Issue with server messages when the KeepAliveDuringTransfer setting is enabled in FTP

Question

When KeepAliveDuringTransfer is enabled and a connection is made to Wing FTP Server (v8.2.5 for Windows), an upload error occurs if a KeepAlive signal is sent during the upload process.
Sending a NOOP command results in the following server response:
"Another command is pending currently, please try again later (451)"

Currently, Rebex FTP 8.0 recognizes the message "Another command is currently pending" as a success, but it fails to recognize "Another command is pending currently."

It would be better to implement a more flexible check.
For example:
StartWith("Another command") && StartWith("pending")

Thank you

Answer 1

When KeepAliveDuringTransfer is enabled, the server can reply with anything. To ensure that the FTP client does not mask a legitimate transfer error, we ignore only well known error messages. The "Another command is currently pending" message was observed with a particular server, so it is supported. The message "Another command is pending currently" has not been observed yet.

Support for this message will be added in the next version.