Web Distributed Authoring

1
Web Distributed Authoring Versioning

• Daniel Wittmer
• Mike Fisk

2
Outline

• Project vision
• Environment
• Expected Risks
• Post Mortem
• Demo

3
Project Vision

• Users access web servers as file servers
• Through a mounted file system
• Through clients with special support
• Read-only access through normal browser
• Server keeps version history of changes
• Users can collaboratively edit documents and
  publish web pages

4
Technology

• HTTP extensions for distributed authoring
• IETF RFC 2518
• Already implemented for Apache
• Additional extensions for versioning
• IETF draft standard
• No finished implementations (client or server)
• Our project a versioning server

5
Project Environment

• Standards body (IETF)
• Distributed authoring (DA) standardized
• Versioning in progress (DeltaV WG)
• Apache, WebDAV module
• Infrastructure that we dont control
• Supports DA, but not versioning
• Open Source Community
• C code, security usability expectations

6
Standards Risks

• We perceived risk that standard could change even
  though it seemed stable
• A new version was released during the project
• Better documentation
• Negligible technical changes
• Some provisions designed to simplify
  implementation clashed with our design
• Poorly designed authorization assumptions
• No mapping of original auths to version
  repository

7
Design Change CVS

• We planned on using CVS as versioning
  infrastructure
• Despite many identified risks
• WebDAV standard specifies that metadata
  represented in XML
• CVS interface didnt match these requirements
  well
• Value only as a compact storage optimization
• Result Dropped CVS from architecture

8
Feature Set Evolution

• Risks of time to market and developer resources
• Shed features along the way in order to meet our
  deadline (Microsoft model)
• Focused on features usable by existing
  (non-versioning) clients
• Developed a strategy for future features

9
Apache WebDA(V)

• Both a boon and a bane
• Apache is a popular 142kloc system
• Basic WebDAV without versioning is a 94 page
  standard --- already implemented in 18kloc
• Legacy code
• Problems using architecture for new tasks
• 96 pages of new standard

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Greg Stein Third Wheel

• 1996-98 Development Manager, in the Commerce
  Server and Site Server groups, Microsoft
• Co-founder and the Corporate Technologist of
  eShop, one of the first electronic commerce
  software companies, before its acquisition by
  Microsoft in 1996.
• Now non-employed open source developer
• Wrote Apache WebDAV codebase

We dont like his code
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Poor Legacy Modularization

• Existing WebDAV module has a poorly executed
  modularization
• A monolithic codebase split into pieces
• Interfaces very brittle, complex, incomplete
• Unexpected time sink
• (Risk of bad scheduling estimates)
• Our implementation more kludgey than desired
• Fixing existing code is out of project scope

12
Summary Update

• On time
• Overcame implementation challenges
• On budget
• Have been stalling on getting boffice space
• Streamlined Feature Set
• Imperceptible loss to current users

13
Futures

• Future Development Efforts
• Add Basic-Server-Workspace Option
• Add Basic-Client-Workspace Option
• Optimized Storage
• Funding Requirements
• Gross revenue 0 (its open source)
• Need staff of 3 FTE for next FY
• If you funnel support through the Free Software
  Foundation, your support is tax deductible as a
  charity donation

14

• DEMONSTRATION
• Mac WebDA(V) client
• Versioning Apache server
• Manually enable versioning