Add an option to change the sftp server's initial root path

[boucaud]

When using the sftp server to download files from a specific folder, girder users have to navigate through various subdirectories before finding the content they wish to download (typically /user/username/Private/folder).

We would like to add an option to simplify this process, and directly expose to users the contents of the folder they are intended to download from.

These proposed changes add a configurable path parameter to the sftp server, that would let plugin developpers change the server's root if they wish. It is probably not the best way to do this, which is why we would like feedback on this.

[zachmullen]

This is an interesting idea. If the plan is to use this in a plugin context, is it possible to do via extension rather than modification of the existing class? Or put another way, is there a way to slightly tweak the base class to make this specific extension straightforward, without having to encode the concept of rootPath or :girderUser in the base class?

[boucaud]

Hi, I think we're going to try and do this via a plugin. I will keep this updated should any issues arise. Thanks.

[boucaud]

After consideration, it is impossible right now to extend _SftpServerAdapter without also changing _SFTPRequestHandler's setup method and SftpServer's constructor, which leads to a bit of duplication.

It would be useful to change SftpServer and _SftpRequestHandler so that they can take optional classes in their constructors (and thus allow us to use a modified _SftpServerAdapter without reimplementing the other classes).

@zachmullen, would it be ok ?

[zachmullen]

Sounds great!

[boucaud]

Does the _processPath change seem fine as well ?