Extending the SP Dynamic Metadata Provider

[Rod Widdowson]

> > This feature is intriguing but I still don't understand the use case.
> 
> Testshib was always a big one, 

Test Shib should benefit massively from this.  By forcing the file name to be the SHA1 of the entityID you immediately solve the "I
have pushed by metadata three times with three different file names for the same EntityID" problem.

> > How do files end up in this directory and what is the file naming convention?
> 
> Ideally there isn't one and it simply monitors the directory and loads what's there, but that's work.

I think you are confusing the (existing) Directory Metadata Provider where everything in the directory is batch loaded with the
Dynamic (Directory) Metadata Provider where the file names have to be derived from the entityID, but are only loaded on demand

> > What file naming convention will be used in the cache dir?
> 
> Unspecified, I would hope.

Ah yes, Good point.  I'd probably use SHA1, but that is reserved to the implementation and could be anything which provides a 1->1
(uni or bidirectional I don't care) mapping.  Bearing in mind that in Windows case sensitivity requires explicit opt in (and even
then only on NTFS) something which gets rid of that would also be useful.

R