Required DIFF format [was Re: PATCH Draft]

	
On Jun 25, 2007, at 1:27 PM, Stefan Eissing wrote:

>>
>>   * Should there be a single minimum recommended diff format
>>     for binary/character based resources.  I know that this has
>>     been controversial in the past and I personally don't have
>>     an opinion on it.  I know that Lisa would prefer for there
>>     to be at least one minimum recommendation
>
> Personally, I think this is not helpful. PATCH cannot require  
> servers to support such a format. For every format it is trivial to  
> think of an application where it does not make sense.

That's true.  To be more clear, what I had in mind was requiring a  
MTI diff format for one particular case, that of a server that stores  
resources exactly as the client PUTs them, and the GET result is also  
byte-for-byte identical.  This is a fairly common case, particularly  
among WebDAV servers.

For resources that are stored exactly the way they appear on the  
wire, I cannot think of a case where a binary diff is going to cause  
problems.

Thus, the language I'd proposed was something like:

	In order to improve potential interoperability, servers that store  
resources unchanged
	(or can apply deltas as if resources are stored unchanged) are  
RECOMMENDED to
	support [FOO] as a common-denominator approach.

The problem with this is not the desirability of it -- for any server  
that wants to support PATCH and returns byte-for-byte identical  
resources, it's desirable to have a PATCH format that clients are  
likely to know.  The problem is rather that there is no binary patch  
format with a legitimately registered MIME type.

Lisa