Re: [Duplicity-talk] FTP backend, consecutive ls

[Kenneth Loafman]

Olivier Croquette wrote:
> I have got an incomparability between ncftp and the ftp server of my
> provider.
> ncftp sends a "NLST -CF" command which is interpreted by the server as
> "list the file named -CF".
> I have contacted the ncftp developers, who suggest using the -x option
> of nclftpls.

We may want a patch just for this server.  Which one is it?

> Anyhow, I have introduced another work-around in duplicity, and while
> doing that, I have noticed that in
> ftpBackend.list(), 2 consecutive listings are requested from the server.
> 
> I don't understand why 2 ls are necessary.
> The reason given is "# try for a long listing to avoid connection reset"

For some reason most of the FTP servers do a connection reset when you
list a directory that is empty, even ncftp.  The workaround for the
connection reset is to ask for a long listing, in which case you get an
empty list.  If its not empty, just ask again for the short list.

> In my workaround, I just use the results of the long listing .
> Indeed I am using the following patch and I have had no problem so far.

Long listings on FTP servers vary, thus the necessity of the short list.

> This is more a call for comments as a request for inclusion by the way :)
> 
> NB: Writing this email, I see that my code has a problem when a file
> contains a space character, but the topic is still interesting.

That is another reason for the short listing.  No parsing needed.

FTP is one place where standards would be really handy.

...Ken

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