[gridsam-discuss] GridSAM, commons-vfs and GSI FTP

[Justin B. <jb...@ec...>]

Hi List,

I thought it was worth making a statement about the intentions  
regarding GridSAM and the use of apache-commons-vfs, specifically in  
relation to GSI FTP.

There have been a couple of issues surrounding this topic for some  
time now.

There have been previous discussions on how to interpret some JSDL  
file path references with respect to relative and absolute paths.
This was mainly in relation to GSI FTP URLs, where it can sometimes be  
open to interpretation as to whether a file path is relative to the  
user's home directory or absolute (ie relative to the root of the  
available file system).
The interpretation of these file paths are down to the vfs GSI FTP  
routines.

I'll include a portion of the original discussion at the bottom of  
this text to give more context.

Further to this Jos and I are now using a set of commons-vfs  
extensions derived from the ones used by the Rapid project.
These appear to supply a suitable starting point to produce a  
configurable vfs library for use with GridSAM.
See, http://forge.nesc.ac.uk/projects/vfs-modules/ for more details.
The extensions covered by this work, currently FTP, SFTP and GSI FTP  
can now been configured on a per protocol basis as to the default  
interpretation of ambiguous file paths.
So file paths without a leading "/" can be set to be relative to the  
user's home directory (notionally ''.") or to the root of the file  
system (or file server).
At present, the current default behaviour is maintained and  
configuration of this behaviour is done by way of an optional  
properties file.
This should give a suitable level of flexibility.

The changes to vfs-modules are still under test, and as such may well  
undergo some further changes.
I'm currently changing the GridSAM code to use the new module for FTP,  
SFTP and GSI FTP and will check in the code changes shortly.
This is in line with releasing another GridSAM (version 2.1.3)  
developers release this month.

In a related and possible future, work will hopefully be done with the  
common-vfs-grid group (http://projects.arcs.org.au/trac/commons-vfs-grid/ 
).
This would aim to converge the current implementations to form a  
single library which would aim to be universally useful.  Rather than  
having the current selection that are currently developed in parallel.

Any questions, feel free to ask.

Regards,
	Justin
--
Justin Bradley
Design & Development Team Leader
j.b...@om...
OMII-UK
Suite 3235, Zepler Building (B59)
University of Southampton