Changes between Version 92 and Version 93 of GSoCIdeas2010

Timestamp:

2010-03-16T21:27:57Z (14 years ago)

Author:

davidsarah

Comment:

more about webdav

GSoCIdeas2010

@@ -77 +77 @@
 Invent your own Summer-of-Code project by building a new web app on top of Tahoe-LAFS. The [#SecureDecentralizedWiki Secure Decentralized Wiki] is one example of a Cloud App. See [wiki:GSoCIdeas/CloudApps] for other ideas.
 
-= WebDAV =
+= WebDAV support =
 
-Implement a WebDAV front-end for Tahoe-LAFS so that files and directories stored in a distributed grid can be accessed by operating systems (including Windows, Mac, and Linux) and applications that speak the WebDAV protocol. For details see #451 which describes what the Tahoe-LAFS web server does now, how this differs from what a WebDAV web server does, and how to get started experimenting with the relevant source code.
+Difficulty: medium to hard, depending on how much of an existing WebDAV implementation you are able to reuse
+
+Implement a WebDAV front-end for Tahoe-LAFS so that files and directories stored in a distributed grid can be
+accessed by operating systems and applications that speak the WebDAV protocol. WebDAV is specified in
+[http://tools.ietf.org/html/rfc2518.html RFC 2518] and [http://www.ics.uci.edu/~ejw/authoring/ a few other documents];
+it essentially extends HTTP to act as a filesystem access protocol. For details see #451 which describes what the Tahoe-LAFS web server does now, how this differs from what a WebDAV web server does, and how to get started experimenting with the relevant source code.
+
+The main attraction of implementing a WebDAV interface is that
+several operating systems have bundled and somewhat integrated support
+for it, including Windows, Mac OS X, and most distributions of Linux.
+In fact WebDAV may turn out to be an easier alternative to
+[http://en.wikipedia.org/wiki/Server_Message_Block SMB/CIFS]
+for allowing filesystem access from Windows.
+
+However, there is currently no working WebDAV implementation in Twisted
+Python. There used to be one (the {{{web2.dav}}} package),
+[http://twistedmatrix.com/trac/ticket/3081 but it bitrotted].
+You'll have to decide whether to help fix that implementation, use a
+non-Twisted implementation such as [http://code.google.com/p/wsgidav/ WsgiDAV]
+that might be more difficult to integrate wth the existing Tahoe code,
+or write your own. In any case, WebDAV is a complicated protocol and
+you will need to decide what subset of it gives most "bang for the buck"
+and is practical to support in the time available. For example, locking
+is optional in the WebDAV spec; is it needed to interoperate with commonly
+used WebDAV clients?
+
+Unlike most filesystems which are constrained to be trees, the structure
+of a Tahoe is in general a cyclic graph.
+[http://tools.ietf.org/html/draft-ietf-webdav-bind draft-ietf-webdav-bind] is
+an Internet Draft that clarifies how WebDAV servers should handle cycles.
+
+[http://savannah.nongnu.org/projects/davfs2 davfs2] is a FUSE-based
+WebDAV filesystem client for Linux. To ensure that this runs correctly
+over your implementation of WebDAV, you'll probably need to adapt the
+tests for the existing Tahoe
+[source:contrib/fuse/impl_c/blackmatch.py "blackmatch"] FUSE interface
+(this would not be redundant since the blackmatch implementation has
+limitations, especially for write access, that davfs2 would not have).
+
+The [http://en.wikipedia.org/wiki/WebDAV#Microsoft_Windows WebDAV mini-redirector]
+is the component of Windows providing its WebDAV filesystem support. It is
+actually the less buggy of
+[http://www.zorched.net/2006/03/01/more-webdav-tips-tricks-and-bugs/ two implementations], but it still has had
+[http://greenbytes.de/tech/webdav/webdav-redirector-list.html bugs] and
+[http://www.microsoft.com/technet/security/bulletin/MS08-007.mspx security vulnerabilities]
+that you may need to take into account.
+
+[http://allmydata.org/trac/tahoe-lafs/query?status=!closed&order=priority&keywords=~webdav Tickets labelled 'webdav']
+
 
 = Distributed Introduction =