Re2: what's doable in Web version control

David G. Durand (dgd@cs.bu.edu)
Mon, 10 Jun 1996 22:30:31 -0400


At 3:43 PM 6/9/96, Larry Masinter wrote:
>Re PUT and all of the possibilities around it:
>
>I think all of the requirements laid on "PUT" can be accomplished with
>"POST", with some standards for the data that is posted. (E.g., a new
>media type. Call it 'multipart/update'.)
   This sound like vtml, to a great extent. I'm not claiming that VTML is
the perfect solution, but a version that is less rigid on policy, and
better adapted to arbitrary data types seems that it meets the needs you
list.

>Yes, multipart/update should contain information about the location,
>variant, entitytag (for validation), and prior version that's being
>updated.
Check. Again, we have to remove policy dependencies.

>>	Going further, something that we (P3) support is atomic checkin
>>	of multiple documents, because it allows you to move the repository
>>	forward in whole chunks rather than a file-at-a-time.  Certainly
>>	we think this is important for Web documents as well, and would
>>	like to see multiple PUTs with a single COMMIT possible.
>
>Well, a single POST of a multipart/update can be performed atomicly.
Is this why the update is multipart? so that several URLs can be updated in
a single operation?  This seems one way to get transactions.
> seiwald@p3.com wrote:
>> Version control.
>>
>>    All the wrinkles that make a simple PUT difficult are going to make
>>    flowing full version control models over HTTP truly daunting.
>>    It might be possible to come up with a limited set of operations that
>>    make sense across all models, but the examples put forth so far --
>>    compute the predecessor revision and show a version tree -- each only
>>    make sense in a subset of the systems.
This should be OK. We do need to make sure that servers can NOP whatever
doesn't apply to their policies harmlessly. We need lists of essential
operations from implementors of these various models.

>Larry

    -- David

----------------------------------------------+----------------------------
  David Durand                 dgd@cs.bu.edu  | david@dynamicDiagrams.com
  Boston University Computer Science          | Dynamic Diagrams
  http://cs-www.bu.edu:80/students/grads/dgd/ | http://dynamicDiagrams.com/