Hello, I am having problems with the new FTP connector node.
I am using KNIME 4.3.2.
The problem I am having is that after the connection has been successfully made KNIME is failing to retrieve the folder structure (source paths) of the FTP server.
If I add a “Transfer Files” node, it throws me an error: “Transfer Files 0:356 An error occured during the process of retrieving the source paths. See log for more details.”
Full error in logs:
2021-05-05 13:36:31,892 : ERROR : SwingWorker-pool-10-thread-3 : : TransferFilesStatusMessageReporter : Transfer Files : 0:356 : An error occured during the process of retrieving the source paths. See log for more details.
org.knime.core.node.InvalidSettingsException: The specified folder /FTP_DATA does not exist.
at org.knime.core.node.util.CheckUtils.checkSetting(CheckUtils.java:269)
at org.knime.core.node.util.CheckUtils.checkSetting(CheckUtils.java:219)
at org.knime.filehandling.core.defaultnodesettings.filechooser.FileChooserPathAccessor.getRootPath(FileChooserPathAccessor.java:289)
at org.knime.filehandling.utility.nodes.transfer.TransferFilesStatusMessageReporter.report(TransferFilesStatusMessageReporter.java:126)
at org.knime.filehandling.core.defaultnodesettings.status.StatusSwingWorker.doInBackgroundWithContext(StatusSwingWorker.java:107)
at org.knime.filehandling.core.defaultnodesettings.status.StatusSwingWorker.doInBackgroundWithContext(StatusSwingWorker.java:1)
at org.knime.core.util.SwingWorkerWithContext.doInBackground(SwingWorkerWithContext.java:106)
at javax.swing.SwingWorker$1.call(SwingWorker.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at javax.swing.SwingWorker.run(SwingWorker.java:334)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
When trying to set the working directory of “FTP Connector” node is throes no warning or errors but the browse button menu shows an empty source (same in “Transfer Files” source browse).
When testing the same FTP site with the same credentials using “FTP Connection (Legacy)”, the connection is successful and when adding the “Download (legacy)” or “List Remote Files (Legacy)” they both show the folder structure:
This bug is not for all FTP servers, when checking with a different FTP server (using FTP Connector) everything works and the source path is displayed:
It is clear it is some kind of server configuration that is leading to this behavior, but I am unable to diagnose what.
Checking with WireShark and comparing the two servers both with “FTP Connector” the connection protocols match, the only difference I see when browsing the directories is the response to “Request: LIST -a /”.
The server that is not working returns:
Response: 125 Data connection already open; Transfer starting.
Response: 226 Transfer complete.
Whilst the working one returns:
Response: 150 Opening BINARY mode data connection for file list
Response: 226 Transfer complete
Both servers work perfectly when viewing the source paths with WinSCP.
Has anybody encountered this behavior or knows what might be the cause for this?
Thanks in advance for your responses!
