Byzantine Askemos Language Layer

WebDAV :: pdf :: context view

inbound links:

Archive version included here without due review so far:


A Word of Warning

Distributed Authoring Extension to HTTP, RFC 2518

This RFC defines extensions to support some aspects of authoring workflow (like locking and version control). Users might be interested to control Askemos agents using the WebDAV protocol from client software which is readily available (see below).

Starting with version 0.7.3 the HTTP-ProtocolAdaptor of BALL has been extended to accept WebDAV requests.

A Word of Warning

WebDAV has several and severe shortcomings: It has been designed under the narrow assumption of document organization in directed, acyclic graphs (tree). These assumptions incure consequencess, which are eventually at least questionable. Therefore we recommend to consider better alternatives for newly developed client software.

Problems with WebDAV

WebDAV distinguishes only two kinds of agents: leaves resources (aka "documents") and intermediate tree nodes (aka collections, directories). Thereby it makes heavy restrictions on the inner workings of collections and documents.

Default Depth is infinity, who did that?

WebDAV protocol parameters seem arbitrarily assigned to HTTP headers and -attributes or ~values. The XML-DTD? violates well known design rules.

This standard is exceptionally hard to read, though the simple matter doesn't give a reason for this hardship.

Bugs

The mentioned restrictions make WebDAV unsuitable for implementation at BALL kernel level and should be left to the agents themself.

The implementation could use some cleanup and the current plan is to implement only those functions which are actually required for a certain purpose. (See below).

The Wiki-agent (see HowToEditThisPage) has to guess which parts of the document is sensitive text, edited by the user and what is constant decoration (forms, author, date etc). If this guess failes alltogether your saved text will include all the decoration.

WebDAV client software

cadaver
A command line client similar to the well known ftp program: http://www.webdav.org/cadaver/
fusedav
mount dav resources under linux as file system in user space (fuse) ((original from http://0pointer.de/lennart/projects/fusedav/)) -- you better use my modified version, which is still buggy but will not lock up as frequently.
Openoffice
http://www.openoffice.org/

Supported Operations

The Wiki Agent (HowToEditThisPage) has been extended to work with WebDAV. You can save pages from your WebDAV enabled software.

Openoffice

Open page like this

$ openoffice http://www.askemos.org/WebDAV

Use the normal save button to update the network. (In case of trouble see OOo.)

cadaver

$ cadaver http://login.softeyes.net/Ad60e3fb123a79b2e5128915116b288f7/

ls
...
get

Related Links

http://lxr.webperf.org/source.cgi/modules/dav/main/mod_dav.c

Atom, an alternative http://bitworking.org/projects/atom/ which runs on application level rather than server level. Maybe that one fits better for our implementation?

CalDAV? calendar extensions to WebDAV http://greenbytes.de/tech/webdav/draft-dusseault-caldav-04.html#urls (I hardly understand why those extennsions are required)


Last modification: Tue, 28 Dec 2010 15:58:41 +0100

Author(s): jfw,

Document number A26b5619be8d5e3348cca356acfc8efea delivered to public at Tue, 12 Dec 2017 09:25:33 +0100

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