IBM BPM, V8.0.1, All platforms > Authoring services in Integration Designer > Services and service-related functions > Access external services with adapters > Configure and using adapters > IBM WebSphere Adapters > FTP > Overview of IBM WebSphere Adapter for FTP > Technical overview
Resume file transfer
WebSphere Adapter for FTP resumes the transfer of files that were interrupted due to an error in connection to the FTP server. When the connection is reestablished you can resume the transfer of files. The files are transferred from the point at which it was interrupted. This feature is useful when downloading or uploading large files.
During a create operation, if the connection to the FTP server breaks, the FTPFileTransferInterruptedException is returned by the adapter. To resume file transfer, a request must be resubmitted to the adapter. Set the ResumeFailedTransfer property to True in the wrapper object, for the adapter to resume the file transfer. The adapter, upon reestablishing the connection to the FTP server, resumes the transfer of the file being created on the FTP server.
The ResumeFailedTransfer property is applicable only for the outbound processing. You can resume a file transfer operation only for an outbound Create operation.
Similarly, for an inbound operation, the adapter tracks the files downloaded partially and resumes downloading the file after the connection is reestablished. The adapter saves the file with a “.partial” extension while downloading to the local event directory and renames the file to the original file after the file is completely retrieved to the local event directory.
The file for which the transfer was interrupted due to connection error must not be modified until the file is completely transferred to the FTP server. You cannot modify the partially uploaded or downloaded file created by the adapter, till the file transfer is complete.
- The FTP or FTPS server must provide support for the REST FTP command to resume the transfer of the file.
- You cannot resume a file transfer (operation) with the SFTP protocol.
See the ResumeFailedTransfer property details in Wrapper and interaction specification properties.