of the TFTPServer Connected event's handler function.
type TFTPServerConnectedEvent func(sender *TFTPServer, args *TFTPServerConnectedEventArgs)

func (obj *TFTPServer) GetOnConnectedHandler() TFTPServerConnectedEvent
func (obj *TFTPServer) SetOnConnectedHandler(handlerFunc TFTPServerConnectedEvent)

Remarks

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

Upon a successful connection, the StatusCode 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 Component)

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

Syntax

// TFTPServerConnectionRequestEventArgs carries the TFTPServer ConnectionRequest event's parameters.
type TFTPServerConnectionRequestEventArgs struct {...}

func (args *TFTPServerConnectionRequestEventArgs) RemoteHost() string
func (args *TFTPServerConnectionRequestEventArgs) RemotePort() int32
func (args *TFTPServerConnectionRequestEventArgs) FileName() string
func (args *TFTPServerConnectionRequestEventArgs) TransferMode() string
func (args *TFTPServerConnectionRequestEventArgs) Operation() int32
func (args *TFTPServerConnectionRequestEventArgs) Accept() bool
func (args *TFTPServerConnectionRequestEventArgs) SetAccept(value bool)

// TFTPServerConnectionRequestEvent defines the signature of the TFTPServer ConnectionRequest event's handler function.
type TFTPServerConnectionRequestEvent func(sender *TFTPServer, args *TFTPServerConnectionRequestEventArgs)

func (obj *TFTPServer) GetOnConnectionRequestHandler() TFTPServerConnectionRequestEvent
func (obj *TFTPServer) SetOnConnectionRequestHandler(handlerFunc TFTPServerConnectionRequestEvent)

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 Component)

This event fires after a transfer is completed.

Syntax

// TFTPServerDisconnectedEventArgs carries the TFTPServer Disconnected event's parameters.
type TFTPServerDisconnectedEventArgs struct {...}

func (args *TFTPServerDisconnectedEventArgs) ConnectionId() int32
func (args *TFTPServerDisconnectedEventArgs) StatusCode() int32
func (args *TFTPServerDisconnectedEventArgs) Description() string
// TFTPServerDisconnectedEvent defines the signature of the TFTPServer Disconnected event's handler function.
type TFTPServerDisconnectedEvent func(sender *TFTPServer, args *TFTPServerDisconnectedEventArgs)

func (obj *TFTPServer) GetOnDisconnectedHandler() TFTPServerDisconnectedEvent
func (obj *TFTPServer) SetOnDisconnectedHandler(handlerFunc TFTPServerDisconnectedEvent)

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 Component)

This event fires once a transfer is completed.

Syntax

// TFTPServerEndTransferEventArgs carries the TFTPServer EndTransfer event's parameters.
type TFTPServerEndTransferEventArgs struct {...}

func (args *TFTPServerEndTransferEventArgs) ConnectionId() int32
func (args *TFTPServerEndTransferEventArgs) Direction() int32
// TFTPServerEndTransferEvent defines the signature of the TFTPServer EndTransfer event's handler function.
type TFTPServerEndTransferEvent func(sender *TFTPServer, args *TFTPServerEndTransferEventArgs)

func (obj *TFTPServer) GetOnEndTransferHandler() TFTPServerEndTransferEvent
func (obj *TFTPServer) SetOnEndTransferHandler(handlerFunc TFTPServerEndTransferEvent)

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 Component)

Fired when information is available about errors during data delivery.

Syntax

// TFTPServerErrorEventArgs carries the TFTPServer Error event's parameters.
type TFTPServerErrorEventArgs struct {...}

func (args *TFTPServerErrorEventArgs) ErrorCode() int32
func (args *TFTPServerErrorEventArgs) Description() string
// TFTPServerErrorEvent defines the signature of the TFTPServer Error event's handler function.
type TFTPServerErrorEvent func(sender *TFTPServer, args *TFTPServerErrorEventArgs)

func (obj *TFTPServer) GetOnErrorHandler() TFTPServerErrorEvent
func (obj *TFTPServer) SetOnErrorHandler(handlerFunc TFTPServerErrorEvent)

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the struct 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 Component)

This event fires once for each log message.

Syntax

// TFTPServerLogEventArgs carries the TFTPServer Log event's parameters.
type TFTPServerLogEventArgs struct {...}

func (args *TFTPServerLogEventArgs) ConnectionId() int32
func (args *TFTPServerLogEventArgs) LogLevel() int32
func (args *TFTPServerLogEventArgs) Message() string
func (args *TFTPServerLogEventArgs) LogType() string
// TFTPServerLogEvent defines the signature of the TFTPServer Log event's handler function.
type TFTPServerLogEvent func(sender *TFTPServer, args *TFTPServerLogEventArgs)

func (obj *TFTPServer) GetOnLogHandler() TFTPServerLogEvent
func (obj *TFTPServer) SetOnLogHandler(handlerFunc TFTPServerLogEvent)

Remarks

This event fires once for each log message generated by the struct. 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 Component)

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

Syntax

// TFTPServerStartTransferEventArgs carries the TFTPServer StartTransfer event's parameters.
type TFTPServerStartTransferEventArgs struct {...}

func (args *TFTPServerStartTransferEventArgs) ConnectionId() int32
func (args *TFTPServerStartTransferEventArgs) Direction() int32
// TFTPServerStartTransferEvent defines the signature of the TFTPServer StartTransfer event's handler function.
type TFTPServerStartTransferEvent func(sender *TFTPServer, args *TFTPServerStartTransferEventArgs)

func (obj *TFTPServer) GetOnStartTransferHandler() TFTPServerStartTransferEvent
func (obj *TFTPServer) SetOnStartTransferHandler(handlerFunc TFTPServerStartTransferEvent)

Remarks

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

Transfer Event (TFTPServer Component)

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

// TFTPServerTransferEventArgs carries the TFTPServer Transfer event's parameters.
type TFTPServerTransferEventArgs struct {...}

func (args *TFTPServerTransferEventArgs) ConnectionId() int32
func (args *TFTPServerTransferEventArgs) Direction() int32
func (args *TFTPServerTransferEventArgs) BytesTransferred() int64
func (args *TFTPServerTransferEventArgs) PercentDone() int32
func (args *TFTPServerTransferEventArgs) Text() []byte
// TFTPServerTransferEvent defines the signature of the TFTPServer Transfer event's handler function.
type TFTPServerTransferEvent func(sender *TFTPServer, args *TFTPServerTransferEventArgs)

func (obj *TFTPServer) GetOnTransferHandler() TFTPServerTransferEvent
func (obj *TFTPServer) SetOnTransferHandler(handlerFunc TFTPServerTransferEvent)

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 Component)

The struct 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 struct, 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 Component)

TFTPServer Errors

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

UDP Errors

SSL Errors

TCP/IP Errors