UA Part 20: File Transfer - 4.4 Temporary file transfer

This ObjectTypedefines a type for the representation of temporary file transfers. It is formally defined in Table 13. The Methods GenerateFileForReador GenerateFileForWritegenerate a temporary FileType Objectthat is not browsable in the AddressSpaceand can only be accessed with the NodeIdand FileHandlereturned by the Methodsin the same Session.This Objectis used to transfer the temporary file between OPC UA Clientand Server.

Table 13– TemporaryFileTransferType

Attribute	Value
BrowseName	TemporaryFileTransferType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the BaseObjectType defined in OPC 10000-5
HasProperty		Variable	ClientProcessingTimeout	Duration	PropertyType	Mandatory
HasComponent		Method	GenerateFileForRead	Defined in 4.4.3		Mandatory
HasComponent		Method	GenerateFileForWrite	Defined in 4.4.4		Mandatory
HasComponent		Method	CloseAndCommit	Defined in 4.4.5		Mandatory
HasComponent		Object	<TransferState>		FileTransferStateMachineType	OptionalPlaceholder
Conformance Units
Base Info TemporaryFileTransferType Base

The Property ClientProcessingTimeoutdefines the maximum time in milliseconds the Serveraccepts between Methodcalls necessary to complete a file read transfer or a file write transfer transaction. This includes the Methodcalls to read or write the file content from the virtual temporary FileType Object. If the Clientexceeds the timeout between Methodcalls, the Servermay close the file and cancel the corresponding transfer transaction. Any open temporary transfer file shall be deleted if the Sessionused to create the file is no longer valid.

The TransferState Objectsare used to expose the state of a transfer transaction in the case that the preparation of a file for reading or the processing of the file after writing completes asynchronous after the corresponding Methodexecution. If the transactions are completed when the Methodis returned, the optional TransferState Objectsare not available. A Servermay allow more than one parallel read transfer. A Servermay not allow more than one write transfer or a parallel read and writer transfer.

4.4.2 File transfer sequences

The sequence of Methodcalls necessary to execute a read file transfer transaction is illustrated in Figure 2.

Figure 2– Read file transfer example sequence

The read file transfer transaction is started with the Method GenerateFileForReaddefined by the TemporaryFileTransferType. After a successful call of this Method, the Clientreads the file content by calling the Method Readdefined by the FileTypeuntil the whole file is transferred from the Serverto the Client. The transaction is completed by calling the Method Closedefined by the FileType.

The sequence of Methodcalls necessary to execute a write file transfer transaction is illustrated in Figure 3.

Figure 3– Write file transfer example sequence

The write file transfer transaction is started with the Method StartWriteTransferdefined by the TemporaryFileTransferType. After a successful call of this Method, the Clientwrites the file content by calling the Method Writedefined by the FileTypeuntil the whole file is transferred from the Client to the Server. The transaction is completed by calling the Method CloseAndCommitdefined by the TemporaryFileTransferType. If the Clientwants to abort the operation it uses the Close Methodof the temporary FileType Object.

4.4.3 GenerateFileForRead

GenerateFileForReadis used to start the read file transaction. A successful call of this Methodcreates a temporary FileType Objectwith the file content and returns the NodeIdof this Objectand the file handle to access the Object.

Signature

GenerateFileForRead(

[in] BaseDataType generateOptions

[out] NodeId fileNodeId

[out] UInt32 fileHandle

[out] NodeId completionStateMachine

);

Argument	Description
generateOptions	The optional parameter can be used to specify server specific file generation options. To allow such options, the Servershall specify a concrete DataTypein the Argument Structurefor this argument in the instance of the Method. If the DataTypeis BaseDataType, the Client shall pass Null for this argument. Examples for concrete DataTypes are OptionSetUsed to provide a bit mask for file content selection String Can be used to provide a string filter or a regular expression StructureCan be used to provide a structure with create settings e.g. to create a report EnumerationCan be used to provide a list of options
fileNodeId	NodeId of the temporary file.
fileHandle	The fileHandle of the opened TransferFile. The fileHandle can be used to access the TransferFile Methods Readand Close.
completionStateMachine	If the creation of the file is completed asynchronous, the parameter returns the NodeId of the corresponding FileTransferStateMachineType Object. If the creation of the file is already completed, the parameter is null. If a FileTransferStateMachineType Object NodeId is returned, the ReadMethod of the file fails until the TransferStatechanged to ReadTransfer.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4for a general description.

Table 14specifies the AddressSpacerepresentation for the GenerateFileForRead Method.

Table 14– GenerateFileForRead Method AddressSpace definition

Attribute	Value
BrowseName	GenerateFileForRead
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

4.4.4 GenerateFileForWrite

GenerateFileForWriteis used to start the write file transaction. A successful call of this Methodcreates a temporary FileType Objectand returns the NodeIdof this Objectand the file handle to access the Object.

Signature

GenerateFileForWrite(

[in] BaseDataTypegenerateOptions

[out] NodeId fileNodeId

[out] UInt32 fileHandle

);

Argument	Description
generateOptions	The optional parameter can be used to specify server specific file generation options. To allow such options, the Servershall specify a concrete DataTypein the Argument Structurefor this argument in the instance of the Method. If the DataTypeis BaseDataType, the Client shall pass Null for this argument. Examples for concrete DataTypes are OptionSetUsed to provide a bit mask for file use selection StructureCan be used to provide a structure with create settings e.g. firmware update settings EnumerationCan be used to provide a list of options like file handling options
fileNodeId	NodeId of the temporary file.
fileHandle	The fileHandle of the opened TransferFile. The fileHandle can be used to access the TransferFile Methods Writeand Close.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4for a general description.

