No response from :ssh_sftp.list_dir/2 when given path other than root

Questions / Help
1

Hello, new to elixir, just worked through almost all of the guide (inlcuding Mix/OTP) on the website and am now dipping my feet with a simple hobby project. Right out the gates, I’m having some trouble with :ssh_sftp.list_dir/2 and I’m not sure where it is hanging up.

I can connect to the server (using same credentials that work fine with Nautilus/WinSCP), and can list the contents of the root directory, but attempting to list with any path other than root it just hangs forever waiting for response.

:ssh_sftp.list_dir(pid, '')
#=> {:ok, ['dir1, 'dir2']}

:ssh_sftp.list_dir(pid, 'dir1')
#=> no response

:ssh_sftp.list_dir(pid, 'nope')
#=> {:error, :no_such_path}

As above, it correctly outputs a list of the directories in root, and returns :no_such_path if given an incorrect path. But never returns anything if given a valid non-root path. Is there something obvious I’m missing?

Thank you for any wisdom and advice you have time to offer!

2

I regret I have no wisdom to offer, but a quick look at the Erlang docs suggest that maybe try :ssh_sftp.list_dir(pid, 'dir1', 5000) and see if that times out or returns some different error? No response seems like, well, no response from the server.

3

Yes, it just times out if you give it a timeout (default is inf). Async/await with Task to give a timeout, similarly times out. So as far as I can tell the server simply never responds, however I know that my list_dir calls are able to “reach” arbitrarily deep directories since it only hangs when a valid path is given. It responds promptly with an error if the path does not lead to something real in the server.

4

any luck solving this problem? I’m running into the same issue.

1 Like
5

I had the same issue and fixed it by switching SFTP protocol to version 3 using sftp_vsn connection option. I think the 4 is the default and some older/misconfigured servers do not fully support it.

3 Likes
6

The “default” is the highest version the two parties both support. There is a buggy Java-based SFTP server out there that has version 4 as the highest version of SFTP it supports, and has a buggy implementation of version 4 to boot.

So setting sftp_vsn to 3 in general might actually degrade your performance with better SFTP servers, so ideally you’d only do it for broken servers like that Java-one.