[Pipet Users] Comments to Zope

Jarl van Katwijk jarl at xs4all.nl
Sun Jul 29 16:09:44 EDT 2001


I still have a hard time understanding the scope of Zope. I've been
playing a bit with the web interface, and looked at some code. So far I
understand Zope has a singel network consisting of Zope Objects. Or is
there more going on, are there any other 'node type' in Zope, or
hiarchic structures of some kind? Also I cant find how the functionality
of the 'nodes' in Zope is arranged. Is it all done by the
ExtensionClass? And what limit's are there in the functionality that can
be plugged into the Zope objects?

About the security model so far I got the impression Zope is handling
access control by a very long and specific rules list, like in
Zope-2.4.0-src/lib/python/AccessControl. The access system compared to
that of Piper is way more detailed and differnent because it's 'node'
oriented, and that of Piper being 'area' oriented. Has Zope an
equivalent like groups? Also Piper does not manage the acccess between
nodes in a singel execution zone. Can access control be disabled on
induvidual node level?

 > Perhaps you could give some concrete examples of how you envision 
Piper being
 > used.  Also, how does Piper interact with information access control
 > mechanisms of other systems?

Piper enhances communication channels like unix pipe to the extend so
that networks of functional units can be build. Piper is focussed on
of-the-shelf technology, being already availeble tools. CLI tools are
the main target, but this can eventualliy grow to scripting or other
application types. Point is that Piper offers channels. The new thing
about Piper is that it isn't limited to 2-way pipes: multi connectivity,
filtering, execution zones for security, marchalling, management user
interface API, etc. All that is needed to make network based execution
is supplied.

Piper aims to be 'general' in not dictating any format to the functional
units (applications ea), it just transports the datastream. Functional
units can receive or send data, that's basically all that Piper is
about. Out a uses's perspective Piper is a management interface that
lets you arrange the set of available units in a network with unlimited

The strenght of Piper is that it offer network execution, where (unix)
shells offer sequential execution, GUI's 2D execution and schedulars
(CA7) event based execution.

 > XML-RPC ftp, SOAP, and WebDAV.  I expect that the BEEP based Python 
 > will also be added to the Zope server eventually.  That addition will 
make it
 > much easier to build a peer to peer interface to Zope.

BEEP looks like being a good candidate for a protocol for communication
between instances of Piper. Shame there is no C implementation yet. (?)

More next time ;)

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