4.4.1 TemporaryFileTransferType

This ObjectType defines a type for the representation of temporary file transfers. It is formally defined in Table 13. The Methods GenerateFileForRead or GenerateFileForWrite generate a temporary FileType Object that is not browsable in the AddressSpace and can only be accessed with the NodeId and FileHandle returned by the Methods in the same Session. This Object is used to transfer the temporary file between OPC UA Client and Server. A file may be readonly, writeonly or readable and writable.

The Property ClientProcessingTimeout defines the maximum time in milliseconds the Server accepts between Method calls necessary to complete a file read transfer or a file write transfer transaction. This includes the Method calls to read or write the file content from the virtual temporary FileType Object. If the Client exceeds the timeout between Method calls, the Server may close the file and cancel the corresponding transfer transaction. Any open temporary transfer file shall be deleted if the Session used to create the file is no longer valid.

The TransferState Objects are 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 Method execution. If the transactions are completed when the Method is returned, the optional TransferState Objects are not available. A Server may allow more than one parallel read transfer. A Server may not allow more than one write transfer or a parallel read and writer transfer.