[Twisted-web] HTTP-AUTH for web2 / Kudos on web2's operation

[Clark C. Evans]

Hello.  I didn't see any examples of how to do HTTP Digest
authentication with twisted.web2, so I updated my ancient code in the
sandbox -- it was easier than I expected.  Nice job with web2. 

   http://cvs.twistedmatrix.com/cvs/sandbox/cce/digest2.py

I had a few observations with my first run /w web2:

 1.  It would be delightful if WebContext had a request()
     helper method that did the appropriate adaptation
     to an IRequest

 2.  It would be excellent if locateChild was deferrable,
     often times you need to access a database to construct
     dynamically the appropriate resource.  This is not a 
     syncronous operation.

 3.  It would be wonderful if HTTPError took arguments that
     would construct an appropriate Response... it is trivial,
     but a nice touch if it did.
     
Overall, web2 is looking quite nice; I'll have more feedback once
my entire application is ported.

Cheers,

Clark