Table 15specifies the AddressSpacerepresentation for the GenerateFileForWrite Method.

Table 15– GenerateFileForWrite Method AddressSpace definition

Attribute	Value
BrowseName	GenerateFileForWrite
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

4.4.5 CloseAndCommit

CloseAndCommitis used to apply the content of the written file and to delete the temporary file after the completion of the transaction.

Signature

CloseAndCommit(

[in] UInt32 fileHandle

[out] NodeId completionStateMachine

);

Argument	Description
fileHandle	The fileHandle used to write the file.
completionStateMachine	If the processing of the file is completed asynchronous, the parameter returns the NodeId of the corresponding FileTransferStateMachineType Object. If the processing of the file is already completed, the parameter is null. If a FileTransferStateMachineType Object NodeId is returned, the processing is in progress until the TransferStatechanged to Idle.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4for a general description.

Table 16specifies the AddressSpacerepresentation for the CloseAndCommit Method.

Table 16– CloseAndCommit Method AddressSpace definition

Attribute	Value
BrowseName	CloseAndCommit
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

4.4.6 FileTransferStateMachineType

The states of the file transfer state machine are shown in Figure 4.

Figure 4– File transfer States

The FileTransferStateMachineTypeand the related type are illustrated in Figure 5.

Figure 5– FileTransferStateMachineType

This ObjectTypedefines the StateMachine for asynchronous processing of temporary file transfers. It is formally defined in Table 17. The transitions are formally defined in Table 19.

Table 17– FileTransferStateMachineType

Attribute	Value
BrowseName	FileTransferStateMachineType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the FiniteStateMachineType defined in B.4.5.
HasComponent		Object	Idle		InitialStateType
HasComponent		Object	ReadPrepare		StateType
HasComponent		Object	ReadTransfer		StateType
HasComponent		Object	ApplyWrite		StateType
HasComponent		Object	Error		StateType
HasComponent		Object	IdleToReadPrepare		TransitionType
HasComponent		Object	ReadPrepareToReadTransfer		TransitionType
HasComponent		Object	ReadTransferToIdle		TransitionType
HasComponent		Object	IdleToApplyWrite		TransitionType
HasComponent		Object	ApplyWriteToIdle		TransitionType
HasComponent		Object	ReadPrepareToError		TransitionType
HasComponent		Object	ReadTransferToError		TransitionType
HasComponent		Object	ApplyWriteToError		TransitionType
HasComponent		Object	ErrorToIdle		TransitionType
HasComponent		Method	Reset	Defined in 4.4.7		Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

The component Variablesof the FileTransferStateMachineTypehave additional Attributesdefined in Table 18.

Table 18– FileTransferStateMachineType Attribute values for child Nodes

Source Path

Value Attribute

Idle

StateNumber

ReadPrepare

StateNumber

ReadTransfer

StateNumber

ApplyWrite

StateNumber

Error

StateNumber

IdleToReadPrepare

TransitionNumber

ReadPrepareToReadTransfer

TransitionNumber

ReadTransferToIdle

TransitionNumber

IdleToApplyWrite

TransitionNumber

ApplyWriteToIdle

TransitionNumber

ReadPrepareToError

TransitionNumber

ReadTransferToError

TransitionNumber

ApplyWriteToError

TransitionNumber

ErrorToIdle

TransitionNumber

Table 19– FileTransferStateMachineType Additional References

SourceBrowsePath	References	IsForward	TargetBrowsePath
IdleToReadPrepare	FromState	True	Idle
	ToState	True	ReadPrepare
	HasEffect	True	TransitionEventType
ReadPrepareToReadTransfer	FromState	True	ReadPrepare
	ToState	True	ReadTransfer
	HasEffect	True	TransitionEventType
ReadTransferToIdle	FromState	True	ReadTransfer
	ToState	True	Idle
	HasEffect	True	TransitionEventType
IdleToApplyWrite	FromState	True	Idle
	ToState	True	ApplyWrite
	HasEffect	True	TransitionEventType
ApplyWriteToIdle	FromState	True	ApplyWrite
	ToState	True	Idle
	HasEffect	True	TransitionEventType
ReadPrepareToError	FromState	True	ReadPrepare
	ToState	True	Error
	HasEffect	True	TransitionEventType
ReadTransferToError	FromState	True	ReadTransfer
	ToState	True	Error
	HasEffect	True	TransitionEventType
ApplyWriteToError	FromState	True	ApplyWrite
	ToState	True	Error
	HasEffect	True	TransitionEventType
ErrorToIdle	FromState	True	Error
	ToState	True	Idle
	HasEffect	True	TransitionEventType

4.4.7 Reset

Resetis used to reset the Error state of a FileTransferStateMachineType Object.

Signature

Reset();

Table 20specifies the AddressSpacerepresentation for the Reset Method.

Table 20– Reset Method AddressSpace definition

Attribute	Value
BrowseName	Reset
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Conformance Units
Base Info TemporaryFileTransferType Base

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