[Twisted-Python] Generic hierarchy interface

Bruce Mitchener bruce at cubik.org
Wed Jun 19 10:24:06 EDT 2002


Jp Calderone wrote:
 >   Its time has come.  The need is pretty clear, partially for
 > blog/news and a lot for Reality, and I'm sure for a lot of other
 > things I'm not aware of.  Basically, what seems to be needed is an
 > interface that allows for a protocol-defined hierarchy to
 > protocol-specific data, organised based on protocol-specific
 > meta-data.

Have you looked at the work done on URNs?

While this page is old, it contains some good pointers to work that had 
been done in that area:

   http://ana-annex.lcs.mit.edu/~edward/urn/single.html

 >   The appropriate places.  There seem to be three basic
 > relationships that are of interest: parent, child, and
 > sibling.  Accessor methods for these should be straightforward
 > enough, and implementions would need to provide the details
 > for each protocol of extracting them from the meta-data
 > available.  The other type of access would be absolute
 > and relative "path" access.  For example,
 > "news://a.server.name/a.group.name/a.message.id".
 > A Reality example:
 > "reality://server/Sol/Earth/Kansas/Smallville/Clark_Kent"
 > In this case, each level of depth would only need to
 > implement a standard accessor interface to allow whatever
 > it may contain to be accessable.

One thing to think about there is the lifetime of a hierarchical 
identifier and the transient nature of some data (like spatial indexing).

  - Bruce





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