TFTPClient Component

Properties   Methods   Events   Config Settings   Errors  

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

Syntax

TipwTFTPClient

Remarks

To use the component, 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 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.

Idle Property (TFTPClient Component)

The current status of the component.

Syntax

__property bool Idle = { read=FIdle };

Default Value

True

Remarks

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

This property is read-only.

Data Type

Boolean

LocalFile Property (TFTPClient Component)

The file on the local host to transfer the data to/from.

Syntax

__property String LocalFile = { read=FLocalFile, write=FSetLocalFile };

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.

Data Type

String

LocalHost Property (TFTPClient Component)

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

Syntax

__property String LocalHost = { read=FLocalHost, write=FSetLocalHost };

Default Value

""

Remarks

The LocalHost 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 multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component 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 multi-homed 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

MaxRetransmits Property (TFTPClient Component)

The number of times to retry sending a failed packet before disconnecting.

Syntax

__property int MaxRetransmits = { read=FMaxRetransmits, write=FSetMaxRetransmits };

Default Value

3

Remarks

This property allows you to specify the number of times that you would like to try re-sending 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

RemoteFile Property (TFTPClient Component)

The file on the remote host.

Syntax

__property String RemoteFile = { read=FRemoteFile, write=FSetRemoteFile };

Default Value

""

Remarks

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

Data Type

String

RetransmitTimeout Property (TFTPClient Component)

Maximum time in seconds to wait for a reply packet from the server before retransmitting the last packet.

Syntax

__property int RetransmitTimeout = { read=FRetransmitTimeout, write=FSetRetransmitTimeout };

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

TFTPPort Property (TFTPClient Component)

The UDP port where the remote TFTP server is listening.

Syntax

__property int TFTPPort = { read=FTFTPPort, write=FSetTFTPPort };

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.

Data Type

Integer

TFTPServer Property (TFTPClient Component)

The address of the TFTP server to exchange files with.

Syntax

__property String TFTPServer = { read=FTFTPServer, write=FSetTFTPServer };

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()

Data Type

String

Timeout Property (TFTPClient Component)

A timeout for the component.

Syntax

__property int Timeout = { read=FTimeout, write=FSetTimeout };

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 component will wait for the operation to complete before returning control.

The component 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 component raises an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. 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.

Data Type

Integer

Config Method (TFTPClient Component)

Sets or retrieves a configuration setting.

Syntax

String __fastcall Config(String ConfigurationString);

Remarks

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

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

Processes events from the internal message queue.

Syntax

void __fastcall DoEvents();

Remarks

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

GetFile Method (TFTPClient Component)

Download a RemoteFile from the TFTP server.

Syntax

void __fastcall 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 Component)

Interrupt the current method.

Syntax

void __fastcall Interrupt();

Remarks

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

PutFile Method (TFTPClient Component)

Upload a file specified by LocalFile to the TFTP server.

Syntax

void __fastcall 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 Component)

Reset the component.

Syntax

void __fastcall Reset();

Remarks

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

EndTransfer Event (TFTPClient Component)

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

Syntax

typedef struct {
  int Direction;
} TipwTFTPClientEndTransferEventParams;
typedef void __fastcall (__closure *TipwTFTPClientEndTransferEvent)(System::TObject* Sender, TipwTFTPClientEndTransferEventParams *e);
__property TipwTFTPClientEndTransferEvent OnEndTransfer = { read=FOnEndTransfer, write=FOnEndTransfer };

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 Component)

Information about errors during data delivery.

Syntax

typedef struct {
  int ErrorCode;
  String Description;
} TipwTFTPClientErrorEventParams;
typedef void __fastcall (__closure *TipwTFTPClientErrorEvent)(System::TObject* Sender, TipwTFTPClientErrorEventParams *e);
__property TipwTFTPClientErrorEvent OnError = { read=FOnError, write=FOnError };

Remarks

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

ErrorCode contains an error code and Description 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 Component)

This event fires when a file starts downloading or uploading.

Syntax

typedef struct {
  int Direction;
} TipwTFTPClientStartTransferEventParams;
typedef void __fastcall (__closure *TipwTFTPClientStartTransferEvent)(System::TObject* Sender, TipwTFTPClientStartTransferEventParams *e);
__property TipwTFTPClientStartTransferEvent OnStartTransfer = { read=FOnStartTransfer, write=FOnStartTransfer };

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 Component)

This event is fired during the file download or upload.

Syntax

typedef struct {
  int Direction;
  __int64 BytesTransferred;
  int PercentDone;
  String Text;
  DynamicArray<Byte> TextB;
} TipwTFTPClientTransferEventParams;
typedef void __fastcall (__closure *TipwTFTPClientTransferEvent)(System::TObject* Sender, TipwTFTPClientTransferEventParams *e);
__property TipwTFTPClientTransferEvent OnTransfer = { read=FOnTransfer, write=FOnTransfer };

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 Component)

The component 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 component, 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 Component)

TFTPClient Errors

	122   Packet too large.
	123   Wrong response type from server.
	124   Server error. Description contains detailed information.
	125   Invalid server response.
	126   A valid LocalFile must be provided for PUT operations.
	127   Can't open local file.
	128   Can't write to local file.
	129   Can't read local file.
	130   Busy performing the current transfer.
	301   Timeout while waiting for server.
	305   Server error.
	306   Wrong or invalid response type received from server.
	307   Invalid response from server.

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

UDP Errors

	104   UDP is already Active.
	106   You cannot change the LocalPort while the component is Active.
	107   You cannot change the LocalHost at this time. A connection is in progress.
	109   The component must be Active for this operation.
	112   Cannot change MaxPacketSize while the component is Active.
	113   Cannot change ShareLocalPort option while the component is Active.
	114   Cannot change RemoteHost when UseConnection is set and the component Active.
	115   Cannot change RemotePort when UseConnection is set and the component is Active.
	116   RemotePort can't be zero when UseConnection is set. Please specify a valid service port number.
	117   Cannot change UseConnection while the component is Active.
	118   Message can't be longer than MaxPacketSize.
	119   Message too short.
	434   Unable to convert string to selected CodePage

SSL Errors

	270   Cannot load specified security library.
	271   Cannot open certificate store.
	272   Cannot find specified certificate.
	273   Cannot acquire security credentials.
	274   Cannot find certificate chain.
	275   Cannot verify certificate chain.
	276   Error during handshake.
	280   Error verifying certificate.
	281   Could not find client certificate.
	282   Could not find server certificate.
	283   Error encrypting data.
	284   Error decrypting data.

TCP/IP Errors

	10004   [10004] Interrupted system call.
	10009   [10009] Bad file number.
	10013   [10013] Access denied.
	10014   [10014] Bad address.
	10022   [10022] Invalid argument.
	10024   [10024] Too many open files.
	10035   [10035] Operation would block.
	10036   [10036] Operation now in progress.
	10037   [10037] Operation already in progress.
	10038   [10038] Socket operation on non-socket.
	10039   [10039] Destination address required.
	10040   [10040] Message too long.
	10041   [10041] Protocol wrong type for socket.
	10042   [10042] Bad protocol option.
	10043   [10043] Protocol not supported.
	10044   [10044] Socket type not supported.
	10045   [10045] Operation not supported on socket.
	10046   [10046] Protocol family not supported.
	10047   [10047] Address family not supported by protocol family.
	10048   [10048] Address already in use.
	10049   [10049] Can't assign requested address.
	10050   [10050] Network is down.
	10051   [10051] Network is unreachable.
	10052   [10052] Net dropped connection or reset.
	10053   [10053] Software caused connection abort.
	10054   [10054] Connection reset by peer.
	10055   [10055] No buffer space available.
	10056   [10056] Socket is already connected.
	10057   [10057] Socket is not connected.
	10058   [10058] Can't send after socket shutdown.
	10059   [10059] Too many references, can't splice.
	10060   [10060] Connection timed out.
	10061   [10061] Connection refused.
	10062   [10062] Too many levels of symbolic links.
	10063   [10063] File name too long.
	10064   [10064] Host is down.
	10065   [10065] No route to host.
	10066   [10066] Directory not empty
	10067   [10067] Too many processes.
	10068   [10068] Too many users.
	10069   [10069] Disc Quota Exceeded.
	10070   [10070] Stale NFS file handle.
	10071   [10071] Too many levels of remote in path.
	10091   [10091] Network subsystem is unavailable.
	10092   [10092] WINSOCK DLL Version out of range.
	10093   [10093] Winsock not loaded yet.
	11001   [11001] Host not found.
	11002   [11002] Non-authoritative 'Host not found' (try again or check DNS setup).
	11003   [11003] Non-recoverable errors: FORMERR, REFUSED, NOTIMP.
	11004   [11004] Valid name, no data record (check DNS setup).